Introduction: Fibro-osseous lesions are benign neoplasms characterized by the replacement of normal bone by fibrous connective tissue containing newly formed mineralized material. They are mainly classified into three different types, whose clinical and histopathological specificities are extremely close, thus bringing greater difficulty to their differentiation. It is commonly diagnosed in women during the fifth decade of life and its treatment varies from non-invasive clinical monitoring to surgical excision of the lesion. The purpose of this study is to describe a case report that brings the technique of hemimaxillectomy as effective surgical management in the treatment of fibro-osseous injuries. Case Report: It is a male patient, 14 years-old, melanodermic, who went to the service of Oral and Maxillofacial Surgery with edema in the posterior region of the right maxilla, clinically painless on palpation and with approximately five years of evolution. Panoramic radiography showed a radiopaque lesion involving the right maxilla, extending from the alveolus to the infraorbital ridge and maxillary tuberosity. The treatment of choice was surgical in order to avoid the continuous development of the pathology and further damage. The patient was submitted to general anesthesia to perform a surgical resection with safety margins. In the postoperative period, he evolved without the presence of phlogistic signs and after one year, a control radiograph was requested, showing satisfactory bone healing with absent recurrence. The patient was referred to the prosthesis sector where he could receive the necessary treatment for his complete rehabilitation. Conclusion & Significance: The study of fibro-osseous lesions is of great importance in science since the success of the treatment depends on early diagnosis for the institution of the correct therapeutic conduct. A pediatric patient, as reported in the present study, requires an immediate surgical approach to prevent devastating physical and psychological consequences.