A rare case of primary cutaneous plasmacytoma-like lymphoproliferative disorder following renal transplantation.

Post-transplant lymphoproliferative disorder (PTLD) is a lymphoid proliferation that develops as a complication of solid organ or bone marrow transplants. PTLD limited to the skin is very rare. Plasmacytoma-like PTLD is an uncommon variant of monomorphic PTLD. Its presentation in the skin is extraordinary with very few cases reported in the literature. We report a new case of plasmacytoma-like PTLD presenting as multiple skin nodules on the leg of a 74-year-old kidney transplant recipient. Histopathologic and immunohistochemical examination of one nodule revealed atypical plasmacytoid and plasmablastic cells that showed kappa light chain restriction and stained positive for CD138. Staging investigations excluded extracutaneous manifestations of the disease. This case is unusual for several reasons including involvement limited to the skin, plasmacytoid phenotype of the tumor, presentation 18 years following transplantation and Epstein-Barr virus negativity.