Background  Dermatoscopy is a noninvasive technique that can be helpful in the diagnosis of pigmented and nonpigmented skin tumours. The dermatoscopic evaluation of Bowen disease (BD) improves diagnostic accuracy.

Objective  To evaluate the usefulness of dermatoscopy as a tool for assessing responses to therapy and recurrence of BD.

Methods  Patients with histopathologically diagnosed BD were prospectively enrolled. In all lesions, 3 months after the end of treatment (photodynamic therapy or 5% imiquimod cream), dermatoscopic and histopathological examinations were repeated to evaluate and correlate changes in dermatoscopic features and histopathological results. Cured lesions were monitored using dermatoscopy during the follow-up period.

Results  A total of 23 patients with 29 histopathologically diagnosed BD lesions were included in this study. After treatment, dermatoscopic examination revealed the disappearance of pre-existing vascular structures in 16 lesions, and remaining vascular structures in 13 lesions. Histopathological evaluation of the treated lesions showed remnant intraepithelial neoplasms and increased dermal vascularity in lesions with persistent dermatoscopic vascular structures. However, normal epidermis and decreased dermal vascularity were observed in all but one of the lesions without previous dermatoscopic vascular structures. During the follow-up period, one lesion showed reappearance of previous vascular structures on dermatoscopy 9 months after treatment. Histopathological examination confirmed the recurrence of BD.

Conclusions  Our study demonstrates that the persistence of dermatoscopic vascular structures of BD appears to be associated with residual disease, and disappearance of vascular structures suggests that the disease has been cured. In addition, reappearance of previous dermatoscopic vascular structures indicates the recurrence of BD. Therefore, we suggest that dermatoscopy can be a useful, reliable and noninvasive tool in the therapeutic follow-up of BD.