Anaplastic carcinoma of the thyroid presenting with hyperthyroidism
JE Dale1, J Watkinson2, MC Sheppard1 & JA Franklyn1
A 76-year-old lady developed a tender thyroid swelling following a fall at home. One month later she was admitted with acute dyspnoea, and increased pain and swelling in her neck. She was found to be hyperthyroid on endocrine testing: free T4 (FT4) 24.8 (9-20) picomoles/litre, free T3 (FT3) 8.1 (3.5-6.5) picomoles/litre and thyrotropin (TSH) 0.2 (0.4-5.5) mIU/litre. She also had a raised erythrocyte sedimentation rate (ESR) at 54 mm/hr. She was commenced on hydrocortisone and antibiotics with a presumed diagnosis of a thyroid bleed or thyroiditis. An ultrasound scan of her neck was suggestive of a solid right-sided nodule or haematoma and she subsequently had a CT scan, which demonstrated a solid thyroid mass and Tc99 thyroid scan, which confirmed a cold nodule.
She was referred to our thyroid clinic, where hyperthyroidism was confirmed: FT4 48 pmols/litre, FT3 13.1 pmols/litre and TSH < 0.01 mIU/litre. We performed a fine needle aspiration of her thyroid. Histological examination was consistent with acute thyroiditis, with acute inflammation, haemorrhage and occasional cellular atypia. There were no features diagnostic of malignancy, but clinical suspicion remained. She developed a left-sided deep vein thrombosis of her leg and was admitted for an open biopsy of her thyroid. This confirmed anaplastic carcinoma of the thyroid and she was referred to our palliative care team where she underwent palliative radiotherapy to relieve dyspnoea.
Anaplastic carcinoma of the thyroid rarely presents with thyroid dysfunction. It could reflect rapid tumour expansion causing compression of surrounding thyroid or local infiltration with tumour causing an inflammatory thyroiditis. This case demonstrates that hyperthyroidism and a negative fine needle aspiration do not exclude malignancy, and the value of open biopsy where there is strong clinical suspicion.