Tailgut cyst adenocarcinoma.

Tailgut cysts (TGCs) are rare congenital entities arising from remnants of the embryological postanal primitive gut. Malignancy in TGCs is rare, with the majority being adenocarcinomas and carcinoid tumors. A search of the published literature yielded only 27 cases of adenocarcinoma developing in TGCs. We described the case of a 54-year-old female who presented with complaints of pelvic and perineal pain of several weeks. After the initial work-up, a mass in the right presacral location was diagnosed. She underwent radical resection of the tumor, using a posterior approach. The lesion was removed en bloc with the middle rectum, coccyx, and sacrum (S4-S5). The histopathologic examination revealed an adenocarcinoma arising in a TGC, and the patient received adjuvant chemoradiotherapy. Our case underlines that diagnosing a TGC is difficult as it is a rare congenital lesion. Clinical examination may be challenging as TGCs present with various symptoms, which can mimic other commonly proctologic disorders. Patients should be referred to a tertiary center with experience in pelvic surgery and must be managed by a multidisciplinary approach to maximize successful treatment. The recommended treatment is surgical excision given the malignant potential of TGCs and their risk of causing local complications.