A rare case of huge intracranial yolk sac tumor presenting as an orbital mass in an infant: case report and literature review.

Primary intracranial yolk sac tumor (YST) with orbital involvement is an exceedingly rare extragonadal germ cell tumor, with only a limited number of cases reported in the literature. Clinically, primary intracranial yolk sac tumor with orbital involvement may present with symptoms that mimic more common benign or malignant orbital disorders in children, potentially leading to diagnostic delays that can adversely impact survival. Diagnostic imaging modalities, including computed tomography (CT) and magnetic resonance imaging (MRI), are instrumental for assessing the tumor's size, precise localization, and extent. Definitive diagnosis relies on serum and cerebrospinal fluid (CSF) alpha-fetoprotein (AFP) levels and histopathological evaluation of biopsy samples. Multimodal therapy with surgery, chemotherapy, and radiotherapy is the cornerstone of therapy. Our case report showed a primary intracranial yolk sac tumor with orbital extension in a 10-month-old infant, and brain Magnetic Resonance Imaging (MRI) revealed a heterogenous suprasellar, parasellar mass with orbital extension. The infant underwent radical left globe exenteration, left pterional craniotomy, and subtotal resection of the tumor. The histopathology and the elevated AFP biomarkers confirmed the diagnosis of the primary intracranial yolk sac tumor.