Orbital Cysts and Cystic Lesions

Cysts are anechoic if their content is pure liquid, or they may be hypoechoic to a certain extent but always associated with a posterior enhancement artifact. Their etiologies are varied, and schematically, one can distinguish malformative orbital cysts, acquired orbital cysts, superficial cysts, cysts from adjacent structures, epithelial inclusion cysts, and cystic tumors. Superficial cysts include dermoid cysts and palpebral cysts: chalazion, stye, hidrocystoma, and pilomatrixoma, and dacryops. Abscesses, bacterial or fungal, correspond to one or more collection areas within a patch of cellulitis or within a pre-existing lesion (tumor, granuloma following foreign body injury). Parasitic cysts are mostly related to hydatidosis or cysticercosis. Cystic granulomas are usually secondary to penetration of a foreign body into the orbit. Hematomas are characteristic of hemolymphangiomas but can occur within other benign vascular lesions such as cavernous hemangiomas and varices, or within all malignant tumors. Cystic tumors, rare, are mainly observed in children. Congenital malformative colobomatous cysts can be encountered under the optic nerve. Cystic lesions extending to the orbit from adjacent spaces include mucoceles, dacryoceles (or dacryocystoceles), and cephaloceles. Finally, epithelial inclusion cysts can be seen after any eye or orbital surgery but are particularly observed after placement of a prosthesis.