Vulvar intraepithelial neoplasia (VIN) is a precancerous lesion on the vulvar epidermis and manifests as atypical intraepithelial hyperplasia on the vulva; however, most patients are diagnosed early. Treatment with standardised therapy often leads to complete regression of symptoms [1]. Without early diagnosis and standardised treatment, the canceration rate of this disease can be as high as 87.5%. Owing to the lack of effective screening methods and inconspicuousness of the condition and clinical symptoms, the diagnosis of VIN is easily overlooked. Therefore, there is a need to improve the awareness and treatment of this disease to achieve early diagnosis and better prognosis, thereby reducing the incidence of high-grade VIN [2].

High-grade intraepithelial neoplasia of the vulva (VHSIL) is a multifocal disease associated with human papilloma virus (HPV) infection; additionally, VHSIL is associated with other lesions of the external genital tract. The onset of VHSIL is often observed in young women. Differentiated VIN (d-VIN) is associated with benign vulvar dermatoses, such as sclerosing moss and chronic simple moss [3], usually as a unifocal disease that often affects older women. Studies have found that, compared to those with D-VIN, patients with VHSIL have a relatively low risk of carcinogenesis with a possibility of conservative treatment to improve prognosis.

Surgery is the standard treatment for VIN. This paper reports the case of a patient with a large-area high-grade VIN lesion complicated by HPV infection. The patient could not be treated surgically but was treated with PDT in our outpatient department. There was no recurrence after 13 months of follow-up.