Challenge of reflectance confocal microscopy in the diagnosis of genital warts.

Abstract

Reflection confocal microscopy (RCM) is commonly used to assist in the diagnosis of skin diseases. RCM has been found to be useful in the diagnosis of genital warts. The characteristics of genital warts under RCM are not specific. This study aimed to face the challenge of diagnosing genital warts with RCM. We retrospectively studied 161 patients with clinical diagnosis of genital warts who underwent RCM examination. Histopathological examination was performed for 75 of these patients. The results of histological diagnosis and RCM diagnosis were compared and analyzed. According to the RCM images, 102 of the 161 (63.35%) patients were diagnosed as genital warts. By comparison with histological results, the misdiagnosis rate of the 75 biopsy cases was 35.48% and the missed diagnosis rate was 20.45%.The diseases of misdiagnosis and missed diagnosis mainly included bowenoid papulosis, pseudocondylona of vulvae, squamous cell carcinoma in situ, molluscum contagiosum, and lichen planus. We further found that the RCM characteristics of genital warts conformed by histology were koilocytes, which mainly appeared in the granular layer or the spinous layer, larger than normal skin keratinocytes, and the cytoplasm with low refractive index. Due to the commonality of the microscopic characteristics of genital warts and related diseases, some cases are easy to be misdiagnosed or missed diagnosed. Diagnostic koilocytes could be an important basis for the diagnosis of genital warts.