Solitary fibrous tumor of the tongue

A rare case of solitary fibrous tumor occurring in the tongue is described. An 80-year old woman presented with a slow-growing painless mass in the apex of the tongue. Under a clinical diagnosis of benign tongue tumor, surgical excision was performed. The tumor was a submucosal well-demarcated mass of two centimeters in diameter. Microscopically, spindle-shaped tumor cells were haphazardly arranged in sheets, fascicles or whirling patterns with thick collagen bundles and marked capillary proliferation. Immunohistochemically, tumor cells were positive for vimentin, CD34 and Bcl-2, but negative for EMA, CD99 and S-100. Some tumor cells were positive for smooth muscle actin and also for angiogenic factors, such as VEGF, bFGF and their receptors, suggesting strong inclination to angiogenic differentiation. Although the tumor showed few signs of malignancy, a high labeling index of p53 was noted, implying a potential for malignant transformation.