[331] Thyroid Bed Fine-Needle Aspiration: A Clinicocytologic Correlation

Laura J Adhikari, Jordan Reynolds, Sarah Jenkins, Aziza Nassar. Mayo Clinic, Rochester, MN; Cleveland Clinic, Cleveland, OH

Background: Monitoring changes in the thyroid bed (TB) is one of the clinical mainstays for surveillance of recurrent thyroid carcinoma. Fine needle aspiration (FNA) is a diagnostic tool that is commonly used to aid in the decision of further clinical treatment options and follow-up.
Design: We retrieved cases of soft tissue masses within the thyroid bed that were evaluated for recurrence between January 1, 2006 and February 1, 2011. All ultrasound-guided biopsies clinically suspected to be lymph node metastasis or had lymphocytes present on the FNA were excluded and only one FNA from each patient was included. If multiple biopsies were performed, only the positive FNA was included.
Results: 292 patients were identified for evaluation of recurrence; 250 papillary thyroid carcinoma (PTC), 15 follicular carcinoma, 21 medullary carcinoma, and 6 Hurthle cell carcinoma. For all FNAs that were clinically suspicious for recurrence the rate of positivity was 66.1% (193 patients). 14 of the 69 patients (20.3%) diagnosed with a negative FNA proceeded on to surgical resection or ethanol ablation. The average time between thyroidectomy and thyroid bed FNA was 76 months. On the subset of patients with a previous diagnosis PTC, who were diagnosed with either suspicious or positive for recurrent PTC on TBFNA; the following clinicopathologic parameters were found to be statistically significant.

P-values for Papillary Thyroid Carcinoma and Associated Risk Factors

Parameter	Other (negative, non-diagnostic, atypical)	Suspicious/ Positive	Total	p-value***
	(N=69)	(N=179)	(N=248)
Sex				0.0188
Female	56 (81.2%)	118 (65.9%)	174 (70.2%)
Male	13 (18.8%)	61 (34.1%)	74 (29.8%)
Mean (SD) Tumor size	1.9cm (1.5)	2.7 cm (1.4)	2.4 cm (1.5)	<0.0001
Metastases				<0.0001
Absent	31 (44.9%)	21 (11.7%)	52 (21.0%))
*Present	38 (55.1%)	158 (88.3%)	196 (79.0%)
Extrathyroidal extension				0.0024
Unknown or confined	53 (76.8%)	103 (57.5%)	156 (62.9%)
Present	16 (23.2%)	76 (42.5%)	92 (37.1%)

*Includes lymph node and all other metastases. ***From chi-square test or Fishers exact test for categorical data; Wilcoxon rank-sum test for continuous data.

Age at thyroidectomy and number of cancer foci were not found to be statistically significant.
Conclusions: Thyroid bed recurrence of PTC is most likely to occur in patients who have the following clinicopatholgic parameters: female sex, documented metastasis to any site, extrathyroidal extension, radioactive iodine treatment prior to FNA and larger primary tumor size.
Category: Cytopathology

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 59, Wednesday Afternoon