The Source(s) of Benign-Appearing Follicular Cells (BAFC) in Fine Needle Thyroid Aspirations (FNA): What Is the Contribution of Extra-Nodular Tissue?

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 280
Sharleen Sidhu*1, Vallikantha Nellaiappan1, Aditi Gupta1, Dhauna Karam1, Ifrah Jamil2 and Charles P Barsano3
1Chicago Medical School, IL, 2Chicago Medical School at Rosalind Franklin University of Medicine and Science and Captain James A. Lovell Federal Health Care Center, North Chicago, IL, 3Capt James A Lovell Federal Health Care Ctr, North Chicago, IL
The abundance of benign-appearing follicular cells in FNA samples is an important factor for the cytological diagnosis of benignity of biopsied thyroid nodules. BAFC derived from thyroid nodules cannot be cytologically distinguished from those present in the extra-nodular tissue through which the biopsy needle must pass (“pre-nodular” tissue). To determine indirectly if the pre-nodular tissue contributes much if any BAFC to FNA samples, the abundance of BAFC in FNA samples was correlated to the depth of the biopsied nodules. Hypothetically, if the pre-nodular tissue is a significant source of BAFC, biopsied nodules deep within the thyroid parenchyma would expectedly exhibit a greater abundance of BAFC than nodules closer to the proximal surface of the thyroid.

   Two hundred four biopsied nodules were graded 0, 1, 2, or 3 on the basis of their abundances of BAFC: 0, acellular [41 nodules]; 1, hypocellular [70 nodules]; 2, normocellular [84 nodules]; 3, hypercellular [9 nodules]. The length of the intra-thyroidal tissue track that the FNA needle traversed to reach the biopsied nodule was measured ultrasonographically [needle tracks ranged from 0 mm to 29 mm]. Nodules diagnosed as “malignant,” “suspicious for malignancy ”or “lymphocytic” were not included among the 204 graded nodules since the relative abundance of BAFC in their FNA samples would not be clinically important and not routinely reported by the cytologist. The biopsies of almost all nodules involved 6 punctures; none less than 4 punctures.

   When the BAFC abundance grade for each nodule was plotted against the nodule’s depth within the thyroid, there was essentially no correlation between BAFC abundance and the length of the pre-nodular thyroid tissue needle tracks (Coefficient of Correlation [r] = -0.08). The lack of correlation was equally evident when nodules biopsied with 25 gauge needles [163 nodules] were compared to biopsies using 23 gauge needles [41 nodules].

   These results confirm that the abundances of benign-appearing follicular cells in FNA samples represent cells predominantly derived from the thyroid nodules and little if any from the pre-nodular thyroid tissue.

Nothing to Disclose: SS, VN, AG, DK, IJ, CPB

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