[A mucin-producing cystadenoma, borderline malignancy, of the renal pelvis and ureter: a case report].

A cystadenoma or a cystadenocarcinoma arising from the renal pelvis is a rare neoplasma and, so far as is known, only two cases have been reported in the literature (Arcadi, 1956, and Ross, 1985). Discussed herein is a case of a 63-year-old woman who developed a mucinous nephrosis, due to a marked retention of mucin produced by a tumor. The ureter as well was found to be involved. The histogenesis of an adenocarcinoma, which includes a cystadenoma and a cystadenocarcinoma, most likely is due to a glandular metaplasia, associated with urolithiasis and pyelonephritis. In this specific case, the patient revealed a history, fifteen years earlier, of renal calculi and pyelonephritis.