Idiopathic thrombocytopenia in association with extragonadal germ cell cancer.

Thrombocytopenia was associated with primary extragonadal germ cell cancer in three patients. All had embryonal cell cancer with anterior superior mediastinal masses. Severe thrombocytopenia was noted initially and persisted throughout the course of the disease. Bone marrow showed increased megakaryocytes. There was no evidence of immune destruction of platelets or sequestration by the mediastinal tumor masses. Therapy with prednisone and splenectomy did not increase platelet counts and chemotherapy was extremely difficult. Idiopathic thrombocytopenia may be an adverse prognostic feature for patients with extragonadal germ cell cancer.