Nodular fasciitis: a sarcomatous impersonator.

Reports of nodular fasciitis among adults are common; however, this condition is relatively rare in the pediatric population. Its clinical and histologic characteristics are similar to malignancies such as sarcoma; thus, it is prudent for the clinician caring for children and adolescents to be aware of the possibility of its occurrence. Nodular fasciitis is a benign mesenchymal tumor. Often presenting as a rapidly enlarging soft tissue mass, clinically, it can easily be mistaken as a sarcoma or other malignancy during clinical evaluation. In addition, the pathologist may recognize its high cellularity, high mitotic index, and infiltrative borders, which, as a result, may lead to erroneous diagnosis as a malignancy. Although more frequently seen in adults, it does occur in the pediatric population and should be considered during evaluation and treatment of soft tissue masses in children and adolescents.