The patient was 28-year-old female who was referred to our hospital with spontaneous pain in the right maxillary premolar region. Upon visiting a pediatric hospital, she was suspected of having Sotos syndrome because she was showing open bite, high-arched palate and congenital absence of permanent teeth, which are characteristic maxillofacial findings for Sotos syndrome. Imaging findings showed impaction of the right second premolar and a cystic lesion around the crown. We performed a cystectomy and the impacted right second premolar extraction under general anesthesia. The histopathological diagnosis was dentigerous cyst. The patient had previously undergone an orthodontic examination at our hospital at the age of 10, however this disease was not suspected at the time. It is important to spread awareness of Sotos syndrome and contribute to diagnosis and treatment in collaboration with other departments.