Presentation
Cough and chest pain for the last few weeks. No fevers.
Patient Data
There is a large cavitating mass in the right middle/upper lobes with internal air-fluid level and some associated volume loss. Other ill-defined lung opacities are seen only on the lateral, with the appearances of an additional cavitation in the superior segment of the right lower lobe. The left lung and the pleural spaces appear normal. The mediastinal contours on the left are normal. No suspicious bone lesions.
There is a large thick-walled cavitating lesion in the anterior right hemithorax, crossing the transverse fissure to involve both the anterior segment of the right upper and middle lobes. Air-fluid level within. Other smaller nodules and thick-walled cavitations in the remainder right lung and a nodule in the lingula. Anterior mediastinum enlarged lymph nodes.
PET-CT (18F-FDG)
PET-CT showing marked radiotracer uptake within the solid component of the pulmonary lesions and the anterior mediastinal nodes.
Pathology
Macroscopy: A. Four pieces of tissue up to 3 mm. B. Four pieces of tissue up to 3 mm.
Microscopy: A. The specimen comprises superficial bronchial mucosa with foci of atypical cellular infiltrate comprising predominantly large atypical cells with irregular nuclear membranes, vesicular chromatin, macronucleoli and minimal amounts of delicate cytoplasm. In some areas, the large atypical cells form sheets and in other areas, they are admixed with small lymphocytes and histiocytes.
Immunohistochemical stains: The large atypical cells are diffusely positive for CD20, CD79a and PAX-5 which show co-expression of MUM-1 and BCL-6 but not CD10. C-myc positivity is seen in approximately 50% of cells and BCL-2 positivity is seen in approximately 10% of cells. The proliferation index as estimated by a stain for ki67 is 70%. The tumor cells are negative for CD30 and EBV-LMP.
Foci of admixed small numbers of CD3 positive T cells and CD68 positive histiocytes are demonstrated.
B. The sections show fragments of bronchial mucosa with a focal atypical cellular infiltrate with morphological features as described for specimen A.
Endobronchial biopsies: Large B cell lymphoma. Final classification requires further stains and clinical correlation. See the discussion below:
The findings are of a large B cell lymphoma. The differential diagnosis includes diffuse large B cell lymphoma, NOS, non-germinal center type and, given the clinical history of multiple cavitating pulmonary nodules, Lymphomatoid granulomatosis (grade 3). EBER-ISH is being performed to evaluate this possibility. Please correlate with other clinical findings.
Case Discussion
This case illustrates the presentation of primary pulmonary large B-cell lymphoma as large cavitating lesions.
Although the gross cavitating lesions were initially thought to be infectious in nature (the first bronchoscopy isolated Klebsiella), the patient did not have any septic symptoms at that time and was relatively well for the degree of lung involvement.
Bronchoscopy was then repeated and confirmed lymphoma. The PET showed that the disease was confined to the chest.
This large cavitating lesion is an atypical presentation for lung lymphoma. Cavitations are known to arise from pure necrosis in the majority of cases but have also been attributed to having a component from concurrent bacterial colonization in the necrotic center of tumors 2.
The patient has started chemotherapy with a good response within a few months (followup CT not shown).
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