p53/CK17 Dual Stain Improves Accuracy of Distinction Between Differentiated Vulvar Intraepithelial Neoplasia and Its
Abstract:
Accurate diagnosis of differentiated vulvar intraepithelial neoplasia (dVIN) is challenging, in part due to the sometimes subtle nature of its atypia. Many dVIN lesions demonstrate aberrant p53 staining; however, staining patterns overlap between dVIN and benign/reactive entities. We evaluate a p53/CK17 dual stain in an initial cohort of dVIN (n=30), benign vulvar skin (n=5), lichen sclerosus (LS, n=10), lichen simplex chronicus (LSC, n=10), and pseudoepitheliomatous hyperplasia (PEH, n=10). In the initial cohort, aberrant p53 staining was seen only in dVIN (50%, 15/30). Equivocal p53 staining patterns were seen in dVIN (37%, 11/30), LS (50%, 5/10), LSC (40%, 4/10), and PEH (40%, 4/10). All 30 dVIN cases were positive for CK17 (strong partial-thickness or full-thickness staining), but positive CK17 staining was also seen in LS (70%, 7/10), LSC (50%, 5/10), and PEH (100%, 10/10). In the initial cohort, the combination of aberrant p53 and positive CK17 was seen only for dVIN (50%, 15/30). Forty cases of LS with known follow-up (20 with progression to dVIN, 20 without) were stained to assess prognostic value. Three LS cases showed aberrant p53 staining with CK17 positivity; all progressed to dVIN. Equivocal p53 staining and CK17 positivity were seen in cases with and without progression. The p53/CK17 dual stain is more diagnostically useful than either stain alone. Negative/focal staining for CK17 argues against a diagnosis of dVIN, while aberrant p53 staining with CK17 positivity strongly supports the diagnosis.
