Intraconal Orbital Hidrocystoma in an Infant.

Intraconal orbital hidrocystoma is a very rare entity. Herein, a 6-month old boy with an intraconal apocrine hidrocystoma will be reported. The patient presented with a left-sided mild proptosis and significant anisometropic hypermetropia. Clinical examinations revealed choroidal folds and optic disc blurring in the left eye. Orbital MRI disclosed an intraconal well-defined cystic lesion that was hypointense in T1 and hyperintense in T2 weighted images. The lesion was excised completely through a lateral orbitotomy and diagnosed histologically as an apocrine hidrocystoma. Excepting partial improvement of anisometropia, other clinical signs were improved after surgery.