LAUSR

Background Only 10 cases of cecal epidermoid cyst (CEC) have been reported in the literature. Furthermore, its pathogenesis remains unclear. We report a rare case of congenital CEC in neonate, and discuss its clinicopathological findings. Case presentation A cystic lesion was incidentally identified in the retroperitoneal area of the abdominal right lower quadrant during a routine prenatal ultrasonography (US), prompting an ileocolectomy 3 days after birth. This congenital cyst was composed of mucosal lining cells and submucosal connective tissues, and the inner lining mucosa was composed of stratified squamous epithelium and focally mucin-producing ciliated epithelium. Based on the macroscopic and microscopic findings, the cystic lesion was diagnosed as a congenital cecal epidermoid cyst. Conclusions The management of a fetal abdominal mass should be tailored individually, considering that epidermoid cysts can occur in the cecum during the perinatal period. We report the clinicopathological findings in this case, including its possible pathogenesis.