Objective: To assess interobserver variability in the diagnosis of anal cancer precursor lesions in the usual scenario of a service consisting of pathologists without previous experience in the diagnosis of these lesions.
Methods: Five hundred and two anal specimens taken from 372 HIV-positive and HIV-negative patients were analyzed at the Pathology Department of the Tropical Medicine Foundation of Amazonas by three pathologists with extensive experience in the diagnosis of infectious and tropical diseases, but without significant prior experience in the diagnosis of anal cancer precursor lesions. The individual readings of each pathologist were compared to the one following the consensus diagnosis in shared optical microscope by kappa statistics.
Results: The absolute agreement between each individual diagnosis and corresponding consensus was poor (kappa = -0.002). Considering only the positive or negative results for anal squamous intraepithelial lesions, we obtained a fair agreement between observers (kappa = 0.35), while the agreement was moderate when the histopathological findings were considered positive or negative for high-grade squamous intraepithelial lesion or cancer (kappa = 0.52).
Conclusion: The interobserver variability in histopathologic diagnosis of anal cancer and its precursor lesions among pathologists with little experience in the area is such that the diagnoses in this field and this scenario should always be a consensus.