Dermatopathology Flashcards Preview

Skin/Musculoskeletal: Anatomy/Dissection > Dermatopathology > Flashcards

Flashcards in Dermatopathology Deck (43)
Loading flashcards...
1
Q

Describe vitiligo

A

Partial or complete loss of melanocytes

Well demarcated macules/patches

Hand/wrist, axillae, perioral/periorbital, anogenital

Pathogenesis: autoimmune

2
Q

What is albinism caused by?

A

it’s usually an inherited defect in tyrosinase

there is no melanin produced

in contrast to vitiligo, there are normal melanocytes in albinism, there just isn’t the enzyme necessary for normal function

3
Q

What are the two general causes of pigmented lesions?

A
  1. excess melanin
  2. increased number of melanocytes
4
Q

What are three examples of pigmented lesions due to excess melanin?

A

freckle

melasma

solar lentigo

5
Q

What are two examples of pigmented lesions due to increased number of melanocytes?

A

melanocyte hyperplasia - lentigo simplex

melanocytic neoplasis - nevi, melanoma

6
Q

What is the technical term for a freckle?

A

ephelis

ephelides

7
Q

Under histology, what do freckles look like?

A

increased pigment in basal melanocytes

normal number of melanocytes

8
Q

Describe melasma.

A

it’s mask-like hyperpigmentaiton on forehead and cheeks due to increased pigment transfer from melanocytes to keratinocytes

occurs in pregnancy or oral contraceptive use

usually will resolve

9
Q

WHat is a solar lentigo?

A

a hyperpigmentation of the basal epidermis due to excess melanin production

it occurs in the elderly in areas of heavy sun exposure - it’s a protective mechanisms of the melanocytes

10
Q

Describe lentigo simplex.

A

it’s localized hyperplasis of melanocytes

it can occur in all ages and isn’t related to sun

you get small brown macules anywhere on the skin

it results from increased number of melanocytes, resulting in increased pigment in stratum ocrneum and basal epidermis\

ITS AN EXAMPLE OF MELANOCYTIC HYPERPLASIA

11
Q

In terms of skin neoplasia, what is a benign neoplasia and a malignant neoplasia

A

a benign neoplasm has no capability for metastasis - this includes those neoplasia that look like they COULD become metastatic, but haven’t crossed the basement membrane yet

malignant neoplasma have the potential for metastasis and have crossed the basement membrane

12
Q

Is squamous cell carinoma in situ melignant or benign?

A

it’s still considered benign because it hasn’t crossed the basement membrane

this means it’s NOT CANCER

13
Q

What are some benign neoplasia of the skin?

A

Melanocytic: Nevi

Epithelial: AK, adenomas

Stromal: leiomyoma, hemangioma

14
Q

What are some malignant neoplasia of the skin?

A

Melanocytic: Melanoma

Epithelial: SCC, BCC

Stromal: DFSP, leiomyosarcoma, angiosarcoma

15
Q

What are the 3 lifes stages of a nevi?

A
  1. junctional (at the junction of the epidermis and dermis - but not in the dermis yet)
  2. compound (in both epidermis and dermis)
  3. dermal (loss of the junctional part and only in the dermis)
16
Q

WHat is the msot common mutatoin in a nevi?

A

BRAF

17
Q

What’s the clinical treatment for a spitz nevus?

A

you have to take the whole thing off whenever you get path report saying its a spitz because they’re very hard to predict and it’s better to just remove the whole thing

18
Q

Why do blue nevi look blue?

A

the pigmentation is deeper than in other nevi, so through the Tyndall effect and light scattering properties, they end up looking dark blue in color

they are dermal proliferations of spindled melanocytes

totally benign

19
Q

WHat is a nevus of Ota

What is a nevus of Ito?

A

Ota - peri-ocular or intraocular dermal melanocytic nevus

ito - “mongolian spot” which is the same type of lesion as the Ota, just on the skin and not the eye

20
Q

How are dysplastic nevi graded?

A

a pathologist will grade them based on the severity of dysplasia - how atypical they are

mild, moderate, and severe

you should excise those of moderate or severe atypia

people with multiple of these have an increased risk of melanoma

21
Q

What is the only reliable way to exclude melanoma from a DD?

A

biopsy and get a path report

22
Q

WHat are the 2 growth patterns of melanoma?

A

radial growth (in situ): just superficial and cannot metastasize

vertical growth: dermal invasion, formation of nodule - potential to metastasize

23
Q

What gives melanoma its color variation?

A

a melanoma likes to spread up into the stratum corneum, but it won’t do so uniformaly, so the pigment is at varying layer sin different areas of the melanoma

24
Q

What is the best predictor of a melanoma’s probability to metastasize?

A

breslow depth!!!!!

less than 1 mm - unlikely to metastasize

the higher the depth of penetration, the greater the liklihood of metastasis - that’s why they do a sentinel LN biopsy for melanomas with breslow depth of over 1 mm

25
Q

What are some other prognistic indicators of melanoma metastasis besides breslow depth?

A

ulceration - more likely to metastasize

increased mitotic rate - depends on mutations

clark level (less accurate breslow)

26
Q

What is a seborrheic keratosis?

A

it’s a very common epithelial neoplasm, typically found on the trunk, head and neck

they are brown and velvety papules/plaques, well demarcated

proliferation of keratinocytes that are pigmented - often confused for nevi or melanoma

Many on elderly patients

solar lentigo can grow into these

they cause super thick epidermis with horn cysts

27
Q

What is an epithelial cst? WHat is it usually filled with?

A

they are down growths of epidermis which become cystic and filled with keratin

they can be subcutaneous or dermal

they rupture easily and become inflamed

28
Q

What is an actinic keratosis?

A

it’s a benign neoplasm of epidermis (that may precede SCC)

it’s induced by sunlight, ionizing radiation or hydrocarbons

it’s a rough spot on the skin - especially sun exposed skin

It’s a form of hyperkeratosis at the basal layer

29
Q

What is the treatment for actinic keratosis?

A

because some will progrss to squamous cell carcinoma if untreated, thy are usually treated with liquid nitrogen

30
Q

What is squamous cell carcinoma?

A

a neoplasm of squamous cells in the skin

in situ - technically not cancer yet

SCC - has crossed the basement membrane, but only 5% will actually metastasize

mostly on elders with sun exposure

31
Q

Histologically, what is the difference between an actinic keratosis and SCC?

A

in AK, the atypical cells are still lined up along the basement membrane

In SCC, the atypical cells have progressed and moved upward to replace the entire epidermis

32
Q

What does a basal cell carcinoma typically look like?

A

a pearly papule with telengiectasia

they rarely metastasize

it’s the most comon human malignancy - all sun related

33
Q

Adnexal neoplasms of the skin can be a clue to internal pathology, with these two syndromes as examples….

A

Cowden’s syndrome

Muir Torre syndrome

34
Q

What is Cowden’s syndrome?

A

it’s a hereditary condition with a mutation in PTEN, making one prone to multiple hamartomas and malignancies

The patient will most oftne present with multiple trichilemmomas on the base (which are benign keratoses on acral skin)

while the skin ones are bening, they probably have internal carcinaoms of the breast, endometrium, and thyroid, also the cerebellar lesions

35
Q

What is a trichilemmoma?

A

benign proliferation of hair follicle epithelial - suggestive of Cowden’s syndrome

36
Q

WHat is a sebaceous hyperplasia?

A

it’s an acquired, localized icnrease in sebaceous glands - they will be larger than normal

it’s not neoplastic

they are common on the face

look like a yellow papule

37
Q

What is Muir-Torre Syndrome?

A

it’s a hereditary germline mutation in DNA mistmatch repair proteins (MLH1 and MSH2)

patients will present with sebaceous adenoma and carcinoma and keratoacanthomas

Internally they will often have colon/rectlal, endometrial, and ovarian carcinaoms

it’s a subset of hereditary non-polyposis colorectal carcinoma syndrome

38
Q

What is a dermatofibroma?

A

they are entirely benign dermal proliferation of histiocytes and fibroblasts

they are tan, brown, firm papules commonly on the legs

test with the pinch test - they’ll dimple

39
Q

Where would you want to bipsy a rash?

A

non-ulcerated/intact skin - usually sample the center and the edge

40
Q

What is the main thing to think about when biopsying discrete lesions?

A

how deep does it go?!

the biopsy needs to be representative in horisontal and vertical axis

41
Q

When would you do a shave biopsy?

When would you do a punch biopsy?

A

shave for superficial lesions like BCC, AK, SCC in situ, pigmented macules. because it’s better cosmetics and you don’t need to stitch

do a punch for neoplasms involving the dermis (like nodular BCC, SCC< melanoma, etc. and most rashes), These require sutues.

42
Q

What’s the difference between an incisional and excisional biopsy?

A

an incisional doesn’t include the entire lesion (punch is an example) and excisional does

43
Q
A