Synovial Cyst of Sternoclavicular Joint as Mediastinal Mass

Excerpt

The sternoclavicular joint is commonly involved in rheumatoid arthritis, but a synovial cyst of this joint has not been recognized as a clinical problem. We report here a patient with such a cyst, which presented as an undiagnosed anterior mediastinal mass and required thoracotomy for definition.

The patient, a 32-year-old housewife, had the onset of symmetrical arthritis 5 years ago. The disease progressed rapidly to most of her peripheral joints but was only moderately disabling and sporadically treated until 2 years ago, when she suddenly developed bilateral foot drop associated with paresthesias of the legs. Treatment with systemic corticosteroids in