Langerhans’ Cells in epidermis, labeled brown
ACUTE ECZEMATOUS
Gr. boiling over
-Allergic contact (poison ivy)
-Atopic
-Drug related
-Photo
-Primary irritant
Acute Eczematous Dermatitis
Erythmetous: papulovesicular oozing and crusted
PATHOGENESIS OF ALLERGIC CONTACT DERMATITIS
- Exposure to poison ivy = altered self proteins
- Langerhans cells migrate to lymph nodes
- Ag to T-lymph, tells them to hate, wait re-exposure
- T-cells migrate to epidermis, release cytokines
- Cytokines/lymp mediate damage to epidermis
Acute Eczematous Dermatitis
Edema/fluid, splays apart keratinocytes → spongiotic dermatitis
PSORIASIS
Gr. the itch
- 1-2% of US population
- Immunologic disease
- Sensitized dermal CD4+ T-cells and epidermal CD8+ T-cells
- Secrete cytokines and growth factors
- Keratinocyte hyperproliferation → acanthosis and parakeratosis
PITAH
Psoriasis
Psoriasis: acanthosis and parakeratosis
SEBORRHEIC KERATOSIS
Latin, tallow
* Very common in middle-aged and elderly (skin barnacles)
* Activating mutation in fibroblast growth factor receptor
* Never become malignant
SB FBGF
Seborrheic Keratosis
VERRUCA
Latin, wart
* Caused by HPV virus
* Distinct low risk types that cannot become malignant
* Undulant epidermal hyperplasia and
koilocytosis (Gr: koilo = hollow)
Verruca
ACTINIC (SUN RELATED) KERATOSIS
- May regress, be stable, or progress to squamous cell ca
- Basal cell hyperplasia
- Cytologic atypia
- Parakeratosis and hyperkeratosis
- Dermal solar elastosis
- Topical freezing or chemotherapy
Actinic Keratosis
BASAL CELL CARCINOMA
- The most common human cancer
- Slowly growing, rarely metastasizes
- Chronic sun exposure, lightly pigmented people
- Dysregulated sonic hedgehog or PTCH pathway
- PTCH functions as a classic tumor suppressor
Basal Cell Carcinoma
Basal Cell Carcinoma
SQUAMOUS CELL CARCINOMA
- Sun exposure, older people, but also burns and ulcers
- Organ transplant recipients/immune suppression
- Less than 5% have metastases at diagnosis,
especially if from actinic keratosis - Much less aggressive than mucosal squamous cell ca
Squamous Cell Carcinoma
Squamous Cell Carcinoma
MELANOMA
- Sunlight (New Zealand – Australia – transported Irish)
- Usually de novo but sometimes pre-existing nevus
- Radial and vertical growth
- Probability of metastases predicted by depth of invasion
- Red hair, fair skin, easy freckling, the Weasleys
- Activating mutations in proto-oncogenes and tumor
suppressor genes - Melanocytes gone bad
- ABCD rules
Melanoma
Melanoma
