Occurrence of multiple myeloma in both donor and recipient after bone marrow transplantation.

The transplantation of malignant cells during allogeneic transplant is a rare occurrence. 27 months after donating progenitor cells, a diagnosis of multiple myeloma was made in a 6/6 HLA-phenotypically matched unrelated donor. The 42-year-old recipient transplanted for chronic phase chronic myeloid leukemia developed IgA myeloma 40 months after transplantation. Serum electrophoresis and bone marrow investigations established the diagnosis of IgA K multiple myeloma in both. This case illustrates the natural history and biology of multiple myeloma.