Objective: To estimate overall interobserver variability of histopathology diagnoses on endocervical curettage (ECC) specimens.
Methods: Five study pathologists, blinded to the original diagnosis, reviewed archived ECC specimens initially interpreted as normal, low-grade dysplasia, and high-grade dysplasia. We assessed interobserver agreement and agreement between pathologists using the κ statistic and analyzed the effect of reducing diagnostic choices to two categories (one method using "normal and dysplasia" and another method using "normal and low-grade" and "high-grade or worse").
Results: A total of 90 specimens were reviewed. The overall observer agreement was moderate (κ = 0.52). For specific diagnoses, cases interpreted as normal or high-grade dysplasia demonstrated greater agreement than those interpreted as low-grade dysplasia. Individual pathologists' comparison κ values ranged from 0.31 to 0.80. Changing diagnostic options to a two-tiered system resulted in significant improvement in κ values for only 1 of 36 pathologist comparisons. Using the gynecologist pathologist consensus interpretation, study pathologists downgraded 44% of cases originally interpreted as high-grade.
Conclusion: Interobserver agreement in the interpretation of ECC specimens is at best moderate, even between those with additional experience and training in gynecologic pathology. Furthermore, reducing diagnostic options to two categories did not improve agreement. It is concerning that important clinical decisions may be made based on an ECC diagnosis that is moderately or poorly reproducible.
Level of evidence: II.