Disorders of cutaneous pigmentation - Jokinen

Question 1

Vitiligo

Answer 1

Hypopigmented disorder.

Autoimmune disease - partial or complete loss of melanocytes.

Question 2

Albinism

Answer 2

No melanin produced (or decreased)

Inherited defect in tyrosinase

Question 3

Pigmented lesions due to too much melanin (but normal # of melanocytes)

Answer 3

Freckle
Melasma - Though to be estrogen related.
“butterfly” distribution
This can go away.

Solar lentigo - Too much sun exposure over a lifetime.

Question 4

Melanocytic Hyperplasia (too many melanocytes): 
Lentigo simplex

Answer 4

Not sun related. basically a small hyperpigmented macule.
Localized hyperplasia of melanocytes
Pigment tends to be uniform.

Question 5

Benign Neoplasm

Answer 5

Neoplasm with no capability for metastasis

Can be destructive or symptomatic – this does NOT define malignancy

Question 6

Malignant Neoplasm

Answer 6

Neoplasm with potential for metastasis and subsequently growth/proliferation at distant site
Often locally destructive but may not be!

Question 7

Nevi

Answer 7

This is a Melanocytic Neoplasm.
Nevi are simply moles.

Melanocytes grow in nests along junction (junctional nevus - generally flat) and in time enter dermis (compound nevus) after aging become intradermal only. The junctional nevi are “bumpy”.
So as they raise - they become compound.

Dermal nevus - very raised nevus

Question 8

What is a spitz nevi? How are they different?

Answer 8

Spitz nevi are unique. The melanocytes are irregular with larger nuclei. These are always taken out, always excised from patients.

Question 9

What is blue nevus?

Answer 9

Nevus that are generally found on the head. These have elongated slender melanocytes.

Question 10

Nevus of Ota/Ito?

Answer 10

These are congenital nevus where melanocytes start off in the dermis.

Ota: Peri-ocular, intra-ocular dermal melanocytic nevus
Ito: Mongolian spot, same type of lesion, different site

Question 11

Dysplastic nevus syndrome

Answer 11

body covered with atypical nevus.

Question 12

Malignant Melanoma

Answer 12

Malignant neoplasm of melanocytes
Used to be uniformly deadly
Most arise in skin
Other sites: oral/anogenital mucosa meninges, esophagus, eye
Risk factors: fair skin, sun exposure, many DPN

Question 13

What are the ABCD’s of melanoma?

Answer 13

Asymmetry
Border
Color
Diameter (>6mm or pencil eraser)

Question 14

Malignant melanoma vs melanoma in situ

Answer 14

Malignant melanoma has access to blood vessels - so it has invaded past basement membrane

In situ is still above the basement membrane and doesn’t have access to the blood vessels.

Question 15

Breslow’s Depth

Answer 15

This is how deep melanoma invades into the dermis. This is the most important correlation to the probability for metastasis.

4mm: 5-year survival is 37-50%

It is from granular layer to deepest melanocyte

Question 16

What is the best predictor that a malignant melanoma will metastasize??

Answer 16

Barlow’s depth

4mm: 5-year survival is 37-50%

Question 17

Seborrheic keratosis

Answer 17

Sign of aging.
Benign epithelial proliferations that can look scary.
Due to excess of melanin, not an excess of melanocytes.
These are raised clinically. Completely benign.

Common epithelial neoplasm
Trunk, head, neck are typical
“stuck on”
Brown and velvety papules/plaques
Leser-Trelat Sign – paraneoplastic, rapid growth of numerous seborrheic keratoses

Question 18

Skin tag/Fibroepithelial polyp/Acrochordon

Answer 18

Very common cutaneous lesion, not neoplastic
Soft flesh colored bag-like tumor with stalk
Inconsequential
May increase in pregnancy
May be increased in diabetes, obesity

Question 19

Epithelial Cyst

Answer 19

Down growth of epidermis which becomes cystic
Filled with keratin
Subcutaneous or dermal nodule
Rupture easily and become inflamed
Subtypes: epidermal, pilar, dermoid, steatocystoma multiplex

Question 20

Actinic keratosis

Answer 20

Sun related lesion.
Benign neoplasm of epidermis (may precede squamous cell carcinoma)
Scaly erythematous papules or plaques.
“old farmer”
Is an epithelial neoplasm that is benign (99% of the time).
Even though they are benign, they are treated by liquid nitrogen, curettage, topical chemotherapy

Question 21

Squamous cell carcinoma - In Situ vs Malignant

Answer 21

In Situ - benign, hasn’t invaded basement membrane

Invasive - invaded past basement membrane and dermis.

less than 5% metastasize

Question 22

Basal cell carcinoma

Answer 22

Most common malignancy.
Usually doesn’t metastasize.
Sun related.
Telangiectasia (widened small blood vessels)

These resemble basal cell layer of epidermis, but it is more likely that this carcinoma arises from base of epidermis, possibly hair follicle derived (controversial)

Question 23

Adnexal Proliferations/Neoplasms

Answer 23

These are neoplasms that differentiate toward hair follicle, eccrine, sebaceous, eccrine and apocrine glands
Benign and malignant types

Main two are:
Cowden’s syndrome
Muir Torre syndrome

Question 24

Cowden’s syndrome

Answer 24

Due to a mutation in PTEN (tumor suppressor gene)
Know that Trichilemmomas are associated with cowden’s syndrome.

Hereditary condition prone to multiple hamartomas and malignancy
Skin: multiple trichilemmomas (face), benign keratoses on acral skin
Mucosal papules, cobblestoning tongue
Internal: breast, endometrial and thyroid carcinoma

(trich = hair, so proliferation of hair follicle??)

Question 25

Sebaceous carcinoma vs Sebaceous adenoma

Answer 25

Sebaceous carcinoma is the malignant form. Extraocular forms less common but more likely to occur in Muir Torre syndrome

Sebaceous adenoma is the benign form.

Question 26

Muir-Torre Syndrome

Answer 26

Caused by germline mutations in DNA mismatch repair proteins: MLH1, MSH2, MSH6, PMS2

Skin: Sebaceous adenoma and carcinoma, keratoacanthomas
Internal carcinomas: Colon/rectal, endometrial, ovarian

Question 27

Skin: Sebaceous adenoma and carcinoma, keratoacanthomas

Internal carcinomas: Colon/rectal, endometrial, ovarian

Answer 27

Very aggressive epithelial neoplasm
Most caused by a polyomavirus
50% rate of death. Widely metastasize to lymph nodes.

Question 28

Dermatofibroma

Answer 28

Very common
Dermal proliferation of histiocytes and fibroblasts

Etiology unknown – many are clearly reactive hyperplasia (After bug bite) and resolve, others uncertain

Raised and firm.
The pinch test - pinch it and see if edges will dimple.

Question 29

Dermatofibrosarcoma Protuberans (DFSP)

Answer 29

Well differentiated fibrosarcoma of skin
Rarely metastasize/locally aggressive
Protuberant nodule within a firm plaque
Often nodular in kids.

(may be a malignant dermatofibroma??)

Question 30

Hemangioma vs Angiosarcoma

Answer 30

Hemangioma = Benign vascular neoplasm

Angiosarcoma = Malignant vascular neoplasm. Aggressive, very bad, kill!

Question 31

Mycosis Fungoides

Answer 31

Type of T cell lymphoma.
Neoplastic cell is CD4+ T cell
T cells go into the epidermis.

Question 32

When to shave vs when to punch for biopsy?

Answer 32

Shave: use for superficial lesions (many BCC, AK, SCC in situ, pigmented macules)
Better cosmetics, no sutures, electrocautery

Punch: use for neoplasms involving the dermis (nodular BCC, SCC, melanoma, etc.) and most rashes
Requires sutures
Various sizes 1.5 mm – 8 mm