Collision Anaplastic Large Cell Lymphoma (T-Cell/Histiocyte-Rich) and Diffuse Large B Cell Lymphoma: A Pathologic and Clinical Evaluation

A collision tumor of T and B-cell lymphomas occur rarely. In this article we report a collision tumor of anaplastic large cell lymphoma and diffuse large B cell lymphoma in a 46 years old female. The tumor showed predominantly neoplasmtic anaplastic large cell lymphoma (ALCL) component expressing CD30 and ALK with smaller areas of CD20+ diffuse large B cell lymphoma component. Polymerase chain reaction for T-cell receptor beta and IgH (VDJ) gene rearrangements detected a clonal T cell and a clonal B cell population. The patient developed CSF involvement approximately 3 months after treatment. CSF analysis at this time showed only monoclonal T cells, probably due to clearing of the B cell component by the chemotherapy. To the best of our knowledge this is the first case report of a composite tumor of ALCL (lymphohistiocytic variant) and DLBCL. This case raises issues related to the classification of these composite lymphomas and the treatment on initial presentation and during relapse.