A primary multiple neoplasm of the brain in a 55-year-old female, diagnosed as microglioma of argyrophilic type is presented. Histopathological diagnosis is based on the presence of transitional mature microglial cells, cytoplasmic metalophilia and of reticulum fibers as well as phagocytic activity of the tumor cells. Histogenesis of this tumor is briefly discussed along the line of histiocytes in the adventitia of the walls of blood vessels.