Non-resolving Pneumonia: Primary Pulmonary MALT Lymphoma

Mucosa-associated lymphoid tissue (MALT) lymphoma is an uncommon extranodal low-grade B-cell lymphoma. Pulmonary MALT lymphomas originate from bronchial MALT and are also referred to as bronchial-associated lymphoid tissue lymphomas. MALT lymphomas of the lung are slow-growing tumours and usually present as asymptomatic chronic alveolar opacities visible on chest radiographs or with non-specific pulmonary symptoms. Here we described a case of a male patient in his early 50s with cough and chest pain for 4 years. His CT chest scan showed consolidation in the lingula and left lower lobe. Histopathology of the specimen obtained from cryobiopsy of the lung lesion showed a dense monomorphic lymphoid infiltrate, and immunohistochemistry confirmed the diagnosis of MALT lymphoma. The prognosis of pulmonary MALT lymphomas is good with >80% 5-year survival rates. This case highlights that MALT lymphoma should be considered as a differential diagnosis while evaluating cases with non-resolving consolidation.