Nodular fasciitis.

Nodular fasciitis is a benign proliferation of fibroblasts and myofibroblasts in the subcutaneous tissues. The lesions are generally small and solitary, arising commonly in the upper extremities of adults and in the head and neck region of infants and children. A history of trauma may precede these reactive lesions, but their cause is unknown. The rapid growth, abundant cellularity, and mitotic activity frequently cause these lesions to be misdiagnosed as sarcomas. Local excision is the treatment of choice for these generally nonrecurring lesions. A case report, differential diagnosis, and review of the literature are presented. Physicians need to be aware of this clinical entity and to work closely with pathology consultants in confirming this difficult diagnosis.