[382] Utility of Thyroglobluin Rinse Levels as an Adjuct to FNA of Neck Nodules in the Evaluation of Metastatic Papillary Thyroid Carcinoma

Julie A Jackson, Michael W Riben, Beverly C Handy, Nancy P Caraway. MD Anderson Cancer Center, Houston, TX

Background: Ultrasound (US) is often used to evaluate patients (pts) for metastatic or recurrent papillary thyroid carcinoma (PTC) of the neck. US-guided fine needle aspiration (FNA) of abnormal nodules is often diagnostic of disease; however, in some instances lesions are small or cystic yielding insufficient number of cells for diagnosis. This study evaluates the utility of measuring thyroglobulin in the aspirate rinse (TG-r) as an adjunct to cytology in evaluating PTC pts for metastatic or recurrent disease.
Design: The pathology database was searched for pts with concurrent US-guided FNAs and TG-r levels performed from 2008-2012. There were 51 FNAs obtained from 45 pts (26 women, 19 men; age range: 20-79 years) meeting the study criteria. Of the 45 pts, 33 had a history of PTC, while the remaining had none. FNA sites included 41 non-thyroidal (25 cervical nodes, 3 supraclavicular nodes, 11 soft tissue, and 2 parotid glands) and 10 thyroidal (9 thyroid bed and 1 thyroid). Based on an ROC curve, 8ng/ml was chosen as a cutoff value for Tg-r (area under curve: .893 {95% CI, .780-1.000}). TG-r levels were correlated with the concurrent cytology diagnoses, subsequent histology, and clinical data.
Results: Of the 41 nonthyroidal FNAs, 27 had elevated TG-r levels, and the concurrent cytology diagnoses were positive for PTC in 7, suspicious for PTC in 6, atypical in 3, negative for PTC in 11. Of these, 20 showed metastatic PTC on subsequent excision or FNA, while 7 were followed clinically. Of the 10 thyroidal FNAs, 8 had elevated TG-r levels and the cytology diagnoses were suspicious for PTC in 1, atypical in 4, negative for PTC in 1 and nondiagnostic in 2. Four of these showed metastatic PTC on subsequent excision and 4 were followed clinically. There were 16 FNAs with nonelevated TG-r levels of which 4 showed PTC on excision, 4 showed no evidence of PTC, and the remainder were followed clinically. The mean TG-r level for cases with PTC on excision was 9365, versus 3 ng/ml for pts with no evidence of PTC on excision. The sensitivity and specificity for TG-r in all sites were 86% and 100%, whereas sensitivity and specificity of a positive/suspicious cytology was 63% and 100%, respectively.
Conclusions: TG-r levels are a useful adjunct to cytology in evaluating radiographically abnormal lymph nodes for metastatic PTC in selective cases, especially if cystic by US or paucicellular on FNA. Our data suggests that while a negative TG-r level does not entirely rule out PTC, markedly elevated levels in aspirates should prompt further investigation for recurrent PTC.
Category: Cytopathology

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 52, Monday Morning


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