Mesonephric Duct Cyst in a Newborn

In the female embryo large portions of the mesonephric duct degenerate before birth,' whereas in the male, the duct remains and is incorporated into the genital system. That which remains in the female forms parts of the urethra and trigone, and contributes to the epoophoron which persists through life. Occasionally the duct remains in the lateral wall of the vagina and uterus as Gartner's duct. All these remnants are subject to cystic and neoplastic change, and it is usually as a result of such pathology that they are identified and studied. The origin of cysts in the vicinity of the kidneys has not been clear, but has not been ascribed to remnants of the mesonephric duct. Some observers, however, have described cysts which they have identified as mesonephric rests.28 Most of these cysts have had no anatomic relationship to any other organ but the kidney, and the cavity has generally been blind, without communications with the renal pelvis. The present report concerns a large retroperitoneal cyst in continuity with the right kidney and the right side of the uterine cervix.