Skin

Question 1

Direct precursor of melanoma

Marker of increased melanoma risk

Answer 1

DYSPLASTIC NEVUS

Question 2

Most deadly of all skin cancers

SUN EXPOSURE - most important risk factor

RAS/BRAF mutations
TERT - most common mutation found in melanomas

Answer 2

MALIGNANT MELANOMA

Question 3

Growth Phase of Melanoma

Answer 3

RADIAL
epidermal, superficial dermis
superficial spreading - MC
lentigo maligna
acral lentiginous

VERTICAL
deep dermis
nodular
(+) metastatic potential
less favorable

Question 4

Melanocytic markers

Answer 4

S-100 - neural crest cell marker
Melan A and HMB-45 - melanocytic markers

Question 5

Prognostic factors of Melanoma

Answer 5

TUMOR DEPTH (Breslow thickness)
MITOSES
EVIDENCE OF TUMOR REGRESSION
Tumor infiltrating lymphocytes
Location
NODAL STATUS

Question 6

Benign but can be mistaken for melanomas grossly

Answer 6

SEBORRHEIC KERATOSES

exophytic and well demarcated lesion
basaloid cells
hyperkeratosis
horn cysts
invagination cysts

Question 7

RAPID INCREASE in seborrheic keratoses

tumor cells produce TFG-a –> keratinocyte stimulation

Answer 7

LESER TRELAT SIGN

paraneoplastic syndrome of GI malignancies

Question 8

Thickened hyperpigmented skin with velvet like texture in flexural areas

Cutaneous marker of benign and malignant conditions

Answer 8

ACANTHOSIS NIGRICANS

BENIGN - DM and obesity
MALIGNANT - GI malignancies

Question 9

Morphologic findings in acanthosis nigricans

Answer 9

undulation of epidermis and dermal papillae
hyperkeratosis
basal cell hyperpigmentation WITHOUT melanocytic hyperplasia

Question 10

Fibrovascular cores w/ benign squamous epithelium

Answer 10

FIBROEPITHELIAL POLYP
acrochordon
squamous papilloma
skin tag

Question 11

Tumors that arise from CUTANEOUS APPENDAGES

Some may be mistaken for BCC

Answer 11

ADNEXAL TUMORS

Question 12

Hyperkeratotic lesion that occurs in SUN DAMAGED SKIN

PREMALIGNANT lesion to SCC

RISK FACTORS:
sun exposure
ionizing radiation
industrial hydrocarbons
arsenicals

Answer 12

ACTINIC KERATOSIS

MORPHOLOGY:
hyperkeratosis –> cutaneous horn
parakeratosis
atypical dyskeratotic cells in basal layer
solar elastosis
blue gray elastic fibers in dermis

Question 13

2nd MC tumor arising on SUN EXPOSED AREA

ULCERATIVE PLAQUES TO NODULES

RISK FACTORS:
sun exposure
immunosuppression (increased susceptibility to HPV 5 and 8)
disorders of DNA repair (Xeroderma pigmentosum)
industrial carcinogens
chronic ulcers and draining osteomyelitis
old burn scars (Marjolin scars)

Answer 13

SQUAMOUS CELL CARCINOMA

(+) metastatic potential

MORPHOLOGY:
ATYPICAL squamous cells with DERMAL INVASION
KERATIN PEARLS
dyskeratotic cells

Question 14

MC invasive cancer in humans

PEARLY papules with TELANGIECTASIA –> extensive ulceration (RODENT ULCER)

pigmentation

RISK FACTORS:
sun exposure
immunosuppression
disorders of DNA repair (Xeroderma pigmentosum)

locally AGGRESIVE
rare metastasis

Answer 14

BASAL CELL CARCINOMA

Associated syndromes:
Gorlin syndrome

MORPHOLOGY:
nests of basaloid w/ peripheral palisading
STROMAL RETRACTION

Question 15

ERYTHEMA MULTIFORME

ASSOCIATED CONDITIONS:
Infections (HSV, Mycoplasma)
Drugs
Cancers
Collagen Vascular Diseases

CD8+ T cell mediated process

Answer 15

SPECTRUM:

Steven Johnson Syndrome - <10% TBSA
SJS-TEN overlap - 10-30% TBSA
TEN >30% TBSA

Question 16

Involves region w/ HIGH DENSITY OF SEBACEOUS GLANDS

Answer 16

SEBORRHEIC DERMATITIS

(+) FOLLICULAR LIPPING

Question 17

6 Ps

Pruritic
Purple
Polygonal
Planar
Papules
Plaques

WICKHAM STRIAE

CD8+ T cell mediated hypersensitivity

Answer 17

LICHEN PLANUS

Question 18

DESMOGLEIN (desmosomes)
SUPRABASILAR
IgG
ACANTHOLYSIS
(+) NIKOLSKY SIGN

Answer 18

PEMPHIGUS VULGARIS

Question 19

Bullous pemphigoid Ags (hemidesmosomes)
IgG
SUBEPIDERMAL
(-) acantholysis
basal cell layer vacuolization
(-) NIKOLSKY SIGN

Answer 19

BULLOUS PEMPHIGOID

Question 20

RETICULIN (fibrils at anchor epidermis to superficial dermis)

SUBEPIDERMAL
IgA
(-) NIKOLSKY SIGN

Answer 20

DERMATITIS HERPETIFORMIS

Question 21

Papillomatous epidermal hyperplasia w/ koilocytic change

Answer 21

VERRUCAE

Question 21

PINK EARLY, firm PAPULE w/ UMBILICATED CENTER

Answer 21

Molluscum Contagiosum

MOLLUSCUM BODY - ellipsoid, cytoplasmic inclusion

Question 22

Fever blisters or cold sores
Gingivostomatitis
Herpetic Whitlow - fingers and palms
Genital Herpes

Answer 22

HSV

Question 23

Intraepidermal vesicles with intranuclear inclusions in keratinocytes

Answer 23

Varicella Zoster

COMPLICATIONS:
POST-HERPETIC NEURALGIA - MC

RAMSAY HUNT SYNDROME - FACIAL PARALYSIS - GENICULATE NUCLEUS INVOLVEMNT

HERPES ZOSTER OPHTHALMICUS - reactivation at OPHTHALMIC division of TRIGEMINAL NERVE – BLINDNESS

Question 24

Furuncle/Boil: Focal suppurative inflammation of skin and subcutaneous tissue (starts at hair follicle)

Carbuncle: Deeper suppurative infections that spreads laterally and superficially (skin sinuses)

Hidradenitis: Chronic suppurative infection of the apocrine glands

Paronychia: Nail bed infection (painful)

Felon: Infection of the palmar side of fingertips (Painful)

Staphylococcal scalded skin syndrome (Ritter disease): sunburn-like rash à fragile bullae à partial or total skin loss (Desquamation at stratum granulosum)

Answer 24

STAPHYLOCOCCAL SKIN INFECTIONS

Question 25

Erysipelas

Answer 25

STREPTOCOCCAL SKIN INFECTIONS

Question 26

HONEY COLORED CRUSTING

Answer 26

IMPETIGO

MICROSCOPIC:
neutrophil accumulation beneath stratum corneum

Impetigo contagiosa - S. pyogenes
Impetigo bullosa - S. aureus

Question 27

Histologic hallmark of ACNE VULGARIS

Answer 27

COMEDOGENESIS