Ch. 24: Skin: Anatomy and Epidermal Diseases

Question 1

What layer of the epidermis is most affected by ichthyosiform dermatoses?

Answer 1

Stratum Corneum gets markedly thickened

(icythyosis=fish-like scales)

Question 2

What are three general defects involved in ichthyoses?

Answer 2

Increased cell cohesiveness, abnormal keratinization, increased basal cell proliferation

Question 3

“J” presents with an abnormal patch of leathery, brown skin after admitting to repeatedly scratching the area when he feels anxious after watching the Red Sox lose. Your biopsy revels an area of thickened epidermis (nucleated and enucleated layers), hyperkaeratosis, and dermal fibrosis. What is the diagnosis?

Answer 3

Lichen simplex chronicus

(Key point: this condition causes the nucleated epidermal layers and stratum corneum to thicken, whereas ichthyosiforms cause ONLY STRATUM CORNEUM.

Question 4

The most common ichthyosis, presents with small white scales on extensor surfaces of extremities, trunk and face.

Answer 4

Ichthyosis Vulgaris

Question 5

Is ichythosis vulgaris due to environmental exposure, an autoimmune disorder, or a genetic disorder?

What protein is decreased or absent?

Answer 5

Genetic (autosomal dominant)

Defect in synthesis of profilaggrin (keratin filament); very thin granular layer

Question 6

Which ichthyosis is due to an absence of steroid sulfatase?

Answer 6

X-linked ichthyosis

(granular layer is preserved)

Question 7

Your 1 week old patient presents with dark blistering, fish-scale-like skin. You quickly recognize epidermolytic hyperkeratosis because you’re that brilliant. To confirm, what distinctive characteristic would you see on pathology slides?

Answer 7

Whorled tonofilaments around the nucleus with a thickened stratum corneum

(Disease due to abonormal keratin synthesis)

Question 8

Which dermatological condition which is associated with neuropsychiatric problems, presents with warty papules due to an ATP2A2 calcium pump defect?

Answer 8

Darier disease/keratosis follicularis

Question 9

You got a 280 on Step 1 so you become a dermatologist. Your first patient comes in complaining of scaly plaques on her elbows and knees. The lesions have silvery edges, and if she itches them her skin bleeds in pinpoint locations. You say, “Any MS2 could make this diagnosis!”

What does she have?

Answer 9

Psoriasis

Caused by excessive proliferation of keratinocytes

Question 10

In psoriasis pathogensis, defective epidermal cell surface receptors lead to a decrease in what molecule?

Answer 10

cAMP

Causes an increase in protein kinases and polyamines, causing a growth-factor like effect for the epidermis

Question 11

What type of microcirculatory change is common in psoriasis?

Answer 11

Capillary loops of dermal papillae become venules.

Question 12

When a psoriatic patient’s capillaries become venualized, which immune cells get recruited to the overlying epidermis?

Answer 12

Neutrophils

(Collect in stratum corneum and throughout the epidermis)

Question 13

What is parakertatosis?

Answer 13

Persistance of nuclei in stratum corneum cells (found in psoriasis)

Question 14

On histological examination, what might you notice about the venules of a dermal papillae below a psoriatic lesion?

What might you notice about the granular layer?

Answer 14

They become tortuous and dilated

It becomes hypogranulized. (Due to fast cell turnover)

Question 15

What is a common side-effect of psoriasis that could be mistaken for an autoimmune disorder?

Answer 15

Psoriatic, seronegative, arthritis

Question 16

What is the common abbreviation for phototherapy after administration of psoralens (compounds that absorb UV light and bind DNA) used in psoriasis treatment?

Answer 16

PUVA

(damage cells to stop over-proliferation)

Question 17

Mr. Soprano, a 45 y/o male comes to your primary care office with large blisters on his scalp and the inside of his lip. The blisters rupture easily and leave behind a crust. The biopsy comes back like the image below. What does Mr. Soprano have?

Answer 17

Pemphigus vulgaris

(intraepidermal blister)

Question 18

Mr. Soprano wants to know if his pemphigus vulgaris is a sign he is being poisoned by the Mafia. You tell him to fuhgeddaboudit, because PV is caused by….?

Answer 18

IgG antibodies to keratinocytes, specifically demoglein 3

(autoimmune disease)

Question 19

When antibodies in PV bind to the self-antigen, what proteinase is released, causing dyshesion between cells?

Answer 19

Plasmin

Question 20

Which layers of skin separate in pemphigus vulgaris?

Answer 20

The outer epidermal layers from the epidermal basal layer.

Question 21

What disorder is associated with “tombstone cells” seen in histology, due to epidermal basal cells that remain adherent to the basement membrane?

Answer 21

Pemphigus vulgaris

Question 22

What are 2 major differences between pemphigus vulgaris and pemphigus foliaceus?

Answer 22

PF has dyshesion between the outer stratum spinosum and stratum granulosum; and has IgG antibodies to desmoglein 1.

PV has dyshesion between the stratum spinosum and the stratum basalis, and has IgG antibodies to desmoglein 3.

Question 23

What structure separates the dermis from the epidermis?

Answer 23

Basement membrane

Question 24

What cell makes up the majority of the epidermis?

Answer 24

Keratinocyte

Question 25

Which layer of the epidermis is the stem cell layer?

Answer 25

Stratum basale

Question 26

Which structures connect cells in the stratum spinosum?

Answer 26

Desmosomes

(Connections make cells look like they have spine)

Question 27

Which cell layer has granules in the cells and is between the stratum spinosum and stratum corneum?

Answer 27

Stratum granulosum

Question 28

What is distinctive about the cells in the epidermal stratum corneum layer?

Answer 28

They have lost their nuclei

Question 29

Name 4 skin structures ONLY found in the dermis?

Answer 29

Hair shafts, blood vessels, sweat glands, and sebaceous glands

Question 30

Which cells are responsible for skin color?

Answer 30

Melanocytes

Question 31

Which skin cells are antigen-presenting cells?

What is the name of their specialized organelles that resemble tennis rackets?

Answer 31

Langerhans cells

Birbeck granules

Question 32

Which type of collagen in the basement membrane is important in the dermal-epidermal junction?

Answer 32

Type IV

Question 33

Which dermal layer is sometimes jointly affected in epidermal disease and superficial vascular bed disorders?

Answer 33

Papillary dermis

Question 34

Which layer of dermis, when disordered, reacts as a part of systemic disease?

Answer 34

Reticular dermis

Question 35

What would be found in a patient with alopecia areata?

Answer 35

Loss of hair in a circumscribed area, usually on the scalp.

Question 36

What type of environmental factors have been implicated in psoriasis?

Answer 36

Trauma (major), also drugs, infection, and photosensitivity

Question 37

What is ancantholysis?

What epidermal disease is it commonly seen in?

Answer 37

Loss of intercellular connections between cells, resulting in loss of cohesion between keratinocytes.

Pemphigus vulgaris

Question 38

What is the dermatologic term for epidermal hyperplasia?

Answer 38

Acanthosis