A Rare Case of Plasmablastic Lymphoma With Difficult Diagnosis and Treatment in a Cardiac Transplant Patient.

Plasmablastic lymphoma (PBL) is a rare lymphoproliferative disease that can affect immunocompromised post-transplant patients. Patients with positive human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) status are at high risk. PBL shares many immunological markers and cytological characteristics with plasmacytic myeloma, which can lead to uncertainty and delay in diagnosis. However, myeloma typically involves the bone marrow, and the presence of other laboratory findings in myeloma, such as paraproteinemia, renal disease, and hypercalcemia, along with careful review of the biopsy, may help to distinguish between the two conditions. Treatment options are limited with poor prognosis and survival; however, intensive chemotherapy regimens such as EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin) are often used, sometimes in combination with agents that are being traditionally used in the treatment of myeloma, such as bortezomib and daratumumab. Here, we describe the case of a 54-year-old male patient who developed post-transplant lymphoproliferative disorder (PTLD) after undergoing cardiac transplantation with biopsy findings suspicious for both PBL and plasmacytic myeloma and treated with rituximab plus the EPOCH regimen, bortezomib, and daratumumab.