Osteomas are osteogenic lesions which have a limited growth potential. They are comprised of histologically and radiographically normal bone. Osteomas are classified as central, peripheral or extraskeletal according to the location. Clinically, peripheral osteomas (PO) are unilateral, sessile or pedunculated and have mushroom-like lesions ranging from 10–40 mm in diameter. Osteomas affecting the mandible are rare but are seen in young adults and usually remain less than 2 cm in size after years of slow growth. In this report a gigantic peripheral mass on the right mandible of a 25-year-old patient exhibiting clinical signs related to neoplasia is presented. The patient also suffered from an impacted canine tooth. The oral and maxillofacial surgeon and the dentist need to be aware of the components of this entity because manifestations in the head and neck including epidermoid cysts, osteoma, odontoma, exostosis, supernumerary and impacted teeth are common.