Primary malignant tumors of the thyroid gland. Histology, age and sex distribution and pathologic correlations in 139 cases.

The classification proposed by Woolner et al. (1961, 1971) has been applied to 139 cases of primary malignant tumors of the thyroid gland diagnosed in one of the largest hospitals of Rome, Italy, over a period of 5 years, from 1977 to 1981. These cases come from 1418 patients with enlargement of the thyroid surgically treated at the 5th Surgical Clinic of the University of Rome. All the histologic slides were re-examined, and the pathology records were reevaluated. Of these tumors, 56.8% were papillary, 30.9% follicular, 9.3% anaplastic or undifferentiated, and 2.1% medullary. There was a female predominance in all age groups and for all types of tumors, reflecting a total female to male ratio of 1.9:1. Papillary carcinoma occurred most commonly in young and young-adult patients, follicular in the middle-age group, and anaplastic in the elderly. The extent of the primary tumor, the presence of regional metastases, and the association with other thyroid nonneoplastic diseases such as lymphocytic and Hashimoto's thyroiditis, and nontoxic and toxic goiter were also recorded. Multicentric tumors were found in 38.9% of cases principally represented by papillary carcinomas. Regional lymph node metastases were observed mainly in young patients, and no correlation was found between thyroid cancer incidence and other nonneoplastic thyroid diseases.