Effect of Subspecialty Sign-Out on the Diagnosis of Follicular-Patterned Thyroid Neoplasms
Deborah J Chute, Tarik M Elsheikh, Aaron P Hoschar. Cleveland Clinic, Cleveland, OH
Background: The diagnosis of follicular variant of papillary thyroid carcinoma (FVPTC) can be quite challenging when nuclear features are subtle or borderline. Several studies have demonstrated significant interobserver and intraobserver variation in the diagnosis of FVPTC, even among expert head and neck pathologists. On July 1st, 2003 our institution switched from a general pathology sign-out to subspecialty sign-out system. In this study, we examine trends in the diagnosis of follicular patterned thyroid neoplasms, including FVPTC, before and after this change.
Design: Primary thyroid resections containing follicular-patterned neoplasms were identified over a period of 16 years (8 years prior to and 8 years after the change in sign-out systems). Only neoplasms with pure follicular growth pattern were examined, including: follicular adenoma (FA), Hürthle cell adenoma (HCA), follicular carcinoma (FC), Hürthle cell carcinoma (HCC), and follicular variant of papillary thyroid carcinoma (FVPTC). Cases of papillary microcarcinoma were excluded from the study. The number of primary thyroid resections with each neoplasm type was tabulated along with the total number of thyroid resections over each time period.
Results: In the first 8 years of the study (pre subspecialty sign-out), there were 1,866 thyroid resections, out of which 258 (13.8%) follicular patterned neoplasms were retrieved. These included133 FA (52%), 37 HCA (14%), 30 FC (11%), 13 HCC (5%), and 46 FVPTC (18%). In the latter 8 years of the study (post subspecialty sign-out) there were 3,535 thyroid resections, out of which 324 (9%) follicular patterned neoplasms were retrieved. These included 108 FA (33%), 34 HCA (10%), 28 FC (9%), 19 HCC (6%), and 138 FVPTC (42%). There was an apparent rapid rise and a statistically significant increase in reporting FVPTC (p<0.001) in association with the onset of subspecialty sign-out. The decrease in reporting FA was statistically significant (p<0.001), but had a slow decline with acceleration in recent years. There was no significant difference in reporting of HCA, FC, or HCC.
Conclusions: Subspecialty sign-out with expert head and neck pathologists was associated with a significant increase in the diagnosis of FVPTC, and a decline in reporting FAs. This may be due to better recognition by head and neck subspecialty pathologists or better overall awareness of subtle papillary carcinoma nuclear features over time.
Monday, March 19, 2012 1:45 PM
Platform Session: Section H, Monday Afternoon