An Atypical Case of Post-transplant Lymphoproliferative Disorder of the Bladder in a Kidney Transplant Recipient

Introduction: Post-transplant lymphoproliferative disorder (PTLDs) represents a spectrum of abnormal lymphoid or plasma cell proliferations that arise in individuals receiving chronic immunosuppression for solid organ transplantation. PTLD encompasses a spectrum of manifestations from benign polyclonal lymphoproliferation to fully developed lymphomas. Case Description: We present a case of a 50-year-old female with ESRD and history of two kidney transplants. The first transplant was from a living unrelated donor in 2003; graft loss occurred five years later due to pulmonary renal syndrome caused by p-ANCA microscopic polyangiitis. The second transplant in 2012 was from a deceased donor. Both transplants were complicated by recurrent ESBL E. coli UTIs requiring IV ertapenem and bilateral native nephrectomies in 2014. Her kidney function remained stable while on Azathioprine 100 mg, prednisone 5mg and tacrolimus 3mg twice daily for immunosuppression after the second transplant for 8 years. In April 2020, she presents with gross hematuria. Renal ultrasound reveals an irregular hypoechoic mass with vascularity within the bladder. She subsequently underwent a cystoscopy showing 3 masses: 8cm, 5cm and 6cm – the 5cm mass was resected. Pathology revealed PTLD (monomorphic subtype, EBV-, DLBCL GCB). The MIB1=70%. cMYC was expressed on 30-40% of cells and BCL2 and BCL6 were expressed in most tumor cells. The sample also stained strongly for CD10 and CD20. Therefore, she did not have a double expressor or double hit lymphoma. She was treated with weekly rituximab for 4 weeks and 4 cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Immunosuppression was decreased. A repeat cystoscopy and CT abdomen showed resolution of lesions in the bladder. Discussion: PTLD is a serious complication after solid organ transplantation. Risk factors for developing PTLD include Epstein-Barr virus (EBV) infection, recipient age, transplanted organ, type of immunosuppression, and genetics. PTLD has a reported incidence of 1-5% in kidney transplant recipients. Outcomes following a diagnosis of PTLD can vary, with 5- and 10-year survival rates of 53% and 45% respectively. Although PTLD can happen in almost every organ system in the body, occurrence in urinary bladder is very rare.