Primary hyperparathyroidism complicated by multiple myeloma.

A patient with primary hyperparathyroidism and multiple myeloma did not have roentgenographic evidence of either disease, yet there was biochemical evidence for both diseases. Hyperparathyroidism was diagnosed by hypercalcemia and increased parathyroid hormone values. Multiple myeloma was diagnosed by serum gamma-globulin component of 2.74 g/dL with a monoclonal spike and bone marrow plasmacytosis of 31%. The serum IgA level was 2.22 g/dL and the IgG and IgM levels were normal. Serum and urine immunoelectrophoresis showed abnormal IgA and lambda arcs. Computed tomography of the neck localized a parathyroid adenoma that was found and removed at surgery.