ULTRASOUND AND MR-IMAGING OF FIBROMATOSIS COLLI (STERNOMASTOID TUMOR OF INFANCY)

The sonographic and CT findings of fibromatosis colli (sternomastoid t umor of infancy) have been described, but the MRI appearance has been reported in only one case in which the mass resolved over time. This c ase describes the detailed MRI findings in a biopsy-proven case of fib romatosis colli; the signal intensity of the mass on T2-weighted image s was slightly less than on gradient-recalled T1-weighted images, cons istent with the presence of some fibrous tissue within the muscle mass . The involved portion of the muscle was better defined on MRI than so nography. MRI was helpful in demonstrating the signal characteristics of the mass; localizing the mass to within the sternocleidomastoid mus cle; and demonstrating clear surrounding fascial planes with lack of a ssociated lymphadenopathy, airway compression, vascular encasement, bo ne involvement or intracranial/intraspinal extension associated with o ther neck masses.