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.

Histiocytic sarcoma is a tumor derived from histiocytes. The tumor is often positive for CD163 and can appear in the thyroid...