Aya Kamaya MD, Presenter: Nothing to Disclose

Gloria Huang Lewis MD, Abstract Co-Author: Nothing to Disclose

Christina Kong MD, Abstract Co-Author: Nothing to Disclose

Terry S. Desser MD, Abstract Co-Author: Royalties, Amirsys, Inc

To determine whether radiologists’ assessment of thyroid nodules can predict malignancy following a cytologic diagnosis of atypia of uncertain significance (AUS) or follicular lesion of undetermined significance (FLUS).  

Patients with initial diagnosis of AUS or FLUS on fine needle aspiration (FNA) were evaluated. Ultrasound images of the thyroid were reviewed by two board certified radiologists blinded to the final pathologic diagnosis. When initial interpretation differed, consensus was reached with a second blinded review. Lesions were assessed in three ways: 1) Mayo Pattern Classification as “benign, indeterminate, or worrisome for malignancy,”2) scored on a scale of 1-5 based on radiologist assessment of likelihood of malignancy, and 3) given a final diagnosis of “benign” or “malignant.” 

126 patients with diagnosis of AUS or FLUS on FNA were identified. Of these patients, 41 had conclusive final pathologic diagnosis and diagnostic ultrasound imaging. Twenty one patients had benign histology, 16 were malignant, and 4 had incidental microcarcinomas (papillary cancer < 10 mm). Mayo score of benign was 100% accurate for benignity. Lesions with Mayo score of indeterminate were malignant 41% (11/27) and benign 59% (16/27). Lesions with Mayo score of malignant were malignant 91% (10/11) and benign in 9% (1/11) of patients. Radiologist binary classification of thyroid nodules as either benign or malignant showed 78% overall accuracy. However, when microcarcinomas were excluded from the analysis, radiologist assessment increased to 86% accuracy. Of the 26 lesions assessed as benign by radiologists, 20 were benign on final pathology, 4 were microcarcinomas, and 2 were malignant. Of 15 lesions assessed as malignant by radiologists, 13 were malignant (87%) and 2 were benign.  

Radiologist assessment of thyroid nodules in cases of AUS or FLUS is highly predictive of final pathology and can help determine management of thyroid nodules with this pathologic diagnosis. Lesions in which the radiologist was incorrect in prediction were very often considered to be indeterminate in sonographic characteristics.

The Bethesda System for reporting thyroid cytopathology (2009) created category III: AUS or FLUS, which often requires further invasive testing or surgery.

Kamaya, A, Lewis, G, Kong, C, Desser, T, Atypia of Uncertain Significance and Follicular Lesions of Undetermined Significance: Sonographic Assessment in the Prediction of Final Pathology.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13014852.html