Fibrous tumor of infancy--report of a case originating in the oral cavity

A fibrous tumor of infancy of the floor of the mouth is reported. The tumor was characterized by congenital occurrence, deeply infiltrating, dense immature fibroblastic cells, focal chondroid differentiation, rapid new growth 3 years following irradiation and no recurrence 6 years after incomplete excision. The diagnosis of an aggressive infantile fibromatosis or juvenile fibromatosis, differentiated fibrosarcoma type, was considered to be the most acceptable.