Nonsclerotic Lichen Sclerosus: Definition of a Concept and Pathologic Description

Abstract

Objective: Nonsclerotic lichen sclerosus (NSLS) refers to the clinicopathologic situation of examination findings consistent with lichen sclerosus (LS) but without dermal sclerosis on microscopy. This review aims to describe the features of NSLS and provide a classification framework.

Methods: The International Society of the Study of Vulvovaginal Diseases tasked the Difficult Pathologic Diagnoses Committee with development of consensus documents for conditions with problematic histopathology. The Difficult Pathologic Diagnoses Committee reviewed the literature on NSLS and formulated descriptions and diagnostic criteria, then approved by the International Society of the Study of Vulvovaginal Diseases membership.

Results: Nonsclerotic LS may be categorized into 4 histopathologic subtypes: lichenoid dermatitis, hypertrophic lichenoid dermatitis, dermal fibrosis without acanthosis, and dermal fibrosis with acanthosis. Each has a pathologic differential diagnosis of 1 or more entities, so clinical correlation is required for final diagnosis of LS. There is no evidence to support a reliable association between absent sclerosis and clinical appearance, duration, or oncogenic potential of LS.

Conclusions: Pathologists and clinicians should be familiar with the concept of NSLS and its implications for patient management. Use of the term "early LS" to indicate a lack of sclerosis in presumed LS should be abandoned. Clinical correlation is required to confirm LS from among the differential diagnoses.

FIGURE 1

Lichenoid dermatitis with clinical findings suggestive of lichen sclerosus (LS): (A) subtle pallor over inner labium minus, erythema and fissure at right interlabial sulcus; (B) biopsy of right interlabial sulcus (circle) shows basal layer degeneration, exocytosis, dense band-like upper dermal lymphocytic infiltrate, and absent sclerosis, hematoxylin and eosin (H&E) ×200.

FIGURE 2

Hypertrophic lichenoid dermatitis with clinical LS: (A) perineal pallor and thickened texture; (B) biopsy of perineum (circle) showing hair-bearing skin with thick parakeratosis (PK) and hyperkeratosis (HK); acanthosis with irregular rete ridges, exocytosis, apoptotic bodies, and vacuolar change confined to the tops of papillae; moderate perivascular lymphoplasmacytic infiltrate; and absent sclerosis, H&E ×100; (C) thick HK alternating with columns of PK (arrows) overlying the tops of dermal papillae and irregular acanthosis, H&E ×200.

FIGURE 3

Dermal fibrosis without acanthosis with clinical LS: (A) diffuse pallor over interlabial sulci and labia majora; (B) biopsy of right labium majus (circle) with normal epidermis apart from basement membrane thickening; dermis contains a thick layer of fibrosis and scant infiltrate, H&E ×200; (C) periodic acid-Schiff stain highlights the thick basement membrane (arrows), ×200.

FIGURE 4

Dermal fibrosis with acanthosis with clinical LS: (A) pallor over the periclitoris, perineum, and interlabial sulci abutting a circumferential red patch over the vestibule accompanied by loss of anterior architecture, consistent with comorbid LS and erosive lichen planus; (B) biopsy of perineum (circle) showing hair-bearing skin with HK and focal PK, irregular acanthosis, clubbed rete ridges, and absent sclerosis, H&E ×20; (C) reactive basal layer without evidence of degeneration, scant lymphocytic infiltrate, and horizontally disposed thick collagen fibers with intervening rows of lymphocytes (arrows), H&E ×100; (D) row of lymphocytes and rare neutrophils, H&E ×200.