Multiple myeloma complicating the course of seronegative systemic lupus erythematosus.

A patient with a 20-year history of clinical systemic lupus erythematosus (SLE) who later developed multiple myeloma is described. SLE was diagnosed on the basis of a butterfly rash, photosensitivity, nondeforming arthritis, pleuropericarditis, and alopecia. However, the patient has never had LE cells, antinuclear antibody, or depressed complement. The patient was treated with intermittent courses of corticosteroids over a 20-year period with good results. Multiple myeloma, diagnosed by bone marrow biopsy, has responded favorably to therapy with L-phenylalanine mustard and prednisone.