A rare case of primary B cell lymphoma of the thymus

Abstract

The thymus is a primary lymphoid organ which establishes and maintains the pool of effector T-cells throughout life; however, it is one of the sites for antigen-independent B-cell maturation. Primary thymic B-cell lymphoma is a rare entity, unremarkable clinically but amenable to chemotherapy. We report a 34-year-old male who presented with nonspecific right-sided chest pain, backache, and shortness of breath for 4 months. Computed tomography scan of the thorax revealed a mass in the superior mediastinum, extending to anterior mediastinum with the right pleural effusion. The suggested diagnosis was thymoma. A median sternotomy was done to resect the thymus. The definitive histologic study revealed a primary thymic B-cell lymphoma positive for CD45/leukocyte common antigen and CD20 and negative for CK and CD30. Thymic lymphoma may be considered among the diagnostic options of a mediastinal mass.