Retrorectal cystic hamartoma unmasked by coccygeal fracture: a case report and review of presacral tailgut cysts and surgical management

Introduction: Tailgut cysts, or retrorectal cystic hamartomas, are uncommon developmental lesions found in the theoretical space between the rectum and the sacrum. Frequently asymptomatic and incidentally detected, they occur predominantly in women. Compression of nearby structures may cause perineal and back pain and even obstructed labor. Case Report: We report a case of a 50-year-old man with prior coccygeal fracture who presented with dull perineal pain, worsened by prolonged sitting. MRI revealed a cystic mass, and surgical excision was performed via a posterior perineal approach. Postoperative recovery was uneventful apart from surgery-related increased perineal pain. Pathology demonstrated a retrorectal cystic hamartoma. Discussion: Tailgut cysts are thought to originate from the embryonic tail, which normally regresses by the eighth week of gestation. MRI is the preferred imaging modality, with cysts appearing hypointense on T1 and hyperintense on T2 images. Solid components or irregular cyst walls on imaging may suggest malignancy. Preoperative biopsy carries risks of hemorrhage, infection, and tract seeding. In purely cystic lesions, complete surgical resection without biopsy is preferred. A perineal approach is recommended for small lesions below S3, while abdominal and abdominoperineal approaches are needed for larger lesions and those superior to S3. Routine coccygectomy was previously thought necessary to prevent recurrence but is now understood to be avoidable unless needed for exposure or the cyst is adherent. Malignant transformation occurs in up to 27% of cases, with recurrence up to 16%. Complete excision is essential to prevent recurrence and obtain a definitive diagnosis. Conclusion: Tailgut cysts, the most common retrorectal tumors, are often asymptomatic. MRI is the preferred imaging modality. Complete surgical resection is crucial to prevent malignancy and recurrence. The role of preoperative biopsy is controversial, and routine coccygectomy is no longer recommended.