[Cystic tumors in the retrorectal space. Do these two cases have something in common?].

Cystic lesions in the retrorectal or presacral space present a broad differential diagnosis. Rare but typical lesions at this site are those related to embryonic development, which are the most frequent presacral congenital lesions in adults. Amongst these tumors, epidermoid cysts and cystic hamartomas are the most common lesions. Cystic masses, which are asymptomatic in approximately 50% of the cases at diagnosis, may show complications such as infection or malignant degeneration. Initial diagnosis is based on imaging techniques although definite lesion characterization, essential due to their malignancy risk, is given by the pathological analysis of the surgical piece.