Dermatologic Therapy, Vol. 23, 2010, 662–675 Printed in the United States · All rights reserved © 2010 Wiley Periodicals, Inc. DERMATOLOGIC THERAPY ISSN 1396-0296 Diagnosis and treatment of cutaneous paraneoplastic disorders dth_1371 662..675 Ana Maria Abreu Velez & Michael S. Howard Georgia Dermatopathology Associates, Atlanta, Georgia ABSTRACT: The skin plays a critical role in the detection of internal malignances. Cutaneous signs of these disorders afford clinicians opportunities for early diagnosis and treatment. We aim to succinctly review the recognition, diagnosis, and treatment of selected cutaneous paraneoplastic diseases. Skin disorders that may be associated with paraneoplastic syndromes include: cutaneous metastases, tripe palms, Sweet’s syndrome, glucagonoma, Paget’s disease and extramammary Paget’s disease, acanthosis nigricans, Birt-Hogg-Dube syndrome, basal cell nevus syndrome, Bazex syndrome (acrokeratosis paraneoplastica), carcinoid syndrome, Cowden’s disease(multiple hamartoma syndrome), dermatomyositis, erythema gyratum repens, ichthyosis aquisita, von Recklinghausen’s disease, pityriasis rotunda, pyoderma gangrenosum, Quincke’s edema (angioedema and paraneoplastic uricaria), paraneoplastic pemphigus, Degos’ disease, superior vena cava syndrome, Werner’s syndrome, diffuse normolipemic plane xanthomas, and yellow nail syndrome. Treatment for these disorders depends on the nature and anatomic distribution of the primary neoplastic process. KEYWORDS: paraneoplastic disorders, skin manifestations Introduction A broad range of cutaneous signs may be related to internal malignancy. Cancer may manifest in the skin as direct metastases (e.g., leukemia cutis, cutaneous T cell lymphoma, mammary Paget’s disease) or as diverse dermatologic entities called paraneoplastic syndromes, which signal that a remote malignancy is present (1–7). Cutaneous manifestations may develop before a diagnosis of malignancy is determined; thus, these findings may aid the dermatology and dermatopathology community in attaining an early identification of malignancy. In general, it has been accepted that a paraneoplastic syndrome may be defined when (i) the malignancy and syndrome appear simultaAddress correspondence and reprint requests to: Ana Maria Abreu-Velez, MD, PhD, Georgia Dermatopathology Associates, 1534 North Decatur Road, NE; Suite 206, Atlanta, GA 30307-1000, or email: abreuvelez@yahoo.com. Conflict of interest: None. 662 neously; and (ii), their clinical courses do not significantly differ (1–7). Furthermore, it has been proposed that, ideally, (iii) remote cutaneous manifestations should be specific to the tumor causing them. It also has been suggested that (iv) paraneoplastic syndromes should be uncommon relative to the prevalence of the neoplastic process (1–7). Finally, (v) the skin manifestations and the malignant neoplasm should be demonstrably and directly associated (1–7). Of note, internal malignancies are often difficult to detect, and they may exert subtle physiologic influences without their diagnosis being established. Finally, the study of these syndromes has contributed greatly to our understanding of the effects of internal malignancy biology upon the skin. Cutaneous metastases Cutaneous metastases are rare, and the reported prevalence varies from 0.7% to 10% of all patients Paraneoplastic skin disorders with malignant neoplastic diseases (1,2). Any malignant neoplasm can metastasize to the skin. Cutaneous metastases from cancers of the lung, large intestine, and kidney are most prevalent in men; cancers of the breast and large intestine are most prevalent in women (1,2). Metastases to the skin are typically flesh-colored to violaceous nodules that often present anatomically close to the primary neoplasm; the most common sites for their presentation are the scalp, neck, and trunk (1,2). Differential diagnoses for a cutaneous metastasis include pilar (trichilemmal) or epidermal inclusion cysts, adnexal tumors, neurofibromas, and lipomas. Cutaneous metastases from the lung are frequently moderately or poorly differentiated. In fact, undifferentiated cutaneous metastases most often originate from the lung in men, from the breast in women, and from noncutaneous primary malignant melanoma (1–7). They typically invade the lymphovascular system and are typically histologically limited to the dermis and subcutaneous tissues. The most common tumor histologic subtype is adenocarcinoma (ACC), followed by squamous cell carcinoma (SCC), small cell carcinoma, and large cell carcinoma (LCC) (1–7). Some studies indicate ACC to have the highest incidence and LCC to have the lowest incidence. However, two Japanese studies found LCC to have the highest incidence, displaying about 10% of LCCs of the lung metastasizing to the skin (1–7). Other types of lung cancer that rarely metastasize to the skin include mesothelioma, bronchial carcinoids, bronchiolar carcinoma, mucoepidermoid carcinoma, pulmonary sarcoma, intravascular bronchioalveolar tumor, well-differentiated fetal ACC, pleural epithelioid hemangioendothelioma, and adenoid cystic carcinoma (1–7). Metastatic ACCs from the lung are usually moderately differentiated. They sometimes show well-differentiated glandular structures or intracytoplasmic mucin. In these cases, gastrointestinal, ovarian, kidney, and breast primaries should be ruled out. Metastatic squamous cell carcinomas from the lung are often moderately or poorly differentiated. In these cases, upper GI primaries should be ruled out (1–7). Small-cell carcinomas are generally anaplastic and have hyperchromatic nuclei with minimal cytoplasm. Clinical information, immunohistochemistry (IHC), and electron microscopy for dense core granules can help distinguish small cell pulmonary carcinoma from other histologically similar cancers. Mesotheliomas most often metastasize to the skin by direct invasion or by traumatic seeding; however, they may rarely metastasize to distant sites (1–7). These tumors may resemble angioendotheliomatous malignancies. In some cases, mesothelioma may require electron microscopy to differentiate its diagnosis vis-a-vis ACC. Cutaneous bronchial carcinoid metastases classically display a histologic trabecular pattern. An additional clue in diagnosing these patients may be the presence of a clinical carcinoid syndrome (1–7). Treatment for these disorders depends upon successful identification and therapy for the primary neoplastic process. Paget’s disease and extramammary Paget’s disease can also produce skin metastases (8,9). Glucagonoma syndrome Glucagonoma syndrome is elicited by a glucagonsecreting tumor, and may be clinically associated with hyperglucagonemia, necrolytic migratory erythema (NME), recent onset of diabetes mellitus, anemia, weight loss, and diarrhea. The NME is widespread, with predilection for the perineum, abdomen, groin, buttocks, and lower extremities (10–18). Frequently, these areas may be dry or fissured as a result (10–18). The eruption begins with uneven patches of intense erythema, superficial flaccid vesicles, and bullae that later rupture and create extensive erosions or exudative, crusted plaques. Other mucocutaneous findings are cheilosis, atrophic glossitis, oral mucosal inflammation, and alopecia (10–18). All stages of lesion development may be observed simultaneously. The initial eruption may be exacerbated by pressure or trauma to the affected areas. Almost all patients with NME have a pancreatic alpha cell tumor, and elevated glucagon levels. In approximately one-half of patients, there are alpha cell tumor liver metastases at the time of diagnosis (10–18). The histopathologic features of NME are nonspecific and include: epidermal necrosis, subcorneal pustules, confluent parakeratosis, epidermal hyperplasia, marked papillary dermal hyperplasia in a psoriasiform pattern, angioplasia of the papillary dermis, and suppurative folliculitis. Histologically, vacuolated, pale, swollen epidermal cells with necrosis of the superficial epidermis are most characteristic (10–18). Immunofluorescence studies are classically negative. The pathogenesis of NME is unknown, although various mechanisms have been suggested. These include hyperglucagonemia, zinc deficiency, fatty acid deficiency, hypoaminoacidemia, and liver disease (10–18). Associated conditions were first outlined in 1942; since then, NME has been described in as many as 70% of individuals with a glucagonoma. NME is further considered an integral part of the “glucagonoma syndrome,” 663 Abreu Velez & Howard which includes hyperglucagonemia, diabetes mellitus, and hypoaminoacidemia (10–18). When NME is identified in the absence of a glucagonoma, it may be considered part of a “pseudoglucagonoma syndrome”(10–18). Pseudoglucagonoma syndrome is less common than glucagonoma syndrome and may occur in a number of systemic disorders such Celiac disease, ulcerative colitis, Crohn’s disease, hepatic cirrhosis, hepatocellular carcinoma, lung cancer(including small cell lung cancer), tumors that secrete insulin or insulin-like growth factor 2, and duodenal carcinoma. With complete resection of the underlying tumor, the NME cutaneous manifestations classically resolve rapidly (10–18). Birt-Hogg-Dube syndrome Birt-Hogg-Dube (BHD) syndrome, initially described in 1977, is a genodermatosis characterized by the development of small, dome-shaped papules on the face, neck, and upper trunk (19–22). It has been associated with renal neoplasms, renal and pulmonary cysts, and benign tumors of the hair follicles. The disorder has been reported in more than 100 families worldwide, and it is inherited in an autosomal dominant pattern. The pattern of mutations and spectrum of symptoms are heterogeneous between individuals. BHD syndrome affects the skin, and increases the risk of certain types of tumors. The BHD tumors classically first appear in a person’s 20s or 30s (19–22). People with BHD syndrome also have an increased risk of developing benign or malignant renal neoplasms (oncocytoma and chromophobe renal cell carcinoma, respectively) and possible tumors in other organs and tissues. Additionally, affected individuals frequently develop cysts in the lungs, which may in turn rupture and cause pneumothoraces and pulmonary collapse. Mutations in the FLCN gene, located on the short arm of chromosome 17 (17p11.2), cause BHD syndrome (19–22). These mutations are often passed in an autosomal dominant fashion, but can occur as new mutations in an individual with no prior family history of the disorder. The FLCN gene produces a protein called folliculin. The normal function of this protein is still being investigated, but it appears to act as a tumor suppressor. Tumor suppressors normally prevent cells from growing and dividing in an uncontrolled manner. Thus, mutations in the FLCN gene may interfere with the ability of folliculin to restrain cell growth and division, leading to the formation of benign and malignant tumors. Recent studies suggest that folliculin accomplishes its function through interac- 664 tion with the mTOR pathway (19–22). People with BHD are born with one mutated copy of the FLCN gene in each cell. During their lifetime, random mutations might inactivate the normal copy of the gene in a subset of cells. When this occurs, the result is that these cells have no functional copies of the FLCN gene, allowing the cells to divide uncontrollably and form tumors (19–22). Such a loss of heterozygosity is a common mechanism in cancer tumorigenesis and is frequently detected in the renal malignancies associated with BHD. The BHD syndrome may be diagnosed by clinical findings and/or molecular genetic testing to detect mutations in the FLCN gene. The classical clinical triad includes: (i) benign growths of the hair follicles, (ii) pulmonary cysts and/or spontaneous pneumothorax, and (iii) bilateral, multifocal renal tumors (19– 22). First, the cutaneous manifestations of BHD were originally described as fibrofolliculomas (abnormal growths of a hair follicle), trichodiscomas (hamartomatous lesions with a hair follicle at the periphery, often found on the face), and acrochordons (skin tags). The dermatologic diagnosis of BHD can be made in an individual five or more skin lesions, at least one of which must be confirmed as a fibrofolliculoma by histology. Second, most individuals (89%) with BHD are found to have multiple cysts in both lungs, and 24% have had one or more episodes of spontaneous pneumothorax. The cysts can be detected by chest computed tomography (CT) scan. Finally, BHD renal tumors may represent multiple histologic types, but certain subtypes (including chromophobe tumors, oncocytoma, and oncocytic hybrid tumors) are more commonly encountered (19–22). Although the original syndrome was discovered and defined beginning with cutaneous findings, it is now recognized that individuals with BHD may only manifest the pulmonary and/or renal findings, without any skin lesions. Some genetic studies testing for FLCN mutations have detected mutations in 88% of probands with BHD (19–22). Thus, either some people with a clinical diagnosis of BHD have mutations that are not detectable by current technology or mutations in another (currently undefined) gene could be responsible for a minority of BHD cases. Genetic testing can be useful in confirming the clinical diagnosis of BHD, and in providing a means of detecting other individuals at risk in a family (19–22). Basal cell nevus syndrome Basal cell nevus syndrome (BCNS) is a rare autosomal dominant disorder characterized by multiple Paraneoplastic skin disorders basal cell carcinomas of the skin, odontogenic keratocysts of the jaws, and a variety of skeletal anomalies. The syndrome represents the consequence of abnormalities in the PTCH gene. The syndrome has been documented for 50 years, but more recent developments in molecular genetics have dramatically increased understanding of its pathophysiology. Other manifestations are palmoplantar pits, atypical facies (broad nasal root, frontal bossing, and hypertelorism), epidermal inclusion cysts, intracranial calcifications, developmental malformations, and a predisposition to other benign and malignant tumors (23–29). Patients with BCNS have an elevated risk of developing medulloblastoma at young ages, with approximately 5% developing this tumor in the first years of life. BCNS has also been associated with meningiomas, and in anecdotic case reports with ovarian cancer, salivary gland carcinoma, non-Hodgkin’s lymphoma, and nasopharyngeal rhabdomyosarcoma (23–29). Abnormalities of the skin, the skeletal system, the genitourinary system, and the central nervous system (CNS) are most common. A variety of less common neoplasms are also associated with BCNS. The prevalence is reported to be approximately one case per 56,000–164,000 population. The prevalence is likely to be considerably higher in individuals younger than 20 years of age. Disease morbidity and premature mortality are primarily related to the development of skin cancers, as well as other tumors associated with the syndrome. Actual mortality rates are unavailable; morbidity from multiple skin cancers and their treatment may be severe (23– 29). The syndrome is found in all races. However, a finite but smaller percentage of African Americans present with skin cancer (and have fewer skin cancers) relative to whites who are affected. The decreased number of skin cancers, a diagnostic hallmark, may account for the comparatively fewer African Americans documented in reviews of the syndrome (23–29). However, full expression of the non-skin cancer features of the syndrome is found in African Americans. Men and women are affected similarly by BCNS. The male-to-female ratio is estimated to be 1 : 1.3. The disease is present (inherited) at birth, and most commonly manifests itself with either basal cell carcinomas (BCC)s (usually multiple) occurring at a young age (i.e., third decade or earlier) or odontogenic keratocysts presenting in the second or third decade (23–29). Other incidental findings, such as cleft lip, or asymptomatic findings such as hypertelorism, may be noticed earlier, but these features may not lead to the diagnosis until the development of more specific findings. Selected findings seen in the syndrome, such as jaw cysts, BCCs, calcification of the falx cerebri, and ovarian fibromas, manifest with increasing age in the affected individual. As previously noted, some findings may present early in childhood. Medulloblastoma, although a relatively uncommon manifestation of BCNS, is a tumor of early childhood. Radiologic abnormalities, such as bifid ribs, or asymptomatic findings, such as palmar pits, may be present at a higher frequency in BCNS in childhood; these findings may be helpful in making an early diagnosis (23–29). Many of the features of this syndrome present as signs rather than symptoms. Symptoms are often related to the following major findings. Cutaneous symptoms may be reported due to local invasion of an aggressive BCC, leading to pain. Metastases are extremely rare. Neurologic symptoms may be reported due to medulloblastoma. Genitourinary symptoms may be reported due to ovarian fibromas; these lesions are classically asymptomatic, but may cause pain secondary to torsion. Dental symptoms may be reported due to odontogenic keratocysts (also called keratocystic odontogenic tumors), manifesting as jaw pain due to abnormal dentition. Despite the recent understanding of the underlying genetic basis of BCNS, the diagnosis remains largely clinical. Kimonis et al. have suggested the following diagnostic criteria to help the clinician. Although not absolute, these criteria help guide the clinician in choosing laboratory evaluations for both diagnostic purposes and ongoing surveillance (23–29). Clinicians must remember that some of the findings listed may present at different ages; therefore, ongoing surveillance with respect to diagnosis may be needed. Diagnosis of this syndrome is made in the presence of two major criteria, or one major and two minor criteria. The major criteria consist of the following: (i) more than two BCCs or one BCC in patients younger than 20 years, (ii) odontogenic keratocysts of the jaw (proven by histologic analysis), (iii) three or more palmar or plantar pits, (iv) bilamellar calcification of the falx cerebri, (v) bifid, fused, or markedly splayed ribs, and (vi) any first-degree relative with this syndrome. The minor criteria include the following: (i) macrocephaly, (ii) congenital facial malformations, such as cleft lip or palate, frontal bossing, coarse facies, and moderate or severe hypertelorism, (iii) other skeletal abnormalities, such as a sprengel deformity, marked pectus deformity, or marked syndactyly of the digits, (iv) radiologic abnormalities, such as bridging of the sella turcica, vertebral anomalies, modeling defects of the hands and feet, or flame-shaped lucencies of the hands and the feet, and (v) ovarian fibroma or medulloblastoma (23–29). 665 Abreu Velez & Howard Bazex syndrome (acrokeratosis paraneoplastica) or acrokeratosis neoplastica Bazex syndrome is a rare, acral psoriasiform dermatosis associated with internal malignancies, most frequently SCC of the upper aerodigestive tract (30– 34). The syndrome typically precedes the diagnosis of malignancy. The term Bazex syndrome describes two concurrent entities, both described by Bazex and colleagues: (i) acrokeratosis neoplastica (AN) and (ii) the genetic syndrome of basal cell carcinomas, follicular atrophoderma, hypotrichosis, and disorders of sweating (30–34). Bazex syndrome is characterized by violaceous erythema and scaling of the hands, feet, nose, auricular helices, and scalp. In advanced stages, the elbows, knees, and cheeks may be involved, and nail dystrophy may also be present. Bazex syndrome is always associated with an underlying neoplasm. As noted, the most commonly associated malignancies are SCCs of the head and neck (30–34). Bazex syndrome has also been associated with GI tract and pulmonary carcinomas. In 63% of cases, skin lesions precede the diagnosis of the tumor by approximately 1 year. Paraneoplastic acrokeratosis generally responds to successful treatment of the underlying tumor, and fails to improve when the neoplasm persists (30–34). The pathophysiology of AN is not well understood. Proposed mechanisms include crossreactivity between skin and tumor antigens, the actions of tumor-produced growth factors, and even zinc deficiency. Approximately 140 cases have been reported in the literature. In one review, only 12 of 140 cases were in women. Patients present with asymptomatic, acrally located psoriasiform, or hyperpigmented lesions (30–34). The lesions are treatment resistant. As the tumor progresses, the lesions of AN may spread and may involve the cheeks, elbows, knees, and trunk. In one review, when skin findings preceded the diagnosis of malignancy, they were present for an average of 1 year. The physician should inquire regarding risk factors for malignancy, including smoking habits, alcohol consumption, and family history. Upon further questioning, patients may admit to mild constitutional symptoms, weight loss, and other nonspecific findings of internal malignancy (30–34). In summary, cutaneous manifestations of AN often present as follows: symmetrical, acral, scaly, red-toviolaceous plaques or patches, with possible involvement of the fingers, distal hands, feet, nose, and helices of the ears: Isolated involvement of the helices is particularly suggestive of AN. Involve- 666 ment of the cheeks, trunk, elbows, knees, palms, and soles in advanced disease are common. Nail dystrophy and swelling of the digits with a blue-toviolet discoloration are common. Acrally distributed, hyperpigmented patches are possible in persons with darker skin types, as well as bullae of the hands and feet. Other physical examination findings suggesting paraneoplasia include ichthyosis, pruritus, a sign of Leser-Trélat, clubbing, and dermatomyositis (DM). A complete physical examination should thus be performed in all pertinent patients. The physical examination should include a thorough head and neck examination, including endoscopic examination and pelvic examination in women (30–34). Most AN cases are associated with SCCs of the upper one-third of the respiratory or GI tracts (i.e., oropharynx/larynx, lungs, or esophagus). Case reports also describe SCCs of the thymus, vulva, and skin. Additional reported associated tumors include poorly differentiated carcinoma, ACCs of multiple primary sites, small cell carcinomas of the lung, malignant lymphomas, ductal carcinomas of the breast, carcinoids, multiple myeloma, transitional cell carcinomas of the bladder, well-differentiated thymic carcinomas, and cholangiocarcinomas (30–34). Carcinoid syndrome Carcinoid syndrome refers to an array of symptoms that occur secondary to carcinoid tumors (35–38). Carcinoid tumors are discrete, yellow, wellcircumscribed tumors that can occur anywhere along the gastrointestinal tract, as well as in the lung. They most commonly affect the appendix, ileum, or rectum. Carcinoids are neuroendocrine tumors that are characterized by production of serotonin (5-hydroxytryptamine; 5-HT). Although clinically rare (15 cases/1,000,000 population), carcinoid tumors account for 75% of gastrointestinal endocrine tumors. Carcinoid syndrome often (75% of patients) includes periodic flushing of the face and trunk, with episodes lasting from 10 to 30 minutes. Associated with the flushing are dyspnea, wheezing, abdominal pain with explosive diarrhea, right-sided heart valvular changes, and hypotension (35,38). Carcinoid tumors represent 90% of appendiceal tumors. Other documented sites of carcinoid tumor include bronchi, ovary, pancreas, and gallbladder. Classically, tumors from the GI tract do not cause symptoms until they metastasize to the liver, because an uninvolved, healthy liver can detoxify the amines responsible for the symptoms. In contrast, carcinoid tumors originating in Paraneoplastic skin disorders locations other than the GI tract (such as ovary and bronchi) can produce symptoms before they metastasize. The carcinoid syndrome occurs in approximately 10% of carcinoid tumor patients, and manifests when vasoactive substances from the tumor(s) enter the systemic circulation while escaping hepatic degradation (35,38). The most important clinical finding is the previously noted flushing of the skin, usually of the head and upper thorax. Secretory diarrhea and abdominal cramps are also characteristic features of the syndrome. When the diarrhea is intensive, it may lead to electrolyte disturbances and dehydration. Other associated symptoms are nausea and vomiting. Bronchoconstriction affects a smaller number of patients, and often accompanies flushing. About 50% of patients have cardiac abnormalities, caused by serotonin-induced fibrosis of the tricuspid and pulmonary valves. Elevated levels of circulating serotonin have been associated with cardiac failure, due to fibrous deposits on the endocardium. Clinically, “TIPS” is a pertinent acronym for tricuspid insufficiency, and pulmonary stenosis (due to fibrosis of tricuspid and pulmonary valves). Abdominal pain is often due to desmoplastic reactions within the mesentery, and/or hepatic metastases (35–38). Interestingly, it is commonly but incorrectly thought that serotonin is the cause of clinical flushing. The flushing results from tumoral secretion of kallikrein, the enzyme that catalyzes the conversion of kininogen to lysylbradykinin. The latter is further converted to bradykinin, one of the most powerful vasodilators known (35–38). Other components of the carcinoid syndrome are a pellagra-like syndrome (probably caused by diversion of large amounts of tryptophan from synthesis of vitamin B3 (niacin), to the synthesis of pertinent 5-hydroxyindoles such as serotonin), and uncommonly, bronchoconstriction. The pathogenesis of the cardiac lesions and the bronchoconstriction are unknown, but the former probably involves activation of serotonin 5-HT2B receptors by serotonin. In most patients, there is also increased urinary excretion of 5-HIAA, a degradation product of serotonin (35–38). The diagnosis is often based on (i) the clinical history, (ii) measurement of plasma levels of tumorally secreted chromogranin A, and (iii) by measuring 24-hour urine levels of 5-HIAA. Patients with carcinoid syndrome usually excrete greater than 25 mg of 5-HIAA per day. For localization of both primary lesions and metastases, the initial imaging method of choice is octreoscan, where 111Indium-labeled somatostatin analogues are utilized in scintilography for detecting tumor-expressing somatostatin receptors. Median detection rates with octreoscan are about 89%, in contrast to other imaging techniques such as CT scans and magnetic resonance imaging scans, both with detection rates of approximately 80%. Usually on CT scan, one will note a spider-like or crab-like change in the mesentery due to the fibrosis from the release of serotonin. Positron electron tomography scans (which can evaluate for increased metabolism of glucose) may also aid in localizing carcinoid tumor primary lesions and/or for confirming metastases (35–38). Cowden’s disease (multiple hamartoma syndrome) Cowden’s disease is an autosomal dominantly inherited condition that results in hamartomatous neoplasms of the skin, mucosa, GI tract, bones, central nervous system, and genitourinary tract. The hamartomas are small, benign growths that are most commonly found on the skin and mucous membranes. People with Cowden’s syndrome have an increased risk of developing several types of cancer, including malignancies of the breast, thyroid, and uterus. Women with Cowden’s syndrome have as much as a 25–50% lifetime risk of developing breast cancer, and up to 75% have benign breast conditions such as ductal hyperplasia, intraductal papillomatosis, adenosis, lobular atrophy, fibroadenomas, and fibrocystic changes (39–41). In addition, over one-half of those affected have follicular adenomas or multinodular goiter of the thyroid. Other malignancies that appear to be associated with Cowden’s syndrome include endometrial and renal cancers. Other signs and symptoms of Cowden’s syndrome can include an enlarged head, a rare benign brain tumor called Lhermitte-Duclos disease, and glycogenic acanthosis of the esophagus. The majority of affected individuals develop the characteristic skin lesions by age 20 (39–41). Specific mucocutaneous that are consistently present include multiple facial trichilemmomas located on the central face and perioral area, multiple papules on the buccal mucosa that coalesce having a cobblestone appearance, acral keratoses, and palmoplantar keratoses. Consistent systemic manifestations include gastrointestinal polyps, thyroid tumors, fibrocystic disease of the breast, and ovarian cysts. Malignancy has been reported to be present in 40–50% of patients with Cowden’s disease; the most common malignancy is ACC of the breast, which occurs in 20–30% of women with Cowden’s disease. To a lesser degree, thyroid, colon, prostate, uterus, cervix, and bladder 667 Abreu Velez & Howard carcinomas are associated with Cowden’s disease. Family members of patients with this syndrome should thus also be evaluated for the presence of disease lesions. Mutations in the PTEN (phosphatase and tensin homolog) gene cause Cowden’s syndrome (39–41). PTEN is a tumor suppressor gene, which means it helps control the growth and division of cells. Inherited mutations in the PTEN gene have been found in about 80% of people with Cowden’s syndrome. These mutations prevent the PTEN protein from effectively regulating cell survival and division, which can lead to the formation of tumors. Cowden’s syndrome is one of several inherited diseases caused by mutations in the PTEN gene (39–41). In the other 20% of Cowden’s syndrome cases, the cause of the disorder is unknown. Some of these cases may be caused by mutations in a region of DNA that regulates the activity of the PTEN gene. Others may have mutations in certain subunits of succinate dehydrogenase, a mitochondrial enzyme. The succinate dehydrogenase mutations are also inherited in an autosomal dominant pattern; thus, one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new “de novo” mutations in the gene. The “de novo” cases occur in people with no history of the disorder in their family. The “de novo” cases are characterized by numerous hamartomas, among other symptoms (39–41). DM DM is an inflammatory condition resulting in (i) proximal myopathy, (ii) violaceous (heliotrope) inflammatory changes of the periorbital areas and eyelids, (iii) erythematous urticarial patches that spread from the face to the neck, and later to the shoulders and arms, and (iv) flat-topped violaceous papules over the knuckles (Gottron’s papules) (42–44). Periungual telangiectasis, cuticular overgrowth, poikiloderma, and scaly alopecia are also found. Calcinosis cutis may be present, most often in juvenile DM. Systemic symptoms may include symmetrical proximal muscle fatigue, fever, anorexia, weight loss, and Raynaud’s syndrome. Patients with DM who are older than 50 years have an increased risk for developing cancer; 25–30% have an associated malignancy (42–44). In a study of 57 patients with DM and malignancy, the authors found that the diagnosis of cancer occurred before diagnosis of DM in 39% of cases, after the diagnosis of DM in 34% of cases, and con- 668 current with diagnosis of DM in 27% of cases. Ovarian cancer is more frequently observed in patients with DM than in the general population; however, the frequency of other types of cancers seen in DM patients are similar to those found in the general population, so patients should have a malignancy workup appropriate for their age. Most cancers occur within 2 years of DM diagnosis, so patients should be screened for at least 3 years following the initial diagnosis of DM (42–44). Erythema gyratum repens Erythema gyratum repens (EGR) is a skin rash characterized by concentric, erythematous, scaly bands with a “wood grain” appearance. The lesions are frequently pruritic, and affect the trunk and proximal extremities, sparing the face, hands, and feet (45–48). Occasionally, palmoplantar keratoderma and ichthyosis may also be present. In one report, 84% of patients with EGR had an associated malignant neoplasia, most commonly lung carcinoma. Other sites developing malignancy related to EGR are breast, urinary bladder, uterus, GI tract, and prostate (45–48). The skin rash usually precedes the detection of the malignancy, and it also commonly improves or resolves after successful treatment of the malignancy. EGR is a migrating, figurate, or cyclic erythema that is believed to be a paraneoplastic process (45–48). In addition to other clinical features, the characteristic concentric erythematous bands forming a “wood grain” appearance help distinguish EGR from other figurate erythemas, such as erythema annulare centrifugum, erythema chronicum migrans, and erythema marginatum. The pathogenesis of EGR remains unknown. The following hypotheses have been proposed: that first, tumor antigens may form and cross-react with endogenous skin antigens (45–48). Second, tumor products may alter endogenous skin antigens, making them susceptible to autoimmune recognition. Third, tumor antigens may form immune complexes with antibodies, which are then deposited into cutaneous tissues. A mechanism explaining the clinical migrating erythema has also been proposed (45–48). The model involves a localized ground substance phenomenon. Granulocytes release factors that stimulate proliferating fibroblasts, producing ground substance with increased viscosity. This viscous ground substance serves to impede or “wall off” the tissue spread of inflammatory mediators. In EGR, the advancing erythema may represent the advancement of inflammatory mediators through Paraneoplastic skin disorders stroma that is unable to keep them “walled off”; thus, the migrating erythema phenomenon is appreciated. EGR is clinically rare. A clinical review in 1992 by Boyd cited 49 patients reported in the medical literature. A current literature search yielded a handful of additional case reports (45– 48). No specific complications are associated with the skin manifestations of EGR, and the condition alone does not lead to death. Rash symptoms include intense pruritus; morbidity and mortality may occur related to the underlying malignancy. EGR occurs predominantly in white persons; the male-to-female ratio is 2 : 1. EGR usually occurs in patients older than 40 years, with a mean age of 63 years; however, it has been reported from age 16–75 years (45–48). The appearance of EGR often precedes the detection of malignancy. The skin eruption is present an average of 9 months prior to the diagnosis of malignancy, with a range of 1–72 months. In a minority of patients, EGR occurred simultaneously with, or up to 9 months after, the detection of the neoplasm. EGR has distinctive dermatologic manifestations characterized by the following: (i) the “wood grain” appearance created by concentric, mildly scaling bands of flat-to-raised erythema, (ii) fairly rapid migration (up to 1 cm/d), (iii) intense pruritus, and (iv) a clinical rash course that closely mirrors the course of the underlying malignancy, with clearance of rash and relief of pruritus within 6 weeks subsequent to resolution of underlying disorder (45–48). epidermal barrier function, and topical applications should be utilized with caution due to possible increased absorption and resultant toxicity. An emollient, preferably plain petrolatum, mineral oil, or lotions containing urea or a-hydroxy acids (e.g., lactic, glycolic, and pyruvic acids), should be applied twice a day, especially after bathing and while the skin is still wet. Blotting with a towel removes excess applied material. Ichthyosis typically responds well to the keratolytic propylene glycol. Occlusion should be maintained overnight. After scaling has decreased, less frequent application is required. Other useful keratolytics include ceramide-based creams, 6% salicylic acid gel, hydrophilic petrolatum combined with water (in equal parts), and the alpha hydroxy acids in various bases. Topical calcipotriol cream has also been used with success; however, this vitamin D derivative can result in hypercalcemia when used over extensive areas, especially in children. Importantly, ichthyosis should be distinguished from xerosis, which frequently responds to lubricating creams (49–53). As noted previously, although the use of selected medications and benign conditions may be related to acquired ichthyosis (including hypothyroidism, sarcoidosis, and malnutrition), new onset of ichthyosis in adult life is often related to an underlying malignancy (49–53). Hodgkin’s disease was found in approximately 70% of patients with acquired ichthyosis and internal neoplasia (49–53). Acquired ichthyosis has also been related to T cell lymphomas, multiple myeloma, and lung, breast, and cervical carcinomas. Ichthyosis acquisita Ichthyosis aquisita is characterized by rhomboidal scales that rise above the skin surface. Ichthyosis may be an early manifestation of selected systemic diseases (e.g., leprosy, hypothyroidism, lymphoma, and AIDS) (49–53). Some drugs cause ichthyosis (e.g., nicotinic acid, triparanol, and butyrophenones). The dry scales may be delicate and localized to the trunk and legs, or thickened and widespread. Biopsy of ichthyotic skin is usually not diagnostic of a systemic disease; however, there are exceptions, most notably sarcoidosis, in which a thick scale may appear on the legs, and a biopsy typically shows the characteristic granulomas. Treatment of ichthyosis includes removal of exacerbating factors, as well as applying moisturizers and keratolytics; infection prophylaxis may also be indicated in select cases. When ichthyosis is caused by a systemic disorder, therapeutic results are greatest if the primary disease process can be corrected (49–53). In any ichthyosis, there is impaired Neurofibromatosis (von Recklinghausen’s disease) Neurofibromatosis is an autosomal dominant disorder characterized by developmental changes in the nervous system, bones, and skin. NF causes benign, clinical tumors (54–58). NF 2 (NF2) is often associated with scoliosis (curvature of the spine), cafe au lait spots, learning difficulties, eye problems, and epilepsy. The skin lesions of NF are neurofibromas, multiple café-au-lait macules, axillary freckles, bronzing, and giant pigmented hairy nevi. In NF type 1, optic gliomas are the most common nervous system tumors. They occur in approximately 15% of patients, and may result in blindness if left untreated. Other associated nervous system neoplasms in NF are astrocytomas, vestibular schwannomas (acoustic neuromas), and, less often, ependymomas and meningiomas (54–58). In NF type 2, there is a close association with acoustic 669 Abreu Velez & Howard neuromas. Patients with NF are at risk for developing other tumors of neural crest origin, such as neurofibrosarcomas, pheochromocytomas, and rhabdomyosarcomas. NF-1 is caused by a mutation of a gene on the long arm of chromosome 17 which encodes a protein known as neurofibromin, which plays a role in intracellular signaling. The neurofibromin is a negative regulator of the Ras oncogene. The mutant gene is transmitted with an autosomal dominant pattern of inheritance, but up to 50% of NF-1 cases arise due to spontaneous mutation. The incidence of NF-1 is about 1 in 3500 live births (54–58). The neurofibromin gene has been sequenced and found to be 350,000 base pairs in length. However, the protein is 2818 amino acids long, leading to the concept of splice variants. For example, exons 9a, 23a, and 48a are expressed in the neurons of the forebrain, muscle tissues, and adult neurons, respectively. Homology studies have shown that neurofibromin is 30% similar to proteins in the GTPase activating protein (GAP) family (54–58). The homologous sequence is in the central portion of neurofibromin and, being similar to the GAP family, is recognized as a negative regulator of the Ras kinase. Additionally, since neurofibromin is such a large protein, other active domains of the protein have been identified. One such domain interacts with the protein adenyl cyclase, and a second with the collapsin response mediator protein. Together with domains yet to be discovered, neurofibromin regulates many of the pathways responsible for cell proliferation, learning impairments, and skeletal defects, and also plays a role in neuronal development. A neurofibroma is a mass lesion of the peripheral nervous system. Its cellular lineage is uncertain; it may derive from Schwann cells, other perineural cell lines, or fibroblasts (54–58). Neurofibromas may arise sporadically or in association with NF. A neurofibroma may arise at any point along a peripheral nerve. A cutaneous neurofibroma presents as a firm, rubbery nodule of varying size under the skin. A solitary neurofibroma may also occur in a deeper nerve trunk, and only be seen on cross-sectional imaging (e.g., CT or magnetic resonance) as a fusiform enlargement of a nerve (54–58). The hallmark lesion of NF-1 is the plexiform neurofibroma. These lesions are composed of sheets of neurofibromatous tissue that may infiltrate and encase major nerves, blood vessels, and other vital structures. These lesions are difficult and sometimes impossible to routinely resect without causing any significant damage to surrounding nerves and tissue (54–58). When a plexiform neurofibroma manifests on a leg or arm, it will elicit extra blood circulation, 670 and thus may accelerate the growth of the limb. The resultant growth may cause considerable differences in length between left and right limbs. To equalize the differences during childhood, epiphysiodesis orthopedic surgery may be utilized, to halt growth at the epiphyseal (growth) plate (54– 58). Epiphysiodesis may be performed on one side of the bone to help correct an angular deformity, or on both sides to stop growth of the bone completely. The surgery must also be carefully planned, as it is nonreversible. The clinical goal is to make the limbs at nearly equal lengths at the end of growth (54–58). Schwannomas are peripheral nerve sheath tumors, seen with increased frequency in NF-1. In practice, the major distinction between a schwannoma and a solitary neurofibroma is that a schwannoma can be resected while sparing the underlying nerve, whereas resection of a neurofibroma requires the sacrifice of the underlying nerve. Malignant peripheral nerve-sheath tumors, once called neurofibrosarcomas, can arise from degeneration of a plexiform neurofibroma; such is, however, a rare complication (54–58). A plexiform neurofibromas has a lifetime risk of 8–12% of such malignant transformation. The central nervous system, cognitive, and the skeletal manifestations of NF are beyond the scope of this review. Paraneoplastic pemphigus Paraneoplastic pemphigus (PNP) is an acantholytic mucocutaneous syndrome characterized by painful mucosal erosions, ulcerations, and polymorphous skin lesions that progress to blistering eruptions on the trunk and extremities (59–63). Histologic findings are vacuolar interface changes, keratinocyte necrosis, and intraepidermal acantholysis. Malignancies associated with PNP are lymphoproliferative disorders such as nonHodgkin’s B-cell lymphoma, chronic lymphocytic leukemia, Waldenström’s macroglobulinemia, Hodgkin’s disease, T cell lymphoma, Castleman’s tumor, and thymoma. PNP is associated with a high mortality rate (75–80%). Other neoplasms associated with PNP include Kaposi’s sarcoma and carcinomas of the breast, skin, mucous membranes, lung, uterus and cervix, ovary, stomach, liver, and gastrointestinal tract. Other authors had identified 16 cases of pemphigus associated with myasthenia gravis and thymoma, 11 associated with myasthenia gravis alone, and eight associated with thymitis or thymoma alone (59–63). Almost half (43%) of the patients had pemphigus erythe- Paraneoplastic skin disorders matosus, and another third had pemphigus vulgaris. The effect of thymic ablation on the course of the skin disease was variable. Pemphigus vulgaris and erythematosus were equally common in the setting of thymoma, each occurring in 44% of cases, and pemphigus foliaceus was seen in 11% of cases (59–63). Sixty-seven percent of patients had benign thymoma, and only two had malignant thymoma. The sequential relationship between the skin manifestations and thymoma was variable (59–63). In more than half of the cases, the thymoma preceded pemphigus (mean 89 months); in 22%, the thymoma was detected after the diagnosis of pemphigus (mean 25 months); and in only one case were the disorders diagnosed simultaneously. The association of pemphigus, thymoma, and autoimmune disease was also described (59– 63). Myasthenia gravis is by far the most common associated autoimmune disease. Other associated autoimmune diseases include bone marrow erythroid aplasia, systemic lupus erythematosus, and bullous pemphigoid. Pemphigus vulgaris, pemphigus erythematosus, and pemphigus foliaceus occur at nearly equal frequencies. Although these skin diseases in this setting are described under the rubric of PNP, perhaps a more precise moniker would be cutaneous paraneoplastic autoimmune vesiculobullous disease. The autoantibodies in the serum of patients with PNP immunoprecipitate a complex of high-molecular weight proteins from keratinocytes with relative molecular weights of 250, 230, 210, 190, and 170 kd. The 250-kd antigen is now known to represent desmoplakin I, and the 210-kd antigen represents desmoplakin II (desmosomal plaque proteins). The 230-kd antigen is bullous pemphigoid antigen. Antibodies to a 130-kd antigen (similar to that seen in pemphigus vulgaris) have also been detected. The desmoplakins play a pivotal role in anchoring the network of intermediate filaments to desmosomes (59–63). Pityriasis rotunda Pityriasis rotunda is an unusual skin condition characterized by round, scaly, hyperpigmented lesions on the trunk and proximal extremities (49). The hands, feet, and face are usually spared. It is more commonly seen in deeply pigmented South African and West Indian patients. Histologically, it is similar to ichthyosis vulgaris. Pityriasis rotunda is associated with internal malignancies in 6% of cases, with gastric carcinoma and hepatic carcinomas being the most frequent neoplasms (49). Pyoderma gangrenosum Pyoderma gangrenosum (PG) is characterized by lesions that begin with painful pustules and/or erythematous nodules, which then form an ulcer that contains raised, violaceous, undermined borders and a hemorrhagic exudate partially covered by necrotic tissue (64–66). Up to 50% of patients have an associated condition such as inflammatory bowel disease, diverticulosis, arthritis, chronic hepatitis, Behçet’s syndrome, or hematologic neoplasia (64–66). The frequency of concomitant malignant disease in patients with PG is uncertain, but it has been estimated at 4.5–7% (64–66). Atypical or bullous PG has been related to hematologic malignancies, acute myelogenous leukemia being the most frequently associated malignancy. It has also been reported in chronic myeloid leukemia, multiple myeloma (usually IgA type), Waldenström’s macroglobulinemia, Hodgkin’s and non-Hodgkin’s lymphomas, and in solid tumor malignancies such as carcinoid, colon, breast, and bladder carcinoma (64–66). Quincke’s edema (angioedema and paraneoplastic uricaria) Angioedema is characterized by acute onset of nonpruritic, nonpitting, and circumscribed areas of edema secondary to increased vascular permeability (67,68). Angioedema is most apparent in distensible tissues, such as lips, eyes, earlobes, and tongue, and also may involve the larynx, extremities, and genitalia. Angioedema can be classified as (i) hereditary angioedema, (ii) angioedema due to acquired deficiency of the inhibitor of the first component of human complement (C1-INH), (iii) angioedema associated with allergic reactions, (iv) angioedema secondary to drugs, and (v) idiopathic angioedema. Angioedema due to acquired deficiency of C1-INH is a rare condition. It is characterized by increased consumption of C1-INH that leads to an enhanced complement system cascade reaction, and results in increased vascular permeability and edema. C1-INH deficiency angioedema is suspected in patients (i) with a history of recurrent angioedema without urticaria, (ii) in or after their fourth decade of life, (iii) with a negative family history of angioedema, and (iv) with C1-INH functional levels below 50% of normal (67,68). The C1-INH type of angioedema has been associated with chronic lymphocytic leukemia, nonHodgkin’s lymphoma, multiple myeloma, and Waldenström’s macroglobulinemia. The associated 671 Abreu Velez & Howard risk for hematolymphoid malignancy is 35% and for other malignancies 8%, based on a study of 128 patients (67,68). Sweet’s syndrome (acute febrile neutrophilic dermatosis) Sweet’s syndrome is characterized by fever, neutrophilia, and an abrupt onset of erythematous, painful papules and nodules that coalesce to form irregular, sharply bordered plaques, primarily on the face, neck, and extremities (69,70). Pseudovesiculation, a vesiculated appearance due to intense edema, is commonly present within the lesions. Extracutaneous manifestations of Sweet’s syndrome are arthritis, conjunctivitis, and episcleritis. Histologically, it is characterized by an inflammatory infiltrate, predominantly containing neutrophils, that is diffusely distributed in the upper dermis (69,70). Sweet’s syndrome may be (i) idiopathic, (ii) associated with an upper respiratory tract infection, (iii) drug induced, or (iv) associated with malignancy (paraneoplastic), in which the onset or recurrence of the skin lesions are temporally associated with the presence of cancer. Some retrospective studies have been performed to assess the incidence of malignancy associated with Sweet’s syndrome. Selected studies have shown that of 448 persons studied, 96 (21%) presented with a simultaneous hematologic malignancy or solid tumor (69,70). The most common hematologic malignancy was acute myelogenous leukemia, and of the solid tumors, carcinomas of genitourinary organs, breast, and GI tract were frequent. Findings that may suggest underlying malignancy include absence of antecedent respiratory infections, anemia, platelet abnormalities, and bullous PG with pronounced ulceration (69,70). Degos’ disease (also called malignant atrophic papulosis) is a rare vasculopathy that affects the endothelial lining of small arteries and veins, resulting in occlusion (blockage of the vessel) and tissue infarction (71–73). The blood vessels affected include those supplying the skin, gastrointestinal tract, and central nervous system (71–73). Thus, the disease may result in bowel ischemia (mesenteric ischemia or ischemic colitis), chronic skin lesions, ocular lesions, strokes, spinal lesions, mononeuritis multiplex, epilepsy, headaches, or cognitive disorders. Pleural or pericardial effusions have also been also reported. The outcome of the disease can be fatal, with a median survival of 2 to 3 years, although some appear to have a benign 672 form (Degos’ acanthoma) which affects only the skin (71–73). There are fewer than 50 living patients at present known worldwide, and fewer than 200 reported in the medical literature. Treatment options are limited, consisting mainly of antiplatelet drugs, anticoagulants, and immunosuppressants; the effect of treatment is limited to case reports. It has been suggested that Degos’ disease is not a discrete nosologic disorder, rather a final clinical and histologic end point of several diverse vascular systemic disorders (71–73). Tripe palms Tripe palms is a condition characterized by pronounced dermatoglyphics and a thickened, velvety appearance of the palms (and sometimes the soles), resembling the surface appearance of small bowel villi (74). Histologically, hyperkeratosis, papillomatosis, and acanthosis are commonly seen. In a review of 77 patients with tripe palms, more than 90% of published cases of tripe palms occurred in patients with cancer, and in 77% of cases, this condition was associated with acanthosis nigricans (74). The most common associated neoplasms were pulmonary and gastric carcinomas. In more than 40% of the reported patients, tripe palms represented the presenting sign of an underlying neoplasm; conversely, in 30%, the tripe palm presentation followed the diagnosis of cancer (74). Superior vena cava syndrome The superior vena cava represents the major venous drainage from the head, neck, upper thorax, and upper extremities. Superior vena cava syndrome (SVCS) is caused by a gradual compression of the superior vena cava, resulting in obstruction of its blood flow (75). Dyspnea and facial swelling are the most frequent symptoms. Facial and upper extremity edema and jugular venous distention (with or without cyanosis) are classically present on physical examination. The most common etiology for SVCS is a mediastinal malignancy. Bronchogenic carcinoma is associated in 80% of cases, with small cell carcinoma representing the majority of these lung cancers; mediastinal lymphomas are associated with 18% of cases. Less commonly, SVCS may be caused by metastases of other malignancies (75). Nonmalignant causes of SVCS consist of mediastinal fibrosis, aortic aneurysms, vasculitis, infections, benign mediastinal Paraneoplastic skin disorders tumors, and thromboses secondary to the presence of central vein catheters (75). Werner’s syndrome associated with malignant neoplasms Werner’s syndrome is a rare, autosomal recessive disease resulting in premature aging (75–79). It is characterized by cataracts, short stature, premature graying of the hair and baldness, laryngeal atrophy, high-pitched voice, distal muscle atrophy, endocrine disorders such as diabetes mellitus, osteoporosis, and hypogonadism. The skin manifestations of Werner’s syndrome include dryness, atrophy, a scleroderma-like appearance, beak nose, hyperkeratosis over bony prominences, and chronic leg ulcers. Some authors have described Werner’s syndrome associated with fibrosarcoma of the mediastinum and multiple basal cell carcinomas. In two of these basal cell carcinomas, since the sclerotic skin made it difficult to assess the extent of the tumor, a microscopically controlled excision (Mohs’ chemosurgery) was utilized (75–79). Xanthomas Diffuse normolipemic plane xanthomas are characterized by large, yellow-brown, plaque lesions, classically involving the eyelids, sides of the neck, upper trunk, buttocks, and the flexural folds in normolipemic persons. Histologically, the lesions contain dermal clusters of perivascular giant cells with foamy cytoplasms. Diffuse normolipemic plane xanthoma has been associated with monoclonal gammopathy, multiple myeloma, mycosis fungoides, and with other lymphoproliferative and myeloproliferative disorders such as leukemia, lymphoma, and Castleman’s disease. An association with angiokeratoma of Fordyce is also documented (80). Yellow nail syndrome Yellow nail syndrome (YNS) is a rare disorder characterized by nail changes, lymphedema, pleural effusions, and chronic respiratory tract infections such as bronchitis and sinusitis (81–83). Affected nails have yellow discoloration, are thickened and grow slowly. Sometimes, nails present with loss of cuticula, and erythema and edema of the proximal nail folds. The nail changes may be the initial manifestation, preceding other symptoms by years. YNS has been associated with autoimmune diseases such as thyroiditis, rheumatoid arthritis, and acquired immunodeficiency syndrome, as well as with certain medications (81–83). YNS has been related to malignancies, including mycosis fungoides, laryngeal carcinoma, gallbladder carcinoma, bronchial carcinoma, breast cancer, nonHodgkin lymphoma, and endometrial cancer. In several reported cases, the nail deformity resolved after successful treatment of the associated neoplasm (81–83). References 1. 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