J Korean Surg Soc.  2011 Aug;81(2):75-84. 10.4174/jkss.2011.81.2.75.

Review of atypical cytology of thyroid nodule according to the Bethesda system and its beneficial effect in the surgical treatment of papillary carcinoma

• Chung YS
• Yoo C
• Jung JH
• Choi HJ
• Suh YJ

• KMID: 2096660
• DOI: http://doi.org/10.4174/jkss.2011.81.2.75

Abstract

PURPOSE
For the atypical cases of fine needle aspiration (FNA) cytology of thyroid nodules, ultrasonographic findings are a primary guideline for the surgical treatment. However, they have the intrinsic risk of overtreatment, as well. In this study we examined whether the Bethesda system could provide a real effect on the diagnostic rate of atypical cytology, and thereby reduce the number of cases diagnosed as atypical from FNA cytology.
METHODS
We reviewed 166 cases diagnosed as atypical by FNA cytology at this institute between the years 2005 to 2010. We classified these cases on the basis of ultrasonographic and cytological findings and compared them with the histological results.
RESULTS
Ultrasonographically, findings suspicious for malignancy and indeterminate were associated with 83.7% and 47.2% of malignancy rates, respectively. Cytopathologically, the malignancy rates varied according to the main cytological features and the highest malignancy rate was 77.3%. Based on the Bethesda system, 39.2% of the cases diagnosed as atypical could be grouped into the category of suspicious for malignancy and yielded a malignancy rate of 76.9%.
CONCLUSION
Although ultrasonography provides an excellent guideline for the surgical treatment of atypical cases, it also showed considerable risk of overtreatment. The Bethesda system did not offer definitive effects on the rate of atypical cytology, but this system seemed to provide stricter boundaries for the atypical cytology and to aid in reducing the rates thereof. This in turn may permit that more limited cases are allotted to ultrasonographic decision making.

Keyword

Thyroid nodule; Cytology; Atypical; The Bethesda system; Ultrasonography

MeSH Terms

Biopsy, Fine-Needle
Carcinoma, Papillary
Decision Making
Thyroid Gland
Thyroid Nodule

Figure

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  Fig. 1 Schematic presentation of guidelines for treatment of thyroid nodules. FNA, fine needle aspiration; USG, ultrasonographic.

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  Fig. 2 (A) Nuclear grooves or pseudoinclusions are significant cytological features strongly suggestive of papillary carcinoma. In these cases, papillary carcinoma could be safely diagnosed inspite of low cellularity. (B) In this case, a suspicious nuclear groove is noted in a few follicular cells, but when most of the sample appears benign, it would be more appropriate to diagnose this as a benign lesion. The histological diagnosis was nodular hyperplasia. (C) In this case diagnosed as nodular hyperplasia after surgery, the cytological features show low cellularity, but also show suspicious nuclear pseudoinclusions (arrow) and irregularity, hence atypical cells of undetermined significance (AUS) is the proper diagnosis. (D) In this case, Hurthle cell changes in the follicular epithelial cells are noted, but suspicious nuclear grooves are also present and hence AUS is the proper diagnosis. The histological diagnosis was papillary carcinoma. (E) If Hurthle cell changes are accompanied with a microfollicular pattern, then the diagnosis of follicular neoplasm should be kept in mind. (F) Even though the typical nuclear features of papillary carcinoma are not distinctive, the presence of papillary fronds, enlarged nuclei or psammoma bodies could be associated with papillary carcinoma. So in these cases, a diagnosis of AUS should be made (Papanicolaou stain, ×400; inlet, ×1,000).

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