Abstract
A 5-year-old boy presented a painful right cheek mass that had enlarged within a month. Magnetic resonance imaging demonstrated a 3.0×2.5×2.0 cm mass infiltrating the right orbit. A mass of the zygomatic bone was biopsied. Histological examination disclosed Langerhans cell histiocytosis (LCH). Chemotherapy was subsequently initiated to prevent central nervous system infiltration and vision sequelae. Complete remission was achieved and maintained for one year. Although there are several options of treatments for unifocal LCH including local excision, radiation therapy, local steroid injection, chemotherapy, and observation alone, chemotherapy was offered to avoid sequelae or extensive surgical resection or radiation.