Early Onset Post-transplant Lymphoproliferative Disorder Presenting with Diarrhea Post-orthotopic Liver Transplant Treated Successfully with Single Rituximab Agent.

Post-transplant lymphoproliferative disorder (PTLD) is a rare complication seen in hematologic stem cell (HSC) and solid organ transplantation that results from immune suppressant medications needed to prevent allograft rejection. Epstein-Barr virus (EBV) has been implicated in a majority of these cases, specifically with B-cell-predominant lymphomas. We present a 57-year-old female who underwent an orthotopic liver transplant and presented with diarrhea and weight loss. At the time of transplantation, the patient's quantitative EBV titers were negative; however, repeat titers during her admission were positive. Infectious etiologies for diarrhea were negative so a colonoscopy was pursued which revealed large ulcerated areas and biopsies consistent with monomorphic, diffuse large B-cell lymphoma, plus EBV. Imaging revealed multiple areas below the diaphragm of lymphadenopathy. The patient was started on rituximab and antivirals, and immune suppressive medications were decreased with a resolution of her symptoms. PTLD after any transplantation can be difficult to diagnose, given the wide range of presenting symptoms. Identifying patients who are at high risk for developing PTLD may lead to a more timely diagnosis to initiate treatment and decrease mortality risk.