Plexiform neurofibromas are peripheral nerve sheath tumors associated with neurofibromatosis type 1. The maxillary sinus is an extremely rare location of the plexiform neurofibroma and only two adult cases have been previously reported. We report the first case of plexiform neurofibroma of the maxillary sinus occurring in a child with neurofibromatosis type 1. This unusual location presents a management challenge considering the infiltrative nature and the potential malignant degeneration of this type of tumor. MRI is highly valuable to diagnose and plan the surgical approach of the plexiform neurofibroma of the maxillary sinus. Due to the location of the tumor and the patient's age, conservative surgery is highly recommended. We performed an endoscopic total en-bloc resection of the tumor with no recurrence after nine months of follow-up.