Congenital encephalomeningocele presenting as a giant orbital mass in a neonate: a case report

Background Congenital orbital masses encompass a broad spectrum of etiologies, among which encephalomeningocele is exceedingly rare and particularly diagnostically challenging when atypical.Case presentation We report a 2-hour-old female neonate who presented with a giant left orbital mass causing marked proptosis. Imaging revealed a mixed cystic-solid lesion with calcifications and septations, but no bony defect was identified preoperatively. A transcranial approach was performed, revealing a small orbital roof defect with herniation into the anterior cranial fossa. Histopathology confirmed encephalomeningocele. The surgery successfully preserved the globe, although mild lagophthalmos resulted in exposure keratopathy. Follow-up imaging showed a small residual lesion.Conclusions This case highlights that congenital orbital encephalomeningocele can present with atypical features, including a giant lesion with a disproportionately small bone defect that was not detectable on imaging, particularly in neonates. Histopathology is essential for diagnosis, and encephalomeningocele should be considered in the differential diagnosis of congenital orbital masses even when classic imaging findings are lacking.