Nodular fasciitis or pseudosarcomatous fibromatosis is a rapidly growing nonneoplastic soft-tissue tumor that is frequently located in the deep subcutaneous region or in the fascia. The most common locations for nodular fasciitis are the volar aspect of the forearm, the lower extremity, and the chest and back.

On sonography, nodular fasciitis can show a single or several, rapidly-growing, well-defined, isoechoic to hypoechoic nodules with increased vascular flow in the deep portion of the subcutaneous fat layer.