Orbital cysts of childhood--classification, clinical features, and management.

There is little in the literature about the clinical spectrum of orbital cysts of childhood and no comprehensive classification has been proposed. The authors propose a classification of orbital cysts of childhood and review their clinical features, pathology, and management. The major categories in the classification include cysts of surface epithelium, teratomatous cysts, neural cysts, secondary cysts, inflammatory cysts, and noncystic lesions with cystic component. Cysts of the surface epithelium are further divided into simple epithelial cyst (epidermal, conjunctival, respiratory, and apocrine gland), and dermoid cyst (epidermal and conjunctival). Epidermal dermoid cyst (dermoid) is by far the most common orbital cystic lesion in children, accounting for over 40% of all orbital lesions of childhood and for 89% of all orbital cystic lesions of childhood that come to biopsy or surgical removal. Neural cysts include those associated with ocular maldevelopment (congenital cystic eye and colobomatous cyst) and those associated with brain and meningeal tissue (cephalocele and optic nerve meningocele). The most important secondary cyst is mucocele that can occur in children with cystic fibrosis. Inflammatory cysts are generally due to parasitic infestations and are more common in tropical areas of the world. Noncystic lesions that can have a cystic component include adenoid cystic carcinoma, rhabdomyosarcoma, lymphangioma, and others. Each type of cyst has rather characteristic, but not pathognomonic, clinical features. Computed tomography and magnetic resonance imaging can help differentiate a cystic lesion from a solid tumor, suggest the type of cyst, and help in planning management. The pathology varies with the cells that line the cyst and with the inflammatory agent. Management varies from local excision to observation, depending on the location and type of cyst. Orbital cysts of childhood can be classified into categories, based mainly on their histopathology. The clinical, radiologic, and histopathologic features can be correlated with the classification in order to better evaluate a child with a cystic lesion in the orbit.