J Korean Neurosurg Soc.  2025 Mar;68(2):229-233. 10.3340/jkns.2024.0184.

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

• Kilinc MC
• Demirel A

• KMID: 2565280
• DOI: http://doi.org/10.3340/jkns.2024.0184

Abstract

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.

Keyword

Pediatrics; Parasellar; Hydatid cyst; Optic canal; Vision loss

Figure

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  Fig. 1. Image of hydatid cyst on cranial MRI and CT. A : In the contrast-enhanced T1-weighted MRI axial image, the yellow star indicates the optic nerve and the red triangle indicates the portion of the cyst extending toward the optic canal orifice. It can be seen that the cystic component is hypointense and the capsule is enhanced. B : Similarly on the sagittal T2-weighted sequence, the red triangle indicates the optic nerve and the portion of the cyst extending toward the optic canal orifice. C and D : DWI and ADC map showed no diffusion restriction. The borders of the cyst are shown with a dashed red circle. E : Brain CT shows a hypodense cyst with no calcification. The borders of the cyst are shown with a dashed red circle. F : On the T2-weighted coronal MRI image, the yellow dashed line delineates the cyst, while the red dashed lines indicate the ICA. It is observed that the cyst displaced the right ICA inferiorly. GR : gyrus rectus, ON : optic nerve, TL : temporal lobe, SS : sphenoid sinus, ICA : internal carotid artery, MRI : magnetic resonance imaging, DWI : diffusion weighted imaging, ADC : apparent diffusion coefficient, CT : computed tomography.

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  Fig. 2. Intraoperative images of optic nerve and cyst. A : Magnification under the microscope shows the anatomical relationship between the optic nerve and the cyst. B and C : Nerve hook is inserted into the optic canal and the cyst is dissected from the nerve. D : Macroscopic view of the total excised cyst. HC : hydatid cyst, ON : optic nerve, NH : nerve hook.

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  Fig. 3. Pathologic staining images of hydatid cyst. A : H&E stained preparation; eosinophilic stained, nucleus-free, acellular lamellar cuticle layer. In addition, inflammatory reaction with fragmented leukocytes (×10). B : H&E stained preparation; germinative membrane and organism compatible with scolex in the lumen (×10). H&E : Hematoxylin A B and Eosin.

Reference

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