Malignant neoplasms composed of MACROPHAGES or DENDRITIC CELLS. Most histiocytic sarcomas present as localized tumor masses without a leukemic phase. Though the biological behavior of these neoplasms resemble lymphomas, their cell lineage is histiocytic not lymphoid.

A rare, usually progressive disorder comprising an invasive proliferation of neoplastic HISTIOCYTES. Many previous cases are now thought to represent ANAPLASTIC LARGE-CELL LYMPHOMA.

Synonyms: Malignant Histiocytosis Sarcoma, Histiocytic Malignant Histiocytoses True Histiocytic Lymphomas Histiocytic Lymphoma, True Histiocytic Sarcoma Lymphoma, True Histiocytic Histiocytosis, Malignant True Malignant Histiocytoses True Malignant Histiocytosis Histiocytosis, True Malignant Histiocytic Lymphomas, True Sarcomas, Histiocytic Malignant Histiocytoses, True True Histiocytic Lymphoma Lymphomas, True Histiocytic Malignant Histiocytosis, True Histiocytoses, True Malignant Histiocytic Sarcomas Histiocytoses, Malignant