Abstract
BACKGROUND: A perianal mass has a wide range of possible diagnoses, including tailgut cysts. Tailgut cysts are congenital, and their development is slow. Because its most common placement is retro-rectal, it is extremely rare to find it on the perianal level only. It is possible to develop neoplastic or infectious problems. Consequently, proper support is required. CASE DESCRIPTION: We present a case of perianal tailgut cyst in a 59-year-old man who sought help for painless anal discomfort. Nuclear magnetic resonance was used to conduct this assessment. The radiologist thought it was probably benign, but he was not able to find a precise diagnosis. Thus, the cyst was completely removed using a transanal way with the patient in a lithotomy position. Then, the anatomopathological examination had confirmed the diagnosis and the benignity of the cyst. The postoperative follow-up was uneventful. We had planned to see the patient for a clinical follow-up every six months, but he has refused so far. CONCLUSIONS: Tailgut cysts are uncommon in the perianal area but should be included in the differential diagnosis of perianal masses and should not be confused with an abscess or a haemorrhoid. The nuclear magnetic resonance appears to be the most appropriate radiological examination for the assessment of these masses. Excision is performed systematically to confirm the diagnosis and exclude a malignant condition thanks to the anatomopathological examination.