Skin Tumour Pathology Flashcards
What is seborrhoeic keratosis
Benign proliferation of epidermal keratinocytes
Describe the histology of seborrhoeic keratosis
Epidermal acanthosis, hyperkeratosis, horn cysts
What are seborrhoeic keratosis often confused with
melanoma
What is a BCC
Malignant proliferation of epidermal, basal layer keratinocytes
What is a BCC
Malignant proliferation of epidermal, basal layer keratinocytes
Name a characteristic histological feature of BCC
Peripheral palisading
What is bowen’s disease
Squamous cell carcinoma in–situ
SCC precursor
Describe histological appearance of bowens disease
Full/ Partial thickness dysplasia of epidermis
Least significant changes in basal layer (usually intact)
Hyperkeratosis on skin surface
Mildly atypical keratinocytes & increased mitotic activity
keratinocytes can appear ‘windblown’
Is bowen’s disease invasive
No - their is no dermal invasion
What might bowen’s disease be confused with
Chronic dermatitis
Fungal infection
Other inflammatory skin conditions
What is actinic keratosis
Type of epidermal dysplasia
Precursor of invasive SCC
Describe histological appearance of actinic keratosis
Partial thickness dysplasia of epidermis
Most significant changes in basal layer
Hyperkeratosis on skin surface
Mildly atypical keratinocytes & increased mitotic activity
What virus is associated with SCC
HPV
Summarise the histology of SCC precursors
dysplasia of epidermis!
hyperkeratosis & mildly atypical keratinocytes
Increased mitotic activity
Summarise the histological features common to SCC precursors
dysplasia of epidermis!
hyperkeratosis & mildly atypical keratinocytes
Increased mitotic activity
What areas of the skin do SCC tend to occur
- sun exposed sites (face, ears, dorsal hand), SSC precursors
Where do SSC occasionally occur in the body
Chronic leg ulcers
Sinuses e.g. in chronic osteomyelitis
Sites of burns
Chronic lupus vulgaris
SCC histological features
Atypical keratinocytes with abnormal mitoses
Hyperkeratosis
Invasion of dermis & deeper structures
Where are melanocytes derived from embryologically
Neural crest
Where do melanoblasts go to from the neural crest during embryological development
•skin
•uveal tract
•leptomeninges
Does the number of melanocytes change with skin colour?
No the amount of melanin produced from melanocytes changes with skin colour, the melanocyte number is constant
What is a freckle (ephilides)
Areas of patchy increase in melanin pigmentation
What are actinic lentigines
pigmented blemishes on the skin associated with aging & exposure to UVR
What histological changes occur in areas of actinic lentigines
