Dermatopathology - Inflammatory Skin Diseases PDF 2024

Dermatopathology – inflammatory skin diseases Jin Guo, MD 2024  Dematopathology – Neoplastic skin diseases – Inflammatory skin diseases Acute inflammatory dermatoses – Urticaria – Acute eczematous dermatitis – Erythema multifor...

Dermatopathology – inflammatory skin diseases Jin Guo, MD 2024  Dematopathology – Neoplastic skin diseases – Inflammatory skin diseases Acute inflammatory dermatoses – Urticaria – Acute eczematous dermatitis – Erythema multiforme Chronic inflammatory dermatoses – Psoriasis – Lichen planus – Lichen simplex chronicus Autoimmune bullous disease Infectious disorders of skin Urticaria What are the causes? Skin: Eosinophils may be present between the edematous collagen bundles normal urticaria  Contact dermatitis A type of eczematous dermatitis Type IV delayed hypersensitivity reaction to exogenous agent Common contactants – Poison ivy – Nickel – Rubber (boots, latex gloves) – Preservatives Acute lesions – vesiculobullous Chronic lesions – erythematous plaques This healthy adolescent developed an itchy eczematous eruption on his arms. Spongiosis (intercellular edema) in the epidermis. spongiosis Intraepidermal vesicles contact dermatitis normal  Erythema multiforme Clinical Features – Acute mucocutaneous eruption – Erythematous & targetoid lesions (papules/vesicles/bullae) – Bilateral, usually symmetric – Acral, extensor surfaces, +/- mucosa – Etiology: Drug (sulfonamides, anticonvulsants), Infection (herpes simplex, mycoplasma), Idiopathic (50%) This healthy 11-year-old boy developed widespread target lesions on his back, chest, and extremities.  Erythema multiforme Histologic features – Early Vacuolar interface dermatitis Scant perivascular lymphocytic infiltrate, rare eosinophils – Late Subepidermal bullae Overlying epidermis often demonstrates liquefactive necrosis and degeneration  Erythema multiforme - severe variants Stevens-Johnson syndrome – Variant of erythema multiforme “major” – More diffuse erythema & skin necrosis – Mucosal involvement – 30% epidermal detachment) – Usually secondary to medication (80%) Chronic inflammatory dermatoses Case An 18-year-old man first discovered an itchy, scaling, red papule on the skin of an elbow Well-demarcated plaques covered by silver- white scales The scaling is surrounded by erythematous skin with sharp outlined borders  In the course of several months, the lesions also appeared on the other elbow, the knees and the scalp. At this time, he saw a dermatologist. When the scale was lifted from a plaque, multiple, minute bleeding points became visible.  Psoriasis Clinical features – Common, chronic papulosquamous disorder – Affects 2% of general population – Well-demarcated erythematous plaques with silvery scale – Scalp, nails, extremities, sacral region  Epidermis shows thickening (acanthosis) with elongation of rete ridges Superficial dermis shows a chronic inflammatory infiltrate Hyperkeratosis with parakeratosis Psoriasis Neutrophils are present in a thick layer of parakeratosis, and the stratum granulosum is almost absent. Munro microabscesses Psoriasis Psoriasis Hypogranulosis Elongated rete ridges  This healthy 5-year-old boy developed a widespread itchy hyperpigmented papulosquamous eruption most densely distributed on his arms and legs.  Lichen planus Purple, pruritic and polygonal papules Histologic features – Hyperkeratosis (usually no parakeratosis) – Acanthosis – Saw-tooth elongation of rete ridges – Lichenoid lymphocytic infiltrate – Occasional eosinophils & plasma cells Lichen simplex chronicus Acanthosis, hyperkeratosis and hypergranulosis elongation of the rete ridges and fibrosis of the papillary dermis with a chronic inflammatory infiltrate Case A 62-year-old man with a painful lesion on his soft palate. On inspection, there are multiple red areas of ulceration. The lesion persists and after a few weeks, skin lesions also appeared. They are round-to-oval vesicles and bullae that easily erupt. They are randomly scattered on the face, chest, axilla and groin. Bullous diseases: The axilla shows large areas of ulceration. What are the complications of blistering diseases?  Autoimmune blistering diseases Pemphigus Vulgaris Pemphigus Foliaceus Bullous Pemphigoid Dermatitis Herpetiformis Paraneoplastic Pemphigus  Pemphigus vulgaris Clinical features – 40 to 60 years; M=F – Flacid blisters and erosions – Frequent mucous membrane involvement  Pemphigus vulgaris Histologic features – Intraepidermal bullae – Suprabasilar acantholysis – “Tombstone row” of basal layer keratinocytes – Sparse dermal infiltrate, often with eosinophils Acantholysis → intraepidermal blister Dermal collagen covered by a layer of basal keratinocytes  Pemphigus vulgaris – IgG circulating autoantibodies to desmoglein resulting in loss of normal cell-to-cell adhesion Direct immunofluorescence – “Chicken wire” pattern  Pemphigus foliaceus Histologic features – Subcorneal split; sometimes absence of stratum corneum – Superficial acantholysis  Pemphigus foliaceus Clinical features – “Superficial” pemphigus – Erythematous patches and crusted erosions; rarely intact bullae – Middle-aged and elderly – Face, scalp, upper trunk – IgG circulating autoantibodies to desmoglein  Bullous pemphigoid Clinical features – Chronic autoimmune blistering disease – 60-80 years of age; M=F – Bullae, erythematous papules, urticarial plaques – Generalized cutaneous lesions and involvement of mucosa – Circulating anti-basement membrane IgG. linear IgG along basement membrane  Bullous pemphigoid Histologic features – Subepidermal bulla with eosinophils – Subepidermal bulla with neutrophils – Cell-poor subepidermal bulla  Dermatitis herpetiformis Clinical features – Intensely pruritic papulovesicular eruption – 20-60 years, male > female (2:1) – Symmetrically distributed on elbows, knees, buttocks – Gluten-sensitive enteropathy  Dermatitis herpetiformis Histologic features – Neutrophil-rich subepidermal bulla Direct immunofluorescence – Granular IgA in papillary dermal tips pemphigus foliaceus pemphigus vulgaris bullous pemphigoid or dermatitis herpetiformis Verruca vulgaris Common viral infection of skin (HPV). hyperkeratosis, parakeratosis, papillomatosis and koilocytosis HPV + Molluscum Contagiosum Self limited infectious dermatosis caused by mollouscum contagionsum virus of pox virus family Molluscum bodies (large cells with cytoplasmic, granular eosinophilic inclusions that displace nuclei and contain viral particles) herpes simplex HSV1,2 Painful diseases caused by herpes simplex virus (HSV) Keratinocytes are multinucleated, with distinct nuclear inclusions Late epidermal necrosis or full-thickness acantholysis Scabies (mite) Erythema Nodosum Thickened septa with Subcutaneous nodules with a inflammatory infiltrate that bright red color and raised extends to the periphery of slightly above the skin. the fat lobule.  Summary Acute inflammatory dermatoses – Urticaria – Acute eczematous dermatitis – Erythema multiforme Chronic inflammatory dermatoses – Psoriasis – Lichen planus – Lichen simplex chronicus Bullous diseases Infection and infestation 32 y/o M medical student with history of recent URI ERYTHEMA MULTIFORE: central blister or zone of epidermal necrosis surrounded by macular erythema Toxic Epidermal Necrolysis PSORIASIS. 50 y/o F with pruritic, purple, polygonal papules involving wrists, the lower arms & mucosa (leukoplakia) lichen planus pemphigus vulgaris Skin, immunofluorescence: deposition of immunoglobulin between the epidermal keratinocytes in a fishnet-like pattern. Skin, 60 y/o man with tense bullae, in an erythematous background. When the blisters rupture, the resulting lesions become crusted. Bullous pemphigoid Direct immunofluoresence shows linear deposition along the dermoepidermal junction. The most likely diagnosis: A. psoriasis B. seborrheic keratosis C. lichen planus D. lichen simplex chronicus E. discoid lupus The most likely diagnosis: A. psoriasis B. seborrheic keratosis C. lichen planus D. lichen simplex chronicus E. discoid lupus The most likely diagnosis: A. psoriasis B. seborrheic keratosis C. lichen planus D. lichen simplex chronicus E. discoid lupus The most likely diagnosis: A Pemphigus Vulgaris B Pemphigus Foliaceus C Bullous Pemphigoid D Dermatitis Herpetiformis E Erythema multiforme The most likely diagnosis: A Pemphigus Vulgaris B Pemphigus Foliaceus C Bullous Pemphigoid D Dermatitis Herpetiformis E Erythema multiforme The most likely diagnosis: A Pemphigus Vulgaris B Pemphigus Foliaceus C Bullous Pemphigoid D Dermatitis Herpetiformis E Erythema multiforme