Basal cell nevus syndrome (BCNS) is a rare autosomal dominant disorder with complete penetrance and variable expressivity. This syndrome is characterized by developmental anomalies, such as odontogenic keratocysts of the jaws, multiple basal cell carcinomas, and skeletal abnormalities. Various neoplasms or hamartomas were observed in association with BCNS.We report on a 45-year-old female patient who presented with a tumefaction of the right maxillary region. After correlating clinical, radiographic, and histological features, diagnosis of BCNS associated with squamous cell carcinoma of the right maxillary sinus was made. A surgical treatment was performed. Because of poor compliance and delayed healing, the postoperative radiotherapy was postponed. Three months after the procedure, the patient has developed symptoms of tumoral activity.This clinical report highlights the importance of early diagnosis of BCNS and strict follow-up to prevent severe complications such as squamous cell carcinoma.