Endocrine Abstracts

Thyroid cancer is rarely seen in the hyperthyroid patient.

We present the case of a 59 year-old lady who presented with marked weight loss of more than 30 kg in less than 6 months, lethargy, palpitations and sweats. Clinically she was obese and thyrotoxic with sweaty palms and a tachycardia. No goitre or neck masses were detected. Thyroid function tests confirmed thyrotoxicosis with free T4 89.1 pmol/l (Normal range 9.8–23.1), free T3 20.2 pmol/l (Normal range 1.8–6.8) and suppressed thyroid stimulating hormone (TSH) <0.01 miu/l (Normal range 0.35–5.5). A clinical diagnosis of autoimmune hyperthyroidism was made. The patient opted for treatment with radioactive iodine and a pertechnate thyroid uptake scan was performed. This demonstrated increased size of the thyroid and homogenous uptake consistent with Grave’s disease. However a focal area of increased uptake was also noted 5 cm below the left lobe of the thyroid. This was also demonstrated on whole body iodine scan following a treatment dose of radioactive iodine. In addition a further lesion was identified in the lower mediastinum and within the body of the tenth thoracic vertebrae. Ultrasound of the thyroid identified an abnormal 2 cm nodule within a multinodular gland. Total thyroidectomy and regional lymph node dissection was performed. Histology demonstrated papillary carcinoma of columnar/ tall cell type. A further dose of radioactive iodine was given.

In this case thyroid carcinoma was detected serendipitously. The diagnosis of thyroid carcinoma is infrequently considered in the presence of hyperthyroidism. When thyroid carcinoma is identified with concomitant hyperthyroidism there is typically a non-functioning cold nodule on uptake scan. In our patient very high uptake within the gland may have obscured the presence of a cold nodule. Only the presence of uptake in distant metastasis alerted us to the possibility of thyroid cancer in this patient.