A 60-year-old man noticed rapid enlargement of a long-standing thyroid
goitre, with dysphagia and difficulty in breathing. Thyrotoxicosis wa
s diagnosed. Chest X-ray revealed multiple pulmonary metastases. He un
derwent near-total thyroidectomy. The histopathology revealed an undif
ferentiated thyroid carcinoma with some areas of papillary carcinoma a
nd its follicular variant. Postoperative I-131 total body scan showed
residual thyroid tissue in the neck and one functioning metastasis in
the right rib, posteriorly. The patient's condition deteriorated rapid
ly and he died from pneumonia. The autopsy showed widespread metastase
s of undifferentiated thyroid carcinoma. Only the right rib contained
the follicular variant of papillary carcinoma.