Thorough examination of complete thyroid glands from 500 consecutive autopsies in a Swedish population revealed 43 primary thyroid carcinomas (8.6%). Thirty-two were papillary, seven follicular, and four medullary. All but three follicular carcinomas were less than 1 cm and clinically unsuspected. The prevalence of occult papillary carcinoma did not differ significantly between men and women and there was no definite increase in frequency with age in the age groups studied (40-90 years).
Cancer 47:319-323, 1981.
L-I HOUGH CLINICALLY EVIDENT thyroid carci-
A noma is rare, small "occult" thyroid carcinomas appear to be surprisingly frequent in thoroughly examined autopsy series. Comparable studies are still few in number but it is apparent from these that there are marked geographical differences in the occurrence of such tumors. The situation in Sweden has hitherto not been elucidated, so this study was undertaken to determine the prevalance of thyroid carcinoma with special reference to "occult" tumors in a Swedish population.
Materials and Methods
Thyroid glands were obtained from 5 10 consecutive autopsies performed at Malmo General Hospital during five months in 1979. Ten cases that had been subjected to thyroid surgery were excluded because resected parts of these glands were lost from the study. Furthermore, the diagnoses were not available in several instances. The distribution of the examined 500 glands by sex and age appears in Table 1.
The glands were weighed and fixed in 10% formalin. Enlarged glands were partially sectioned to obtain a good state of preservation, otherwise the glands were intact when fixed. After fixation the glands were cut at 1-2 mm intervals with a scalpel. Visible lesions were recorded in drawings and selected for microscopic examination. At least one histologic section was prepared from each lobe of macroscopically normal glands. Hematoxylin-erythrosin was used for routine staining. Suspected C-cell proliferations were first From the