9. Dermatopathology - BP

Question 1

Give a basic description of melanocytic nevus.

Answer 1

Benign proliferation of nevus cells, which are derived from melanocytes.

Question 2

What are the 3 types of melanocytic nevus?

Answer 2

1. Junctional –> Proliferation of nevus cells confined to the basal portion of the epidermis.
2. Compound –> basal portion of epidermis + upper dermis.
3. Intradermal –> dermis only.

Question 3

What is the microscopic morphology of melanocytic nevus?

Answer 3

1. Nests of uniform round cells with inconspicuous nucleoli and few if any mitotic figures.
2. As cells get deeper into the dermis, they acquire more of a neural appearance as a result of maturation of the cells.

Question 4

Give a basic description of dysplastic nevus.

Answer 4

Proliferation of dysplastic nevus cells - PRECURSOR OF MELANOMA.

Question 5

What is the gross morphology of dysplastic nevus?

Answer 5

1. Variable pigmentation
2. > 5mm in size
3. Irregular borders

Question 6

What is the microscopic morphology of dysplastic nevus?

Answer 6

1. Fusion and coalescence of nests of nevus cells in epidermis.
2. Also, single nevus cells are present in basal portion of epidermis.
3. The nevus cells have cytologic atypia.

Question 7

Give a basic description of melanoma.

Answer 7

Malignant tumor of the melanocytes.

Question 8

What are the 4 types of melanoma?

Answer 8

1. Superficial spreading
2. Lentigo maligna (older patients)
3. Nodular melanoma –> vertical growth early
4. Acral lentiginous melanoma –> nail bed, sole of the foot, palms of African Americans.

Question 9

What is the pathogenesis of melanoma?

Answer 9

UV that damages the DNA of the melanocytes –> CDKN2A prominent role.

Question 10

What are the two growth patterns of melanoma?

Answer 10

1. Radial –> not associated with metastases.

2. Vertical –> downward into the dermis - associated with metastases.

Question 11

Mention some risk factors for melanoma.

Answer 11

1. Sun exposure in faired skin individuals.

2. History of atypical nevi, giant nevi (>20cm), or a large number of nevi.

Question 12

What is the gross morphology of melanoma?

Answer 12

1. > 10mm in size
2. Variable pigmentation
3. Irregular borders

Question 13

What is the microscopic morphology of melanoma?

Answer 13

1. Large cells with prominent nucleoli forming poorly defined nests.
2. Single cells are present.

Question 14

What is important to remember about melanoma?

Answer 14

For staging, the depth of penetration into the DERMIS is crucial –> more likely to metastasize.

Question 15

Mention some warning signs of melanoma.

Answer 15

1. Increasing size of nevus.
2. Itching or pain
3. Change is size, shape, color
4. Growth of new nevus
5. Irregular borders

Question 16

Mention some favorable prognostic factors for melanoma.

Answer 16

1. Depth of invasion of <1.7mm (Brenslow depth).

2. Absence of mitotic figures.

Question 17

Mention the two common markers of melanoma.

Answer 17

S-100 and HMB-45.

Question 18

What is the microscopic morphology of seborrheic keratosis?

Answer 18

1. Sheets of basal-like cells
2. Hyperkeratosis
3. Keratin-filled cysts

Question 19

What is the sign of Leser-Trelat?

Answer 19

Sudden onset of multiple seborrheic keratoses, which is a cutaneous manifestation of internal malignancy - associated with ADENOCARCINOMA OF THE GI.

Question 20

What is the gross morphology of actinic keratosis?

Answer 20

Rough, sandpaper-like lesion, which may have a keratin horn.

Question 21

What is the microscopic morphology of actinic keratosis?

Answer 21

1. Dysplasia of the keratinocytes in basal portion of epidermis.
2. Can have parakeratosis.

Question 22

What are the risk factors for actinic keratosis?

Answer 22

UV light.

Question 23

What is important to remember about actinic keratosis?

Answer 23

It is a PRECANCEROUS LESION –> SCC.

Question 24

What is the common mutation in actinic keratosis?

Answer 24

p53

Question 25

What are the risk factors for cutaneous SCC?

Answer 25

1. Sun exposure
2. Older patients
3. Chronic ulcers
4. Osteomyelitis
5. Burns (Marjolin ulcer)

Question 26

What is important to keep in mind about cutaneous SCC?

Answer 26

Only 5% metastasizes - may arise at sites of arsenic exposure.

Question 27

What are the two precursor lesions of cutaneous SCC?

Answer 27

1. Actinic keratosis

2. SCC in situ

Question 28

What are the mutations associated with cutaneous SCC?

Answer 28

LOH of 3, 9, 17 + p53.

Question 29

What is the common location of cutaneous SCC?

Answer 29

Head, hands, face.

Question 30

What is the gross morphology of cutaneous SCC?

Answer 30

Painless nodule with possible evidence or keratin formation - may ulcerate.

Question 31

What is the microscopic morphology of cutaneous SCC?

Answer 31

1. Invasive squamous-appearing cells in dermis.

2. Keratin pearls and intercellular bridges.

Question 32

What are the risk factors for basal cell carcinoma?

Answer 32

Sun exposure and old age.

Question 33

What is important to keep in mind about basal cell carcinoma?

Answer 33

Most commonly develop on sun-exposed areas (nose, lip).

Question 34

What mutations are associated with basal cell carcinoma?

Answer 34

1. PTCH

2. p53

Question 35

What is the gross morphology of basal cell carcinoma?

Answer 35

Pearly papule with dilated subepidermal blood vessels - can ulcerate - formerly called “rodent ulcers”.

Question 36

What is the microscopic appearance of basal cell carcinoma?

Answer 36

Nests of neoplastic cells resembling basal cells of the epidermis - they have peripheral palisading and separation clefts and are embedded in mucoid matrix.