Retrorectal Cystic Hamartoma (Tail Gut Cyst): An Institutional Experience

Abstract

Abstract Objectives Tailgut cyst (TGC) is a rare congenital benign cystic lesion arising from a remnant of the embryonic postnatal hindgut. TGCs are typically multinodular, uncapsulated, but usually well circumscribed. TGCs are generally rare in adults and the majority of the lesions are benign. Malignant transformation is rare and malignancies reported include adenocarcinomas and neuroendocrine tumors. Methods A retrospective database search was conducted and coded as “tailgut cyst or retrorectal cystic hamartoma” to identify cases of possible TGC between January 2005 and January 2019. The search utilized the pathology files of Yale-New Haven Hospital using CoPath laboratory information system. Clinical and surgical data were gathered from the surgical pathology report and surgical operative note when available. Results A total of 13 cases (10 women) were identified with a median age of 51 years. All the specimens were obtained by surgical excision. Most of the cases were excised from the presacreal area (11 cases), and two cases were excised from the retrorectal area. The two cases resected from the retrorectal area had a malignant component. The first case was a 33-year-old female who had a 1.5-cm tailgut cyst that showed a multifocal neuroendocrine tumor (carcinoid); the resection margin was also positive. The second case was a 59-year-old female who had a tailgut cyst that showed mucinous adenocarcinoma; the resection margin was also positive. Conclusion Diagnosis of tailgut is sometimes challenging. Possible differential diagnoses in this location include teratoma, dermoid cyst, anterior sacral meningocele, and presacral abscess. Imaging is an important component of the initial workup. Surgical resection is the treatment of choice when the cyst grows in size and if a solid component is present. Exclusion of other benign entities and malignant transformation/component on histological examination is crucial.