Recurrence of Gastric Mucosa-associated Lymphoid Tissue Lymphoma in the Pleura: A Case Report

Mucosa-associated lymphoid tissue (MALT) lymphoma is classified as marginal zone lymphoma, a form of low-grade malignant B-cell non-Hodgkin’s lymphoma. It affects the gastrointestinal tract with lung and pleural involvement considered to be rare. We describe a case of a 71-year-old man with a history of MALT lymphoma in remission who presented with dyspnea due to pleural effusion. Pleural fluid flowcytometry analysis showed monotypic B-cell population that expressed cluster of differentiation (CD)19, CD20, CD22, and kappa surface light chains. Medical pleuroscopy and pleural biopsy showed fibroadipose tissue with poorly defined lymphoid aggregates displaying a so-called “monocytoid” appearance, a histologic finding typical of marginal zone lymphoma. The patient underwent pleurodesis and achieved resolution of pleural effusion; however, the patient developed several complications and was discharged on home hospice.