Surgical Excision of A Giant Presacral Epidermoid Cyst: A Case Report and Review of the Posterior Surgical Strategy

Retrorectal tumors are rare lesions arising in the potential space between the rectum and the sacrum. Their nonspecific clinical presentation frequently leads to misdiagnosis and inappropriate surgical management. Epidermoid cysts represent a significant subset of congenital retrorectal lesions, typically occurring in middle-aged women.We report the case of a 32-year-old male presenting with a two-year history of a slowly progressive, painless gluteal mass. Physical examination revealed a fluctuating mass in the sacrococcygeal region. Magnetic Resonance Imaging (MRI) demonstrated an unilocular cystic lesion in the retrorectal space below the S3 vertebral level. The patient underwent complete en bloc excision via a posterior (Kraske) approach. Histopathological analysis confirmed a benign epidermoid cyst. The postoperative course was uneventful, with no evidence of recurrence during follow-up.This case highlights the diagnostic importance of pelvic MRI in evaluating indeterminate perianal masses. Preoperative biopsy is contraindicated for cystic lesions due to the risk of infection. The posterior approach provides excellent exposure for low-lying tumors, allowing for complete resection while preserving pelvic floor function. A high index of suspicion is essential to avoid confusion with common anorectal conditions such as pilonidal disease.