A case of familial sternocleidomastoid tumor of infancy

Sternocleidomastoid tumor of infancy (STOI) is a benign, firm, fibrous swelling predominantly involving the middle or inferior third of the sternocleidomastoid muscle. Patients may present simultaneously with, or progress to the development of, congenital, muscular torticollis (CMT) during childhood. This pseudotumor affects infants in their first few weeks of life with the vast majority showing complete regression over the ensuing few months. Multiple postulates have been presented as to the exact etiology of STOI; however, the cause is still unknown. Two siblings, both requiring vacuum extraction during delivery, presented at 4 weeks of age to the Children's Hospital of Philadelphia (CHOP) with STOI. The possible genetic predisposition of these siblings to develop STOI is hypothesized. Familial cases of CMT have been reported along with the possible genetic or peripartum factors that could play a role in its development. We reviewed these same mechanisms that could also predispose to familial STOI. Currently, magnetic resonance imaging is the diagnostic modality of choice. Fortunately, the majority of STOI responds to conservative measures with aggressive physical therapy, thus avoiding the need for operative intervention.