We report a case of benign fibrous histiocytoma, a rare lesion in the oral cavity, arising in the cheek. The patient, a 69-year-old woman, had noticed swelling in the right buccal mucosa for about 3 years and was admitted because the swelling had increased. Magnetic resonance imaging showed homogeneous enhancement of the mass in the cheek. The biopsy specimens were pathologically diagnosed benign fibrous histiocytoma, and the lesion excised. There has been no recurrence as of 5 years after excision. Macroscopically, the lesion was an encapsulated mass measuring 30×15×10mm with partial adhesion to muscle. Histological examination revealed mixed proliferation of histiocytic and fibroblastic cells without atypia. The lesion showed a polymorphous population of fibroblastic cells arranged in a vague striated and fascicular pattern. Histiocytic cells were positive for CD68, α 1-antichymotrypsin, and α 1-antitrypsin, and fibroblastic cells were positive for both α-smooth muscle actin and vimentin.
