A rare cervical dystonia mimic in adults: congenital muscular torticollis (fibromatosis colli)

Congenital muscular torticollis (CMT), also known as fibromatosis colli, is recognized as unilateral contracture and shortening of the sternocleidomastoid (SCM) muscle due to muscle atrophy and interstitial fibrosis, causing ipsilateral head tilt and turn (Do, 2006). Its frequency ranges from 0.3 to 2% in newborns with history of perinatal injury, but it is far less common in adults, who are often misdiagnosed as cervical dystonia (Patwardhan et al., 2011). In cases recognized during adulthood, subtle torticollis may have been overlooked since infancy or become apparent in the second decade of life or later (Brans et al., 1996). We report two cases recognized in adulthood initially misdiagnosed as cervical dystonia, whereby standard antidystonic treatments were unrewarding but SCM release proved beneficial.