Therapy-related megakaryoblastic leukemia with pituitary involvement following treatment for non-Hodgkin's lymphoma

A case of a 66-year-old Japanese man developed therapy-related megakaryoblastic leukemia with pituitary involvement after chemotherapy for non-Hodgkin's lymphoma. Alkylating agents had been administered for the treatment of non-Hodgkin's lymphoma and 6 years later, megakaryoblastic leukemia with myelofibrosis and myelodysplasia developed. The blast cells expressed CD41, and immature antigens also. These findings were compatible with therapy-related megakaryoblastic leukemia. An autopsy revealed blast-cell infiltration into multiple organs including the posterior pituitary lobe. Therapy-related megakaryoblastic leukemia is very rare, and pituitary involvement may be associated with immaturity of blast cells.