Vulvar squamous cell carcinoma arising on human papillomavirus‐independent precursors mimicking high‐grade squamous intra‐epithelial lesion: a distinct and highly recurrent subtype of vulvar cancer

Abstract

AimsEach category of vulvar squamous cell carcinoma (VSCC), human papillomavirus (HPV)‐associated and HPV‐independent, arises on a specific intra‐epithelial precursor: high‐grade squamous intra‐epithelial lesions (HSIL) and differentiated vulvar intra‐epithelial neoplasia (dVIN), respectively. However, a subset of HPV‐independent VSCC arises on an intra‐epithelial precursor closely mimicking HSIL. We aimed to explore the clinicopathological features of the HPV‐independent tumours with HSIL‐like lesions and compare them with HPV‐independent VSCC with dVIN and HPV‐associated tumours with HSIL.Methods and resultsWe retrospectively identified 105 cases of surgically treated VSCC with adjacent intra‐epithelial precursors. The cases were classified into three groups based on the HPV status and the adjacent precursor identified: (i) HPV‐associated VSCC with HSIL (n = 26), (ii) HPV‐independent VSCC with dVIN lesions (n = 54) and (iii) HPV‐independent VSCC with HSIL‐like lesions (n = 25). We analysed the histological and clinical features including the recurrence‐free survival and disease‐specific survival in the three groups. Patients with HPV‐independent VSCC with HSIL‐like lesions and with dVIN were older than patients with HPV‐associated VSCC (76 and 77 versus 66 years, respectively, P < 0.001). HPV‐independent VSCC with HSIL‐like lesions recurred more frequently [hazard ratio (HR) = 3.87; P < 0.001] than HPV‐independent VSCC with dVIN (HR = 2.27; P = 0.1) and HPV‐associated VSCC (HR = 1). In the multivariate analysis, HPV‐independent VSCC with HSIL‐like lesions remained significant for recurrence. No differences in disease‐specific survival were observed between the three groups.ConclusionsEven though VSCC with HSIL‐like lesions are not associated with higher mortality, they are more likely to recur and might benefit from more intensive treatment strategies and closer surveillance after treatment.