Prevalence and Malignancy Rates of Focal Thyroid Incidentaloma Detected By 18F-FDG PET/CT : Results of a Prospective Cohort Study

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 273
Philippe Thuillier, Nathalie Roudaut, Genevieve Crouzeix, Veronique Kerlan* and Pierre-Yves Salaun
Objective : To evaluate in a prospective study the prevalence and malignancy rates of focal thyroid incidentaloma (FTI) in a population of patients undergoing a 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography/ computed Tomography (PET/CT) for nonthyroid purpose.

Materials and Methods: From January 2013 to November 2014, patients with one or more FTI in PET-CT and who underwent cervical ultrasonography (US) +/- fine needle aspiration biopsy (FNAB) were included in the cohort. Grade of FTI uptake was quoted according to Deauville scale (DS). Diagnostic management and exploration results (US, cytological and histological data) were detailed.

Results: 131/10 118 FTI in 127 patients undergoing a PET/CT were detected (1.3%). Ninety-two (70.2%) FTI were explored by US and 60 (46%) by US + FNAB. Malignancy ratio of FTI explored by US + FNAB and / or surgery was 16.6%. 19 of 92 FTI (20.6%) underwent surgery with 10 malignant lesions (6 papillary thyroid carcinoma). Unexplored patients were more often affected by a metastatic neoplastic disease (p=0,041) and FTI classified 4 or 5 on DS were more explored than FTI classified 2 or 3 (p = 0.005).

Conclusion: Our study is to our knowledge the only French prospective study focusing on the FTI in PET-CT. Malignancy rate in our cohort (16,6%) is lower than described in the literature. Futhermore, in our study, FTI with lower uptake (2 or 3 on DS) and patients with an advanced neoplastic disease are less explored.

Nothing to Disclose: PT, NR, GC, VK, PYS

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