Thyroid neoplasia in beagles receiving whole-body irradiation during development

Twenty malignant and 17 benign thyroid neoplasms have been diagnosed in 37 Segment III beagles. Nine males and 8 females had follicular adenomas, and 7 males and 13 females had thyroid carcinomas. The dogs ranged in age from 5.16 to 10.66 years. Twenty-nine of the 37 dogs (78.4 percent) were hypothyroid. Twenty-six (70.3 percent) dogs were irradiated. Of the 26 irradiated dogs 15 had malignant tumors. Fourteen (37.8 percent) of the 37 dogs had the same sire