Eosinophilic granuloma of the occipital bone in an adult: a case report.

Eosinophilic granuloma (EG) refers to the most common and benign form of the disorder known as Langerhans' cell histiocytosis. The disease is typically found in children and adolescents and rarely affects adults. We present a case of EG in the occipital bone in a 36-year-old man, who visited our hospital with the chief complaint of left occipital palpable tumor mass with local tenderness and pain for one month. An X-ray of the skull revealed a rounded osteolytic lesion. A computed tomography scan revealed a shadow of soft tissues in the left occipital site involving the entire thickness of the calvaria, which was indicative of marked destruction of the bone. The soft mass was successfully removed. The margins of the skull lesion were excised, and cranioplasty was performed simultaneously with bone cement. A definitive diagnosis of EG was made by histopathology and immunohistochemical detection of S-100 antigen in the tissue samples. With respect to management, we believe surgery is the best option for most accessible cranial lesions of EG. A cranioplasty with bone cement or autologous bone can be performed in the same session to repair the cranial defect.