豊永敬之の肛門管重複症・手術・肛門超音波検査の論文 Copy of 福岡の大腸・肛門科専門医による痔・肛門科・大腸内視鏡（大腸カメラ）のサイト　大腸肛門武者修行

Anal canal duplication (ACD) is a rare congenital malformation, usually detected early in life. We report a case of a 67-year-old female with symptomatic ACD associated with a presacral cyst. Physical examination revealed an accessory opening located in the midline, posterior to the true anus. Imaging examinations, including fistulography, endoanal ultrasonography and magnetic resonance imaging, revealed a blind-ending fistulous tract without connecting with the rectum and a presacral cyst posterior to the rectum. Complete surgical excision of the tract with cyst was performed through a posterior sagittal approach. Histologic examination revealed squamous epithelium lining and smooth muscle bundles, thereby confirming ACD. The postoperative course was uneventful, and the patient was doing well, without recurrence, 4 years after surgery.
ACD can present for the first time not only in infants and children but also in adults. Imaging examinations are useful for diagnosis and preoperative assessment of ACD. Therefore, ACD should be considered in the differential diagnosis, even in adults, when a posterior perineal orifice is encountered, particularly in female patients. Once ACD is suspected, aggressive image inspection is recommended to visualize the ACD and associated anomalies and surgical removal is warranted to prevent inflammatory complications or malignant changes.