Desmoid-Type Fibromatosis of the Tongue

Desmoid-type fibromatosis rarely occurs in the oral tongue. Diagnostic imaging, including ultrasound, is useful for delineating the extent of the lesion and can aid in treatment planning. However, definitive diagnosis is made based on the characteristic histologic features, which include cytologically bland spindle cells with surrounding collagenous matrix and minimal mitotic activity. Immunohistochemical analysis of these lesions reveals that they are classically positive, at least focally, for smooth muscle actin, calponin and muscle-specific actin. These features are exemplified in this sine qua non radiology-pathology correlation article.