Post-transplant lymphoproliferative disorder with ileal stricture masquerading as Crohn disease

Post-transplant lymphoproliferative disorders (PTLDs) are a group of hematopoietic proliferations classified into four categories depending on their morphology and resemblance to established lymphomas, including nondestructive, polymorphic (P-PTLD), monomorphic (M-PTLD) and classic Hodgkin lymphoma. They are a consequence of immunosuppression following solid organ or stem cell transplants and can occur at nearly any site with highly variable presentations. The two most important risk factors for the development of PTLD are immunosuppressive duration and intensity, rather than specific therapeutic agents, and pre-transplant EBVseronegativity. We report a case of diffuse large B-cell lymphoma (DLBCL) M-PTLD with focal EBV-positivity diagnosed following small bowel resection in a 57-year-old woman status post remote bilateral lung transplant for cystic fibrosis and with long-term chronic idiopathic inflammatory bowel disease (CI-IBD), who was clinically thought to have Crohn disease (CD) following development of inflammatory ileal strictures. She underwent resection due to imminent small bowel obstruction, at which time the PTLD was discovered. No features of CD were identified, and the patient was successfully treated conservatively. Our case of M-PTLD DLBCL with focal EBV-positivity in a patient with a longstanding history of both bilateral lung transplant and CI-IBD demonstrates a unique presentation that was clinically thought to be CD in an EBV-seronegative patient. We aim to highlight the importance of considering PTLD when a transplant recipient develops a new lesion or mass, particularly as the risk of developing PTLD increases with duration of time following the transplant.