Endocrine Abstracts

Introduction: The coexistence of hyperthyroidism and thyroid cancer is rare (below 2% of cases with hyperthyroidism). If this association predisposes to larger, multifocal or more aggressive cancer (especially in Graves’ disease) is a matter of debate. We describe the clinical and hystopathological aspects and evolution in two patients with hyperthyroidism and thyroid cancer.

Patient 1, a 42-year-old woman, was diagnosed in 2008 with Graves’ disease (overt hyperthyroidism, mild exophtalmos of the right eye, medium goitre with multiple nodules in the right lobe on ultrasound (1.1–1.7 cm, one 1.5 cm ill-delineated, hypoechoic, with small calcifications). TSH <0.03 mIU/l, high T₃ and T₄). She was treated with methymazole but lost to follow-up for 2 years. In 2011 she presents with overt hyperthyroidism and a large goiter, with a 4 cm ‘cold’ nodule in the right lobe with microcalcifications and internal vascularisation. She underwent total thyroidectomy and was diagnosed with multifocal papillary carcinoma: 3.3 cm in the right lobe, with capsular invasion, and 1.5 cm in the isthmus (‘follicular variant’). No metastases have been detected. The patient has received a total of 150 mCi I131 and is disease-free at 2.5 years of follow-up.

Patient 2, a 56-years-old woman, was diagnosed at the age of 35 with a thyroid nodule and then at the age of 56 with subclinical hyperthyroidism, normal TPOAb and a toxic nodular goitre with a 2 cm nodule with peripheral calcification in the right lobe and a 4 cm ‘hot’ hypoechoic nodule of in the left lobe. She underwent total thyroidectomy and was diagnosed with multifocal papillary thyroid carcinoma ‘follicular variant’: 2 cm in the right lobe, 0.1 cm in the isthmus and 0.2 cm in the left lobe. The large nodule in the left lobe was a follicular adenoma. No local metastases were found. The patient is planned to receive 100 mCi I131.

Conclusion: Although the occurrence of thyroid cancer in hyperthyroid patients is thought to be a rare event, the presence of a suspicious nodule in a hyperfunctioning thyroid should be carefully evaluated to exclude the presence of concurrent malignancy.