One case of pulmonary lymphoma of MALT origin is reported. The diagnosis was made by histological and immunohistological study of surgical specimen. Cytologically, the tumoral proliferation was made by an admixture of centrocyte-like cells, small lymphocytes and vacuolized plasma cells. Lympho-epithelial lesions were particular because induced by tumoral plasma cells. From this case, problems of diagnosis and physiopathology of pulmonary MALT lymphomas are discussed.