[Ectopic salivary amylase-producing IgA- lambda-type multiple myeloma with expression of MDR-1/P-glycoprotein]

We report a case of ectopic salivary amylase-producing IgA- lambda-type multiple myeloma. A 70-year-old man was admitted because of anemia and renal failure. After chemotherapy for eight months, the serum amylase markedly increased. Amylase activity in the supernatant of cultured myeloma cells, which were obtained from the bone marrow, also increased. The myeloma cells expressed MDR-1/P-glycoprotein). The case implies the association of drug resistance and the ectopic amylase production in a case of multiple myeloma.