Syndrome of plasma cell dyscrasia, polyneuropathy, and diabetes mellitus.

Multiple myeloma associated with sclerotic bone lesions and polyneuropathy represents a distinct subset of the plasma cell dyscrasias. We describe a case of biclonal gammopathy (the second case reported), insulin-resistant diabetes mellitus, and no evidence for anti-insulin receptor antibodies. After treatment with chemotherapy and irradiation, the diabetes resolved, the polyneuropathy lessened greatly, and the patient is alive without evidence of progression five years later. The reports of 95 other cases are reviewed. This syndrome occurs in younger patients (mean age, 48 years) and is frequently associated with organomegaly, endocrinopathies, and skin changes. Irradiation to the sclerotic bone lesions frequently lessens the neuropathy and endocrinopathies and may result in long-term remission. The mechanism of action leading to the systemic effects seen in this syndrome is unknown but is likely related to proteins secreted by the abnormal plasma cells.