Unusual cause of painful shoulder in an elderly woman with rheumatoid arthritis.

The painful shoulder is a very common condition encountered in the rheumatology clinic with rotator cuff disorders, glenohumeral disorders, acromioclavicular joint disease and referred neck pain being the most common causes. Other rare causes have to be considered in the presence of "red flag" indicators. We describe a case of a patient with mild rheumatoid arthritis and a past medical history of stage 2C epithelial ovarian carcinoma who presented to the rheumatology clinic with a painful shoulder and who was initially diagnosed with rotator cuff tendinopathy. When seen 3 months later she was found to have a 15 x 10-cm firm, non-tender soft tissue mass over the right scapula and X-rays showed a large lytic mass destroying much of the upper border of the scapula, suggestive of metastasis. Bone metastases in patients with ovarian carcinoma are very rare; they occur in about 2% of cases and are invariably predictors of poor prognosis. To our knowledge, this is the first case of ovarian cancer metastasised to the scapula. We suggest that rheumatologists should be aware of the differential diagnosis of painful shoulder and look for "red flag" indicators in patients with known rheumatic conditions.