Retrorectal developmental cysts in adults: Clinical and radiologic-histopathologic review, differential diagnosis, and treatment

Developmental cysts are the most common retrorectal cystic lesions in adult s, occurring mostly in middle-aged women. They are classified as epidermoid cysts, dermoid cysts, enteric cysts (tailgut cysts and cystic rectal dupli cation), and neurenteric cysts according to their origin and histopathologi c features. Although developmental cysts are often asymptomatic, patients m ay present with symptoms resulting from local mass effect (eg, constipation , rectal fullness, lower abdominal pain, dysuria), with a palpable retrorec tal mass at digital rectal examination, or with a complication. Infection w ith fistulization, bleeding, and malignant degeneration are the major compl ications of developmental cysts. A well-defined, unilocular or multilocular , thin-walled cystic lesion is the main imaging feature. Uncommonly, a sacr al bone defect and calcifications are associated with developmental cysts. The differential diagnosis includes cystic sacrococcygeal teratoma, anterio r sacral meningocele, anal duct or gland cyst, necrotic rectal leiomyosarco ma, extraperitoneal adenomucinosis, cystic lymphangioma, pyogenic abscess, neurogenic cyst, and necrotic sacral chordoma. Complete surgical excision i s indicated to establish the diagnosis and avoid complications.