Pathology of Non-Pigemented Lesions

Question 1

What is an example of a benign epidermal tumour?

Answer 1

Sebarrhoeic keratosis

Question 2

What are some epidermal tumours that have precancerous dysplasia?

Answer 2

Bowen’s disease, actinic keratosis, viral lesions

Question 3

What are some malignant epidermal tumours?

Answer 3

Basal cell carcinoma, squamous cell carcinoma

Question 4

What are some features of sebarrhoeic keratosis?

Answer 4

Very common in aging skin, common on face and trunk, benign proliferation of epidermal keratinocytes, stuck on appearance (greasy hyperkeratotic surface), epidermal acanthosis, hyperkeratosis, horn cysts

Question 5

What is the Leser Trelat sign?

Answer 5

Eruptive appearance of many lesions may indicate internal malignancy

Question 6

Where do basal cell carcinomas arise, and who gets them?

Answer 6

Sun-exposed sites; in UK middle aged and elderly (younger age groups in Australia)

Question 7

What are the three main subtypes of basal cell carcinomas?

Answer 7

Nodular, superficial, infiltrative (morphoeic, most important type as can invade tissues)

Question 8

How do basal cell carcinomas arise?

Answer 8

Basal cells sprout from epidermis, groups of cells invade dermis, peripheral palisading, mitoses and apotoses very numerous

Question 9

What are some features of basal cell carcinomas?

Answer 9

Slow growing, locally destructive, almost never metastasise, may kill by invading eye and spreading to brain, prominent desmoplastic fibrous stroma, margins poorly defined, may spread along nerves, resection may be challenging

Question 10

What are some precursors of squamous cell carcinoma that all show squamous dysplasia?

Answer 10

Bowen’s disease (especially on legs), actinic keratosis (especially on head/neck), viral lesions (especially on anogenital skin)

Question 11

What are some features of Bowen’s disease?

Answer 11

Squamous cell carcinoma in-situ, female excess, mostly on lower leg, scaly path/plaque, irregular border, no dermal invasion

Question 12

What are some features of actinic keratosis?

Answer 12

Very common, sun-exposed skin (especially scalp, face and hands), variable epidermal dysplasia, severely atypical lesions are Bowenoid, common precursor for invasive squamous cell carcinoma

Question 13

What are some features of viral lesions?

Answer 13

Viral genital lesions often dysplastic, erythroplasia of Queryat = penile Bowen’s, associated with HPV (type 16 linked to dysplasia)

Question 14

What is the association between HPV and dysplasia?

Answer 14

HPV found in about 100% of penile dysplasia and 50% of invasive penile squamous cell carcinomas

Question 15

What is the most common clinical setting for squamous cell carcinoma?

Answer 15

Elderly, sun-exposed sites (face, ears, dorsal hands), UV implicated

Question 16

Where can squamous cell carcinomas occasionally arise from?

Answer 16

Chronic leg ulcers (e.g stasis ulcers), sires of burns (sinuses e.g chronic osteomyelitis), chronic lupus vulgaris

Question 17

What are some rare associations of squamous cell carcinomas?

Answer 17

Xeroderma pigementosum, dystrophic variant epidermolysis bullosa

Question 18

What are some features of squamous cell carcinomas?

Answer 18

Generally good behaviour, locally invasive, low but definite risk of metastasis

Question 19

What are some adverse prognostic features of squamous cell carcinomas?

Answer 19

Thickness > 4mm and poor differentiation
Lymphatic/vascular space invasion
Perineural spread

Question 20

Which sites have poorer prognosis for squamous cell carcinomas?

Answer 20

Scalp, ears, nose

Question 21

Where are some skin sites that miscellaneous tumours can arise from?

Answer 21

Dermal connective tissue, blood vessels, nerves, sweat glands, hair follicles, smooth muscle of arrector pili, lymphoid tissue, Langerhans cells, Merkel cells subcutaneous fat