Adult orbital langerhans cell histiocytosis with frontal bone involvement

A 28-year-old woman presented with a 2-week history of right upper eyelid swelling and intermittent frontal headaches. CT demonstrated an ill-defined superior right orbital mass with adjacent right frontal bone erosion and undeveloped frontal sinuses. The orbital biopsy revealed tissue strongly positive for CD1a and S100, diagnostic of Langerhans cell histiocytosis. The systemic workup was negative for multifocal lesions and for diabetes insipidus. In addition to subtotal resection, the patient was treated with a 6-month course of oral prednisone and intravenous vinblastine.