Pleomorphic plasma cell leukemia.

T his peripheral blood smear is from a 72-year-old woman, taken several hours before she died of recurrent plasma cell myeloma and newly developed secondary plasma cell leukemia. Her white blood cell count increased from 39.53 10/mL to 233.2 3 10/mL in 28 hours. The peripheral blood smear shows marked leukocytosis with numerous smallto medium-sized bizarre-looking cells (95% of white blood cells) (panels A-E), which were not seen in her initial bone marrow aspirate. These cells have pleomorphic nuclear shapes such as a fish mouth, a mushroom, or a moon. All cells have scant pale cytoplasm, and some have cytoplasmic vacuoles. Mitotic figures are identified (panels A and F).