Pseudotumor of infancy and congenital muscular torticollis.

Pseudotumor of infancy presents as a discrete, firm mass in the distal sternocleidomastoid muscle in infants two to four weeks of age. Congenital muscular torticollis may develop from the resultant fibrosis in 10 to 20 percent of cases. Hip dysplasia is an associated feature of congenital muscular torticollis in approximately 10 percent of cases. Pseudotumor of infancy must be differentiated from other causes of cervical soft tissue masses. Diagnostic choices include fine-needle aspiration biopsy, cervical radiography, ultrasonography, computed tomographic scanning of the head and neck, and magnetic resonance imaging. Left untreated, congenital muscular torticollis may lead to significant craniofacial asymmetry and scoliosis. Heat, massage and passive stretching exercises are the preferred initial treatments for pseudotumor and torticollis. More than 70 percent of patients will respond to this approach. Surgery should be reserved for treatment of cases that persist past the first year of life.