Tumor Epithelium lecture 19 Flashcards
Normal histology and function of the skin
- Protective barrier ( Fluid loss, mechanical injury, and micro-organisms )
- Sensation: Touch, temperature, pressure, and pain
- Termoregilation
- Control evaporation
- Storage : lipids and water
Classification of skin layers
Upper surface: Epidermis (contains squamous cells and melanocytes)
Middle layer: Dermis (Contains blood vessels hair follicles and nerves, it is the connective tissue )
Lower layer: Hypodermis (contains nerves and larger blood vessels )
Discuss the squamous papilloma
- Common benign cutaneous lesions
* The most common is a viral wart
Discuss the histology of squamous papilloma
- Hyperkeratosis
- papollomatosis
- Acanthosis( think)
- elongated rete ridges
- koilocytosis
Discuss the histology of squamous papilloma
> Squamous Tumors
- Hyperkeratosis
- papollomatosis
- Acanthosis( think)
- elongated rete ridges
- koilocytosis
Discuss the solar (actinic keratosis)
> ST
*It is due to chronic exposure to the sun
*More common in light-skinned individuals
*
Clinically you will see hyperkeratosis, tan/brown lesions and may form cutaneous horns
*may regress, remain unstable, or undergo malignant transformation
Discuss the histology of solar (Actinic ) keratosis
ST
- Defining features (epidermal dysplasia (mild, moderate/severe)
- Hyperkeratosis, parakeratosis, and solar elastosis (sun damage )
Discuss Bowen’s disease and its sites
> Carcinoma in-situ
Full-thickness epidermal dysplasia
HPV implicated
> Sites
- skin: Bowen’s disease
- Vulval intraepithelial neoplasm
- Glans: Erythroplasia of queyrat
Discuss the squamous cell carcinoma Aetiology
> Commonly secondary to basal cell carcinoma
Often arises from pre-existing dysplasia eg solar keratosis but can arise de novo
1.Chronic sun exposure( most important) 2Chronic ulceration (marjolin's ulcers) or scarring 3.ionising radiation 4.albinism ,xeroderma pigmentatosum 5. chemicals arsenic ,tar
What are the clinical manifestations of squamous cell carcinoma
> Raised, rolled, everted edges
often central ulcerations
Usually locally aggressive
and cured by excision
Recurrence :
- twice as the frequency of BCC
- Risk factor for recurrence include incompletion and aggressive histological patterns
Discuss the metastasis of the SCC
- uncommon
- deoendent on clinical setting :0,5%in sun-damaged skin vs % in marjolins ulcer
- Usually to regional lymphoma nodes
- pulmonary metastasis is uncommon
Discuss the histology of SCC
- Invasion beyond the basement membrane into underlying dermis
- Comprises nest of malignant squamous cells
- Intercellular bridges ,abundant eosinophilic cytoplasm
- keratin formation
- mitotic activity
- may have dysplasia of the overlying epidermis with or without ulceration
discuss the Seborrhoeic keratosis (AKA seborrhoeic wart / basal cell papilloma )
*It is common among middle-aged individuals
*Benign
*Arises spontaneously in the trunk, extremities, head, and neck
*Round, flat, dark plaques with a velvety granular surface
*has a stuck-on appearance
*
Discuss the seborrhoeic keratosis histology
- Exophytic and sharply demarcated
- Basaloid cells: small with dark nuclei and scanty cytoplasm
- Variable melanin pigmentation
- Exuberant keratin production
- Horn cysts
Discuss the BCC
- Due to UV exposure
- most common malignant tumor
- Usually elderly caucasian patients (in more sunny areas ,patients are often younger )
- Mainly on the face and it cured by adequate excision
- Locally aggressive but almost never metastasis