CLINICOPATHOLOGICAL COMPARISON OF VULVAR AND EXTRAGENITAL LICHEN-SCLEROSUS - HISTOLOGIC VARIANTS, EVOLVING LESIONS, AND ETIOLOGY OF 141 CASES

Lichen sclerosus (LS) is a persistent inflammatory dermatosis of unkno wn etiology with a predilection for the vulva, where it is a risk fact or for carcinoma. We performed a clinicopathologic study on 121 cases of vulvar LS and 20 of extragenital LS, and we reviewed 49 vulvectomy specimens with LS to define morphologic findings, identify the earlies t lesions, and correlate outcomes with histologic findings. The vulvar LS lesions were pruritic/burning, white/red, ill-defined patches pred ominately affecting the labia, perineum, introitus, and perianal regio n. The extragenital LS lesions were asymptomatic, pink to ivory white, coalescing macules or patches with well-defined borders. All of the L S cases showed dermal sclerosis, vacuolar interface changes, and a lym phocytic infiltrate underlying the sclerosis, but vulvar LS showed cha nges of lichen simplex chronicus or spongiotic dermatitis, dermal eosi nophils, and a frequent absence of atrophy. The presence of eosinophil ic spongiosis, marked lymphocyte exocytosis, dermal eosinophils, and e xcoriations predicted poor symptomatic response to treatment. Patch te sting is recommended for these individuals as these findings suggest a n allergic contact dermatitis. Examination of vulvectomy specimens rev ealed either a lichenoid interface or a spongiotic dermatitis in conti nuity with pathognomonic LS, Additionally, in these contiguous regions , we identified histologic changes that might represent evolving lesio ns of LS, suggesting a multifactorial etiology. In conclusion, vulvar LS was significantly different clinicopathologically from extragenital LS, and if only classic features of LS were used for pathologic diagn osis, many cases of vulvar LS would be missed. Therefore,we proposed a s the minimal histologic criterion for TS the presence of a vacuolar i nterface reaction pattern in conjunction with dermal sclerosis (homoge nized and hyalinized eosinophilic collagen bundles) of any thickness i ntervening between the inflammatory infiltrate and epithelium and or v essel walls.