Orbital Hydatid Cyst: CT and MRI

Abstract

Orbital hydatid cyst is rare. We present a case with CT and MRI, emphasizing the superiority of the latter.

Primary orbital hydatid cyst: computed tomography and magnetic resonance imaging findings

“…Orbital involvement is usually unilocular, without right or left dominancy. (2,3) The cysts are usually located in the retrobulbar region, and may be extraconal or, as in our case, intraconal. The superior quadrant of the visual field is usually affected in cases of extraconal involvement.…”

“…(3,4) The orbita is a rare location for echinococcal infestation and makes up less than 1% of all cystic involvements. (5) Hydatidosis of the orbit is more common among young adults and children.…”

“…(2) Unilateral proptosis is the most common clinical finding in intraorbital hydatid cyst cases. (2,3) Other findings include loss of vision, orbital pain, chemosis, palpebral oedema, and orbital cellulitis. Painless and slow-growing proptosis is a highly suspicious indicator of orbital hydatid cyst in endemic regions.…”

“…(6) MR imaging is superior to CT with regard to the evaluation of the inner structure of the cyst and determining its association with neighbouring soft tissues. (3) However, it is difficult to distinguish hydatid cysts from other mass lesions of the orbita via radiological imaging methods. Therefore, other cystic mass lesions like abscesses, mucocele, intraorbital haematomas, lacrimal tumours or cysts, and lymphangiomas must be considered in the differential diagnosis.…”

“…(1)(2)(3) The disease is more common in the rural areas of South America, East and North Africa, and the Middle East, mainly in the Mediterranean countries, and is less common in developed countries. (4) Hydatid cysts with orbital involvement are rare, comprising less than 1% of all systemic involvements of hydatid cysts.…”