Congenital tumors of the retrorectal space in the adult: report of two cases and review of the literature

Abstract

Aims and background: To describe and discuss, on the basis of the authors' experience and a review of the literature, the main aspects regarding the etiology, diagnosis, treatment and prognosis of congenital tumors of the retrorectal space.

Methods: We present 2 cases of congenital retrorectal tumors, a sacrococcygeal teratoma and a dermoid cyst, which represent, from the pathogenetic point of view, the most frequent presentation of the rare tumors of the retrorectal space.

Results: The reported cases are typical. The teratoma presented as an encapsulated, mixed mass located in the pelvic cavity behind the rectum and the vaginal canal, without signs of sacral involvement. The dermoid cyst appeared as a unilocular lesion filled with sebum and hair, which extended laterally to the iliopubic branch, medially to the urethra and anal canal, and posteriorly to the adipose tissue of the right buttock. Pelvic MRI produced a precise picture of the extension of the lesion and of the relationship between the mass and the pelvic organs and surrounding bony structures. Both lesions were completely removed via the perineal approach without coccygectomy. No recurrences were observed at 2 years of follow-up.

Conclusions: Congenital retrorectal tumors are rare. MRI is crucial for diagnosis and preoperative planning. Complete surgical removal is the treatment of choice. Resection of the coccyx is necessary only in case of its involvement by the neoplastic mass or suspected malignant transformation.