Abstract: A 31-year-old male presented with a solitary subcutaneous nodule on the right forearm for five days with mild tenderness. High-frequency ultrasound examination found elliptical hypoechoic nodules in the deep dermis and subcutaneous tissues, with clear boundaries and a size of about 6.30 mm×6.23 mm×3.20 mm. Histopathological examination found a large number of spindle cells in the dermis and subcutaneous tissue arranged in bundles, collagen fibers hyperplasia, interstitial mucous-like changes, with a small amount of lymphocyte infiltration and erythrocyte exudation. The diagnosis of nodular fasciitis was made.

Key words: nodular fasciitis, high-frequency ultrasound