Pathology Of Non-Melanocytic Tumours Flashcards
What are benign epidermal tumours?
Seborrhoeic keratosis
What are precancerous dysplasias of the epidermis?
Bowen’s disease
Actinic keratosis
Viral lesions
What are invasive malignancies of the epidermis?
BCC AND SCC
What is a seborrhoic keratosis?
Benign proliferation of epidermal keratinocytes
Common on face and trunk
Stuck on appearance, greasy hyperkeratotic surface
What do seborrhoic keratosis look like histologically?
Epidermal acanthosis
Hyperkeratosis
Horn cysts
Eruptive appearance of many lesions may indicate internal malignancy (leser trelat sign)
What are the different types of BCC?
Nodular
Superficial
Infiltrative
Where do BCCs originate from?
Basal cells sprout epidermis Groups of cells invade the dermis Peripheral palisading Mitosis and apoptosis very numerous Slow growing and locally destructive Can kill by invading eye
What do basal cell carcinomas look like histologically?
Prominent desmoplastic fibrous stroma
Poorly defined margins
Can spread along nerves
What is Bowens disease?
SCC in situ Female mostly Scaly plaque on lower leg Irregular border No dermal invasion
What is actinic keratosis?
Very common on sun exposed skin
Variable epidermal dysplasia
Several atypical lesions are bowenoid
What viral precursors can lead to SCC?
Viral genital lesions often dysplastic
Erythoplasia of Queryat penile
HPV type 16
What can a SCC arise from occasionally?
Chronic leg ulcers
Sites of burns
Chronic lupus vulgaris
What can SCC arise from rarely?
Xeroderma pigmentosum
Dystrophic variant epidermolysis bullosa
What are adverse prognosis features of SCC?
Thickness over 4mm and poor differentiation Lymphatic invasion Vascular invasion Perineural spread Scalp, ear and nose
Where else can tumours arise from in the skin?
Dermal connective tissue Blood vessels Nerves Sweat glands Hair follicles Smooth muscle arrector pili Lymphoid tissue Langerhans cells Merkel cells Subcutis fat
