Proliferative fasciitis.

The clinical and pathologic features of 53 cases of proliferative fasciitis, a pseudosarcomatous process involving fascia and interlobular fibrous septa of the subcutaneous fat, were reviewed. In the reviewed material, the lesion affected adults exclusively, with a high incidence in patients older than 40 years (median 54 years). It involved most commonly the upper and lower extremities, and microscopically was characterized by a diffuse infiltrative fibroblastic growth intimately associated with multifocal proliferation of large basophilic cells, closely resembling ganglion cells--a microscopic picture akin to proliferative myositis. In 16 of the 53 cases, the lesion had been initially confused with sarcoma because of its rapid growth and its bizarre histologic features. Although the term "proliferative fasciitis" has been used in the past as a symptom for nodular fasciitis, it is suggested that it be limited to the lesion under discussion, in order to emphasize its close relationship to proliferative myositis. Followup information revealed a benign clinical course. Therefore, despite its rapid growth and bizarre microscopic appearance, the lesion is adequately treated by local excision, and there is no indication for radical surgery.