[Retrorectal cystic hamartoma (tailgut cyst): radiologic and pathologic findings]

Cystic hamartoma is a rare congenital lesion that presents as a presacral mass. It arises from remnants of the embryonic postanal gut. It is more common in women and usually presents in middle age. It is usually asymptomatic. It is difficult to distinguish the imaging appearance of cystic hamartoma from that of many other presacral cysts; therefore, histologic analysis is essential for the definitive diagnosis. Complete surgical excision is indicated to establish the diagnosis and avoid complications (infection and malignant transformation).