Retrorectal cystic hamartoma (tailgut cyst): a rare etiology of anal neoplasia - case report

<p><strong>Background:</strong> Retrorectal cystic hamartoma, also known as a tailgut cyst, is a rare type of space-occupying lesion. It is a cystic hamartoma that predominantly forms in the retrorectal region and may serve as a potential etiology for anal neoplasia.<br /><strong>Case Presentation</strong>: A 58-year-old female patient was initially treated for a high-grade squamous intraepithelial lesion of the anal canal, which was surgically removed on May 20, 2023, followed by radiotherapy. She also had a known tailgut cyst with a fistula connecting it to the perianal skin at the 6 o’clock position in the lithotomy view. The cyst had been asymptomatic until then. As a prophylactic measure to prevent potential malignant transformation, the decision was made to excise the tailgut cyst. The operation was performed laparoscopically and included perianal mobilization of the fistula. During follow-up, the patient developed perianal pain. A computed tomography scan revealed a fluid collection at the site of the excised tailgut cyst. The collection was surgically drained and identified as a seroma without any signs of infection. The patient was discharged after 7 days and experienced no further long-term complications.<br /><strong>Conclusion</strong>: Retrorectal cystic hamartomas are rare and often asymptomatic. When symptomatic, they may present with lower abdominal pain, back pain, obstipation, urinary retention, or complications such as anal abscesses and fistulas. Research to date remains inconclusive regarding the incidence of malignant transformation.</p>