Derm

Question 1

What happens during wrinkling of the skin?

Answer 1

Following sun exposure there is decreased Collagen fibril production and increased degredation of collagen and elastin of the dermis

Question 2

PKU inheritance pattern?

Answer 2

ar

Question 3

36 y/o M presents with pruiritic rash over the elbows and knees x 2 mo. He also has a long gx of abdominal discomfort, flatulence, and greasy stools. Papulovesicular rash in groups with erosion and excoriations. What would be seen on GI histology?

Answer 3

Increased intestinal intraepithelial lymphocytes

Dermatitis herpetiformis is strongly associated with Celiac’s

Question 4

A pt has a bx of a lesion on her eyelid that demonstrates lipid laden macrophages. Dx and what is it associated with?

Answer 4

Xanthelasma

Primary or secondary hyperlipidemia (ie cholestatic dz)

Question 5

In a pt with M. leprae a test is conducted where heat killed M. leprae is inj intradermally and pt develops a large nodules. why?

Answer 5

Increased IL2 and IFN gamma in skin lesions
Positive lepromin skin test
Pts with a negative test but are sympotomatic are negative due to a weak Th1 mediated immune response

Question 6

Pr presents with a bluish lesion under the nail that is extremely tender. What function is related to the cells of origin to this tumer?

Answer 6

Thermoregulation
Glomangioma - very tender, small, red-blue lesion under the nail bed. Originates from modified smooth muscle cells that control thermoregulation of dermal glomus bodies

Question 7

Woman presents with multiple firm violaceous nodules on the upper arm on the same side of her body that she had a breast carcinoma removed 12 years ago. There were no signs of metastasis in her lymph nodes at removal. Etiology of the skin lesions?

Answer 7

Angiosarcoma
Axillary lymph node dissection is a risk factor for chronic lymphedema involving the ipsilateral arm.
Chronic lymphedema is a risk factor for cutaneous angiosarcoma (Stewart-Treves syndrome)

Question 8

What is the MOA of terbinafine?

Answer 8

Inhibition of squalene oxidase

Question 9

Pt presents with an itchy rash on his chest. PE annular scaling plaque with central clearing. KOH prep shows branching septate. Dx?

Answer 9

Tinea corporis

Tx - topical terbinafine

Question 10

What is the aggravating substance that plants produce to cause Type IV HS reaction?

Answer 10

urushiol

Question 11

A pt is applying a new topical to her skin and presents with a severe rash. PE eythematous, papulovesicular, weeping lesions. What would be seen on histology?

Answer 11

Spongiosis
Acute allergic contact dermatitis (type IV HS)
Accumulation of edema fluid in the intercellular spaces of the epidermis. With chronic exposures lesions become less edematous with thickening of the stratum spinosum and stratum corneum

Question 12

Benign epidermal tumor presents as a tan or brown round lesion with a well-demarcated border and “stuck-on” appearance

Answer 12

Seborrheic keratosis

Can be pruiritic

Question 13

A pt has been treating his eczema with corticosteroid cream. What would be seen on bx?

Answer 13

Dermal atrophy
Local AE’s of corticosteroid use - atrophy/thinning of the dermis associated with loss of dermal collagen, drying, cracking, and/or tightening of the skin, telangiectasias, and ecchymoses

Question 14

What is the pathology of graft vs. host dz?

Answer 14

Graft T cell sensitization against MHC antigens

Question 15

What happens in vitiligo?

Answer 15

Autoimmune destruction of epidermal melanocytes

Question 16

Pt presents with atopic dermatitis following ingestion of certain foods. What else is he likely to develop?

Answer 16

Asthma
Pruritic, erythematous, weeping/crusted papules and plaques in response to environmental Ag
Associated with other atopic dz’s like allergic rhinitis and asthma

Question 17

A pt has sutures places and weeks later presents with a painful subcutaneous nodule.
Bx - granuloma formation
Dx?

Answer 17

Response to a foreign Ag
Granulomatous inflammation is a form of chronic inflammation characterized by aggregates of activated macrophages that assume and epithelioid appearance. Persistent granulomatous inflammation with subsequent fibrosis can cause organ dysfunction as in other granulomatous dz’s

Question 18

Skin finding associated with HSV?

Answer 18

Erythema multiforme
cell-mediated inflammatory disorder of the skin characterized by erythematous papules that evolve into target lesions
Also seen with sulfonamides use, malignancy and collagen vascular dz

Question 19

Pemphis vulgaris (loose bullae) is autoantibodies againse?

Answer 19

Desomosomes

Question 20

Small erythematous epidermal lesions with adherent scale as a result of chronic sun exposure.

Answer 20

Actinic keratoses
Histology - keratinocyte atypia, hyperkeratosis, parakeratosis, sandpaper like texture
Small percentage progress to invasive squamous cell carcinoma. Frequent monitoring is necessary
AKs do NOT invade the dermis

Question 21

Brain bx with neoplastic tissue and mutation that encodes BRAF

Answer 21

Metastatic melanoma

BRAF = protein kinas, activates the pathway in melanocyte proliferation