Composite Nodular Sclerosis Hodgkin and Diffuse Large B Cell Non-Hodgkin Lymphoma Arising from the Thymus.

Abstract We report the first case of composite Nodular Sclerosis Hodgkin and Diffuse Large B-Cell Non-hodgkin’s lymphoma of the mediastinum. We present a case of an inmunocompetent patient operated on for a mediastinal tumor similar to a Thymoma, which the histological examination morphological, and immunophenotyping were performed and confirmed the existence of 2 independent, unrelated tumors. The pathology blocks submitted show a composite lymphoma, with components of both classical Hodgkin lymphoma (Hodgkin’s disease), nodular sclerosis type, grade 2 of 2 in all three blocks. One block also shows non-Hodgkin lymphoma, namely diffuse large B-cell lymphoma, with a distinct immunophenotype. The Hodgkin-Reed-Sternberg cells were positive for CD15, CD20, CD30, PAX-5 (weak/partial), and EBV (EBERs), and negative for CD45. In contrast, the large B-cells are positive for CD20, PAX-5 (strong), CD45, and CD30 (very focal), and negative for CD15 and EBERs. The large B-cell area had an increased mitotic rate. Taken together, these data indicate that these Hodgkin and the Non-Hodgkin’ lymphomas arose as a consequence of independent malignant transformation events.