Retrorectal cystic hamartoma (tailgut cyst): report of a case and review of literature.

Retrorectal cystic hamartoma is a rare type of congenital cystic lesion usually diagnosed in middle-aged women. Although mostly asymptomatic, patients may present with symptoms resulting from local mass effect or with a complication. The most important complications of these cysts are infection with secondary fistulization and malignant degeneration. Because of such non-specific nature of symptoms and rare incidence, it is not unusual to have a delay in clinical diagnosis. MRI has evolved to be the investigation of choice for the evaluation of presacral tumors as it can provide excellent anatomic detail and soft tissue contrast. Role of preoperative biopsy is controversial especially with improvements in the imaging techniques. When diagnosed these lesions should be excised because of the risk of malignant transformation.