Clinical and histopathologic review on 28 cases of nodular fasciitis

Abstract

Background: Nodular fasciitis presents as a solitary, slightly painful, rapidly growing nodule. It is associated with a reactive, proliferative process of unknown cellular origin and can be misdiagnosed as a sarcoma. Objective: Our study was designed to investigate the process and cellular origin of the disease. Methods: The clinical and histopathologic findings from 28 cases of nodular fasciitis were reviewed. Additional histochemical and immunohistochemical staining was done. Results: The mean age of onset was 29.8 years. A majority of patients with nodular fasciitis had a duration of symptoms of less than 6 months. The upper extremity and face were most frequently involved. Most of the lesions had diameters less than 2 cm. Total excisions were performed in 23 lesions; 3 lesions recurred thereafter. Histopathologically, a subcutaneous plane was most frequently involved. The nodule consisted of numerous large, pleomorphic fibroblasts growing haphazardly in a vascular stroma containing varying amounts of mucoid ground substance, which was confirmed by histochemical stains. In the immunohistochemical stain, most lesions had positive findings for smooth muscle actin (SMA), vimentin and negative findings for CD34 except in a few cases. The stains for desmin and S-100 were negative in all cases. Conclusion: It is suggested that nodular fasciitis is associated with a reactive proliferation of myofibroblasts rather than with a sarcomatous process. (Korean J Dermatol 2009;47(6):649∼657)