Neurofibroma is a benign peripheral nerve sheath tumor consisting of an admixture of Schwann cells, fibroblasts, perineurial-like cells, and axons. It is usually considered as a part of neurofibromatosis type-1 （von Recklinghausen disease）. Solitary neurofibroma is an uncommon tumor of the oral and maxillofacial region. A man in his 40s was referred to our hospital with the chief complaint of a mass in the right cheek. Physical examinations revealed a well-defined, elastic-soft, mobile, painless 25-mm mass in the cheek. Ultrasonography revealed a hyperechoic mass with clear borders, internal nonuniformity, and a low blood flow signal. Magnetic resonance imaging revealed that the mass was adjacent to the masseter muscle, and had a relatively homogenous and equal signal intensity with the muscle on T1-weighted image, and high signal intensity on T2-weighted image. The tumor was surgically resected under general anesthesia. Microscopic examination showed random rearrangement of spindle cell proliferation, and positive immunostaining for the S-100 protein and CD34. The tumor was diagnosed as a neurofibroma. Neither café au lait spots nor other tumors were observed on physical examination. The final diagnosis was solitary neurofibroma arising in the cheek. Three years after the surgery, the patient showed no signs of tumor recurrence.
