4.1 Histopathology of common skin neoplasms

Question 1

What are the three layers of the skin?

Answer 1

Epidermis
Dermis
Subcutis (hypodermis)

Question 2

What are the layers and components of the epidermis?

Answer 2

Stratum corneum 
Stratum ganulosum 
Stratum spinosum 
Stratum basale 
Keratinocytes 
Basal cells 
Melanocytes

Question 3

Define macule

Answer 3

flat discoloured lesion up to 10mm

Question 4

Define patch

Answer 4

flat discoloured lesion >10mm

Question 5

Define papule

Answer 5

elevated (dome, flat topped) lesion up to 10mm

Question 6

Define nodule

Answer 6

Elevated (dome) lesion >10mm

Question 7

Define plaque

Answer 7

elevated flat topped lesion >10mm

Question 8

Define vesicle

Answer 8

fluid filled lesion up to 10mm

Question 9

Define bulla

Answer 9

fluid filled raised lesion >10mm

Question 10

Define pustule

Answer 10

pus filled raised lesion

Question 11

Define Lichenification

Answer 11

thickened rough skin with prominent markings

Question 12

Define excoriation

Answer 12

traumatic lesion with breakage of the epidermis and raw liner area

Question 13

What is hyperkeratosis

Answer 13

thickening of the stratum corneum

Question 14

What is parakeratosis

Answer 14

retention of nuclei in stratum corneum

Question 15

What is hypergranulosis

Answer 15

hyperplasia of the stratum corneum

Question 16

What is acanthosis

Answer 16

Diffuse epidermal hyperplasia

Question 17

What is papillomatosis

Answer 17

Surface elevation caused by hyperplasia and enlarged dermal papillae

Question 18

What is spongioisis

Answer 18

intracellular edema of epidermis

Question 19

What is dyskeratosis

Answer 19

abnormal premature keratinization below stratum granulosum

Question 20

What neoplasms can you have of the keratinocytes

Answer 20

Epidermal cyst
Actinic (solar) keratosis
SCC
Keratoacanthoma

Question 21

What neoplasms can you have of basal cells?

Answer 21

Seborrhoeic keratosis

BCC

Question 22

What neoplasms can you have with melanocytes?

Answer 22

Ephelis (freckles)
Lentigo (age spots)
Naevocellular naevi (moles)
Melanome

Question 23

What is the microscopic appearance of epidermal cysts?

Answer 23

Keratin debris containing cyst lined by benign squamous epithelium (found in the dermis) - benign

Question 24

What is the appearance of actinic keratosis and who does it usually occur in?

Answer 24

Scaly patches due to too much keratin (confined to the epidermis) - usually in the elderly from sun exposure

Question 25

What is the microscopic appearance of actinic keratosis?

Answer 25

Hyperkeratosis Epidermal dysplastic (neoplastic but not invasive) Solar elastosis of the dermal collagen

Question 26

What is the treatment of actinic keratosis and why is it important?

Answer 26

Freezing, curettage, topical treatments, excision Important because it is a precursor for SCC

Question 27

What is the macroscopic appearance of SCC?

Answer 27

Nodular, scaly, ulcerated - Red scaling plaques when in situ - Nodular keratin producing when invaded

Question 28

What is the microscopic appearance of SCC?

Answer 28

Invasion beyond BM Resemble keratinocytes Focal keratinization

Question 29

What is the appearance of Solar elastosis?

Answer 29

Looks blue as apposed to healthy pink collagen bundles

Question 30

What is the macroscopic appearance of keratocnathoma?

Answer 30

Crateriform

Question 31

What is the microscopic appearance of keratocanthoma?

Answer 31

Nodule with a central crater filled with keratin

Question 32

What type of neoplasm is keratocanthoma?

Answer 32

Benign rapidly developing neoplasm which mimics a well differentiated SCC

Question 33

What is the macroscopic appearance of seborrhoeic keratosis?

Answer 33

Raised warty lesions

Question 34

What is the microscopic appearance of seborrhoeic keratosis?

Answer 34

Proliferation of benign basal cells | Keratin nests

Question 35

what is the macroscopic appearance of BCC?

Answer 35

Pearly papules with surface telangiectasia (blood vessels)

Question 36

What is the microscopic appearance of BCC?

Answer 36

Malignant basal cells Peripheral palisading Apoptotic debris Retraction artefact - clefting around

Question 37

What are ephelis?

Answer 37

Freckles which appear after sun exposure

Question 38

What is the microscopic appearance of ephelis?

Answer 38

Increased melanin pigment in basal layer but normal number of melanocytes

Question 39

What are lentigo?

Answer 39

benign age spots which do not darken on sun exposure

Question 40

What is the microscopic appearance of lentigo?

Answer 40

Linear (non nested) melanocytic hyperplasia | Above the BM