CRA81 NOT ALL THAT INFILTRATES IS CARCINOMA: LYMPHOMAS IMITATING LUNG CANCER

Nor Syamimi Mohd Isa, Suhashini Ganapathy, Izyan Ismail and Mona Zaria Nasaruddin

Hospital Sultan Idris Shah,Serdang, Selangor, Malaysia

Introduction
Aggressive lymphomas involving the lung are rare but can closely mimic primary bronchogenic carcinoma. Delays in diagnosis are common due to misleading histology or discordant imaging findings. Prompt recognition is essential, as these tumors are highly chemosensitive and potentially curable with timely treatment.

Case Series
We describe three cases of aggressive lymphoma in patients in their early 40s, each presenting with lung masses, respiratory symptoms, weight loss, and imaging features suggestive of advanced lung cancer with chest wall involvement.

Two patients—one a non-smoking woman, the other a non-smoking man—had non-diagnostic or misleading initial biopsies (chronic inflammation and solitary fibrous tumor, respectively). Definitive diagnosis was achieved only after re-biopsy: ALK-negative anaplastic large cell lymphoma in the first case, and diffuse large B-cell lymphoma (DLBCL) in the second.

The third patient, a male smoker, presented with cough, hemoptysis, chest wall swelling, and a mediastinal mass invading the left upper lobe, pleura, and pericardium—further reinforcing the suspicion of primary lung carcinoma. However, biopsy revealed DLBCL.

Discussion
Primary pulmonary lymphomas are rare, accounting for <1% of lung malignancies, with aggressive subtypes such as ALCL and DLBCL even less common. Their radiological resemblance to carcinoma, particularly when presenting with local invasion or chest wall involvement can mislead the initial diagnosis. As shown in our series and previous reports, histopathological limitations, including necrosis or inadequate sampling, may delay accurate diagnosis. One of our patient even had normal LDH despite extensive disease, highlighting that biochemical markers may not reliably reflect malignancy.

Conclusion
Aggressive pulmonary lymphomas can mimic lung cancer. When histology is incongruent with clinical and imaging features, repeat biopsy and multidisciplinary reassessment are essential to avoid diagnostic delay and initiate appropriate therapy.