Eosinophilic granuloma presenting as an epidural hematoma and cyst.

Langerhans' cell histiocytosis (LCH) is a rare immunologic disorder characterized by histiocyte proliferation in multiple organ systems. Eosinophilic granuloma, a benign bone lesion, represents a focal form of LCH. We experienced a case of Langerhans' cell histiocytosis in a patient who presented with intracranial epidural hematoma and cyst on the midline of the frontal skull. A 10-year-old boy presented with a rapidly growing large scalp mass on the midline frontal area after mild head trauma. The scalp mass was painless and immobile. Plain skull x-ray showed a punched-out bone lesion. Computed tomography and magnetic resonance imaging showed a non-enhancing osteolytic lesion presenting with an epidural hematoma and cyst on the midline of the frontal skull. The lesion of the skull was completely resected and the patient's recovery was uneventful. The acute presentation of a solitary eosinophilic granuloma of skull with an epidural hematoma has been described in only five cases in the literature and we report the first case of LCH presenting as an intracranial epidural hematoma on frontal area.