35.    Marginal fibrosing alopecia, fibrosing alopecia in a pattern distribution and central scarring alopecia: one new and two known variants of circumscribed lichen planopilaris. 
Andreas Finner, Jerry Shapiro, Department of Dermatology and Skin Science, University of British Columbia, Vancouver, Canada.

Case reports: We report three cases of primary lymphocytic cicatricial alopecia due to Lichen planopilaris (LPP) in non-reticulated, circumscribed locations. The first case is a 63 yo Caucasian postmenopausal woman who developed a receding atrophic irregular frontal, temporal and occipital hairline with eyebrow thinning. The second case is a 25 yo Caucasian male presenting with scarring alopecia confined to the frontoparietal and vertex scalp, which is also affected by pattern hair loss (PHL). The third case is a 40 yo Caucasian female with an expanding scarred alopecic patch in the vertex. In all three patients, adjacent hair-bearing areas show clinical and histologic features of LPP. The lesions are itchy, there are no signs of lichen planus of other cutaneous sites, mucous membrane or nails. Discussion: This new variant of LPP, which we call Marginal Fibrosing Alopecia, not only affects the frontal and temporal hairline as previously described in Postmenopausal Frontal Fibrosing Alopecia (PFFA), but also the occipital hairline. As in cases of PFFA, there is eyebrow thinning and the condition is clinically and histologically indistinguishable from multifocal LPP, except for the special location. The second phenotype resembles a variant previously described as fibrosing alopecia in a pattern distribution. Its relation to PHL has not been clearly defined. The third case represents a central morphologic variant of LPP, which is commonly observed by us and other authors. The central scalp appears to be a generally more susceptible area for primary scarring alopecias. Summary: Marginal fibrosing alopecia is a new variant of circumscribed LPP not previously described. Other variants present as frontal fibrosing alopecia, fibrosing alopecia in a pattern distribution and central scarring alopecia. The significance and reasons for the preference of certain scalp regions in these subsets of LPP and in cicatricial alopecia in general have yet to be elucidated.