Week 8 - Derm

Macule:

Flat discoloration of skin or mucosa, seen but not palpated

Papule:

Small elevated bump of skin or mucosa

Vesicle:

Fluid-filled blister

Bulla:

Large fluid-filled blister

Pustule:

Blister filled with fluid and neutrophils

Ulcer:

Complete loss of surface epithelium with exposed connective tissue

Complete loss of surface epithelium is called _____.

Ulcer

Erosion:

Partial loss/wearing away of epithelial cells

Erythema:

Redness of skin or mucosa from inflammation

Urticaria / hives:

Erythema with soft edematous papules or plaque-like lesions

Keratosis / hyperkeratosis:

Increased keratinized layer, often presenting as a plaque

Oral keratotic plaques are called _____.

Leukoplakias

Scale:

Flaking/desquamating keratin from a keratotic lesion

What does pruritic mean?

Itchy

Excoriation:

Loss of surface cells from scratching

Maculopapular rash:

Usually infectious in children, allergic/drug reaction in adults

What is an example of infectious maculopapular rash?

Measles

Maculopapular rash in adults usually suggests:

Allergic or drug reaction

What stage of syphilis would you see macules and papules?

Secondary syphilis

Vesicular eruptions usually suggest:

Viral infection

What are examples of viral diseases that cause vesicles?

Herpes, chickenpox, smallpox, shingles

What to suspect when children have a widespread rash?

its usually viral, like measles or rubella

What to suspect when adults have a widespread rash?

drug reaction

Morbilliform exanthematous drug eruption:

Measles-like drug rash

Why does blister location matter?

the level of epithelial split helps diagnose the disease

Suprabasilar split:

separation of spinous layer cells from basal cells

Subepithelial/junctional split:

the entire epithelium separates from underlying connective tissue

Pemphigus vulgaris:

Autoimmune bullous disease with antibodies to desmoglein causing suprabasilar/intraepithelial blister

What is the Pemphigus vulgaris target antigen?

Desmoglein 1 and 3

Why can untreated pemphigus vulgaris be fatal?

Loss of protective epithelium → bacteremia, fluid loss, electrolyte imbalance

Mucous membrane pemphigoid:

Autoimmune blistering disease with antibodies to basement membrane/hemidesmosome proteins

What are the MMP target antigens?

BP180 and BP230

What procedures to do to diagnose bullous disease?

Biopsy for histology + direct immunofluorescence

Lichen planus:

Cell mediated disease with T-lymphocytes damaging epithelium

What are the skin findings in lichen planus?

Purple, pruritic, polygonal/planar papules, often flexor surfaces

Lichen planus oral findings:

Bilateral white striated/spiderweb lesions, erosions or ulcerations

Psoriasis:

Keratotic pruritic plaques, usually extensor surfaces and trunk

Does psoriasis commonly affect the mouth?

No, oral manifestations are rare

Auspitz sign:

scraping psoriasis leaves small points of hemorrhage

Describe the histological appearance of psoriasis ?

Neutrophils in epidermis

Verruca vulgaris:

Common wart, benign keratinocyte tumor

Verruca vulgaris location:

Hands and fingers

Describe the appearance of verruca vulgaris:

Round yellow/white keratotic nodules

Verruca vulgaris HPV types:

HPV 2 and 4

Seborrheic keratosis:

Benign brown waxy/oily lesion from epithelial hyperplasia

Seborrheic keratosis location:

Face, forehead, temples

Do verruca vulgaris and seborrheic keratosis have malignant potential?

No

Basal cell carcinoma:

Locally aggressive keratinocyte tumor that does not metastasize

BCC risk factor:

Sun exposure

Why is BCC dangerous if untreated?

it can invade locally into bone/brain causing tissue destruction

Actinic keratosis:

Flat scaly keratotic precancerous lesion caused by solar radiation

Squamous cell carcinoma:

Invasive keratinocyte malignancy that can metastasize

Describe the histological appearance of SCC:

Invasive epithelial islands with spinous/keratin layer differentiation and cytologic atypia

SCC spread:

Local lymph nodes or hematogenous spread

Nevus:

Benign melanocytic hamartoma

Melanoma:

Malignant tumor of melanocytes, one of the most deadly cancers

Melanoma pigmentation:

Usually brown/blue, but can be amelanotic

Superficial spreading melanoma:

Lateral spread along epidermal/dermal junction, low metastatic potential, better prognosis

Nodular melanoma:

Invasive melanoma with high nodal/hematogenous metastasis risk and poor prognosis

Melanoma oncogene mutation:

BRAF (40-50% of cases)

Fibrocystic disease of breast:

benign cystic duct derived masses with scar-like collagen

Does fibrocystic disease predispose to breast cancer?

No

Breast cancers are typically ______ and many subtypes exist.

adenocarcinomas

Hereditary breast cancer genes:

BRCA1/BRCA2 (5-10% of breast cancers)

HER2:

Human epidermal growth factor receptor Tyrosine kinase receptor

What is the treatment for HER2-positive breast cancers?

Trastuzumab / Herceptin