Abstract
A 54-year-old woman was referrd to the service for further examination of a mass in the pelvis. A soft mass was palpable with the finger tip on the posterior wall of the rectum. CT scans showed a well marginated cystic lesion with a smooth surface, which measured 8cm in diameter at the retrorectal space. Bariumenema examination demonstrated forward displacement of the posterior wall of the rectum. Transrectal endoscopic ultrasonography revealed a large hyperechoic mass with some hypoehoic spots. The scan identified all layer of the rectal wall, and showed the capsule of the tumor and no evidence of tumor invasion to the rectum. The mass was excised via a transsacral approach. Examination of the resected specimen revealed a smooth-walled biloculated cyst measuring 9×6×5cm and containing greyish granular material. Microscopically, the cyst wall was composed of stratified squamous epithelium without any skin appendages, so a diagnosis of epidermoid cyst was made.
There have been 17 cases of developmental cyst and only 7 cases of them had presacral epidermoid cyst up to 1994 in Japan. Complete excision of those presacral cysts is advised because of possible complications including infection and malignancy.
