Incidence of thyroid carcinomas in an extended retrospective study of 526 autopsies.

Thyroid cancer accounts for 1% of all malignancies, and is becoming increasingly common worldwide. The literature reports a prevalence of ~50% of thyroid nodules detected during autopsies in subjects with unknown thyroid pathology. An extended retrospective study of 526 autopsy cases was performed to identify the prevalence of thyroid carcinoma, among various types of thyroid nodules identified incidentally. Tissue samples were taken from thyroid nodules, for investigation of the presence of thyroid carcinoma, along with their macroscopic and microscopic features by means of histopathology and immunohistochemistry (IHC) methods. Histopathological diagnosis of malignancy was found in 51 cases of analyzed thyroid samples. Systematic detailed studies demonstrated that a thyroid gland, apparently normal on macroscopic examination, may be the site of pathological manifestations, sometimes presenting carcinomatous findings. Among thyroid carcinomas, the highest frequency was that of papillary microcarcinomas, which have a long evolution, and are incidentally detected during autopsies. Papillary microcarcinoma is an extremely common incidental finding and the vast majority of these tumors pursue a benign course. Furthermore, it is therefore necessary to create national screening programs for the early detection of thyroid carcinoma.