A case of usual (basaloid)-type vulvar intraepithelial neoplasia that failed to respond to imiquimod cream: clinical implications.

The authors report a case of usual-type (basaloid-type) vulvar intraepithelial neoplasia (VIN) 3 that failed to respond to imiquimod cream. A 51-year-old Japanese woman visited her local gynecologist complaining of vulvar itching. Atypical cells were noted in cytology smears, but nine vulvar biopsy specimens showed benign proliferation of epithelial tissue. The patient was placed under careful observation for 8 months, when the vulvar smears once again showed atypical cells and biopsy specimens revealed VIN3. The patient was then referred to our hospital where she was given a diagnosis of VIN 3, basaloid type of usual type. The biopsy specimens were positive for p16 and the lesions were confirmed to be human papilloma virus (HPV)-related. We recommended simple vulvectomy but the patient requested conservative treatment with imiquimod cream. With her written informed consent, we prescribed imiquimod cream to be self-administered 3 times a week. Colposcopy and pap smear test were performed every 2 weeks. Four weeks after the start of treatment, a fingertip-sized papule was detected at the patient's vaginal introitus. By 6 weeks, the lesion had enlarged, and biopsy specimens revealed invasive squamous cell carcinoma. At 7 weeks, we performed simple vulvectomy. The surgical specimen showed stage pT1b keratinizing-type squamous cell carcinoma. HPV-16 DNA was detected in the specimen.