Ann Surg Treat Res.  2014 Mar;86(3):109-114. 10.4174/astr.2014.86.3.109.

Atypia of undetermined significance on thyroid fine needle aspiration: surgical outcome and risk factors for malignancy

• Ryu YJ
• Jung YS
• Yoon HC
• Hwang MJ
• Shin SH
• Cho JS
• Lee JS
• Kim HK
• Kang HC
• Lim HS
• Yoon JH
• Park MH

• KMID: 2266890
• DOI: http://doi.org/10.4174/astr.2014.86.3.109

Abstract

PURPOSE
This study was performed to analyze the surgical pathology results of the "atypia of undetermined significance" (AUS) category from thyroid fine needle aspiration (FNA) and to describe the characteristics to distinguish a malignant from a benign nodule.
METHODS
A retrospective analysis was done on 116 patients who underwent thyroid surgery from December 2008 to December 2012, following a diagnosis of AUS from preoperative thyroid FNA. We investigated the age, gender, size and site of the nodules, ultrasonographic criteria, cytological features, the number of atypia results after repeated FNAs, surgical method, and final pathologic results.
RESULTS
Sixty-five out of 116 patients underwent total thyroidectomy and the rest had partial thyroidectomy. The final pathologic results were 41 malignancies (35.3%) and 75 benign diseases (64.7%). AUS was divided into group 1: 'cannot rule out malignancy' or group 2: 'cannot rule out follicular neoplasm'. After surgery, group 1 revealed papillary thyroid cancer in most cases and group 2 revealed follicular adenoma in most cases. Age over 40 years, ultrasonographic findings suggestive of malignancy, more than 2 results of atypia from repeated FNAs and nodules less than 2 centimeters were risk factors for malignancy on univariate analysis. Multivariate analysis showed that ultrasonographic findings suggestive of malignancy was a significant risk factor for malignancy.
CONCLUSION
For proper evaluation of the risk for malignancy in thyroid AUS patients, the ultrasonographic criteria should be considered along with other clinicopathological findings such as age, nodule size, number of atypia, cytologic features.

Keyword

Atypia of undetermined significance; Fine needle aspiration; Thyroid neoplasms

MeSH Terms

Adenoma
Biopsy, Fine-Needle*
Diagnosis
Humans
Methods
Multivariate Analysis
Pathology, Surgical
Retrospective Studies
Risk Factors*
Thyroid Gland*
Thyroid Neoplasms
Thyroidectomy

Figure

• 

  Fig. 1 Summary of surgical outcome in AUS patients.

Reference

1. Baloch ZW, Sack MJ, Yu GH, Livolsi VA, Gupta PK. Fine-needle aspiration of thyroid: an institutional experience. Thyroid. 1998; 8:565–569.

2. Gharib H, Goellner JR, Johnson DA. Fine-needle aspiration cytology of the thyroid: a 12-year experience with 11,000 biopsies. Clin Lab Med. 1993; 13:699–709.

3. Gharib H, Goellner JR. Fine-needle aspiration biopsy of the thyroid: an appraisal. Ann Intern Med. 1993; 118:282–289.

4. Alexander EK. Approach to the patient with a cytologically indeterminate thyroid nodule. J Clin Endocrinol Metab. 2008; 93:4175–4182.

5. Baloch ZW, Cibas ES, Clark DP, Layfield LJ, Ljung BM, Pitman MB, et al. The National Cancer Institute Thyroid fine needle aspiration state of the science conference: a summation. Cytojournal. 2008; 5:6.

6. Ohori NP, Schoedel KE. Variability in the atypia of undetermined significance/follicular lesion of undetermined significance diagnosis in the Bethesda System for Reporting Thyroid Cytopathology: sources and recommendations. Acta Cytol. 2011; 55:492–498.

7. VanderLaan PA, Marqusee E, Krane JF. Clinical outcome for atypia of undetermined significance in thyroid fine-needle aspirations: should repeated fna be the preferred initial approach? Am J Clin Pathol. 2011; 135:770–775.

8. Baloch ZW, Fleisher S, LiVolsi VA, Gupta PK. Diagnosis of "follicular neoplasm": a gray zone in thyroid fine-needle aspiration cytology. Diagn Cytopathol. 2002; 26:41–44.

9. Tuttle RM, Lemar H, Burch HB. Clinical features associated with an increased risk of thyroid malignancy in patients with follicular neoplasia by fine-needle aspiration. Thyroid. 1998; 8:377–383.

10. Rago T, Di Coscio G, Basolo F, Scutari M, Elisei R, Berti P, et al. Combined clinical, thyroid ultrasound and cytological features help to predict thyroid malignancy in follicular and Hupsilonrthle cell thyroid lesions: results from a series of 505 consecutive patients. Clin Endocrinol (Oxf). 2007; 66:13–20.

11. Wiseman SM, Baliski C, Irvine R, Anderson D, Wilkins G, Filipenko D, et al. Hemithyroidectomy: the optimal initial surgical approach for individuals undergoing surgery for a cytological diagnosis of follicular neoplasm. Ann Surg Oncol. 2006; 13:425–432.

12. Baloch ZW, LiVolsi VA, Asa SL, Rosai J, Merino MJ, Randolph G, et al. Diagnostic terminology and morphologic criteria for cytologic diagnosis of thyroid lesions: a synopsis of the National Cancer Institute Thyroid Fine-Needle Aspiration State of the Science Conference. Diagn Cytopathol. 2008; 36:425–437.

13. Layfield LJ, Cibas ES, Baloch Z. Thyroid fine needle aspiration cytology: a review of the National Cancer Institute state of the science symposium. Cytopathology. 2010; 21:75–85.

14. Kim YM, Kim TC, Moon YB, Rho YS, Park YM. The clinical significance of fine needle aspiration cytology in the surgical management of thyroid nodules. Korean J Otolaryngol-Head Neck Surg. 1995; 38:1081–1087.

15. Agrawal S. Diagnostic accuracy and role of fine needle aspiration cytology in management of thyroid nodules. J Surg Oncol. 1995; 58:168–172.

16. Hamburger JI. Diagnosis of thyroid nodules by fine needle biopsy: use and abuse. J Clin Endocrinol Metab. 1994; 79:335–339.

17. Bahar G, Braslavsky D, Shpitzer T, Feinmesser R, Avidan S, Popovtzer A, et al. The cytological and clinical value of the thyroid "follicular lesion". Am J Otolaryngol. 2003; 24:217–220.

18. Kim ES, Nam-Goong IS, Gong G, Hong SJ, Kim WB, Shong YK. Postoperative findings and risk for malignancy in thyroid nodules with cytological diagnosis of the so-called "follicular neoplasm". Korean J Intern Med. 2003; 18:94–97.

19. Hegedüs L. Clinical practice: the thyroid nodule. N Engl J Med. 2004; 351:1764–1771.

20. Tysome JR, Chandra A, Chang F, Puwanarajah P, Elliott M, Caroll P, et al. Improving prediction of malignancy of cytologically indeterminate thyroid nodules. Br J Surg. 2009; 96:1400–1405.

21. Sippel RS, Elaraj DM, Khanafshar E, Kebebew E, Duh QY, Clark OH. Does the presence of additional thyroid nodules on ultrasound alter the risk of malignancy in patients with a follicular neoplasm of the thyroid? Surgery. 2007; 142:851–857.

22. McHenry CR, Thomas SR, Slusarczyk SJ, Khiyami A. Follicular or Hürthle cell neoplasm of the thyroid: can clinical factors be used to predict carcinoma and determine extent of thyroidectomy? Surgery. 1999; 126:798–802.

23. Schlinkert RT, van Heerden JA, Goellner JR, Gharib H, Smith SL, Rosales RF, et al. Factors that predict malignant thyroid lesions when fine-needle aspiration is "suspicious for follicular neoplasm". Mayo Clin Proc. 1997; 72:913–916.

24. Tyler DS, Winchester DJ, Caraway NP, Hickey RC, Evans DB. Indeterminate fine-needle aspiration biopsy of the thyroid: identification of subgroups at high risk for invasive carcinoma. Surgery. 1994; 116:1054–1060.

25. McHenry CR, Huh ES, Machekano RN. Is nodule size an independent predictor of thyroid malignancy? Surgery. 2008; 144:1062–1068.

26. Nayar R, Ivanovic M. The indeterminate thyroid fine-needle aspiration: experience from an academic center using terminology similar to that proposed in the 2007 National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference. Cancer. 2009; 117:195–202.