High rates of false negative cytological diagnosis and incidental
multifocal microcarcinoma in solitary thyroid nodule and multinodular
goitre, justifying a preference for total thyroidectomy
Background: Our purpose was to detect false negative rate (FNR) of
preoperative cytology and prevalence of thyroid carcinoma in patients
who underwent total thyroidectomy for solitary thyroid nodule (STN) and
multinodular goitre (MNG). Cytology-histology discrepant cases were also
further evaluated. Methods: Database of 141 patients were conducted
retrospectively. Demographics, ultrasound (US) features with Thyroid
Imaging Reporting and Data System (TI-RADS), fine-needle aspiration
(FNA), histology reports, risk factors and malignancy rate were
recorded. Statistical analyses were performed using Fisher’s exact and
Mann-Whitney U tests. Results: Of the 43 patients with confirmed thyroid
carcinoma (30.4%), 21 had incidentalomas (48.8%). Even the prevalence
of carcinoma was higher in STN (39.2% vs 28.3%, p<0.001),
incidental cancers were more common in MNG (56.2% vs 27.2%,
p<0.001). While macrocarcinomas were significantly more
frequent and larger in STN (63.6% vs 21.8%, p<0.001; 2.4+1.9
cm vs 1.2+0.8 cm; p<0.001, each), microcarcinomas (≤1 cm) were
seen to be in higher ratio and smaller in MNG (56.2% vs 27.2%,
p<0.001; 0.48+0.34 cm vs 0.64+0.3 cm, p<0.05).
Multifocality was more significant in MNG (43.7% vs 18.1%). FNR in MNG
was higher than that of STN (15.9% vs 10.7%, p<0.001).
Indeterminate cytology was more frequent in MNG group (20.3% vs 14.2%,
p<0.001). Mean TI-RADS was 3 in each group
(p>0.05) and displayed mostly sampling errors (76.1%).
Family history and previous radiation treatment were more significant in
patients with STN (25% and 10.7%, respectively). 77.3% of patients
were from the endemic Black Sea Region. Conclusions: The risk of
malignancy in a presumably benign thyroid diseases should not be
ignored. Since both the FNR of cytology and the prevelance of malignancy
in STN and MNG are comparably high, other predictive factors of
malignancy should be evaluated in detail, especially in endemic areas.
Complete resection during the first thyroid surgery have a good outcome.