Primary yolk sac tumor of orbit: Report of a rare case.

Extragonadal germ cell tumors (GCTs) of head and neck region account for 5% of all benign and malignant GCTs. Orbit is an uncommon site for occurrence of extragonadal GCTs. Pure yolk sac tumor (YST) of orbit is a rare neoplasm and only a few cases are reported in the literature. An 18-month-old boy presented with right eye proptosis of 2 months duration. Because of rapid clinical course and magnetic resonance imaging (MRI) findings, neoplastic lesion was suspected. Histopathological examination of the biopsy revealed neoplasm with possibility of GCT. Raised serum alpha-feto-protein levels suggested YST component. Positivity for immunohistochemical markers Glypican-3 and SALL4 confirmed pure YST nature of the tumor. The child received six cycles of cisplatin-based chemotherapy with significant reduction in size of the tumor, followed by exenteration of the orbit. This case is reported for its rarity as well as for highlighting diagnostic characteristics and management of orbital YST.