Aims and background: The goal of the study was to report and discuss the neoplastic and non-neoplastic diseases of the thyroid gland present in a historical series of surgical material examined during the period 1945 to 1989 at the Pathology Department of the São Paulo University Medical School.
Methods: Records of 281,175 cases were reviewed to select those which affected the thyroid gland. The slides of these selected cases were analyzed and classified according to current terminology.
Results: Non-neoplastic lesions comprised 86.68% of the cases (n = 7024), and most of them were nodular goiter (n = 6458). Neoplastic lesions were divided into two groups: primary and metastatic. Of 1072 primary neoplasms, 530 were benign and 542 were malignant. Of the malignant neoplasms, papillary and follicular were the most frequent types (n = 201 and 187, respectively), followed by undifferentiated (n = 86), Hürthle (n = 46), medullary (n = 16) and others (n = 6). Of 8 metastatic neoplasms, 4 were from and undetermined primary epidermoid carcinoma.
Conclusions: We concluded that owing to the high incidence of neoplastic lesions (13.32%), half of which were malignant, examination of the thyroid gland should be done with strict criteria in view of the therapeutic and prognostic implications.