Histopathology | 2021
Interobserver reproducibility of differentiated exophytic vulvar intraepithelial lesion (DEVIL) and the distinction from its mimics.
Abstract
AIM\nMost vulvar squamous cell carcinomas are HPV-associated or TP53-mutant. A third category of HPV-independent, TP53-wild-type lesions is uncommon and not fully understood. Differentiated Exophytic Vulvar Intraepithelial Lesion (DEVIL) has been characterized as a precursor in this latter category. The reproducibility of DEVIL and its distinction from lesions with overlapping morphology has not been studied.\n\n\nDESIGN AND RESULTS\nA set of 35 slides was evaluated by 8 reviewers (2 trainees, 6 practicing gynaecologic pathologists). The set included DEVIL as well as condyloma, established vulvar precursors (high-grade squamous intraepithelial lesion (HSIL) and differentiated vulvar intraepithelial neoplasia (dVIN)) with superimposed acanthosis or verruciform growth, lichen simplex chronicus (LSC) and psoriasis. Kappa (κ) values were calculated. Overall, interobserver agreement was moderate (κ=0.56), improving to substantial (κ=0.7) when evaluated among practicing pathologists. Diagnosis of HSIL reached strong agreement (κ=0.88), whereas the diagnosis of DEVIL (κ=0.61), dVIN (κ=0.59), condyloma (κ=0.79) and LSC (κ=0.72) reached substantial agreement. Diagnosis of psoriasis reached moderate agreement (κ=0.53). Perfect agreement (6/6) among practicing pathologists was observed in 43% cases and majority agreement (5/6 or 4/6) in 48%.\n\n\nCONCLUSIONS\nThe reproducibility in the diagnosis of verruciform vulvar lesions, including the novel DEVIL, is overall acceptable. Reproducibility is higher in well-known lesions such as HSIL and condyloma, compared to more challenging diagnoses such as DEVIL, dVIN and psoriasis. Agreement is higher among practicing gynecologic pathologists, suggesting that training and experience improves reproducibility. Our findings support including DEVIL as a diagnostic entity in the classification of vulvar squamous lesions.