Case report. Primary mucosa-associated lymphoid tissue lymphoma as a pleural mass.

Primary pleural lymphoma is a rare entity that has been described in association with human immunodeficiency virus (HIV) infection or pyothorax. It occurs in only 7% of primary lymphoma cases. We report the case of a 52-year-old male with no history of HIV infection or pyothorax who was diagnosed of obstructive sleep apnoea syndrome (OSAS) and underwent a routine chest X-ray to screen for any organic cause of the symptoms. The radiograph revealed two voluminous masses with extraparenchymatous features but without pleural effusion. A contrast-enhanced CT was performed and confirmed the existence of the pleural masses that showed homogeneous attenuation. Neither mediastinal lymphadenopathy nor pleural effusion were present. A percutaneous CT-guided fine needle aspiration cytology (FNAC) with a 25-G needle was performed (two samples were obtained) and the first diagnosis was of non-Hodgkin's lymphoma. The final diagnosis of primary pleural mucosa-associated lymphoid tissue (MALT) lymphoma was confirmed by a CT-guided core biopsy with a 20-G needle. To the best of our knowledge, no cases of MALT lymphoma presenting as pleural masses without pleural effusion have been reported in immunocompetent patients. In this report, we describe the case of a patient with a primary pleural MALT lymphoma and include a short review of the literature.