Affiliation:
1. Dermatology Department Saint‐Pierre University Hospital—Université Libre de Bruxelles Brussels Belgium
2. Dermatology Department Saint‐Pierre University Hospital Brussels Belgium
3. Anatomy Pathology Department University Hospital of Brussels—Université Libre de Bruxelles Brussels Belgium
4. Dermatology Department Saint‐Pierre and Brugmann University Hospitals—Université Libre de Bruxelles Brussels Belgium
Abstract
AbstractBackgroundNail squamous cell carcinoma (NSCC) is the most frequent ungual malignant tumor, but its incidence remains low. The histopathological description is sparse. We aim to characterize NSCC histopathological aspects, search for a correlation with clinical subtypes, and investigate immunohistochemistry expression of p16, p53, and Ki67.MethodsThis retrospective study collected NSCC diagnosed in our dermatology department between 2007 and 2021. The histopathological features were correlated with the clinical signs and immunohistochemistry.ResultsA total of 48 patients were included, and immunohistochemistry was available for 36 of them. Two histopathological patterns became prominent: a blue‐basaloid type characterized by koilocytosis (p < 0.001), and a pink‐keratinizing type. Mean ages were similar when comparing basaloid and periungual versus keratinizing and subungual (p < 0.001). p16 was positive in 31 of 36 cases: 18 basaloid and 13 keratinizing (p = 0.167). p53 and Ki67 were all abnormal.ConclusionsOur study described two histopathological NSCC subtypes and associated them with the two clinical subtypes: the blue‐basaloid type, HPV‐induced, in situ, of periungual localization in younger males; and the pink‐keratinizing type, non‐HPV‐induced, invasive, of subungual site, in elderly. Immunohistochemistry was not contributing on its own, but p16 positivity associated with basaloid histopathological profile helps support HPV etiology.