[Amylase-producing extramedullary plasmacytoma with multiple cutaneous metastasis following a solitary plasmacytoma of bone].

A 65-year-old woman was admitted because of multiple cutaneous tumors in the left lumbar area in March 1983. In 1979, she had been diagnosed as solitary plasmacytoma (IgG, kappa) of the left femur and amputation of the left leg had been performed. In 1981, the tumor relapsed in the left ilium in association with an increased level of serum IgG with M-component and normal activity of serum amylase. The serum M-protein had been disappeared after resection of the tumor. On admission laboratory examinations showed a slightly high level of serum IgG and elevated activities of serum and urine amylase. Amylase isoenzyme analysis revealed a predominance of the S-isozyme. Bone marrow aspiration revealed no atypical plasma cells. The supernate of cultured plasma cells obtained from the cutaneous tumor contained high amylase activity consisting exclusively of S-type. Thereafter serum amylase activities changed approximately in parallel with serum M-protein levels and total tumor volumes after chemotherapy or radiotherapy. At the terminal phase in 1986, however, serum amylase activities became extraordinarily high compared with serum M-protein levels, suggesting a clonal change of the plasmacytoma cells.