Isolated peritoneal lymphomatosis defined as post-transplant lymphoproliferative disorder after a liver transplant: A case report

BACKGROUND Post-transplant lymphoproliferative disorder(PTLD) is a fatal complication of solid organ transplantation or allogenic hematopoietic stem cell transplantation that is associated with immunosuppressive therapy. Potential manifestations are diverse, ranging from reactive lymphoid hyperplasia to high-grade lymphoma.PTLD is usually of B-cell origin and associated with Epstein-Barr virus(EBV)infection. Herein, we describe a case of PTLD involving the peritoneal omentum.There has been only case of PTLD as a diffuse large B-cell lymphoma(DLBCL) in the peritoneum.CASE SUMMARY The patient was a 62-year-old man who had been receiving immunosuppressive therapy with tacrolimus since undergoing a liver transplant 15 years prior. He reported that he had experienced abdominal discomfort and anorexia 1 month prior to the current admission. Abdominal pelvic computed tomography(CT)revealed peritoneal and omental mass-like lesions without bowel obstruction.Ultrasonography-guided biopsy was performed, and he was histologically diagnosed with EBV-negative DLBCL. Positron emission tomography(PET)-CT depicted peritoneum and omentum involvement only, without any lymphadenopathy or organ masses, including in the gastrointestinal tract. Six cycles of chemotherapy with a "R-CHOP" regimen(rituximab-cyclophosphamide, doxorubicin, vincristine, prednisolone) were administered,and PET-CT performed thereafter indicated complete remission.CONCLUSION This is the first report of isolated peritoneal lymphomatosis defined as PTLD in a liver transplant recipient.