Fibrosis of the omohyoid muscle--an unusual cause of torticollis.

An 11-year-old boy had a left neck mass with torticollis. On exploration, a fibrotic mass in the superior belly of the left omohyoid muscle was found, which shortened the muscle and pulled the hyoid bone downward. Resection of the fibrotic muscle was performed. The patient recovered well after the operation with resolution of his torticollis.