Abstract
We present a case of a 16-year-old girl with interruption of papyracea lamina and herniation of the periorbital fat covered by a bone shell. The patient presents with a history of diplopia and visual disturbances ever since she can remember. Thanks to radiological imaging and biopsy, we have done differential diagnosis with periorbital lipoma, intraosseous lipoma and intramuscular lipoma of medial rectus. Diagnostic for images is necessary for a correct operative planning. Endoscopic sinus surgery with computer-assisted navigation is the safest and most effective method to remove the lesion that was closely related to the medial rectum muscle and to the anterior ethmoidal artery. The patient after surgery and in 1 year of follow-up reports the disappearance of symptoms.