A rare case of intraoral nodular fasciitis: diagnosis and immunohistochemical profile.

Nodular fasciitis is a benign, idiopathic, reactive proliferation of myofibroblasts found in the subcutaneous fascia; intraoral occurrence is very rare. An 18-year-old woman was referred to the oral diagnosis service with a 1-month history of a nodular mass in the gingiva. Clinical examination disclosed a well-circumscribed, mobile, pedunculated mass in the left mandibular gingiva. The clinical diagnoses included pyogenic granuloma. She underwent an excisional biopsy under local anesthesia through an intraoral approach. Microscopic examination showed a proliferation of spindle cells arranged in intersecting fascicles. The spindle cells exhibited plump, vesicular nuclei without significant pleomorphism. Scattered multinucleated giant cells also were present. Immunohistochemical stains showed that the lesional cells were positive for smooth muscle actin and vimentin and negative for S-100 protein. The features were those of an inflammatory, benign myofibroblastic lesion, consistent with intraoral nodular fasciitis.