[Presacrococcygeal congenital cyst in the adult].

Two cases of congenital cyst of the presacral space in the adult are presented. The unusualness of the lesion is stressed, and reference is made to the usefulness of a classification covering all retrorectal neoformations, including congenital forms. Attention is given to the manner of diagnosis. Variations in the surgical technique employed depend on the clinical and anatomical picture, and the potential inflammatory and degenerative aspects of the lesion. Emphasis is placed on the absolute need to section the sacrococcyx to prevent recurrences.