Elastophagocytosis and interstitial granulomatous infiltrate are more common in extragenital vs genital lichen sclerosus

Abstract

Background: Genital and extragenital lichen sclerosus (LS) share similar histopathologic features. A recent small series documented elastophagocytosis uniquely in extragenital LS. We evaluated a larger series of LS for elastophagocytosis, elastic fiber loss, and other histopathologic features. We evaluated matrix metalloproteinase (MMP) expression to determine if these proteins play an etiologic role. Methods: Genital (n = 42) and extragenital (n = 41) LS biopsies were examined for histopathologic features, elastic fiber alteration (Verhoeff van Gieson staining), and MMP-2 and MMP-9 expression (immunohistochemistry). Results: Elastophagocytosis and an interstitial granulomatous pattern were significantly more common in extragenital LS than genital LS (43.9% vs 4.7% and 56.1% vs 9.5%). Extragenital LS had mild/focal elastic fiber loss (43.9%), while genital LS had moderate (61.9%) or marked (19%) loss. MMP-9 was diffusely expressed in histiocytes in both types of LS (genital 97.5%; extragenital 100%). Weak MMP-2 expression was seen in genital (58%) and extragenital (55%) LS. Conclusions: Extragenital LS, but not genital LS, frequently exhibits elastophagocytosis and interstitial granulomatous infiltrate, and these patterns could contribute to elastic fiber destruction in extragenital LS. While MMP-2 and MMP-9 expression are common in LS, expression did not significantly differ depending on anatomic site and thus is unlikely to explain observed histopathologic differences.

Multiphoton microscopy assessment of the structure and variability changes of dermal connective tissue in vulvar lichen sclerosus: A pilot study

“…An increase in signal from the affected dermis was demonstrated, which was independent of the VLS degree (Figure 7H, P < .03). Elastic fibers in the affected tissue may be preserved (Figure 3C), affected by lysis (Figures 2C and 4C to 6C) or accumulate excessively [58, 59]. However, the presence or absence of the elastic fibers in tissue did not significantly affect the mean TPEF signal intensity in our study, and there were no significant differences between the VLS groups (Figure 7H, P = 1).…”

Extragenital lichen sclerosus: A comprehensive review

“…Also, EGLS cases showed mild/focal elastic fibre loss (43.9%) compared with genital LS, which had moderate (61.9%) or marked (19%) loss. 48,49 In a study by Borges L, upper dermal hyalinization was found to be the most common finding in EGLS cases, while vascular ectasia was the most common finding in genital LS cases. 48 In a study by Knio et al, perineural inflammation in histopathology was observed in 22/60 cases (33.8%), which is a novel finding in LS that might help in differentiating it from close LS mimics such as lichen planus.…”

“…In a study by Kendal et al, elastophagocytosis and interstitial granulomatous infiltrates were most common findings in EGLS than in genital LS (43.9% vs 4.7% and 56.1% vs 9.5%). Also, EGLS cases showed mild/focal elastic fibre loss (43.9%) compared with genital LS, which had moderate (61.9%) or marked (19%) loss 48,49 …”

Genital Wound Repair and Scarring

“…An increased autoimmune response with formation of auto-antibodies against ECM-1 protein are features of this multifactorial disease [ 60 ]. Interestingly, a higher dermal inflammatory infiltrate with immune cells degrading elastic fibers was found in extra-genital LSC compared with genital skin [ 61 ]. LSC is associated with the development of squamous cell carcinoma in women in about 5% [ 62 ] and in men up to 30% [ 63 ].…”