The impact of methodology on the reported prevalence of thyroid pathology: comparison of two autopsy series from Switzerland performed with different methods

To investigate the impact of methodology on the detection and hence reported prevalence of pathological findings in thyroids, in the geographic area of Kt. Thurgau in Switzerland, we used two different methods in two consecutive autopsy series of 420 patients. In series A, the thyroids were sliced unfixed and only suspect lesions were examined histologically. In series B, the thyroids were fixed in formalin and sectioned in a standardized manner. At least one specimen per lobe was taken for histological examination. Series A revealed that five patients had adenomas, four malignant primary tumors, two metastases and four inflammatory changes in the thyroid. Series B detected ten patients with adenomas, eight with primary malignant tumors, eleven with metastases and twenty-eight with inflammatory changes in the thyroid. These differences were significant (p < 0.001). In conclusion, the methodology has an important impact on the detected prevalence of pathological findings in the thyroid.