Erosive LP and malignancy risk
The relation between genital LP and cancer is not well-stablished. There are some reasons pointed to refute an association between vulvar LP and VSCC. First, erosive LP is usually seen on nonkeratinized epithelium of the vestibule and vagina, where primary HPV-independent cancer has seldom been reported. However, establishing the exact location of the malignant and premalignant lesions in relation to the mucocutaneous junction can be difficult, given the anatomical and structural changes often present in the field of vulvar dermatosis or in the presence of locally advanced cancer. Second, LS has consensually been associated with premalignant lesions (d-VIN) in contrast to carcinogenic potential of vulvar LP; the possibility of coexistence of LP and LS in the same patient, can be a confounder factor when analyzing the malignant potential of vulvar LP.2 Nevertheless, the existence of case reports and series describing neoplasia in a field of vulvar LP and the association between oral LP and cancer, justifies the need for more evidence.7,8,4,16
While we could not establish an association between LP and d-VIN or non-HPV VSCC, we had 3 cases (2.4%) of vulvar HSIL, with two (1.6%) later having a diagnosis of VSCC. Our rate of malignancy was similar to that found by others: 2.3% in a total of 175 cases reported in a multicentric vulvar LP case audit in the UK15; 2.1% in 95 cases of LP from a vulvar clinic in Rotterdam17; 1.2% of vulvar HPV-induced HSIL from a total of 584 patients with vulvar LP4; and 0.14% of vulvar cancer in the largest cohort described of any type and location of LP7. While we cannot exclude an association, the risk, if any, is low. In all the 3 cases we report, a close follow-up was maintained, and the patients were compliant with both treatment and follow-up appointments. Even so, in the case number 2, the short interval between a diagnosis of HSIL and that of VSCC, may be explained by: a) invasion already present, but missed in the biopsy; or b) multicentric lesions with rapid progression.
We cannot determine what was the role of treatment and surveillance, given the low figures. However, the third case is an example of success, highlighting the importance of maintaining close surveillance and performing as many biopsies as necessary when facing a suspicious lesion.