Adult and infantile myofibromatosis: a report of three cases affecting the oral cavity.

Myofibromatosis is a rare but well recognized entity which was originally thought to affect only neonates and infants. It is now apparent however that adults may also be affected. Solitary cases affecting the oral cavity appear to be rare and only two cases of solitary lesions in adults appear in the literature. This report documents three solitary cases; two typical lesions in infants and a lesion from the tongue of an adult. The lesions were composed of small polygonal cells and large elongated cells in a scant fibrous stroma. The elongated spindle cells were identified as myofibroblasts by immunocytochemistry and electron microscopy. The lesions showed characteristic features which enabled them to be distinguished from other fibrous lesions and from benign or malignant smooth muscle tumors with which they have frequently been confused.