Rethinking congenital anal stenosis: a systematic review with histological observations toward a revised conceptual framework.

The concept of congenital anal stenosis remains poorly defined, encompassing anatomically distinct conditions that may differ in pathogenesis and management. This study aimed to re-evaluate the current concept of congenital anal stenosis through a systematic review and histological examination of representative cases. We conducted a systematic review of English-language publications to assess clinical characteristics, treatment methods, and outcomes in patients diagnosed with congenital anal stenosis. In addition, we performed histological analysis of surgical specimens obtained from two representative surgical cases. Among 28 identified studies involving 70 cases, 50 cases without Currarino syndrome responded well to bougie dilatation or minor anoplasty. In contrast, 20 cases (28.6%) associated with Currarino syndrome showed poor response to conservative treatment and frequently required treatment of associated presacral lesions or more invasive procedures. Histopathological analysis of two representative surgical cases revealed dense fibrosis located between the dentate line and the anal verge, supporting the possibility that anal membranous stenosis can occur as a distinct skin-level lesion. Our findings support reconsidering the terminology of congenital anal stenosis and suggest that congenital skin-level anal stenosis should be distinguished from anorectal stenosis. Further anatomical and histopathological studies are needed to validate this framework.