Nodular fasciitis (NF) is a benign reactive condition that typically presents as a solitary, rapidly growing subcutaneous nodule on the upper body. NF is most commonly seen in adults aged 20-40 years and has no sex predominance. Approximately 10% of cases arise in the pediatric population. A history of trauma to the affected site is the only known risk factor for the development of NF.

NF grows rapidly over a period of weeks. It may present with mild pain, discomfort, or soreness. Less frequently, sensory disturbances such as paresthesias, numbness, or radicular pain can occur if the nodule impinges on a peripheral nerve. NF nodules reach a maximum of 4-5 cm in diameter. They may be round or oval; white, skin-colored, or gray; and tender to touch. NF can present in any superficial soft tissue of the body, but it is most often encountered on the upper extremities (especially the volar aspect of the forearm) and the trunk (especially the chest wall and the back). In childhood, the head and neck are most frequently involved. More rarely reported locations include the oral mucosa, external ear, parotid gland, breast, and maxillary sinus.

NF is a benign proliferation of fibroblasts and myofibroblasts. It is most frequently seen histopathologically in a subcutaneous location. It may be centered along the fascial plane. Dermal, intramuscular, and intravascular variants are less frequently encountered.