Subcutaneous plasmacytomas with tropism to sites of previous trauma in a multiple myeloma patient treated with an autologous bone marrow transplant.

We report the case of a 59-year-old woman with Durie-Salmon stage IIIB IgGkappa multiple myeloma (MM), who presented 83 days after autologous hematopoietic stem cell transplant (HSCT) with multiple subcutaneous plasmacytomas. These lesions were confined exclusively to sites where the patient had sustained local trauma. The patient had no pre-transplant history of extramedullary disease and no evidence of plasma cells in the peripheral blood at any time throughout the course of her disease. This case represents the first report of refractory MM presenting as multiple subcutaneous plasmacytomas with specific tropism to sites of previous trauma. Selection of tumor cell subclones with unique chemokine receptor expression profiles that may explain this clinical observation is discussed.