Acute basophilic leukemia

A rare acute myeloid leukemia characterized by primary differentiation to basophils. Microscopically, peripheral blood and bone marrow blasts contain coarse cytoplasmic basophilic granules which are positive with metachromatic staining (toluidine blue). Electron microscopy confirms that granules show features characteristic of basophil precursors. Mature basophils are usually sparse. Patients may present with manifestations related to bone marrow failure, as well as hepatosplenomegaly, cutaneous involvement, lytic lesions, and hyperhistaminemia. The disease is associated with a poor prognosis.