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Definition of Histiocytosis, malignant

Medically reviewed by Min Clinic Staff | Updated: January 2026

Histiocytosis, malignant: A term sometimes used to refer to a group of tumors including monocyte-related leukemias (for example, acute monocytic leukemia, acute myelomonocytic leukemia), extramedullary monocytic tumor, and histiocytic sarcoma. Treatment is by radiation and chemotherapy, and in some cases bone-marrow transplantation.

See also histiocytosis.