Subcutaneous amyloid-tumor of beta-2-microglobulin origin in a long-term hemodialysis patient.

beta 2-Microglobulin (beta 2M)-derived amyloidosis has become a major concern in long-term hemodialysis patients. Clinical symptomatology is largely restricted to the articular and periarticular sites and in rare cases systemic manifestations have been described. We present a long-term hemodialysis patient, who after 16 years of hemodialysis with regenerated cellulosic membranes not only had a bilateral carpal tunnel syndrome, cystic bone translucencies and humeroscapular periarthritis but also developed two subcutaneous tumors in both gluteal regions, causing discomfort when sitting. Histology, immunohistology and electron microscopy of the tumor from the right side showed that it consisted of beta 2M-derived amyloid with concurrent scattered amyloid infiltration of the overlying skin. This report therefore adds a new clinical manifestation to the symptomatology of this type of amyloid.