Rapid involution of proliferative fasciitis
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- Kato, K., Ehara, S., Nishida, J. et al. Skeletal Radiol (2004) 33: 300. doi:10.1007/s00256-003-0738-6
A process of evolution and involution is a characteristic feature of reactive fibrous lesions, but has not been emphasized in either the radiology or pathology literature. We report a case of proliferative fasciitis, pseudotumorous fibrous proliferation similar to nodular fasciitis, showing evolution and involution during a 1-month period. A 35-year-old Japanese woman presented with a tender soft tissue mass in the forearm that had grown over a 2-week period. MR imaging revealed a soft tissue mass of nonspecific signal intensity on the muscle fascia. Needle biopsy revealed diffuse proliferation of fibroblastic spindle cells representing proliferative fasciitis. Two weeks after biopsy the mass had rapidly decreased in size, and the pain subsided. MR imaging obtained 1 month later demonstrated only minimal residual reactive change along the fascia. Conservative treatment may be a reasonable treatment option for this condition.
KeywordsForearmProliferative fasciitisSpontaneous regressionSoft tissue tumorMagnetic resonance imaging
Evolution and subsequent involution is typical of an inflammatory process, rather than neoplasm, with some exceptions. Spontaneous regression has been reported in malignant neoplasms, such as malignant lymphoma, melanoma and choriocarcinoma . Proliferative fasciitis is a pseudosarcomatous reactive proliferative lesion of soft tissue, similar to nodular fasciitis. It may grow rapidly, but rapid regression is rarely observed . In this paper, we describe the rapid regression of proliferative fasciitis along with a brief discussion.
Proliferative fasciitis occurs in adults between 40 and 70 years of age. About two-thirds of the lesions occur in the extremities, especially in the forearm and the thigh. They usually present as a firm palpable subcutaneous nodule that is movable and unattached to the overlying skin, and in most patients they grow rapidly for a few weeks . The histological findings closely resemble those of another pseudosarcomatous lesion described as proliferative myositis . Proliferative fasciitis, arising from the fascia, is a subcutaneous variant of proliferative myositis. The active proliferation of immature-appearing cells may lead to an incorrect diagnosis of sarcoma [4, 5]. The etiology of proliferative fasciitis is unknown. Although mechanical trauma has been implicated, a history of preceding injury is rare [3, 6].
Imaging findings of proliferative fasciitis have not been well discussed. Those of nodular fasciitis, a similar lesion, vary according to the subtype (myxoid, cellular, fibrous) and the location (subcutaneous, intermuscular, intramuscular) [7, 8].
Nodular fasciitis and proliferative fasciitis are known to be reactive fibrous proliferations with rapid growth, but descriptions of spontaneous involution are scarce. Particularly with imaging findings, the rapid evolution and involution as seen in this patient is only rarely observed. Surgical resection is an option for treatment, but is not indicated in lesions with rapid regression.
This type of involution and evolution is typical of an inflammatory process. Although it is not typical of neoplastic proliferation, it may be seen uncommonly in some neoplastic processes, such as malignant lymphoma . Follow-up policy should be based on the histology of lesion.