Strengths and limitations
The main strength of this study is the total number of vulvar LP cases, gathering both clinical and follow-up information over a large period. Also, all the cases were diagnosed and treated by a vulvar pathology specialist, diminishing the practice differences between clinicians and some other potential selection bias.
The diagnosis of vulvar LP was made either based on clinical features and/or histology. In most cases, the diagnosis was clinical; histology was reserved to the cases refractory to first line treatments and/or when suspicious lesions were observed. Nevertheless, while some authors defend that clinical appearance are nonspecific for vulvar LP and often shared with other dermatosis, like LS,14,22 among different guidelines the use of histology for the diagnosis of vulvar dermatosis is not consensual.23–25 In the light of these conflicting positions about the diagnostic criteria of vulvar LP and considering that we normally used the clinical criteria for establishing the diagnosis, it could be seen as a limitation of this study. We cannot exclude that in some of the described cases there was an overlapping of different vulvar dermatosis, such as LP and LS. Future studies about vulvar LP that could use a combination of standard clinicopathologic criteria, like the ones proposed by Day, et al. , could be source of more robust evidence.14
Another relevant pitfall in our results is the absence of immunohistochemistry stain for p16 in the HSIL histology. A block-positive p16 is a surrogate marker of transforming infection with HPV high-risk-genotypes, and it allows a more reliable diagnosis of HSIL, when considering differential diagnosis, such as d-VIN or erosive LP.2,14