Dermatopathology II - Fung

Question 1

From what components of the skin can benign or malignant neoplasms arise?

Answer 1

1. Epidermis - squamous or melanocytic in origin
2. Dermis
3. adnexal structures

Question 2

What are some benign epithelial tumors?

Answer 2

1. sebhorreic keratosis
2. skin tags
3. hypertrophic scars or keloids
4. epidermal inclusion cyst

Question 3

Describe sebhorreic keratosis.

Answer 3

1. very common
2. unknown origin
3. no malignant potential
4. presents as round, waxy, flat coil-like lesions
5. uniform in color or pigmented
6. velvety, granular surface

Question 4

What is a classic microscopic finding of sebhorreic keratosis?

Answer 4

Horn cysts - invaginations of the epidermis.

Question 5

Describe skin tags.

Answer 5

1. also called fibroepithelial polyps
2. very common
3. no malignant potential
4. microscopically - loose stroma surrounded by epidermis

Question 6

Describe hypertrophic scars or keloids.

Answer 6

1. more common in African Americans
2. formed by deposition of collagen in scar formation
3. microscopically - see a dense dermis due to deposition of keloidal collagen

Question 7

Describe epidermal inclusion cysts.

Answer 7

1. formed by invagination of epidermis into dermis with the production of keratin
2. can rupture and will have inflammation

Question 8

What is actinic keratosis?

Answer 8

1. a premalignant epidermal tumor
2. lesions are due to sun damage
3. appear as tan, brown or red toned papules
4. surface is rough like sand paper

Question 9

What does actinic keratosis look like microscopically?

Answer 9

1. hyeprkeratosis
2. solar elastosis in dermis - sun breaks down collagen
3. dyskeratosis - but does net extend down the whole thickness of the epidermis
4. atypical keratinocyes with abnormally large and dark nuclei

Question 10

What is squamous cell carcinoma in situ (Bowen’s disease)?

Answer 10

1. premalignant epidermal tumor
2. lesions are caused by sun damage
3. microscopically - will see rete ridges and atypical cells that extend the whole thickness of the epidermis but have not invaded the basement membrane yet

Question 11

What is invasive squamous cell carcinoma?

Answer 11

This is the next step in the pathway from squamous cell carcinoma in situ. The cells in this case have invaded and gone through the basement membrane so these are malignant lesions.

Question 12

What is basal cell carcinoma?

Answer 12

1. a malignant epidermal tumor
2. presents as pearly papules that can be pigmented or not
3. these are locally aggressive tumors that can erode into bone and cause local damage
4. microscopically - will see basaloid cells and peripheral palisading of nuclei

Question 13

Describe melanocytic neoplasms.

Answer 13

1. can be neoplasms or just freckles - they are on a spectrum from benign to malignant
2. includes nevus, dysplastic nevus and melanoma
3. lesions are due to sun damage

Question 14

Describe Nevi.

Answer 14

1. common benign neoplasms that are acquired by activating mutations in the RAS and BRAF signaling pathways
2. progress through a series of morphologic changes over time from junctional nevus to compound nevus to intradermal nevus

Question 15

What is a junctional nevus?

Answer 15

A nevus where nevoid cells are only located in the epidermis.

Question 16

What is a compound nevus?

Answer 16

A nevus where nevoid cells are located in the epidermis and dermis.

Question 17

What is an intradermal nevus?

Answer 17

A nevus where nevoid cells have matured and moved into the dermis. They are only found in the dermis.

Question 18

What are some characteristics that would confer that a melanocytic lesion is more likely just a nevus?

Answer 18

1. symmetrical shape
2. smooth borders
3. evenly pigmented

Question 19

If a nevus if flat what stage is it likely in?

Answer 19

It is most likely a junctional nevus.

Question 20

If a nevus is raised what stage is it likely in?

Answer 20

It is more likely to be a compound or intradermal nevus.

Question 21

Describe a dysplastic nevus.

Answer 21

1. may be a direct precursor of melanoma
2. vast majority are stable and never progress
3. they are nevi that have acquired activating mutations in NRAS and BRAF signaling pathways and that do not have characteristic macroscopic features. i.e. - not smooth border, symmetry and possibly variably pigmented

Question 22

What is melanoma?

Answer 22

1. skin cancer lesions
2. most deadly of all skin cancers with ability to metastasize
3. mostly occurs in skin but could occur in mucosa
4. exhibits at least one of the ABCDEs

Question 23

Describe the genetics of melanoma.

Answer 23

1. autosomal dominant in 10-15% of cases
2. mainly sporadic - due to UV damage of DNA
3. DNA damage causes mutations to cell cycle control genes, mutations that activate pro-growth signaling pathways and mutations that activate telomerase

Question 24

What do the ABCDEs sand for?

Answer 24

These are a way of differentiating melanoma from other pigmented lesions.
A = assymetry
B = uneven borders
C = color
D = diameter
E = evolution or changing of lesion

Question 25

What are the two growth phases of melanoma?

Answer 25

1. radial growth phase - grows within epidermis - no metastasis
2. vertical growth phase - grows through dermis and basement membrane - can metastasize

Question 26

What are some prognostic factors for melanoma?

Answer 26

1. Breslow scale - depth of invasion of melanoma - deeper is worse prognosis
2. ulceration - no ulceration of skin is a better prognosis
3. lymph node involvement - if lymph nodes involved then prognosis worse

Question 27

What are some types of adnexal neoplasms?

Answer 27

1. sebaceous hyperplasia/adenoma
2. pilar cyst - cyst of hair follicle
3. pilomatricoma - cyst of hair follicle that calcifies