Retrorectal cyst: a rare tumor frequently misdiagnosed.

BACKGROUND: The rarity of retrorectal cysts and their nonspecific clinical presentations often lead to misdiagnoses and inappropriate operations. In recent years, several such patients have been referred to our institutions for evaluation and treatment of misdiagnosed retrorectal cysts. A review of these patients is presented. STUDY DESIGN: Medical records of the colorectal surgery divisions at two institutions were reviewed. Patients found to have previously misdiagnosed retrorectal cysts were identified. Preliminary diagnoses, radiologic examinations, operative procedures, and final diagnoses were obtained. RESULTS: Seven patients with retrorectal cysts who had been misdiagnosed before referral were identified. These patients had been treated for fistulae in ano, pilonidal cysts, perianal abscesses; psychogenic, lower back, posttraumatic, or postpartum pain, and proctalgia fugax before the correct diagnosis was made. Patients underwent an average of 4.1 operative procedures. Physical examination in combination with CT scanning made the correct diagnosis in all patients. All patients underwent successful resection through a parasacrococcygeal approach, and six of seven did not require coccygectomy. The resected tumors included four hamartomas, two epidermoid cysts, and one enteric duplication cyst. CONCLUSIONS: Retrorectal cysts are a rare entity that can be difficult to diagnose without a high index of clinical suspicion. A history of multiple unsuccessful procedures should alert the clinician to the diagnosis of retrorectal cyst. Once suspected, the correct diagnosis can be made with physical examination and a CT scan before a definitive surgical procedure.