Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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August 1, 2019
Orbital Xanthoma (Adult Onset Xanthogranuloma)
- Background
- Adult onset xanthogranuloma (AOX) is 1 of 4 subtypes in a rare, heterogeneous group of non-Langerhans histiocytic disorders/syndromes called adult orbital xanthogranulomatous disease that also includes other subtypes necrobiotic xanthogranuloma, Erdheim-Chester disease and adult-onset asthma and periocular xanthogranuloma.
- AOX is the least common subtype and unlike the other 3, AOX is an isolated lesion without significant systemic involvement.
- Affected age range is between 38-79, with no sex predilection.
- Clinical Presenatation
- Slowly progressive proptosis due to enlarging intraorbital mass associated with headache.
- Key Diagnostic Features
- Histopathologic features show sheets of mononucleated foamy histiocytes (xanthoma cells) with variable numbers of lymphocytes, plasma cells and Touton giant cells. Radiologic imaging is not definitive, but can show an infiltrative intraorbital mass with extraocular muscle and lacrimal gland enlargement/involvement that can track along, or within, the orbital muscles and fat.
- Encasement of the optic nerve, bone destruction, and intracranial extension are not often seen. Facial bones are not involved.
- Differential Diagnosis
- AOX must be differentiated from inflammatory orbital pseudotumor which is characterized by acute onset orbital pain, lymphoma, as well as Langerhans histiocytosis and Rosai-Dorfman disease, which can have orbital involvement, and Graves disease which is usually bilateral.
- Treatment
- The best therapy is unknown. Multiagent chemotherapies have been used to address associated systemic symptoms in 3 of the 4 subtypes.
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