Plasmacytoma/multiple myeloma type posttransplant lymphoproliferative disorder.

Abstract

A 38-year-old male with a history of lupus nephritis and kidney transplantation 3 years ago, presented with fever, night sweats, and lymphadenopathy while being treated with tacrolimus, mycophenolate mofetil, and prednisone. Evaluation with PET and CT scan showed generalized lymphadenopathy and splenomegaly. (Left-sided figure). Biopsy of an inguinal lymph node showed a monotypic plasma cell proliferation (CD138+, kappa+, CD20-), as part of a monomorphic variant of post-transplant lymphoproliferative disease (PTLD) (Right-sided figure). The specific type was determined as plasmacytoma/multiple myeloma type PTLD. However, a diagnosis of PTLD type plasma cell-rich marginal zone lymphoma was also possible, although no separate malignant lymphocytic B-cell component could be demonstrated. No Epstein–Barr virus (EBV) positivity was found. Bone-marrow showed a similar monomorphic PTLD with an increased amount of plasma cells. Laboratory testing showed only mild anemia and no kidney function decline or hypercalcemia. M-protein was identified as IgA-kappa, 24 g/L. There were no bone lesions. Cytogenetics of the bone marrow showed no abnormalities. A diagnosis of plasmacytoma/multiple myeloma type PTLD was made, and treatment was commenced with thalidomide, bortezomib, and dexamethasone. Multiple myeloma/plasmacytoma-like PTLD is a rare complication of solid organ transplant. It is characterized by plasmacytic histology with the presence of CD138 and lack of CD20. Only 3.5% of PTLD are of this subtype [1]. In a retrospective cohort and case series, the median time from organ transplant to disease was 3–10 years [1-4]. Bone lesions were only present in a minority of patients [2] and many patients presented with extranodal disease [1, 3, 4] Similar to our patient, no significant hypercalcemia or renal insufficiency was found, and only mild anemia [3, 4] Patients had both positive and negative EBV immunohistochemical staining [2-4]. Patients underwent a reduction in immunosuppression and treatment with proteasome inhibitor-based regimens with 20% also receiving autologous stem cell transplants. The median overall survival was 2.4 years and survival was decreased compared to regular multiple myeloma patients [1]. In conclusion, plasmacytoma/multiple myeloma type PTLD often presents without bone lesions, hypercalcemia, or renal insufficiency. Differentiation between this entity and other PTLD's with a prominent component of plasma cells (including marginal zone lymphoma) can be difficult, as both can produce monoclonal paraproteins. Treatment for plasmacytoma/multiple myeloma type PTLD is currently similar to conventional myeloma, however outcomes are inferior.