Fibrosarcoma of the toe: a destructive lesion of the distal phalanx.

A rare case of well differentiated fibrosarcoma occurring in the left second toe is described in a 12-year-old boy who presented with a destructive lesion that had almost totally destroyed the distal phalanx, except for the epiphysis. Amputated specimens showed microscopic evidence of proliferation of uniform spindle cells arranged in both fascicles and a characteristic herringbone pattern with a small number of mitotic figures. This tumor did not show any specific immunoreactivity except for vimentin and had basic ultrastructural characteristics of fibroblasts and myofibroblasts. The tumor was treated by amputation at the middle phalanx level and had not recurred 3 years later. From the presenting radiographic features, some benign neoplasms and reactive lesions were considered in the differential diagnosis. Only results from the pathologic examination were useful in reaching a correct diagnosis.