[Urogenital amyloidosis: clinico-pathological study of 8 cases].

Amyloidosis of the genito-urinary tract is uncommon. We report 8 cases, often misdiagnosed as a neoplastic process (6/8). Amyloidosis was localized in the bladder (3 cases), in the ureter (1 case) and in the prostate and/or seminal vesicles (4 cases). The amyloid protein was characterized in 7 cases by immunohistochemistry. Among the bladder and ureter amyloidosis, 2 cases were classified as AL lambda amyloidosis and one case as AA amyloidosis in a patient with long history of chronic arthritis. In the fourth case, the deposits could not be identified. Nevertheless an AL amyloidosis might be suggested. Two cases of prostate and/or seminal vesicles amyloidosis were stained with an anti-B2M antibody, in hemodialyzed patients. The 2 others, positive with the anti-Transthyretina antibody, were classified as senile amyloidosis. This small series illustrated the heterogeneous pathogenic types of amyloidosis in the urogenital tract and emphasized the interest of immunohistochemistry to identify the chemical composition of these deposits.