Histopathological features of plasma cell dyscrasia with polyneuropathy and endocrine disturbances, with special reference to germinal center lesions.

The biopsy and autopsy materials of 41 cases showing clinical manifestations consistent with those of plasma cell dyscrasia with polyneuropathy and endocrine disturbances were studied by light microscopy and immunohistochemistry. The results obtained are as follows: 1) Lymph node swelling was generalized and the size of the nodes varies up to that of a thumb tip. 2) Angiosclerosis in the germinal centers of swollen lymph nodes is one pathognomonic feature in this disorder and was common to all the cases examined and occurred in the early stage. 3) The other feature is monoclonal proliferation of plasma cells (plasmacytoma) occurring not only in the bone marrow (five biopsy cases, seven autopsy cases) but also in the lymph nodes (nine biopsy cases, four autopsy cases). 4) If all the bone lesions detected roentgenologically are regarded as being due to monoclonal proliferation of plasma cells, it was demonstrated in 26 of 31 biopsy cases (84%) and in 14 of 16 autopsy cases (88%). This suggests that the plasmocytoma participates in the development of clinical manifestations of the disorder. 5) Besides the characteristic lesions in the lymph nodes, proliferation of small blood vessels and hemangioma-like lesions were found in the spleen, subcutaneous connective tissue and visceral adipose tissues, and hemangiomatous verrucae were also seen in the skin. As to the pathogenesis of the vascular lesions, vasculitis may be suggested. 6) The histologic features in the other organs and tissues seem to be closely related to the development of varied clinical manifestations and are represented by atrophy in the sural nerves, gastrocnemius muscles, and endocrine or reproductive organs.