PULMONARY NODULES
Mita Sanghavi Goel, M.D.
January 22, 2003
Overview
 Pulmonary nodules are lesions which range from as small as 5mm to as large as 4-6 cm. Anything
larger is considered a “mass,” and predicts higher probability of malignancy
 It is important to distinguish between single and multiple pulmonary nodules, as this may affect the
workup.
Solitary Pulmonary Nodule
General Information
 Common entity and was found in 1 out of 500 serial cxrs in one study.
Characteristic Appearances
 Size: The larger the lesion, the more likely it is to be malignant.
 Border: Benign nodules tend to have smooth, sharp borders and malignant nodules tend to be
larger with irregular, fuzzy margins
 Calcification: Central, diffuse, laminated, and popcorn patterns indicate benign lesions. Eccentric
or multiple fleck patterns may be more indicative of malignancy.
 Cavitation: Can occur with both benign and malignant lesions
Differential Diagnosis
Malignant Tumors (25-50%)
 Variation in incidence is due to geographic variation in prevalence of granulomatous diseases
(histoplasmosis, coccidioidomycosis, tuberculosis, cryptococcosis in immunocompromised)
 Probability of malignancy increases with size.
 Most common malignancies are bronchogenic carcinoma, bronchial adenoma (carcinoid),
and solitary metastatic lesions (sarcoma, colon, breast, kidney, testicular). In patients with a
history of extrapulmonary malignancy, solitary pulmonary nodules are metastatic disease in
25-50% of cases.
 Doubling time of 20-400 days, whereas benign lesions are usually <20 or >400 days.
Benign Tumors (3%)
 Hamartoma: Popcorn calcifications (sharply circumscribed lobulated margins)
Infectious Granulomatous Diseases (up to 50%)
 Tuberculoma: Decreasing in incidence over time in the United States
 Histoplasmoma
 Coccidioidoma
 PCP
Non-infectious Granulomatous Diseases (3%)
 Rheumatoid nodules
 Wegener’s granulomatosis
 Paraffinoma
Other Causes (4%)
 Pulmonary infarcts
 Amyloidoma
 Hematoma
 Dirofilaria (dog heartworm) nodule: present as noncalcified, pleural-based nodule.
 Pseudotumors
 Spherical pneumonias
Workup
 History/Physical: Age, smoking status, occupational exposure, immune status, and prior cancer
history and medical history are important to elicit. Look for physical signs of systemic illnesses
that may present as pulmonary nodules (such as rheumatoid arthritis).
 CT: To evaluate calcification pattern and look for additional nodules and lymphadenopathy
 Biopsy: Bronchoscopy has lower yield than FNA. VATS is another option.
 Assess patient’s preference for treatment/additional evaluation.
Beth Israel Deaconess Medical Center Residents’ Report
Multiple Pulmonary Nodules
Differential Diagnosis
Malignant Tumors
 Metastatic Disease (80%)
o Most commonly testicular, ovarian, kidney, breast, anal, melanoma, and sarcoma.
o Hematogenous: Lower lobe predominance, range from 0.5-10cm and occasionally have
cavitation. If calcifications present, think of osteogenic sarcoma or condrosarcoma.
Wide range in size of nodules is suggestive of this.
o Lymphogenous: Lower lobe predominance, not calcified and rarely cavitated. Most often
secondary lymphoma. Look for associated lymphadenopathy.
 Multicentric Alveolar Carcinoma
 Lymphoma: Non-Hodgkin’s has lower lobe predominance.
 Multiple primary neoplasms (bronchogenic carcinomas, adenomas)
 Plasmacytomas
 Kaposi’s sarcoma: Peribronchovascular distribution and often >1cm at diagnosis.
Benign Tumors
 Hamartomas
 Juvenile papillomatosis
 Chondromas (Carney’s syndrome)
 Benign metastasizing leiomyomas
Other benign causes
 Infectious
o Granulomas (see list for solitary pulmonary nodules).
o Abscesses associated with bacteremia are generalized but more numerous in lower
lobes and are well defined 0.5-3cm lesions with thick walls and occasional cavitation.
o Septic emboli have a predilection for the periphery of the lower lobes. Cavitation and thin
walls are often seen.
o Invasive aspergillosis has no set pattern of distribution, but often has a surrounding
ground glass appearance (halo sign) because of local hemorrhage, or later, cavitation
with air crescents.
 Noninfectious granulomas (sarcoid, Wegener’s, rheumatoid, paraffinomas, lymphomatoid
granulomatosis).
o Wegener’s is widely distributed and lesions may be as large as 10cm. 1/3 to 1/2 have
cavitations. They are often thick-walled and have focal areas of air-space consolidation.
o Sarcoid is widely distributed and are 0.5-3cm large. They do not typically have
calcification or cavitation.
 Parasitic (paragonimiasis, hydatid cysts, dirofilariasis): paragoniomiasis has a predilection for
the lower lobes, usually in the periphery. May also have linear shadowing from burrow tracts.
 AVMs: lower lobe predilection and are well-defined oval lesions ranging from 1-several
centimeters. Diagnosed by spiral CT which can identify feeding artery and draining vein)
 Bronchial lesions (cystic bronchiectasis, mucoid impaction syndrome, ABPA)
 Mycetomas
 Amyloidomas
 Pneumoconioses: Upper lobe predominance. Does not have calcification, but occasionally
has cavitation. Often has a background of diffuse nodular or reticulonodular shadows. May
see compensatory hyperinflation.
 Silicosis: Upper lobe predominance with “angels’ wings” (lateral margin parallel to chest wall),
with occasional cavitation. May see other changes of silicosis as well.
 Pseudometastases
Workup
 H&P
 Spiral CT scan: Standard for detection of nodules because of ability to reduce respiratory motion,
perform 3D reconstruction. Also can detect 1-2 mm peripheral nodules and differentiate between
tubular and spherical structures in cine view.
 Biopsy: May not be required if history, radiographs, and non-invasive studies provide diagnosis (i.e.
Wegener’s). Choose between CT-guided, transbronchial forcep or needle biopsy, and thoracoscopy
based on location and size of lesion.
Beth Israel Deaconess Medical Center Residents’ Report