Post-Transplant Lymphoproliferative Disorder following Heart Transplantation Presenting as a Retroperitoneal Plasmacytoma: A Case Report and Review of the Literature.

<p>Introduction: Plasma cell neoplasms (PCNs) are a rare type of post-transplant lymphoproliferative disease (PTLD). Extramedullary plasmacytoma is a rare type of PCN, and is infrequently located in the retroperitoneum. According to the current literature, heart transplant recipients are considered at intermediate risk for developing PTLD. Case Presentation: We report a case of a 70-year-old patient with a history of heart transplantation, who was admitted to the hospital with back pain and swelling of the left lower limb. Imaging revealed a large retroperitoneal mass involving the left kidney, descending colon, left iliopsoas muscle, bladder, and prostate. Histopathological analysis confirmed the diagnosis of extramedullary plasmacytoma. Immunosuppressive therapy was reduced and chemotherapy was initiated; however, the patient passed away after two cycles of treatment. Conclusion: To the best of our knowledge, only once has retroperitoneal plasmacytoma in a heart transplant recipient been previously reported. Our case should raise suspicion for recognizing and considering this rare diagnosis in similar clinical scenarios. </p>.