Solitary neurofibroma of the maxillary sinus: Report of a case

Although neurofibroma frequently occurs as a local manifestation of von Recklinghausen's disease, solitary lesions in the oral and maxillofacial region are rare. Here, we describe an extremely rare solitary neurofibroma that arose in the maxillary sinus of a 41-year-old man. Panoramic radiography and a CT scan showed a slightly swollen maxillary sinus mucosa and a well-circumscribed cystic lesion suggesting a radicular cyst associated with a maxillary molar. The lesions were removed by radical sinusotomy under general anesthesia. A histopathological examination revealed that the nodular lesion of the sinus mucosa was not encapsulated and that it was composed of somewhat increased numbers of spindle cells accompanied by delicate hyperplastic fibers. These cells had flexed, wavy and linear spindle nuclei. Immunohistochemistry revealed that these tumor cells were positive for S-100 and neuron-specific enolase (NSE). A few spindle cells that were positive for α-SMA within the tumor were thought to be fibroblastic cells (myofibroblasts) derived from the endoneurium or surrounding connective tissue. These findings overall were compatible with the characteristics of neurofibroma. The cystic lesion was diagnosed as a radicular cyst. The patient remained free of tumor recurrence at 26 months of follow-up.