Synchronous Hodgkin's disease and myelofibrosis terminating with granulocytic sarcoma and acute megakaryocytic leukemia. Our patient had stage IIIAI Hodgkin's disease with synchronous myelofibrosis and myeloid metaplasia. A slowly progressive myeloproliferative disease developed over 9 1/2 years and terminated in a painful osteolytic bone disease, spinal extradural granulocytic sarcoma and acute megakaryocytic leukemia. It is likely that this was a result of the myeloproliferative disease rather than a late complication from combination chemotherapy. Our case demonstrates the importance of a curative approach to Hodgkin's disease even in the face of a coexistent disease with a long or unknown natural history. 