"Moderate interobserver variability exists in the diagnosis of Grade 3 Endometrioid Carcinoma with a significantly greater diagnostic agreement rate in gynecologic pathology–focused sign-out than in general sign-out practice."

Sumi Thomas, Yaser Hussein, Sudeshna Bandyopadhyay, Michele Cote, Oudai Hassan, Eman Abdulfatah, Baraa Alosh, Hui Guan,Robert A. Soslow, and Rouba Ali-Fehmi (2016) Interobserver Variability in the Diagnosis of Uterine High-Grade Endometrioid Carcinoma. Archives of Pathology & Laboratory Medicine In-Press.

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Interobserver Variability in the Diagnosis of Uterine High-Grade Endometrioid Carcinoma

Sumi Thomas , MD; Yaser Hussein , MD; Sudeshna Bandyopadhyay , MD; Michele Cote , PhD; Oudai Hassan , MD; Eman Abdulfatah , MD; Baraa Alosh , MD; Hui Guan , MD; Robert A. Soslow , MD; Rouba Ali-Fehmi , MD;

Reprints: Robert A. Soslow, MD, Department of Pathology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10065 (email: soslowr@mskcc.org).

Context.—Low interobserver diagnostic agreement exists among high-grade endometrial carcinomas.

Objective.—To evaluate diagnostic variability in International Federation of Gynecology and Obstetrics (FIGO) grade 3 endometrioid adenocarcinoma (G3EC) in 2 different sign-out practices.

Design.—Sixty-six G3EC cases were identified from pathology archives of Wayne State University (WSU, Detroit, Michigan) (general surgical pathology sign-out) and 65 from Memorial Sloan Kettering Cancer Center (MSK, New York, New York) (gynecologic pathology focused sign-out). Each case was reviewed together by 2 gynecologic pathologists, one from each institution, and classified into the G3EC group or a reclassified group. Clinicopathologic parameters were compared.

Results.—Twenty-five WSU cases (38%) were reclassified as undifferentiated (n = 2), serous (n = 4), mixed endometrioid and serous carcinomas (n = 12), and FIGO grade 2 endometrioid adenocarcinomas with focal marked nuclear atypia (n = 7). Eleven MSK cases (17%) were reclassified as undifferentiated (n = 5), serous (n = 1), mixed endometrioid and serous carcinomas (n = 4), and mixed endometrioid and clear cell carcinomas (n = 1). Agreement rate between original and review diagnosis was 83% (54 of 65) at MSK and 62% (41 of 66) at WSU (P = .01) with an overall rate of 73% (95 of 131). There were more undifferentiated carcinomas at MSK than there were at WSU (45% [5 of 11] versus 8% [2 of 25]; P = .02). There were more grade 2 endometrioid adenocarcinomas with focal, marked nuclear atypia at WSU (28%; 7 of 25) than there were at MSK (0%) (P = .03). Mixed endometrioid and serous carcinoma was the most common misclassified subtype (44%; 16 of 36).

Conclusion.—Moderate interobserver variability exists in the diagnosis of G3EC with a significantly greater diagnostic agreement rate in gynecologic pathology–focused sign-out than in general sign-out practice.