[407] Thyroid FNA Atypia of Undetermined Significance (AUS): Variability in Pathologist Reporting and Clinical Follow-Up.

Aparna Mahajan, Katherine Kasper, Xiaoqi Lin, Denise DeFrias, Charles Clevenger, Piotr Kulesza, Cord Sturgeon, Ritu Nayar. Northwestern University, Chicago, IL

Background: It is suggested that AUS comprise approximately 7% of thyroid FNA results; however post-Thyroid Bethesda publications show a wide inter institutional variation in AUS percentages. We are a medical center with board certified cytopathologists and a large thyroid FNA volume. We have a high institutional AUS rate; however we have used a 6-tired system for reporting thyroid FNA since 2001 and included cases limited by qualitative factors and cystic lesions in AUS. Implementation of Bethesda criteria for thyroid reporting and transition from our previous reporting pattern was inconsistent between pathologists in 2008/2009, prior to the publication of the Bethesda atlas in December 2009. This review was undertaken to measure the variability between our cytopathologists with the aim of improving AUS reporting and its outcomes.
Design: We queried our institutional database for FNA biopsies categorized as AUS between 6/2008 and 12/2009. 399 thyroid biopsies were identified. We reviewed the cytopathology reports, along with repeat FNA and surgical pathology follow up data.
Results:

Pathologist Reporting and FNA/Surgical Pathology Follow Up

Pathologist	P1	P2	P3	P4	P5	P6	Total
Total Thyroid FNA	154	545	343	158	586	519	2305
AUS # cases	13	48	120	14	106	98	399
AUS Rate (%)	8.4	8.8	35	8.9	18.1	18.9	17.3
REASON FOR AUS
% Hyperplasia vs. FN	54	73	62	36	64	64	64
% Quality	8	8	23	43	8	13	15
% CLT	31	8	9	14	10	14	12
% r/o Carcinoma/Lymphoma	8	2	3	7	18	3	7
% Cystic	0	8	4	0	0	5	4
REPEAT FNA* AFTER INITIAL AUS
Negative %	67	33	65	33	42	48	53
AUS %	33	44	24	33	42	33	32
Neoplasm/Suspicious/Malignant %	0	22	4	33	17	19	12
SURGICAL OUTCOME
Non Neoplastic %	67	69	85	50	50	32	54
Neoplastic (adenoma) %	0	25	15	25	29	49	31
Malignant %	33	6	0	25	21	19	15
Intradept. Consult %	15	21	8	0	6	2	7

* 3% of Repeat FNA were 'Unsatisfactory'


Conclusions: Our data confirms wide variation in the reporting of thyroid atypia among cytopathologists, with corresponding variable outcomes on repeat FNA and surgical follow up. We have identified specific trends for each pathologist. The results of this study will serve a useful quality assurance measure and be used for consensus building within our group. The use of intradepartmental consultation and review of specific thyroid Bethesda criteria for AUS, using representative case material from ones own practice are additional methods that may improve intra and inter institutional consensus in reporting thyroid FNA.
Category: Cytopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 54, Wednesday Afternoon