[Frequency of thyroid gland carcinoma in hyperthyroidism]

From 1980 to 1989, 226 patients (199 females, 27 males, median age 41 [18-76] years) underwent surgery because of clinical hyperthyroidism. 152 patients had autoimmune thyrotoxicosis, and 74 functional autonomy. Histological examination of resected thyroid tissue revealed carcinoma in 6 cases (2.6%): 3 (2%) in autoimmune hyperthyroidism, and 3 (4%) in functional autonomy. Five tumours fulfilled the criteria for occult papillary thyroid carcinoma (highly differentiated, less than 1.5 cm diameter). One woman had both a multilocular papillary carcinoma and a medullary carcinoma without proven metastases. In none of the cases was a malignant tumour suspected preoperatively from sonography or scintigraphy studies. In the patients with occult carcinomas, extended bilateral subtotal resection was regarded as curative. In the patient with papillary and medullary carcinoma, remaining thyroid therapy was given. One patient with Basedow's (Graves') disease and a papillary carcinoma of diameter 1.3 cm received radioiodine at her own request. She and the four remaining patients received suppression therapy (150-200 micrograms L-thyroxine daily), with frequent follow-up. During follow-up for a mean period of 24 months (range 6-51 months) there were no metastases or tumour recurrences.