Langerhans-cell histiocytosis of the orbit. A case study

Purpose: Langerhans' cell histiocytosis is a rare disease representing less than 1% of orbital tumors. Methods: We report a case of Langerhans cell histiocytosis with orbital involvement in a 9-year-old boy. He presented with an inflammatory swelling if the left lateral orbital wall. The computed tomographic scan revealed an orbital cellular mass with lytic bone lesion within the orbital roof and intracranial enlargement. Results: The cytological study after a biopsy showed infiltrates of histiocytes derived from Langerhans cells. Diagnosis was confirmed by immunohistochemistry, which identified positive staining with anti-S100 and anti-CD1a antibodies. The rapidly expanding orbital tumor, posing a threat of ocular compression as well as intracranial spreading, was treated by chemotherapy (Vinblastine) combined with a steroid. Conclusion: A 2-year follow-up showed no evidence of recurrence or systemic involvement. According to this observation, the authors describe the clinicopathological and histological features of orbital involvement in Langerhans cell histiocytosis.