Odontogenic fibroma (OF) is a rare benign neoplasm derived from the dental mesenchymal tissues. According to the World Health Organization (WHO), there are two histological types of lesion: the epithelium-poor type (formerly called the simple type) and the epithelium-rich type (formerly called the complex or WHO-type). A 45-year-old man was referred to our department due to swelling of the lower right gingiva. A panoramic radiograph showed a well-demarcated unilocular radiolucent lesion between the 45 and 46 without root resorption. CT showed slight absorption of lingual cortical bone. We underwent biopsy and suspected as fibroma, so we examined tumor excision under general anesthesia. Histopathological diagnosis was odontogenic fibroma. We diagnosed it as epithelium-poor type OF because there were mainly connective tissue lesions and scattered remnants of odontogenic epithelium. The patient has not suffered recurrence after follow-up for 1 year and 4 months.
