Timely evaluation of shoulder pain in a teenager.

First rib lesions can present as musculoskeletal pain involving the shoulder and arm. Chronic musculoskeletal symptoms must be pursued in an adolescent. Plain radiographs remain an integral part of the diagnostic plan. While delay in the diagnosis of a benign rib lesion may not jeopardize the outcome, brachial plexus compression can result from an enlarging mass. The outcome can be worse if the lesion is malignant.