Mediastinal germ cell tumour associated with malignant histiocytosis and high rubella titres

Two further cases of a haematological malignancy are reported in patients with mediastinal germ cell tumours. Two young men developed bone marrow infiltration with histiocytes showing erythrophagocytosis shortly after subtotal excision of a malignant teratoma of the anterior mediastinum. Serial viral titres showed a rise in rubella antibody titres by haemoagglutination inhibition in both cases, antirubella IgG (ELISA) in one case and rubella RH zone in the other, in the absence of detectable IgM rubella antibodies. In case 1 a diagnosis of virus associated haemophagocytic syndrome was made and he was treated with interferon and steroids. In case 2 the diagnosis was initially idiopathic thrombocytopenia purpura but he deteriorated on steroids, and was subsequently unsuccessfully treated with chemotherapy and gamma globulin infusions. The disease ran a rapid downhill course with progressive marrow failure and they both died 5 months after diagnosis. Review of the presenting histology, the progressive course of the disease and post mortem histology, suggests that they had malignant histiocytosis. The association between mediastinal teratoma and haematological malignancy is of biological importance. Serial viral titres should be measured in patients with malignant histiocytosis to see if there is a raised rubella titre. Such viral studies are also warranted where there is an association between a mediastinal germ cell tumour and haematological malignancy.