[Oncocytic cancers of the thyroid. Hürthle cell cancers]

Hürthle cell cancers of the thyroid have been a subject of debate for many years because it is difficult to differentiate between benign and malignant tumours. Diverse therapeutic strategies have thus ensued. Recent work describing the morphologic and biologic criteria for a more precise diagnosis have led to better therapeutic strategies. We report a series of 85 tumours of the thyroid with Hürthle cells including 19 Hürthle cell tumours (22%) operated between 1976 and 1994. Hürthle cell tumour represented 6.7% of 282 thyroid cancers operated during the same period. The mean age of the patients was 56.6 years (range 23 to 78 years) and 63% of the tumours were large > or = 4 cm (classed T3T4). Treatment was total thyroidectomy in 79% of the cases. 5-year survival was 58.3% and 25% of the cases had metastatic extension at the time of initial treatment. Hürthle cell cancer have now been recognized as a particular anatomic and clinical entity. They were formerly confounded with vesicular cell cancers but now have been separated into a single entity due to a poor prognosis, lack of response to radioactive iodine and high incidence of metastasis. The current histological criteria make diagnosis more precise and allow more logical treatment with total thyroidectomy. A few familial cases have been reported. Although less frequent than in medullary cancer, this form would suggest that a genetic survey should be conducted for this particular type of thyroid cancer.