a variety of sarcoma; a malignant tumor originating in the hematopoietic cells of the bone marrow, the lymph nodes (the term was formerly lymphosarcoma), the tonsils, and occasionally the lymphoid tissue of the viscera. Reticulosarcoma cells may outwardly resemble normal reticular cells, the main histochemical distinction being the large number of argyrophil (silver-absorbing) fibers in reticulosarcoma tissue. All forms of reticulosarcoma progress rapidly and metastasize through the lymphatic system and blood vessels. Disseminated, or multiple, reticulosarcoma (reticulosarcomatosis) is clinically indistinguishable from acute leukemia. It is treated by drugs and radiation.