Non-human-papillomavirus-related malignancies of the vulva: A clinicopathological study

Background: Malignant tumor of the vulva is the fourth gynecological malignancy in frequency. Close to 70% of all vulvar malignancies are related to high-risk human papillomavirus (HPV) infection. Methods: A search for non-HPV-related malignant tumors of the vulva was performed in the last 20 years (2000-2020) in the pathology database of a single tertiary institution. We aim to estimate the prevalence of non-HPV-related malignancies in our population, describe clinicopathological features of these tumors and investigate the expression of some potential therapeutic targets. Results: A total of 71 patients were recovered; 26 patients (36%) had the diagnosis of extramammary Paget disease, 17 patients (24%) had basal cell carcinomas, 17 patients (24%) had primary melanomas, 10 patients (14%) had metastatic disease to the vulva and one patient (1%) had a primary dermatofibrosarcoma protuberans. Fifty-four percent of patients with extramammary Paget disease had a secondary malignancy and 12.5% had invasive disease. Programmed death-ligand 1 (PDL-1) was positive in seven out of nine primary melanomas and Her2/neu was overexpressed in six out of seven extramammary Paget disease. Conclusion: Non-HPV-related malignancies are important differential diagnoses in patient with vulvar lesions. Additional research is necessary to further understand these complex malignancies and potential new therapeutic targets.