A Parasellar Hydatid Cyst Extending to the Opticocarotid Triangle, Pediatric Case.

The causes of sudden vision loss in one eye include isolated eye diseases, vascular pathologies, and optic nerve compression. This report highlights a case of parasitosis (Echinococcus granulosus) causing sudden vision loss due to optic nerve compression. To our knowledge, this is the first reported case of a hydatid cyst extending into the optic canal through opticocarotid triangle in a pediatric patient. A 12-year-old girl presented to the ophthalmologist with progressive visual deterioration over a period of 1 week. Examination revealed reduced visual acuity in her right eye. No ocular abnormality was detected on examination, cranial imaging revealed a lesion compressing the right optic nerve and the patient was referred to neurosurgery. The bright white lesion with a microscopic appearance resembling an epidermoid tumor was completely excised after aspirating the contents with transcranial access. Pathology was reported as hydatid cyst. Hydatid cysts invading the optic canal should be considered in the differential diagnosis of sudden visual loss in the pediatric age group; however, it continues to be an important health problem in developing countries. Meticulous excision of the cyst capsule without rupture ensures the success of surgical treatment.