Peripelvic cysts of the kidney occur rarely, they are usually small in size and most cases have been noted by pathologists as incidental findings at necropsy. In only a few cases have these cysts caused clinical symptoms, and these were usually large cysts tending to distend the abdomen; their perinephric origin was in most cases recognized only on the operating table or at necropsy. Abbe1reported two cysts which were large enough to pass beyond the midline of the abdomen. One contained 2 pints (946 cc.), the other 12 pints (5,678 cc.) of fluid. Albarran and Imbert2reviewed 18 cases reported before 1903. Eight of these patients had been treated surgically, 4 by removal and 4 by drainage. Przewoski3and Albarran and Imbert, as well as other authors, suggested that the cysts arose from embryonic remnants of the wolffian body. Lüdin and Howald4reported a case