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

J Cutan Pathol. 2020 Oct;47(10):903-912. doi: 10.1111/cup.13741. Epub 2020 Jun 9.

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.

Keywords: elastic; elastophagocytosis; genital dermatoses; lichen sclerosus; matrix metalloproteinase.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biopsy / methods
  • Diagnosis, Differential
  • Elastic Tissue / metabolism
  • Elastic Tissue / pathology*
  • Female
  • Genitalia / pathology*
  • Granuloma / pathology*
  • Histiocytes / metabolism
  • Histiocytes / pathology
  • Humans
  • Immunohistochemistry / methods
  • Lichen Sclerosus et Atrophicus / diagnosis*
  • Lichen Sclerosus et Atrophicus / metabolism
  • Lichen Sclerosus et Atrophicus / pathology
  • Male
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Middle Aged
  • Phagocytosis / physiology

Substances

  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9