A case of proliferative fasciitis in the abdominal region.

A 20-year-old woman complained of a subcutaneous nodule accompanied by spontaneous pain and tenderness in the right hypochondriac region approximately two weeks prior to initial evaluation. The spontaneous pain and tenderness gradually worsened. Histopathological examination revealed a proliferative lesion that extended from the deep dermis to the fatty tissue and consisted predominantly of stellate or spindle-shaped fibroblast-like cells intermingled with gangliocyte-like giant cells. Consequently, proliferative fasciitis was diagnosed. Our investigation revealed only 19 cases of proliferative fasciitis reported in Japan. The overall age range of them is 20 to 75 years (mean, 57.6 years). The lesion site in them is the head and neck in 10%, the trunk in 30%, and the extremities in 60%. It follows that the extremities are predominantly the site of proliferative fasciitis, and truncal lesions are relatively rare. It is rare for proliferative fasciitis to occur at a young age or in the abdominal region. We therefore examined the differences between proliferative fasciitis and similar disorders, namely proliferative myositis and nodular fasciitis, based on summaries of cases reported in Japan.