Posterior surgical approach for excision of retrorectal epidermal inclusion cyst, a road less travelled by surgeon: case report

Retrorectal epidermal inclusion cysts are rare congenital cystic lesions, mostly an incidental finding usually diagnosed in middle-aged women. Surgical resection is the main stay of treatment and 3 operative approaches are commonly used: abdominal, trans-sacral/coccygeal (posterior), and combined abdomino-posterior depending on the nature and location of the lesion. We report a case of a 22-year-old male presented with complaints of on-off constipation since 4 years, perineal heaviness since 2 years. Based on digital rectal exam, trans-rectal ultrasound, computed tomography, and magnetic resonance imaging findings, a presumptive diagnosis of retrorectal cyst was made. Patient underwent excision of cystic lesion by posterior trans-coccygeal approach. Post operative histopathology confirmed diagnosis of the retrorectal epidermal inclusion cyst. On follow-up after one month, symptoms of constipation and perineal heaviness completely resolved. Posterior resection allows proximal extension for elimination of the infection and in cases of adherence of the cyst to surrounding structures or in malignancy, which require en bloc resection. Posterior approach for resection is preferred for patients with posterior retrorectal cyst or presacral cyst because it provides adequate exposure with minimum dissection.