Recurrent, Multisubtype Posttransplant Lymphoproliferative Disorder Masquerading as Inflammatory Bowel Disease.

Posttransplant lymphoproliferative disorder (PTLD) is a severe posttransplant complication that occurs because of immunosuppression within the first year; however, recurrent PTLD or development of multiple histologic subtypes are rare. Our case demonstrates a renal transplant recipient with rare, recurrent PTLD with multiple histologic subtypes (monomorphic and polymorphic PTLD) despite a previous response to rituximab and resolution of inflammatory changes on endoscopy. It is essential that clinicians maintain a high suspicion for PTLD when caring for patients with previous transplantation and that they have a lower threshold for biopsy with endoscopic findings of nonspecific inflammatory changes.