A difficult case of inflammatory myositis

A 79-year-old lady presented with subclinical autoimmune hypothyroidism and proximal muscle weakness, which failed to respond to thyroxine. Subsequent electromyography and muscle biopsy confirmed polymyositis, which responded well to immunosuppressive therapy. She presented 4 months later with a thyroid carcinoma, most likely anaplastic, and died shortly afterwards. Although the association between malignancy and polymyositis remains controversial, to our knowledge this is the first report of thyroid carcinoma occuring in association with polymyositis and autoimmune hypothyroidism.