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 True Histiocytic Lymphomas Malignant Histiocytoses 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 Lymphomas, True Histiocytic True Histiocytic Lymphoma Histiocytic Sarcomas Histiocytoses, True Malignant Malignant Histiocytosis, True Histiocytoses, Malignant