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TAILGUT CYST PRESENTING AS PERINEAL PAIN IN A 50-YEAR OLD MAN: CASE REPORT AND SURGICAL APPROACH
Kaiser O. Sadiq
*, Ashley Alden, Jin Kim, Nicole Riddle, Allen P. Chudzinski
Surgery, University of South Florida, Tampa, FL
Tailgut cysts, or retrorectal cystic hamartomas, are uncommon congenital lesions found between the rectum and sacrum. Various tumors can occur in this potential space, with tailgut cysts being the most common cystic lesion. Over half are asymptomatic, often incidentally detected, and predominantly occur in women.
We report a 50-year-old man with a prior coccyx fracture and recurrent presacral fluid collection who presented with dull perineal pain exacerbated by prolonged sitting. MRI revealed a 2-cm T2-hyperintense homogenous cyst in the retrorectal space (Fig. 1). Exam under anesthesia ruled out intraluminal or perianal pathology. Given his symptoms, recurrences, and lesion size, he opted for surgery. After mechanical bowel preparation, he was taken to the operating room. In a prone jack-knife position, a Kraske-type technique was executed, excising the cyst completely without violating the capsule (Fig 2). Postoperatively, the patient experienced expected post surgical pain managed with a multimodal analgesic regimen and soft stools from residual effects of the bowel preparation. His postoperative course was otherwise uneventful. Histopathological examination showed retrorectal cystic hamartoma with ciliated columnar epithelium and surrounding fibroconnective tissue (Fig 2).
Tailgut cysts are thought to arise from the embryonic tail, which typically regresses by the eighth week of gestation. These cysts may be more often detected in women due to routine pelvic examinations. Symptoms, when present, result from infection or mechanical compression of adjacent structures leading to pain, constipation, or even obstructed labor. MRI is the preferred imaging modality, with uncomplicated tailgut cysts appearing hypointense on T1-weighted images and hyperintense on T2-weighted images. Solid components or irregular cyst walls may suggest malignancy.
Preoperative biopsy carries risks of infection, hemorrhage, and tract seeding in case of malignancy. For purely cystic lesions, imaging often obviates the need for biopsy, and surgical resection is preferred for definitive diagnosis and treatment. The choice of surgical approach depends on the size, location, and nature of the lesion, with a perineal approach recommended for small lesions below S3. Abdominal and abdominoperineal approaches are needed for larger lesions and those above S3. Routine coccygectomy was thought necessary to prevent recurrence but is no longer recommended unless required for exposure or if the cyst is adherent. Malignant transformation may be seen in up to 27% and recurrence up to 16%.
In conclusion, tailgut cysts represent the most common etiology of retrorectal cysts and carry a risk of malignancy. MRI is preferred for preoperative evaluation and surgical planning, and complete surgical excision is essential to provide a definitive histopathological diagnosis and minimize recurrence.
Fig 1 (A) Sagittal section of T2-weighted MRI and (B) coronal section T2 STIR MRI of the sacrum and coccyx showing a 2 cm homogenous, hyperintense cyst in the retrorectal space (yellow arrow).
Fig 2 (A) Intraoperative photograph showing the dissected retrorectal mass (white arrow). (B) Photograph of the resected surgical specimen. Histopathological slides showing (C) ciliated columnar epithelium with fibroconnective tissue on high power, and (D) proximity to bone (green arrow) on low power.
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