Endocrine Abstracts

Thyroid cancer in patients with hyperthyroidism is considered to be a rare event and its course seems to be more aggressive in patients with Graves’ disease. The coexistence of medullary thyroid cancer and hyperthyroidism is very rare and there are only 14 cases reported in the literature.

The aim of this retrospective study is to assess the clinical and histological characteristics and the evolution of thyroid cancer in patients with different types of hyperthyroidism.

Patients/Methods: Among 652 patients with thyroid cancer, 52 (11 males and 41 females), with mean age 51±13 years, were operated because of hyperthyroidism between 1988–2004, due to: toxic multinodular goiter 26(5%), toxic adenoma 19(36.5%) and Graves’ disease 7(13.5%). Pathology revealed differentiated thyroid cancer (DTC) in 49 patients (94.2%) and medullary Ca in three (5.8%). The tumor was multifocal in 15/52 patients (28.8%) and bilateral in 5/15 (33.3%) and its size ranged from 0.2–6 cm. Extrathyroidal disease was observed in 6/26 with multinodular goiter, 5/7 with Graves’ disease and 3/19 with toxic adenoma. After surgery, 25 patients received ablation therapy with radioactive iodine ¹³¹I. The mean duration of follow up was 50 months. During follow up 4 patients presented with local reccurence or multiple metatastases (1 with medullary and 3 with DTC). Two of these patients had a history of multinodular goiter and 2 of toxic adenoma. None of our patients with Graves’ disease presented with local reccurence or metastases.

Conclusions: Thyroid cancer may occur in any type of hyperthyroidism. Its course was not found more aggressive in patients with Graves’ disease. The coexistence of medullary thyroid cancer and hyperthyroidism is not a rare event. Given the coexistence of both diseases, we recommend surgery instead of radioiodine treatment, mainly in patients with suspicious nodules.