Derm Path II

Question 1

What causes a freckle?

Answer 1

Increased melanin pigment production (that is distributed to keratinocyte)

Question 2

How does a lentigo appear clinically?

Answer 2

Small, oval-tan brown spot that occurs at any age on the mucous membranes

Question 3

What is a lentigo histologically?

Answer 3

A non-confluent typical single cell melanocytic hyperplasia along the basal layer

Question 4

Differentiate nevi from lentigo histologically

Answer 4

nevi form hyperplastic NESTS of melanocytes

Nevi= Nests

Question 5

What is the link between dysplastic nevi and melanoma?

Answer 5

People with dysplastic nevi have an increased risk of developing melanoma

Question 6

Describe melanoma histologically

Answer 6

Confluent nests and single atypical melanocytes

There are melanocytes lined up next to each other, rather than being buffered in between by keratinocytes

Question 7

Describe the progression of a melanocytic nevi from junction –> compound –> intradermal

Answer 7

Melanocyte at the junction –> compound (both in the eipdermis and dermis) –> intradermal

Take home: the melanocytic nevi progress deeper into the skin

Question 8

What is one way of differentiating melanocytic nevi from melanoma?

Answer 8

Melanocytic nevi “mature” from nest cells to single cells in the dermis.

Melanoma cells do not mature- they just invade and take over

Question 9

“Shouldering” of the epidermal component that extends at least 3 rett ridges beyond the dermal component suggest what type of skin finding?

Answer 9

Dysplastic nevi

Question 10

Describe the “bridging” seen in dysplastic nevi

Answer 10

confluence of rete ridge nests

Question 11

What is the worst prognostic factor for melanoma

Answer 11

Finding (even) a single cell in the sentinel lymph node

Question 12

Which is more concerning, radial growth or vertical growth for melanoma?

Answer 12

Vertical growth- nodular and any invasive type of melanoma

Blood vessels are there in the dermis, so the cells can metastasize

Question 13

Which are the two more important predisposing risk factors for melanoma?

Answer 13

1) Sun exposure (Men- upper back, women- posterior calf)

2) Inherited genes: CDKN2A, BRAF, NRAS, PTEN, C-KIT

Question 14

Non sun-exposure melanomas are associated with which mutation?

Answer 14

C-KIT

Question 15

Which two gene mutations are seen in both familial and sporadic melanoma cases?

Answer 15

BRAF and CDKN2A

CDKN2A is seen in more familial melanomas
BRAF are seen in more sporadic melanomas

there are specific BRAF and CDKN2A tx’s

Question 16

What is the most important prognostic feature for invasive melanomas?

Answer 16

Breslow thickness

The more deep a melanoma goes, the greater its chance of metastasizing

Question 17

“Buckshot” and “pagetoid spread” indicate what type of lesion?

Answer 17

melanoma

Question 18

What is a follicular epidermal inclusion cyst?

Answer 18

hard nodule under skin- epidermis appears normal with a punctum in the middle of it.

Cyst with full thickeness epidermal layer- punctum open up and keratinous material comes out

Question 19

Follicular Trichilemmomas are associated with what syndrome?

Answer 19

Cowden’s syndrome: PTEN mutation that leads to increased risks of breast, endometrial and thyroid cancers

Question 20

Describe the histology of trichilemommas

Answer 20

Pushing border, some palisading cellular architecture with clear cell change

These are completely benign

Question 21

What’s a way to distinguish a dermatofibroma from a melanoma

Answer 21

Squeeze it- dermatofibromas show a dimple sign

Question 22

Name two histologic features characteristic of dermatofibroma

Answer 22

Tabeling of rete ridges

Collagen trapping

Question 23

What are dermatofibrosarcoma protuberans

Answer 23

large nodules with multiple protuberances, most common on the trunk of young to middle aged adults

Question 24

Describe the histology of a dermatofibrosarcoma protuberans

Answer 24

Dense proliferation of spindle cells in the dermis demonstrating a storiform (irregularly whorled pattern) of fibroblasts

Question 25

What type of cell proliferates in a keloid scar?

Answer 25

Spindle cells (fibroblasts and myofibroblasts) –> thick glassy bands of collagen

Question 26

Sebaceous adenomas are yellowish pale or small nodules that may be a part of which syndrome?

Answer 26

Lynch Syndrome- MLH1, MSH2,

Question 27

Leiomyomas in the skin arise from which muscle?

Answer 27

Erector pili muscles of the hair follicles

Question 28

Cytoplasmic bubbles and cigar shaped nuclei are found in which lesion?

Answer 28

Leiomyoma