Orbital Hydatid Cysts

1 Signs and Symptoms

• Symptoms are often insidious, with proptosis and pressure symptoms leading to impaired motility, diplopia, papilledema, and optic atrophy (Fig. 1) [1].

• The cyst can be intra- or extraconal, with a predilection for supero-medial orbit [2].

• Rarely, the cyst may rupture, and the patient may present with fulminant orbital inflammation (Fig. 2).

2 Differential Diagnosis

Hydatid is rare within the orbit, and hence other cystic lesions are often considered as a possibility [3]. Circumscribed lymphangioma, cystic schwannoma, colobomatous cyst, orbital dermoid cyst, epidermoid cyst, teratoma, encephalocoele, and hematinic cyst are some of the differentials to be considered. Not uncommonly, it is an intraoperative diagnosis based on the classic finding of the cyst wall.

3 Diagnosis

• Orbital ultrasonography can identify the cyst as unilocular well-circumscribed anechoic lesion [4]. However, it is of limited value in differentiating between various cystic lesions of the orbit.

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