Definition/General

Introduction:
-Vulvar lichen planus (LP) is a chronic inflammatory dermatosis characterized by interface dermatitis with lichenoid inflammation
-It represents a T-cell mediated autoimmune condition affecting the vulvar mucosa and skin
-Can present as erosive or non-erosive variants
-Affects women predominantly in the 4th-6th decades
-Associated with significant morbidity due to pain and sexual dysfunction.
Origin:
-Results from T-cell mediated autoimmune reaction against basal keratinocytes
-Molecular mimicry between self and foreign antigens proposed
-Genetic predisposition with HLA associations
-Triggered by drugs, infections, or stress
-Lichenoid tissue reaction pattern
-Interface dermatitis with basal cell damage.
Classification:
-Classified as reticular/papular (non-erosive) or erosive (ulcerative) variants
-Hypertrophic lichen planus (rare vulvar variant)
-Atrophic lichen planus
-Bullous lichen planus
-May be localized to vulva or part of generalized disease
-Overlap with lichen sclerosus possible.
Epidemiology:
-Peak incidence in 4th-6th decades
-Female predominance for genital involvement
-Vulvar involvement in 25-50% of women with cutaneous LP
-Erosive variant more common in vulva
-Associated with oral lichen planus in 40-60%
-HLA-DR1 and DQ1 associations
-Risk of malignant transformation controversial.

Clinical Features

Presentation:
-Violaceous papules and plaques with white lacy pattern (Wickham striae)
-Erosive variant: painful erosions and ulcers
-Burning pain (characteristic symptom)
-Vestibular involvement common
-Vaginal involvement may cause discharge
-Scarring and adhesions in chronic cases.
Symptoms:
-Severe burning pain (80-90% cases)
-Dyspareunia (70-80%)
-Contact bleeding
-Vaginal discharge (if vaginal involvement)
-Dysuria
-Pruritus (less common than in lichen sclerosus)
-Functional impairment
-Introital stenosis (chronic cases).
Risk Factors:
-Genetic predisposition (HLA associations)
-Autoimmune diseases (thyroid, diabetes)
-Viral infections (hepatitis C, HPV)
-Drug reactions (antimalarials, NSAIDs, ACE inhibitors)
-Psychological stress
-Mechanical trauma
-Contact allergens.
Screening:
-No specific screening program
-Careful examination of oral cavity and skin
-Biopsy confirmation essential
-Regular follow-up for monitoring
-Screening for hepatitis C recommended
-Assessment of other mucosal sites
-Psychological support evaluation.

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Gross Description

Appearance:
-Violaceous, polygonal papules with flat-topped surface
-White lacy network (Wickham striae) on surface
-Erosive variant: well-demarcated erosions with fibrinous exudate
-Vestibular erythema and erosions
-Vaginal involvement: friable, erythematous mucosa.
Characteristics:
-Symmetric distribution
-Well-demarcated lesions
-Shiny, violaceous color
-Flat-topped papules
-Koebner phenomenon (trauma-induced lesions)
-White striations on surface
-Erosions may be deep and painful.
Size Location:
-Variable size from 2-10 mm papules to confluent plaques
-Most commonly vestibule and vaginal introitus
-Labia minora frequently affected
-Gingival involvement (vulvovaginal-gingival syndrome)
-May extend to perianal area.
Multifocality:
-Multifocal disease common
-Bilateral symmetric involvement
-Skip areas may be present
-Concurrent oral involvement in 40-60%
-Cutaneous lesions elsewhere
-Nail involvement possible
-Esophageal involvement rare.

Microscopic Description

Histological Features:
-Interface dermatitis with basal cell damage
-Dense, band-like lymphocytic infiltrate at dermal-epidermal junction
-Civatte bodies (apoptotic keratinocytes)
-Hypergranulosis in non-erosive areas
-Saw-tooth rete ridges
-Melanin incontinence.
Cellular Characteristics:
-Lymphocytic infiltrate predominantly T-cells
-Basal cell vacuolization
-Apoptotic keratinocytes (Civatte bodies)
-Melanophages in upper dermis
-Plasma cells may be present
-Eosinophils usually absent.
Architectural Patterns:
-Lichenoid tissue reaction pattern
-Band-like inflammatory infiltrate
-Max Joseph spaces (clefting at DEJ)
-Saw-tooth acanthosis
-Orthokeratotic hyperkeratosis
-Wedge-shaped hypergranulosis
-Basement membrane thickening.
Grading Criteria:
-No standard grading system
-Assessment based on inflammatory activity
-Extent of interface changes
-Degree of erosion
-Scarring and fibrosis
-Epithelial atrophy
-Basement membrane changes.

Immunohistochemistry

Positive Markers:
-CD3 (T-lymphocytes in infiltrate)
-CD8 (cytotoxic T-cells predominant)
-CD68 (melanophages)
-PAS (thickened basement membrane)
-Collagen IV (basement membrane)
-Fibrin (areas of erosion)
-Ki-67 (proliferation assessment).
Negative Markers:
-CD20 (few B-cells in infiltrate)
-HPV ISH (not HPV-related)
-HSV/CMV (viral inclusions absent)
-p16 (negative or weak)
-Elastic fibers (preserved unlike lichen sclerosus)
-Smooth muscle actin (myofibroblasts variable).
Diagnostic Utility:
-Limited utility in typical cases
-CD8 predominance supports diagnosis
-PAS stain highlights thickened basement membrane
-Elastic stain shows preserved elastic fibers
-Direct immunofluorescence may show fibrinogen and IgM at DEJ
-HPV ISH excludes viral etiology.
Molecular Subtypes:
-Classic lichen planus: interface dermatitis pattern
-Hypertrophic variant: prominent acanthosis
-Atrophic variant: minimal acanthosis
-Bullous variant: subepidermal separation
-Drug-induced: similar histology
-Post-inflammatory: residual changes.

Molecular/Genetic

Genetic Mutations:
-HLA class II associations: HLA-DR1, DQ1, DR10
-TNF-alpha polymorphisms
-IL-10 gene variants
-Autoimmune susceptibility genes
-T-cell receptor gene rearrangements
-Apoptosis pathway genes
-Cytokine gene polymorphisms.
Molecular Markers:
-T-cell activation markers
-Cytokine dysregulation (IL-2, IFN-gamma, TNF-alpha)
-Apoptosis markers (p53, Bcl-2)
-Adhesion molecules (ICAM-1, VCAM-1)
-Matrix metalloproteinases
-Heat shock proteins.
Prognostic Significance:
-Erosive variant has worse prognosis
-Risk of scarring and functional impairment
-Malignant transformation risk controversial
-Chronic inflammation promotes complications
-Response to treatment variable
-Psychological impact significant.
Therapeutic Targets:
-Topical corticosteroids: clobetasol propionate
-Calcineurin inhibitors: tacrolimus
-Systemic corticosteroids (severe cases)
-Methotrexate
-Cyclosporine
-Biologics under investigation
-Photodynamic therapy.

Differential Diagnosis

Similar Entities:
-Lichen sclerosus
-Cicatricial pemphigoid
-Pemphigus vulgaris
-Erosive vulvar dermatitis
-Behcet disease
-Crohn disease
-Aphthous ulcers
-Drug eruption.
Distinguishing Features:
-LP: interface dermatitis, lichenoid infiltrate
-LS: homogeneous dermal sclerosis
-Pemphigoid: subepidermal blistering, eosinophils
-Pemphigus: intraepidermal blistering, acantholysis
-Behcet: deep ulcers, neutrophils
-Crohn: granulomatous inflammation
-Histology essential for diagnosis.
Diagnostic Challenges:
-Distinguishing erosive LP from other erosive conditions
-Chronic changes may obscure typical features
-Overlap with lichen sclerosus
-Drug-induced lichenoid reaction
-Secondary infection complicating picture
-Biopsy timing important.
Rare Variants:
-Hypertrophic lichen planus
-Bullous lichen planus
-Atrophic lichen planus
-Linear lichen planus
-Annular lichen planus
-Lichen planus pemphigoides
-Vulvovaginal-gingival syndrome.

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Specimen Information

Vulvar biopsy from [site], measuring [size] cm

Diagnosis

Lichen planus, [erosive/non-erosive] variant

Classification

Classification: [Erosive/Non-erosive/Hypertrophic], activity: [Active/Chronic]

Histological Features

Shows [interface dermatitis] with [lichenoid infiltrate] and [epithelial changes]

Interface Changes

Interface shows [basal cell damage] with [Civatte bodies] and [vacuolization]

Inflammatory Infiltrate

Infiltrate is [band-like/diffuse] composed of [lymphocytes] with [density]

Epithelial Changes

Epithelium shows [acanthosis/atrophy] with [hyperkeratosis] and [erosion status]

Basement Membrane

Basement membrane: [thickened/normal] with [PAS positivity]

Special Studies

Direct immunofluorescence: [performed/not performed]: [results]

IHC: [if performed]: [results]

[other study]: [result]

Prognostic Factors

Risk factors: variant type, extent of disease, scarring

Final Diagnosis

Vulvar lichen planus, [variant], [activity status]