Primary malignant tumours associated with thyroid carcinoma in autopsy material.

In our Department 37,504 autopsies were performed in the last 30 years. Double multiple primary malignant tumours were found in 385 cases (4.2% of the cases with malignant tumours). In thyroid cancer cases, tumours of other organs were more frequent (20 cases, 22.7%), and these tumour associations were observed mainly simultaneously; there were no significant sex differences. In the more frequent synchronous cases, the thyroid cancer was a tumour only accessory to other malignancies; in the rarer metachronous cases, the thyroid cancer was secondary to postoperative irradiation of the first tumour (4 of 5 cases). Thyroid cancers were seen most frequently together with lung, breast and digestive system tumours; there was no special association recognizable to certain other malignancies. Follicular carcinoma was more frequent among the cancers associated with another tumour (12 of 20 cases), while in general the papillary was the most frequent type (48 of 88 cases).