Tumefactive fibroinflammatory lesion of the extremity. Report of a case and review of the literature. Tumefactive fibroinflammatory lesion is an idiopathic fibroinflammatory process of the head and neck region. Although benign histopathologically, it is invasive, destructive, and locally recurrent, leading to uncertainty regarding its proper management; as the disease is rare, determining optimal treatment is difficult, given the anecdotal nature of reports. We report the first case of a tumefactive fibroinflammatory lesion occurring outside the head and neck region. Our patient was treated with corticosteroids and had a favorable response, supporting this approach as initial treatment. Immunohistochemical studies performed on a pretreatment specimen were consistent with a secondary inflammatory component because no monoclonal nor aberrant phenotypes were detected. The tumefactive fibroinflammatory lesion appears to be indistinguishable from the other known idiopathic fibroinflammatory processes; patients presenting with any one of these should be evaluated for the others. 