Abstract
A statistical study is presented of biopsies positive for thyroid tumors in the Department of Pathology of Hospital San Juan de Dios, San Jose, Costa Rica, during the period 1928-1953. Out of 37, 347 biopsies, 903 were positive for thyroid tumor, of which 874 (96.79%) were benign and 29 (3.21%) were malignant. Because of lack of yearly census data, all cases are referred to the 1950 census (it being necessary for our study to relate the number of cases to the total population) and this ratio is called the "conventional frequency". The various types of tumors are consid@red separately, including: a) Colloid adenoma. The number of cases considered is 760, of which 72 (9.48%) occurred in males and 688 (90.52%) in females. The progressive distribution, by provinces, as shown by the conventional frequency, is as follows: Puntarenas, Cartago, Limon, Heredia, Guanacaste, Alajuela, San José. The least number of cases of coUoid adenoma is found in Puntarenas most of whose inhabitants live by die sea, and in the two provinces on the Atlantic watershed. The ratio of women to men among patients is as 10:1. The lack of iodine in drinking water, the usual type of diet, and perhaps the scanty hardness of drinking water (mean for the Republic, 74,86 p. p. m., expressed as ca1cium carbonate) are considered the causes for endemic goiter in this country. Typical cases of cretinism and deaf mutism are sporadic in Costa Rica; the authors therefore believe our endemic goiter does not reach a toxic state sufficient to produce typical clinical pictures. Considering the mean temperature (20°C. for regions above 800 m., and 26°C. for coastal lowlands ) and the mean relative humidity (interior, 78%; coastal regions, up to 90 % ) the use of iodized salt is recommended in daily doses of 0.1 mg. of iodine, as approved by the International Conference for Endemic Goiter in London. b) Basedow's disease. The number of cases considered is 100, of which 92 were in females and 8 in males. The progressive distribution by provinces. as shown by the conventional frequency, is the followirig: Puntarenas, Guanacaste, Alajuela; Heredia, Cartago, Limon, San Jose. The highest incidence is in San Jose, where the capital is situated and life offers greater complexities, and in the Atlantic provinces. Dysthyroidism is not very frequent in Costa Rica, and most cases are basedowified col1oid adenomas. Women are more frequently affected than men, in a ratio of 11.5:1, and most cases were patients in full sexual activity. c) Other benign tumors. There were 8 cases of solid adenoma (0.91%), 3 ceses oE Hashimoto's thytoidit is (0.34%) and 3 cases of Riedel's thyroiditis (0.34%). All these patients were females. Patients with Bashimoto's and Riedel's thyroiditis ate equally distributed through the various age groups, so that neither may be held to be a precursory stage of the other, but rather thay must be considered as distinct diseases following parallel courses. In comparison with other published data, Hashimoto's thyroiditis is seen to be relatively rare in Costa Rica, while the incidence of Riedel's thyroiditis places us in second place among previously studied series. d) Malignant tumors. There were 29 cases of malignant neoplasy of the thyroid, or 3,21 per cent of the total of 903 thyroidectomies considered. Such a small incidence of malignant tumors in a country where there is such a high incidence of colloid goiter indicates that the latter can not be related to malignancy. The increase in the number of cases in recent years is thought to reflect the improvement in local diagnostic facilities. The female sex is more frequently affected; but proportionally to the number of benign cases in either sex, there is a greater tendency to malignancy among males. Patients were of all age groups. The histological type prevailing in our study was that of carcinoma.