A 59-year-old man, a farmer, was hospitalized complaining of severe lumbago, pallor and emaciation.
X-ray films of the bones disclosed generalized osteoporosis and punched-out lesions in the skull. Bence Jones proteinuria was detected. A bone marrow aspirate showed 83.2% replacement of normal marrow elements by markedly atypical myeloma cells resembling monocytes or lymphoreticular cells, being confirmed by electron microscopy.
The patient was diagnosed as IgD myeloma on immunoelectrophoretic examination. Normal serum total protein level (6.6 g/dl), presence of Bence Jones proteinuria, lambda light chains and electrophoretic mobility in β-range of myeloma protein, which have been mentioned as the characteristics of IgD myeloma in comparison with other types of myeloma, were observed also in this case.
Analysis of the literature concerning IgD myeloma in Japan suggested that cellular atypism of IgD myeloma cells in this case was the most remarkable one in Japan.
Administration of cyclophosphamide was moderately effective on lumbago.
