Dermatology Flashcards by Roma Bannon

Describe the histology of atopic eczema

Flexures of elbows and knees -Associated with asthma and hay fever
Histologically- spongiosis formation- accumulation of fluid in the epidermis
- Perivascular inflammation in superficial dermis
- Usually lymphocytes and mast cells are inflammatory cells

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Describe the histology of chronic plaque psoriasis

Well demarcated, red scaly and thickened areas of skin with silvery scale
Extensors of knees and elbows
Scalp and nails involved

Histology- Chronic inflammation dermis and thickening of dermis

No eosinophils involved in psoriasis*
Hyperkeratosis , epithelial hyperplasia (acanthosis), chronic inflammation

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What is erythema multiforme

A hypersensitivity reaction triggered by infections like herpes simplex
Acute skin eruption with characteristic targeted lesion

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What are the main type of inflammatory cells seen in drug skin reactions

eosinophils

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Describe Lichen Planus

Idiopathic -Itchy purple polygon shaped flat raised skin lesions
Lower back wrists and ankles
Histology: Chronic inflammatory cell infiltrate along the dermal-epidermal junction

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What is lichen sclerosus

Chronic skin condition with white patches appearing on genitals, itching and slight risk of cancer
Zones of hyalinisation or sclerosis in the superficial dermis

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Describe erythema nodosum and it’s causes

-Panniculitis (inflammation of subcutaneous fat) causing tender red nodules on the shins

Caused by

Strep throat
OCP and antibiotics
Sarcoid
IBD
Pregnancy

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What is pemphigus vulgarisms

Severe blistering of the skin and mucous membranes (mouth nose throat genital)

Intraepidermal blisters
Anti-desmosome antibodies - cells falling apart from one another - chicken wire pattern on immunoflurosecence

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What is bullous pemphigoid

Blisters affecting the skin and occasionally mouth, sub epidermal blister with anti basement membrane antibodies, IgG found along the basement membrane

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What is dermatitis herpetiformis

Itchy blistering skin associated with coeliac disease causing sub epidermal blisters
-IgA TTG and IgA anti-edomysial antibodies

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Describe cutaneous sarcoidosis

Non-infectious non-caveating granulomatous inflammation
-Plaques and papules on body anywhere
2/3 patients will have systemic sarcoidosis

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What is granuloma annulare

Zones of degenerate collagen surrounded by a rim of histiocytes/ macrophages (necrobiotic granulomatous inflam)
Localised is most common
-Round pink purple patches on bony sites- knees and elbows

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What is necrobiosis Lipodica

Necrobiotic granulomatous inflam
Risk factor is T1 and T2D
Yellow brown patches on lower legs- tender
-Overlying skin prone to ulceration

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How does herpes simplex virus affect the skin

-Intra-epidermalblister localised - lips, genitals and rectum- can recur
With intracellular viral inclusions

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What is molluscum contagious

Cutaneous infection by Molluscum contagiosum virus with round raised lesions and a central crater, resolve without treatment

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What are the two main bacterial infections of the skin

Impetigo- infection of the superficial dermis- staph aureus

Cellulitis- infection of the dermis and subcutaneous fat- staph aureus or strep pyrogenes

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What are the 3 cateogories of pre-cancers in dermatology

Squamous dysplasia
- Actinic keratosis -Bowen’s disease
Melanocytic
- Dsyplastic naevus -Melanoma in situ
Glandular
- Paget’s disease of nipple -Extra-mammary pagets

What are the 4 types of invasive cancer in dermatology

Epithelial cancers- basal carcinoma -squamous cell carcinoma
Malignant melanoma
Cutaneous T-cell lymphoma
Kaposi sarcoma

Explain the term dysplasia

Normal cells transforming into cancer cells gradually due to accumulation of genetic mutation in tumour suppressor and oncogenes- dysplasia is cells in the transitional period

What are some of the risk factors for dysplasia

For Acitinic keratosis and Bowen’s disease-chronic sunlight exposure, immunosuppression (renal transplant patients), previous irradiation and chemical carcinogens

Groin and perineum- anal-vulval intraepithelial neoplasm
-HPV

Describe the steps in squamous dysplasia

Normal dermis undergoes mild dysplasia with abnormal hyper chromatic nuclei and increased number of mitotic figures on the lower 1/3 of the epidermis
Moderate dysplasia is when these nuclei and mitotic figures extend to include the lower 2/3 of the epidermis
Severe dysplasia is when the full thickness of the dermis is involved
Invasive squamous cell carcinoma is when there is invasion of the basement membrane

What is dysplastic naveus

A pre-malignant melanocytic lesion that has acquired atypical histology with no invasion
can be sporadic or familial (dysplastic naves syndrome- 2 hit hypothesis)

Describe a melanoma in situ

Severe dysplasia of melanocytes in the epidermis
Risk factors - UV light exposure/ sun beds, fair skinned

Lentigo maligna: slow growing pigmented lesion on face

Describe Paget’s disease of the nipple

Abnormal glandular or mutinous cells in the epidermis (adenocarcinoma in situ) can resemble eczema

Abnormal cells migrate along lactiferous duct system to reach the surface epidermis
Underlying ductal carcinoma in situ with or without invasive component

Extramammary pages disease happens in fairly parts of the body

Describe a basal cell carcinoma

- Originates from undifferentiated stem cells in the basal layers of the epidermis - Common and rarely mets - found in H zone of face- high risk areas less likely for successful excision - Cells at the periphery of tumour are columnar and parallel to each other like a fence

Describe a squamous cell carcinoma

An invasive tumour that shows squamous differentiation | -Is more agressive and has potential to metastasise

Describe a malignant melanoma

Malignant tumour of melanocytes where abnormal cells have invaded the dermis Upward spread of cells = pagetoid spread Horizontal spread of cells= radial spread -Measures Breslow thickness and depth- distance between granular cell layer of epidermis and deepest malignant cell Risk factors- sunlight, sunbeams, dysplastic naevus syndrome -Much more aggressive

What treatment can you give if a patient's skin cancer has the BRAF mutation

Vemurafenib

What is mycosis fungoides

- Cutaneous t-cell lymphoma (non- hodgkins lymphoma) - Involves the epidermis and dermis - low grade and can resemble eczema, is slow growing - disease caused by infection with a fungus Sezary syndrome = more aggressive

What is a Kaposi Sarcoma

Malignant vascular proliferation within the dermis (or internal organs) Can be HIV related or transplant related, endemic related -Human herpes virus 8 spreads it but most people don't develop it unless immunosuppressed or genetically susceptible

Describe a cutaneous cyst

Spherical epithelial lined structure in the dermis with cheesy keratinous material most common= epidermal inclusion cyst

What is seborrhoea keratosis

Seen in elderly - barnacles - Can be confused for melanoma but their base is flat with makes it benign - Dark warty greasy lesion associated with aging - Often more than 1

What is a fibrous-epithelial poly/ skin tag

A round structure of mostly connective tissue with a thin epithelial cover - soft benign polypoid lesion most common in skin fold areas - axilla

What is a papilloma

A benign epithelial tumour arising from usually squamous epithelium with complex branching and fibrovascular core - breast, nasal cavity and larynx -Can be single or multiple and some are caused by HPV infection

What is a dermatofibroma

A benign fibroblastic proliferation in the dermis typically on the lower legs can represent an inflammatory response to trauma (insect bite)

Describe a skin ulcer

Full thickness loss of epidermis so granulation tissue is in a bed of ulcer ( a mix of new blood vessels and inflam cells - neutrophils and lymphocytes) Causes: Arterial/ venous insufficiency, diabetes, trauma, surgery, immobility (pressure ulcer) Squamous cell carcinomas can sometimes ulcerate

What is a pyogenic granuloma

A benign fast growing vascular tumour involving polypoid proliferation of small blood vessels that can ulcerate and bleed -raspberry or mince Causes: Trauma, infection, pregnancy, medication

What is a pilonidal sinus

fragmented hair shaft material in a sinus tract in the dermis surrounded by inflam cells and fibrous scar tissue -Sacrum/ buttocks of hairy men

Describe what a freckle is and what is solar lentigo

Increase in basal pigmentation but no increase in melanocytes Solar lentigo: Increase in basal pigmentation and a small increase in basal melanocytes but no nuclear atypia - elderly- can be a differential for lentigo malignant

What is lentigo malignant

Melanoma in situ on a persons face -Greater number of melanocytes with nuclear enlargement, atypia and increase no of mitotic figures with upward (pagetoid) spread

What is the difference between junctional naevus, intradermal naevus and compound naevus

1. Junctional naevus - proliferation of benign melanocytes confined to the epidermis 2. Proliferation of benign melanocytes within the dermis 3. Combined features of both of the above and an intradermal naevus

What is halo naevus

"Halo around the naevus" | -Prominent lymphocytic infiltrate and melocytic lesion due to immune mediated regression of the lesion