The painful, erythematous and eroded vulva often proves to be a diagnostic problem both clinically and histologically. Its differential diagnosis includes both non-neoplastic and neoplastic diseases like Bowen's disease and squamous cell carcinoma (SCC). We report the case of a 62-year-old woman diagnosed, after considerable delay, with Bowen's disease of the vulva that eventually progressed to invasive SCC, despite the treatment with imiquimod 5% cream. Our case indicates, on one hand, that dermoscopy could contribute to the accuracy of the pre-operative clinical diagnosis. On the other hand it confirms the fact that treatment of Bowen's disease of the vulva could be rather intriguing. Although imiquimod 5% cream is an effective, non-invasive treatment option for large lesions or poor healing sites, it should be administered with great consideration in carefully selected cases.