Dueling Malignancies: A Rare Instance of Both Kaposi Sarcoma and Cardiac Plasmacytoma in a Patient Post OHT

Introduction Judicious immunosuppressive therapy is important to balance immune tolerance of the donor organ, while minimizing the risk of infection and malignancy. This case highlights the development of two unusual malignancies post orthotopic heart transplant (OHT). Case Report A 69 year old male, with a history of ischemic cardiomyopathy and no prior history of hematological malignancies underwent OHT. His post-transplant course was complicated by multiple infectious complications, leading to discontinuation of mycophenalate mofetil and he was maintained on an immunosuppressive regimen of tacrolimus and low-dose prednisone. Two years post OHT he noticed the development of a nodule on his 2nd right toe. Biopsy revealed Kaposi Sarcoma (KS). The patient underwent a total body PET scan and was found to have bilateral hypermetabolic inguinal lymph node involvement confirmed as KS by biopsy. His tacrolimus goal was lowered and he was treated with 8 cycles of paclitaxel, which resulted in complete PET resolution. One year later as part of a routine endomyocardial biopsy the patient was found to have a population of plasma cells with kappa restriction that were EBV negative. A TTE showed a structurally normal heart without evidence of mass/tumor. Magnetic resonance imaging showed late gadolinium enhancement in the inferior, basal inferolateral and anterolateral segments. Workup for MGUS/Multiple Myeloma was unrevealing. The diagnosis was thought to be a solitary cardiac plasmacytoma. The decision was made to further minimize immunosuppression to single agent tacrolimus with a goal tac level of 4-6. Summary Kaposi Sarcoma and cardiac plasmacyotoma are infrequent to rare tumors encountered in the transplant population. The literature on treatment for patients who develop malignancy post transplantation is sparse, with the majority of anecdotal evidence suggesting that reducing the level of baseline transplant immunosuppression is adequate for resolution of the underlying malignancy.