Liver cancer. Light micrograph of a section through a histiocytic sarcoma of the liver. Histiocytic sarcoma (HS) is an exceedingly rare malignancy in both children and adults. It is characterized by neo-plastic cells with specific markers of histiocytic differentiation. (left of image) The disease carries a dismal prognosis when patients present with advanced-stage disease. Because of the poor response rates to conventional chemotherapy and the rarity of the disease, no standard of care exists for patients with HS. Magnification: x150 when printed at 10 centimetres wide. Human tissue.