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Fibromatosis colli

Dr Henry Knipe and Dr Frank Gaillard et al.

Fibromatosis colli is a rare form of infantile fibromatosis that occurs within the sternocleidomastoid muscle.


There may be a slight male predilection. It typically presents a few weeks after birth.

Clinical presentation

Presentation is usually with torticollis, and is most frequently related to birth trauma (e.g. forceps delivery) or malposition in the womb. 


The importance of fibromatosis colli, above all else, is that it must be recognised for the benign lesion that it is. It is unilateral in most cases.

Radiographic features


Ultrasound is the imaging modality of choice. The sternocleidomastoid (SCM) is diffusely enlarged in a fusiform manner, with resultant shortening and therefore head turned away from the affected side (mastoid process drawn down towards the ipsilateral head of clavicle). Echogenicity may vary. Colour Doppler interrogation may reveal a high resistance waveform. The enlarged area often moves synchronously with the rest of the SCM muscle on real time sonography 1.


Typically shows a diffusely enlarged SCM that is isoattenuating to normal neighbouring musculature. Adjacent fat planes are well preserved. At times calcification may be present 2.

Treatment and prognosis

It is a self limiting condition and usually resolves within 4-8 months 3 and requires no more than physiotherapy.

Differential diagnosis

For a general differential see: differential diagnosis of paediatric cervical lesions.

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