B.M. Dobyns and B.A. Hyrmer: Thyroid Neoplasms and Hydrogen Bomb Fallout 137 tissue. Some lesions metastasize although they may appearto the largest lesion that had given rise to the metastases. Emphasis on the occurrence of multicentricity seems to have passed with the decline in the use of external irradiation to the neck (40, 41]. Total thyroidectomy for multicentric papillary lesions was thought to be appropriate by some authors[32, 33, 37, 38, 41-43, 44], but the occurrence of complications in the hands of some surgeons and the indolent nature of the disease caused a decrease in interest in total thyroidectomy [34, 40, 41, 45]. Although 36 years have passed, the final story on these surgical fallout in a population. told. Most of these thyroid carcinomas, like those found else- produit pendant les essais atomiques 4 Bikini dansle Territoire Trust des Iles du Pacifique. Des débris radio-actifs sont tombés sur les atolls inhabités des Iles Marshall aprés la détonation cases and on the remaining exposed individuals has not been where in the world, are a very low degree of malignancy. As shown by annual examinations and routine diagnostic chest x-ray films, there has been no recurrenceof carcinomathusfar. Although wide removal of the deep jugular and upper mediastinal nodes was donein most cases of carcinoma, somepositive lymph nodes may have been missed andare now inaccessible to physical examination. The fact that a lesion in question had been widely removed or thought not to have spread was no guarantee that the lesion did not have the potential to spread or might still appear. There has not been full agreement about the natureof the lesions in 2 of the 3 cases that were reoperated for regrowth. The lesions from the first operation in those cases were considered atypical adenomas and were probably not carcinoma. A minority considered the lesions from the second operations to be locally malignant. It seems that, where the be benign. This series of observations over many years represent the sequential developmentof thyroid neoplasms, resulting from a single simultaneous exposure to radioiodines from Résumé Le 1 mars 1954, un accident de retombée radio-active s'est d’un énorme appareil thermonucléaire, en raison d’un change- mentinattendu des conditions climatiques. Juste aprés la détonation, une surveillance militaire aérienne et maritime a permis de suivre les déplacements de la portion la plus chaude du nuagé parabolique. Celui-ci s’est déplacé vers |’est et le sud-est tout en diminuant d’intensité et en se dispersant. Le centre du nuage radio-actif est passé au nord de l’atoll Rongelpa, atoll peuplé le plus prés. Cet article rapporte le développementdes lésions thyroidiennes, les conditions particuliéres et les résultats de la chirurgie des lésions bénignes et malignes de la thyroide rencontrées dans cette population dans les suites de cet accident. irradiated thyroid tissue remains, neoplasms maystill develop. Resumen Summary En marzo 1 de 1954 sucedié un grave accidente de contaminacién en el curso del programa de ensayos atémicos de los EUA en Bikini en el Pacffico. Después de la detonacién de un gran Radiation from radioiodines produced benign and malignant neoplasms in some Marshallese who were accidently exposed to fallout. Thorough annualstudy of each of 245 exposed person has been accomplished over37 years or within their natural life time. More than 1000 other Marshallese have served as various controls. Seventy-seven irradiated and control cases have been operated for thyroid masses. In 8 of 23 cases of carcinoma, the disease had spread to lymph nodes. Five of the 8 primary lesions that spread were 1 cm or less in diameter. Minute multicentric carcinomas and atypical adenomas were foundin addition to adenomas, presumably because the whole thyroid was at risk. Total or very near total thyroidectomy was the preferred procedure when carcinomais present or suspected. There have been no recurrences of carcinoma; no disfigurement; no recurrent laryngeal nerve injuries; and no deaths related to surgery. There has been 1 case of postoperative hypoparathyroidism and another asymptomatic hypocalcemia which only becamedetectable 20 years after surgery. When neoplasms might be expected from radioiodines in fallout, repeated meticulous examinations of the thyroid are required because some small lesions may metastasize early. Since multiple carcinomas have been found along with atypical adenomasin the irradiated glands and there has beendifficulty distinguishing between the two, the observations in this study suggest that atypical lesions may eventually develop frank histological features of carcinoma and have a potential to metastasize. Furthermore, an interpretation of descriptive an- atomical features of a thyroid neoplasm doesnot alwaysreflect the physiological and behavioral processes going on in that artefacto termonuclear, un inesperado cambio en la direccién de los vientos causé el depdsito de desechos radioactivos en varios islotes habitados en las Islas Marshall. En la fase inmediatamente siguiente a la detonaci6n, el seguimiento militar, marino y aéreorastreé la porcién mas ‘‘caliente’’ de la nube parabolica en la medida que se movilizaba en un patrén de decreciente concentracién hacia el este y hacia el sudeste de Bikini. El centro de la nube pas6 al norte del islote Rongelap. queera el islote habitado mds cercano. El presente informe se refiere al desarrollo de lesiones tiroideas, las circunstancias especiales que fueron encontradas en el curso dela cirugia y los resultados de! manejo quinirgico de la lesiones benignas y malignas halladas en esta poblacion. Se realizé el estudio anual de 245 personas expuestas, en el curso de 37 afios o en el curso natural de su vida. Se han operado 77 personas irradiadas y personas control por la presencia de masastiroideas. En 8/23 casos de carcinoma se hallé extensién ganglionar. También se encontraron pequefios carcinomas multicéntricos y adenomas atipicos, ademas de adenomas, presumiblemente debido a que toda la glandula estuvo en riesgo. Se realizé tiroidectomiatotal o casi total como procedimiento de eleccién, sin mortalidad ni complicaciones mayores. Se presento un caso de hipoparatiroidismo postoperatoria y otro de hipocalcemia asintomatica, detectada solo 20 afios después de la cirugia. Esta serie presenta el desarrollo secuencial de neoplasias tiroideas comoresultado de una ex- posicién unica a radioyodosa partir de la contaminacion de una poblacién.