Multiple myeloma and secondary plasma cell leukemia.

Plasma cell leukemia is very rare condition characterized by malignant proliferation of plasma cells in blood and bone marrow, which is aggressive and has a short survival even with conventional treatment. This ominous entity may be primary, or develops secondarily during the course of multiple myeloma. A 53-year-old Brazilian woman with multiple myeloma is described with bone marrow evaluation revealing 25% plasma cells. The quantification of plasma cell infiltration in bone marrow aspirate and immunohistochemistry study revealed consistent features of myeloma and plasma cell leukemia, and lambda light chain expression. Worthy of note was the absence of CD56 expression and the expression of CD20; moreover, 23% of circulating plasma cells were detected in peripheral blood smears. Therefore, the diagnosis of plasma cell leukemia was characterized and therapeutic schedules with dexamethasone, thalidomide, cisplatin, doxorubicin, cyclophosphamide, and etoposide were utilized. With significant clinical improvement, the patient is currently waiting for bone marrow transplant.