Primary pulmonary mucosa-associated lymphoid tissue lymphoma in a patient with acquired immune deficiency syndrome.

Non-Hodgkin lymphoma usually arises from lymphoid or nodal tissue, and can occasionally involve other sites. Extra-nodal marginal-zone B-cell lymphoma of mucosaassociated lymphoid tissue (MALT lymphoma) is uncommon and constitutes around 8% of all non-Hodgkin lymphomas. Most MALT lymphomas are of gastric origin and lung involvement is rare. Primary pulmonary lymphoma is defined as clonal lymphoid proliferation, which can affect one or both lungs and/or bronchi, with no extrapulmonary involvement at diagnosis or within the subsequent 3 months.1,2 The majority (58–87%) of primary pulmonary lymphomas are low-grade MALT lymphomas; the rest are diffuse large-B-cell lymphomas and other highgrade lymphomas (11–19%).3,4 Patients with immunodeficiency are predisposed to nonHodgkin lymphoma. In patients with human immunodeficiency virus (HIV), non-Hodgkin lymphoma is predominantly high-grade lymphoma, but a 14-fold relative risk of low-grade non-Hodgkin lymphoma has also been reported.1 Primary pulmonary lymphoma usually has an indolent course and can cause diagnostic dilemmas because of its nonspecific clinical and radiological presentation. We report a case of this rare MALT lymphoma that suggested a diagnosis of acquired immune deficiency syndrome (AIDS), and discuss the clinical, radiology, and pathology findings that can assist in the diagnosis.