Malignant histiocytoses/disseminated histiocytic sarcoma with hemophagocytic syndrome in a patient with mediastinal germ cell tumor.

We describe a case of a 24-year-old man with a large anterior mediastinal mass showing a nonseminomatous germ cell tumor then subsequently developed hemophagocytic syndrome involving the bone marrow and liver. During the course of chemotherapy, he developed profound thrombocytopenia, eccymoses, and bleeding. He had moderate splenomegaly and splenectomy was performed to restore adequate hematologic reserve to permit further chemotherapy. The spleen showed marked erythrophagocytosis and markedly atypical histiocytes consistent with malignant histiocytoses. Atypical histiocytes stained positive for CD68, CD163, CD4, CD45 (LCA), and S-100. Cytogenetics studies were negative for i12p. The patient was refractory to therapy and ultimately died 5 months after diagnosis.