California Tumor Tissue Registry’s
Case of the Month, vol. 7(11),
August, 2005
(Presented to the L.A. Society
of Pathology. June 14, 2005)
“A 16 year-old Female with an Abdominal Mass”
A previously healthy 16 year old Hispanic female presented with a two-day history of
abdominal pain and vomiting. An abdominal CT showed a mass with cystic changes in
the retroperitoneum. Laparatomy revealed a well-circumscribed, partially cystic 17 x
13.5 x 8.0 cm mass abutting the pancreatic head. The cut surfaces exposed multiple
hemorrhagic and cystic areas with central necrosis surrounded by a rim of solid dark-red
tissue.
Microscopically there were areas of extensive necrosis with preserved solid tissue at the
periphery. The tissue exhibited solid monomorphic areas with cells having foamy
cytoplasm and variable sclerosis. More centrally there was a pseudopapillary pattern
with uniform polyhedral cells arranged around delicate, fibrovascular stulks with small
vessels. The spaces between the pseudopapillary structures were filled with red blood
cells.
Diagnosis: “Solid-pseudopapillary Tumor of the Pancreas”
Nazila Zekry M.D., and Donald R. Chase M.D.
Loma Linda University and Medical Center
Department of Pathology and Human Anatomy
Pancreatic tumors can be divided into three categories:
 Exocrine tumors arising from acinar and ductal cells,
 Endocrine tumors, and
 Rare mesenchymal neoplasms
Pancreatic tumors are relatively less common than other malignancies, but they generally
have an extremely poor prognosis. Solid-pseudopapillary Tumor of the Pancreas (SPT)
is a very rare entity, with a reported incidence of 1.3% to 2.7% of all pancreatic tumors
(1). Frantz first described SPT in 1959 (2). Since then, various names have been used to
describe this unusual tumor such as solid and cystic tumor of the pancreas, papillary
cystic tumor, solid and papillary epithelial neoplasm and SPT of the pancreas.
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August, 2005
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Solid-pseudopapillary tumor of the pancreas is rare and accounts for approximately 1-2%
of all exocrine pancreatic tumors (3). They are almost exclusively encountered in young
females (mean age 35 years), are rare in males and can happen in all the races. The
strong gender and age distribution of tumor suggests a genetic and hormonal factor as an
important role in their development, however no reports indicate an association with
endocrine disturbances such as over production of estrogen and progesterone or any
relation with long-term oral contraceptives usage. This tumor shows no preferential
localization within the pancreas. They usually are found incidentally or they present with
vague abdominal symptoms with fullness and discomfort and abdominal pain generally
after mild trauma. Physical examination is often normal apart from presence of an upper
abdominal mass. Usually there is no evidence of pancreatic insufficiency, abnormal liver
function tests, cholestasis, elevated pancreatic enzymes, or an endocrine syndrome.
Tumor markers are also unremarkable. The abdominal ultrasound and CT reveal a wellencapsulated, complex mass with both solid and cystic components and displacement of
nearby structures. Occasional marginal calcification as well as intravenous contrast
enhancement inside the mass can be present which are suggestive of hemorrhagic
necrosis. Angiography shows a hypovascular or mildly vascular tumor with
displacement of surrounding blood vessels.
In approximately 85% of the patients, SPT is limited to the pancreas, however 10-15% of
the tumors have already metastasized at the time of presentation (4). The most common
sites for metastasis are the liver, regional lymph nodes, mesentery, omentom and
peritoneum.
Grossly SPT appears as a well demarcated large, round solitary mass (3-18 cm). The cut
surface is usually solid, lobulated, light brown and has areas of hemorrhage and necrosis
as well as cystic spaces filled with necrotic material. Hemorrhagic cystic changes can
involve the entire tumor, which can be mistaken for a pseudocyst.
The origin of SPT remains an enigma. Kosmahl (5) attempted to correlate the
immunoprofile of tumors in 59 patients with a cellular origin for SPT. They used a
number of different stains, including exocrine markers of acinar differentiation (trypsin,
chymotripsin), ductal differentiation (glycoproteins), and neuroendocrine markers
(synapthophysin and chromogranin). They found that the most consistently positive
markers were vimentin, NSE, alpha-1 antitrypsin, alpha-1 antichymotripsin and
progesterone receptors. Their results, however failed to reveal a clear phenotypic
relationship with any of the defined cell lines of the pancreas. On the basis of trypsin and
chymotrypsin positivity an exocrine cell line has been postulated, however NSE, and
synaptophysin positivity favor an endocrine origin. Kosmahl also suggested that tumor
cells may be derived from the celomic epithelium and rete ovarii. (5)
Microscopically, the large tumors usually show extensive necrosis with preserved solid
tissue at the periphery. The tumor exhibits a solid monomorphic pattern with variable
sclerosis. More centrally there is a pseudopapillary pattern with the components
gradually merging into each other. In both patterns, uniform polyhedral cells are
arranged around delicate, often hyalinized fibrovascular stalks with small vessels. The
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August, 2005
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neoplastic cells that are arranged radically around the minute fibrovascular stalks may
resemble ‘ependymal’ rosettes. In the solid parts, disseminated aggregates of neoplastic
cells with foamy cytoplasm or cholesterol crystals surrounded by foreign body cells may
be found. The spaces between the pseudopapillary structures are filled with red blood
cells. The hyalinized connective tissue strands may contain foci of calcification and even
ossification. The neoplastic cells have either eosinophilic or clear vacuolar cytoplasm.
Occasionally they contain eosinophilic diastase-resistant PAS-positive globules, which
may also occur outside the cells. The round to oval nuclei have finely dispersed
chromatin and are often grooved or indented. Mitoses are usually rare (3). The presence
of high mitotic activity, vascular invasion, perineural invasion and deep invasion into the
surrounding tissue are all considered to be criteria for malignancy and allow for a
malignant designation. Nishihara et al. (6) found that venous invasion, degree of nuclear
atypia, mitotic count and prominence of necrobiotic cell nests were associated with
malignancy, however outcome prediction in any case is difficult and metastasis may
occur without any of features for malignancy. Consequently, benign appearing solidpseudopapillary neoplasm must be classified as lesions of uncertain malignant potential.
The most consistently positive markers for solid-pseudopaillary neoplasms are alpha-1antitrypsin, alpha-1-antichymotrypsin, neuron specific enolase (NSE), vimentin and
progesterone receptors. Although alpha-1-antitrypsin and alpha-1-antichymotrypsin
staining is almost always intense, it usually only involves small cell clusters or single
cells, a finding that is characteristic of this neoplasm. Staining for NSE and vimentin is
usually diffuse.
Solid-pseudopapillary neoplasms appear to have wild-type KRAS genes and do not
immunoexpress p53. An unbalanced translocation between chromosomes 13 and 17
resulting in a loss of 13q14-qter and 17p11-pter has been described in one solidpseudopapillary neoplasm.
In general SPT has a good prognosis, and if it is completely removed more than 95% of
patients are cured.
The differential diagnoses for this neoplasm include:
 Endocrine tumors of pancreas
 Acinar cell carcinoma
 Pancreatoblastoma, and
 Ductal adenocarcinoma
These four processes may be separated from SPT by their:
 Gross appearance
 Histologic pattern
 Gender
 Age of distribution and
 Histochemical staining
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August, 2005
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In conclusion, SPT of the pancreas is a rare indolent neoplasm with an unclear origin that
typically occurs in young females. The diagnosis is based on imaging characteristics
with histologic confirmation. Complete surgical resection has generally been curative,
but close follow up is advisable specially when there are histologic characteristics of
more aggressive tumor.
References:
1. Crowford BE 2nd. Solid and papillary epithelial neoplasm of the pancreas, diagnosis by
cytology. South Med J 1998; 91:973-977.
2. Frantz VK. Papillary tumors of pancreas: Benign or malignant? Tumors of the pancreas.
Atlas of tumor pathology, 1st Series, Fascicle 27 and 28. Frantz VK (ed). Washington.
DC, Armed Forces Institute of pathology, 1959: 32-33.
3. Stanley R. Hamilton & Lauri A Aaltonnen, Pathology and genetics tumors of digestive
system, World Health Organization classification of tumors.
4. Mao C, Guvendi M, Domenico DR, Kim K, thomford NR, Howard JM. Papillary cystic
and solid tumors of the pancreas: A pancreatic embryonic tumor? Studies of three cases
and cumulative review of the world’s literature. Surgery 1995; 118: 821-828.
5. Kosmahl M, Seda LS, Janig U, Hrms D, Kloppel G. Solid-pseudopapillary tumor of the
pancreas: its origin revisite. Virchows Arch 2000; 436: 473-480.
6. Nishihara K, Nagoshi M, Tsuneyoshi M, Yamaguchi K, Hayashi Y (1993). Papillary
cystic tumors of the pancreas. Assessment of their malignant potential. Cancer 71: 82-92.
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August, 2005
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