Thrombocythaemia and multiple myeloma. A report on two cases.

A report is presented on two patients with the very rare combination of thrombocythaemia and multiple myeloma. Both patients displayed an increase in monoclonal immunoglobulin in the serum, an increased amount of plasma cells in the bone marrow, and multiple osteolytic lesions in the skeleton, along with a platelet count exceeding 1 mill./mm3, haemorrhagic diathesis, and thromboembolic complications. In case 1, both diseases reacted favourably to treatment with melphalan during a 36-month follow-up. In case 2, the thrombocythaemia had been brought under control with busulphan prior to the diagnosis of myeloma. The latter patient died before initiation of treatment of the myeloma. The signifacance of the combination is discussed.