Fetal Orbital Epidermal Cyst Pre-postnatal Imaging Findings: A Case Report and Literature Review

Background: Fetal ultrasonographic evaluation is a routine part of pregnancy follow-up, and examination of orbital structures is also part of the routine evaluation. Although orbital developmental anomalies are common in the neonatal period, diagnosis in the intrauterine period is not common. To our knowledge, three cases with a diagnosis of congenital orbital epidermal cysts have been reported in the literature, and two of them had fetal imaging findings. In this article, we present the prepostnatal imaging findings of a case diagnosed with orbital cyst in the fetal period and histopathologically diagnosed as epidermal cyst in the neonatal period. Case Report: A 25-year-old woman applied for ultrasonography (USG) examination at 22 weeks of gestation. A 35x45 mm cystic lesion causing proptosis, without solid component and vascularity, surrounding the optic nerve and causing its thinning was observed in the left orbit. In fetal magnetic resonance imaging (MRI), the intraorbital cystic lesion, which was hyperintense on T2W images and hypointense on T1W images, had no relationship with intracranial structures and no solid component. The lesion of the patient, followed up with a multidisciplinary approach, was shown similarly with computed tomography (CT) and magnetic resonance imaging (MRI) in the postnatal period. Subsequently, the patient underwent globe-sparing surgery, and the pathological diagnosis was made as the epidermal cyst. Conclusion: Orbital epidermal cysts are rarely seen, and detection in the fetal period is even rarer. It should be considered in the differential diagnosis of orbital cystic lesions that cause proptosis in fetal and neonatal periods.