Koyanagi T, Tsuji I, Motomura K, Sakashita S
Int Urol Nephrol. 1977;9(1):41-6. doi: 10.1007/BF02082664.
An unusual cystic tumor of retrovesical space was reported. After puzzling speculation on its histogenesis this extremely rare tumor was concluded to be a cloacal cyst with transitional cell carcinoma. Review of the literature revealed no similar case.