Head and Neck ImagingFibromatosis colli
most common type of
congenital torticollis, with the development of a soft tissue mass in the sternocleidomastoid muscle. Most patients are initially normal at birth, and present with a palpable neck mass and torticollis at 1 - 8 weeks of age. The mass results from
trauma to the muscle with
haemorrhage and subsequent
fibrosis. It may increase in size over a few weeks, stabilizes for a few months, and then resolves spontaneously.
Ultrasound shows an oval or fusiform homogeneous mass within the muscle, iso- or slightly hypoechoic compared to surrounding muscle.
The exact cause usually remains unknown; it may be due to intrauterine malposition or birth trauma.
RH