R.TAN1, S.C.LOKE1, B.M.MANISH1, K.A.AMIT1, J.P.N.GOH1, J.Y.J.GAN1, E.W.Z.FU1, J.S.H.WONG1, T.W.T.HO2, M.Y.LIM1, H.LI1
Tan Tock Seng Hospital1, Mt Alvernia Hospital2
Because follicular thyroid carcinoma (FTC) has a higher mortality rate than that of papillary thyroid carcinoma, how not to miss FTC during the evaluation of thyroid nodules deserves consideration. Previous studies compared the sonographic characteristics of FTC with benign nodules arising from different patients. We sought to reduce the effect of confounders by comparing the sonographic features of FTC with benign nodules arising from the same patient.
Retrospective review of the electronic medical records of all patients diagnosed with follicular carcinoma on thyroidectomy in a tertiary general hospital in Singapore between 2009 and 2016. Univariate and multivariate conditional logistic regressions were used to compare the sonographic characteristics of FTC with that of the benign nodules.
21 out of 55 patients with FTC had coexisting benign nodules. On multivariate analysis, FTCs were associated with internal vascularity [p=0.009, odds ratio:49.568 (2.664-922.196)], marked hypoechogenicity [p=0.024, odds ratio: 341.8 (2.124-54993.22)], and microcalcifications [p<0.001, odds ratio 124201.5 (739.658 – 2.09e+07)], but microcalcification was only present in 10% of the FTCs. FTC was associated with a large size [mean of 32.5 vs. 8 mm, p=0.010, OR 1.07 (1.02-1.13)] on univariate analysis but not on multivariate analysis. No significant difference in sonographic features was found between the subtypes of FTC.
Internal vascularity and marked hypoechogenicity suggest a likelihood of FTC in thyroid nodules. Large size is not independently predictive of FTC. Incorporating internal vascularity into the risk assessment risk of thyroid nodules should be considered.