Multinucleated giant cells in plantar fibromatosis.

Specimens from 13 patients with plantar fibromatosis were reviewed with particular attention to the presence and number of multinucleated giant cells in the lesions. These were found in all specimens but one and ranged from very few to many. The nuclei of the giant cells were uniform, rounded to somewhat elongated, and arranged in circles, semicircles, ovals, clusters, chains, and V's. Aside from the giant cells, the lesions were composed of the usual uniform fibroblastic spindle cells. The growth pattern was almost always multinodular, with nodules having moderate to high cellularity. Maximal mitotic rate varied up to more than 10 mitotic figures per 10 high-power fields but was most often between 1 and 4 mitotic figures per 10 high-power fields. The patients were from 10 to 66 years of age; nine were male and four were female. Two had bilateral involvement. Five patients had recurrence, including three with multiple recurrences, and all but one of the remainder had only short follow-up. Judging from the available data, recurrence did not appear to be related to any specific clinical or pathologic feature.