A Case of Torticollis in an 8-Month-Old Infant Caused by Posterior Fossa Arachnoid Cyst: An Important Entity for Differential Diagnosis.

Torticollis is a clinical diagnosis with heterogeneous causes. We present an unusual case of acquired torticollis in an 8-month-old female infant with a large cerebellopontine angle arachnoid cyst. Symptoms resolved after surgical fenestration. Non-traumatic acquired or new-onset torticollis requires brain imaging, and posterior fossa lesions are an important entity in the differential for pediatric clinicians.