CYSTIC ORBITAL LESIONS 1. Dacryops 2. Dermoid cyst Superficial Deep 3. Mucocele 4. Encephalocele Anterior Posterior

Dacryops Ductal cyst of lacrimal gland Frequently bilateral Round, cystic lesion originating from palpebral portion of lacrimal gland Protrudes into superior fornix

Superficial dermoid cyst Presents in infancy No displacement of globe Most commonly superotemporal Occasionally superonasal Freely mobile under skin Posterior margins are easily palpable

Deep dermoid cyst Presents in adolescence or adult life Non-axial proptosis May be extension into temporalis fossa or intracranially Associated bony defects May leak and cause granulomatous inflammation and fibrosis CT shows a heterogenous, well-circumscribed lesion

Mucocele Presents - adult life Caused by obstruction of drainage of normal sinus secretions (frontal or ethmoidal) Slowly expanding lesion which gradually erodes sinus walls Gradual proptosis or globe displacement Periorbital or upper lid swelling

Encephalocele Encephalocele - herniation of intracranial contents through congenital skull defect Meningocele - contains only dura Meningoencephalocele - contains dura and brain tissue Anterior (fronto-ethmoidal) Posterior (spheno-orbital) Transmission of CSF pulsation causes pulsating proptosis without a bruit

Anterior encephalocele Involves supero-medial part of orbit Displaces globe forwards and laterally

Posterior encephalocele Caused by congenital defect in sphenoid bone Globe displacement forward and downward

Associations of encephaloceles Ocular Other congenital bony defects Neurofibromatosis - 1 Colobomas Morning glory anomaly Hypertelorism Hare lip and cleft palate Common in posterior encephalocele