Orbital xanthogranuloma: clinical and morphologic features in eight patients.

PURPOSE: To describe the clinical and morphologic features of patients with orbital xanthogranuloma (XG) with or without Erdheim-Chester disease (E-Cd).
METHODS: Retrospective, noncomparative case series. A review of 8 consecutive histopathologically proven cases of orbital XG from 3 medical centers. Four male and four female patients with ages ranging from 23 to 79 years presented with 4 bilateral and 4 unilateral orbital XGs.
RESULTS: Age at diagnosis, ocular and systemic manifestations, histopathologic and radiologic features, type of treatment, and prognosis were evaluated for each patient. Six of 8 patients had proptosis and 2 presented with afferent pupillary defect and severe extraocular motility limitations. Other signs and symptoms included eyelid retraction, mechanical ptosis, and chemosis. Planar xanthomas of eyelids were present in 3 individuals. CT and MRI showed infiltrating soft tissue masses within the orbit in 7 and 2 patients, respectively. Histopathology revealed proliferation of foamy histiocytes intermingled with Touton and multinucleated giant cells and lymphocytes. The absence of Birbeck granules within the histiocytic elements of the tumor, indicating that the cell of origin is a non-Langerhans histiocyte, was documented with electron microscopy in 3 cases. The most common treatment was surgical excision combined with oral corticosteroids. Two patients with E-Cd with involvement of the long bones of the upper and lower extremities and retroperitoneal region died of kidney failure within approximately 1 year of diagnosis.
CONCLUSIONS: Orbital XG is a proliferative lesion of the non-Langerhans histiocytes, which may present as a solitary orbital lesion or may be associated with a systemic condition known as E-Cd with very poor prognosis.