Solitary eosinophilic granuloma of the parietal bone in an adult patient.

Eosinophilic granuloma (EG) is a well-recognized benign form of Langerhans-cell histiocytosis. The estimated incidence of EG is 3-4 per million of the population. More patients are children and adolescents between the ages of 1-15 years. In this report, we present an adult patient. A 37-year-old male was admitted with headache and right parietal swelling that was present for 2 months together with epileptic attacks. Cranial CT scan revealed a right parietal osteolytic lesion with large epidural and subcutaneous mass, causing brain compression. Total removal of the mass was carried out with cranioplasty. Histopathological examination disclosed Langerhans cell histiocytosis and immunohistochemical detection of S-100 antigen. At follow-up, he had no neurological deficits, and control CT was normal. For symptomatic solitary calvarial EG, surgical excision is the main treatment option. Surgical treatment is simple, quick, and allows histological diagnosis of the osteolytic lesions.