Fig. 12. This 9-year-old boy had a 3-week history of right progressive proptosis associated with inward and downward displacement of the globe. CT demonstrated an osteolytic mass with an enhancing rim destroying the lateral orbital wall. Biopsy revealed Langerhans cell histiocytosis, and he was treated with surgical excision and intralesional steroids. He remains well after 5 years of follow-up. (Rootman J, Stewart BA, Goldberg RA: Orbital Surgery: A Conceptual Approach, p 45. Philadelphia: Lippincott-Raven, 1995.)