[Clinical evaluation of the hot nodule on 99mTcO4- and 123I thyroid scintigraphy: correlation of scan appearance and histopathology].

Histopathology and scan findings of hot nodule on 99mTcO4- and/or 123I were correlated in 34 patients with thyroid nodules. In a series of 30 hot nodular lesions, 29 were either adenomas or benign nodules; however, one was proved follicular carcinomas histopathologically. And four patients were chronic thyroiditis without nodular lesions in the thyroid lobes, which were diagnosed pathologically and clinically. In 6 patients with palpable thyroid nodules, thyroid scans performed with both 99mTcO4- and 123I were compared. A discrepancy of the two types of scan existed in only one case. Subsequent surgery revealed no malignancy in this patient. From the results of 201T1 imaging of the thyroid gland in 30 patients with cold or hot nodules on either 99mTcO4- or 123I thyroid scanning, we found no distinct difference between the degrees of 201T1 malignant and nonmalignant tumors. It appears that 201T1 accumulation demonstrates only tumor volume and tumor cell viability in these subjects. From these results, it is confirmed that the functional heterogeneities exist in thyroid adenoma tissues as well as in thyroid cancerous tissues. Therefore, the development of the reliable techniques used to distinguish a benign from malignant lesion is indispensable.