Correlation between indeterminate aspiration cytology and final histopathology of thyroid neoplasms

Pang, Tony; Ihre-Lundgren, Catharina; Gill, Anthony; McMullen, Todd; Sywak, Mark; Sidhu, Stan; Delbridge, Leigh

doi:10.1016/j.surg.2010.01.018

« Previous Next »Surgery
Volume 148, Issue 3 , Pages 532-537, September 2010

Correlation between indeterminate aspiration cytology and final histopathology of thyroid neoplasms

Tony Pang, MBBS
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
Catharina Ihre-Lundgren, MD, PhD
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
Anthony Gill, MD, FRCPA
- Department of Pathology, University of Sydney, Sydney Australia
Todd McMullen, MD, PhD
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
Mark Sywak, MD, FRACS
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
Stan Sidhu, PhD, MD, FRACS
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
Leigh Delbridge, MD, FRACS
- University of Sydney Endocrine Surgical Unit, Royal North Shore Hospital, Sydney, Australia
- Reprint requests: Leigh Delbridge, MD, FRACS, University of Sydney Endocrine Surgery Unit, Wallace Freeborn Building, Royal North Shore Hospital, St Leonards 2065 NSW, Australia.

Accepted 21 January 2010. published online 17 March 2010.

Background

Of all thyroid nodules assessed by fine needle aspiration cytology (FNAC), 10–20% are classified as indeterminate/atypical. Traditionally, this group is considered to primarily represent follicular neoplasia. We hypothesize that papillary carcinoma accounts for a significant proportion of lesions classified as “atypical” on FNAC.

Methods

This retrospective study includes 228 patients who had an atypical FNAC result and who were subsequently found to have a malignancy on histologic examination of the excised thyroid lesion. Patients with papillary microcarcinomas, defined as lesions less than 10-mm diameter, were excluded. The study period was from 1987 to 2005. The patients were divided chronologically into 3 groups (n = 76) for analysis: group 1, December 1987–March 1997; group 2, July 1997–October 2002; and group 3, October 2002–December 2005.

Results

Age- and sex-distribution of the 3 groups were not significantly different. Median nodule size of group 3 was significantly smaller. The distributions of histopathology of the 3 time periods were significantly different overall (P = .0325). Prevalence of papillary carcinoma was not statistically significant (33/76 vs 34/76 vs 46/76; P = .0636), but showed a statistical significant trend to increase over time (P = .0349). Prevalence of follicular variant papillary carcinoma was also found to be significantly different between the groups (7/76 vs 12/76 vs 19/76; P = .0320; P = .0349).

Conclusion

Papillary carcinoma accounted for most histopathologically confirmed cancers that had an atypical cytology. Papillary cancer in this group of patients trended up, probably due to a significant increase in the diagnosis of follicular variant of papillary cancer.