Endocrine Abstracts

The vast majority of thyroid cancers are solid. Predominantly cystic tumors occur in <3% cases. Guidelines report as US characteristics consistently associated with a higher risk of malignancy eccentric position of the solid component, acute angle interface and microcalcifications and as less robustly associated lobulated margins and increased vascularity of the solid portion. We reviewed the US characteristics of predominantly cystic papillary carcinomas confirmed on histological analysis diagnosed at our institution in 2021. The patients had no identifiable clinical risk factor for malignancy. Ultrasound evaluation: Patient 1, 49 y.o. female: predominantly cystic 15 mm nodule with a 5 mm eccentric mixed isoechoic and hypoechoic solid component with irregular margins and hyperechogenic foci, on the isthmus. Histology confirmed 12 mm PTC, pT1b(s)NxMx. Patient 2, 30 y.o. male: predominantly cystic nodule with 61 mm on the right lobe, with an isoechoic solid component with irregular margins and an area of thick wall with hyperechoic foci. Histology confirmed the rare macrofollicular encapsulated variant of the PTC with 50 mm, pT3 NxMx. Patient 3, 42 y.o. male: A solid hypoechoic nodule with lobulated margins and hyperechoic foci with 29 mm on the isthmus and a predominantly cystic nodule with a solid lobulated hypoechoic component with hyperechoic foci that showed increased sign on color-doppler on left lobe. Histology confirmed a 25 mm PTC, pT2(s)N1aR2. All patients had a single mixed supra-centimetric nodule. Margin irregularity or lobulation, microcalcifications and eccentric position of the solid component were present in all three. In all cases the nodules had more than one suspicious feature on US, but not all were described in the US report. US image review is crucial in thyroid nodule evaluation as it alerts the clinician and enables identification of at risk patients to be selected for timely and proper treatments.