Malignant Histiocytosis

**Semantic type:** Neoplastic Process

**Definition:** An antiquated term referring to cases of systemic non-Hodgkin lymphomas which are composed of large, atypical neoplastic lymphoid cells and cases of hemophagocytic syndromes. In the past, cases of anaplastic large cells lymphoma were called malignant histiocytosis.

**Synonyms:** - Histiocytic Medullary Reticulosis - Malignant histiocytosis