Endocrine Abstracts

Introduction: Many recent studies have shown that detection of an incidental thyroid cancer among patients operated for a toxic thyroid disease is not infrequent. We aimed to compare cytology and histopathology results of cold, warm and hot nodules in patients who had thyroidectomy due to toxic multinodular goiter (TMNG).

Methods: The cytology, histopathology and scintigraphy records of 1069 thyroid nodules from 413 patients who had operation with TMNG were reviewed in this study. The nodules were categorized as hypoactive (cold), normoactive (warm) and hyperactive (hot) groups according to scintigraphy. 0f 1069 nodules, 560 with undetermined scintigraphic activity were excluded. The cytology and histopathology results were compared.

Results: Of these 413 patients (118 men, 295 women), 23 (5.6%) had malignant and 390 (94.4%) had benign histopathology. In malignant group, 16 patients had papillary thyroid carcinoma (PTC), 3 had follicular thyroid carcinoma (FTC), 1 had an undifferentiated thyroid cancer (UTC), and 3 had thyroid tumors of uncertain malignant potential (TT-UMP). The 509 thyroid nodules were grouped as normoactive [n=23 (4.5%)], hypoactive [n=122 (24.0%)], and hyperactive [n=364 (71.5%)] according to scintigraphy. Cytological evaluations of 23 normoactive nodules were as follows: 7(30.4%) nondiagnostic (ND), 15(65.2%) benign, 1(4.3%) suspicious for follicular neoplasia (SFN). The cytology of 122 hypoactive nodules were ND in 25(20.5%), benign in 86(70.5%), atypia of undetermined significance (AUS) in 5(4.1%), follicular lesion of undetermined significance (FLUS) in 3 (2.5%), SFN in 1(0.8%), and finally suspicious for malignancy (SM) in 2 (1.6%). The 364 hyperactive nodules were determined as ND, benign, AUS, FLUS, SFN, SM, and malignant in 80 (22%), 259(71.2%), 10(2.7%), 7(1.9%), 2 (0.5%), 2 (0.5%) and 4 (1.1%), respectively. There were no differences according to cytological results between groups (P=0.616). Histopathology of normoactive nodules were PTC in 1(4.3%) nodule and benign in 22 (95.7%) nodules. However, 7 (5.7%) nodules had PTC and 1 (0.8%) nodule had FTC, 114 (93.4%) nodules had benign histopathology in hypoactive group. Histopathologies of the hyperactive group were as follows; 8 (2.2%) nodules with PTC, 2(0.6%) with FTC, 1(0.3%) with UTC, 3 (0.8%) with TT-UMP, and 350 (96.1%) nodules with benign pathology. There were no differences according to histopathological results between groups (P=0.905).

Conclusion: Recently, incidental papillary carcinomas originating from hot nodules have been reported. Contrary to conventional knowledge, we demonstrated similar malignancy rates in hot nodules when compared with cold and warm nodules.