Lectin- and immunohistochemical studies on acquired cystic kidney and associated renal cell carcinoma.

Nine specimens of acquired cystic kidney were studied by means of lectin- and immunohistochemistry. The cysts appeared to originate from any part of the nephron, but mostly from the proximal tubule. The cause of multicyst formation is still unclear, but the results of this study suggested that obstruction of the lower nephron might play an important role. Many microscopic carcinomas or dysplastic epithelial cells were observed in the cyst wall. All these carcinomas originated from the proximal tubule, except for one which was of Bellini duct origin and showed papillary growth. The reasons why almost all of the carcinomas originated from the proximal tubule were: 1) the majority of the cysts originated from the proximal tubule, and 2) dysplastic epithelial cells in the cysts originating from the proximal tubules were more frequent in number than those in cysts originating from other parts of the nephron. Histological observation showed that stimulation due to oxalate crystals in the proximal cysts was one of the causes of dysplastic epithelial cell hyperplasia.