Proliferative fasciitis of the forearm: Case report with immunohistochemical, ultrastructural and DNA ploidy studies and a review of the literature

A case of prollferative fasclitis arising In the left forearm of a 56-year-old man was examined. The lesion was preceded by blunt trauma, measured 1.5 times 1.3 times 1.0 cm, was poorly circumscribed and appeared white to light gray on the cut surface. Light microscopic examinations revealed that spindle cells and giant cells with one or two nuclei and abundant basophllic cytoplasm ware arranged without any organized patterns In collagenous stroma. Ultrastructurally, well-developed rough endoplasmic reticulum separated by varying amounts of fine to course fibrillar materials was detected in the giant cells. Only vimentin lmmunoreactivity was detected In both spindle and gtant cells. The Ki-67 labeling Index of spindle cells was 35% but that of giant cells was less than 5%, and this reflects the quiescent or slow-growing features of these giant cells in proliferative fasclitis. DNA content of the calls, which was examined by Image cytometry, demonstrated diploidy In both spindle (DNA Index = 1.01) and glant (DNA Index = 1.09) calls.