Pediatric post-transplant lymphoproliferative disorder identified on random gastrointestinal biopsies shows non-mass-forming PTLD with clonal plasma cells: report of 2 cases

EBV-related lymphoproliferations in post-transplant settings range from non-destructive hyperplasia to polymorphic post-transplant lymphoproliferative disorder (PTLD) to overt lymphoma. Here we present two unusual cases of pediatric non-mass-forming gastrointestinal (GI) PTLDs with mixed pathologic features of non-destructive and polymorphic categories. Both patients were EBV naïve and presented within 1 year of transplant with non-specific gastrointestinal symptoms (diarrhea, abdominal pain, and food intolerance) with hypoalbuminemia, cytopenia, and EBV viremia. No mass lesions were found on imaging and endoscopy. Random GI biopsies showed a non-mass-forming, but polymorphic-appearing lymphoid infiltrate with EBV positivity, monotypic plasma cells, and clonal B cells. Cyclophosphamide, steroids, and rituximab treatment had good clinical response in all cases, including one case which had poor response initially with rituximab alone. Based on these cases, we conclude that GI PTLD in children can present with vague abdominal symptoms, cytopenia, and hypoalbuminemia, and can be non-mass-forming and non-destructive. A high level of suspicion with random GI biopsies and clinicopathologic and laboratory correlation are required. Since these patients have no mass lesions, evaluating symptomatic relief, EBV viral load, improvement in cytopenia(s), serum albumin levels, and/or resolution of other systemic symptoms may be needed to monitor response to therapy.