Dermatopathology II

Question 1

Dermatofibroma (5):

Answer 1

• Benign fibrous histiocytoma
• Slow growing
• Flesh-colored to pigmented papule
• Displays the “dimple sign”
• Fibrous reaction to some past trauma

Question 2

Dermatofibroma histological features (3):

Answer 2

• Benign proliferations of fibroblasts with collagen
• Whirling fibroblasts with collagen bundles
• May be overlying hyperkeratosis and hyperpigmentation

Question 3

Uticaria pigmentosa (2):

Answer 3

• Type of mastocytosis
• Usually multiple mastocytomas - round to oval, red-brown papules and plaques, pruritic and may blister, appear shortly after birth

Question 4

Systemic mastocytosis (3):

Answer 4

• Usually adults
• Skin lesions similar to uticaria pigmentosa plus:
  
  • Multi-organ mast cell infiltration

Question 5

Mastocytoma histologic features (4):

Answer 5

• Metachromatic granules within dendritic mast cells
• Monomorphous dermal infiltrate
• No epidermotropism
• Fried egg cells

Question 6

Ichthyosis:

Answer 6

Disorders which impair epidermal maturation

Question 7

Irritant contact dermatitis (3):

Answer 7

• Substance has direct toxic effects on the skin
• Not an immunologic condition
• Rash begins shortly after exposure

Question 8

Allergic contact dermatitis (3):

Answer 8

• Cell-mediated, delayed-type hypersensitivity reaction (Type IV)
• Sensitization of skin occurs 1-2 weeks after 1st exposure to allergen
• Reexposure causes dermatitis in hours to days

Question 9

Atopic dermatitis (2):

Answer 9

• Chronic, waxing and waning, extremely pruritic condition beginning in the 1st year of life
• Condition is worse in winter due to decreased humidity

Question 10

Lichenification:

Answer 10

Epidermal thickening characterized by visible and palpable skin thickening with accentuated skin lines
- Chronic dermatitis leads to this

Question 11

Nummular dermatitis (3):

Answer 11

• Coin shaped
• Itchy red plaques with vesicles and distinct borders
• More likely in young adults

Question 12

Asteatotic dermatitis (3):

Answer 12

• Winter itch
• Older people in winter
• Dry, cracked skin that becomes itchy

Question 13

Erythema multiforme (EM) (4):

Answer 13

• Immune-mediated, hypersensitivity reaction resulting in epidermal cell injury
• Epidermal cells are attacked by CD8+ cytotoxic T-cells; target Ag unknown
• Erythematous macules and papules, vesicules and bullae on extremities that are strikingly symmetric
• Target lesions are diagnostic

Question 14

Stevens-Johnson Syndrome (4):

Answer 14

• 10-30% Body surface involvement
• More severe than EM
• Involvement of mucous membranes including mouth and conjunctivae
• Systemic manifestations may include fever, difficulty eating, renal failure and sepsis

Question 15

Toxic Epidermal Necrolysis (TENs) (4):

Answer 15

• > 30% body surface involvement
• More severe than Stevens-Johnson syndrome
• Dermatologic emergency
• Detachment of large areas of epidermis

Question 16

Pityriasis rosea (6):

Answer 16

• Subacute spongiotic dermatitis
• Most common in winter
• Get initial herald patch that resembles ring worm
• Progresses to generalized oval, slightly elevated, scaling papules that are smaller
• Lesions pink with scaling near the border
• Christmas tree pattern

Question 17

Venous insufficiency (2):

Answer 17

• Venous incompetence causes increased hydrostatic pressure and capillary damage leading to extravasation of RBCs and serum
• Starts as edema and hyperpigmentation and leads to pruritic erythema and stasis dermatitis

Question 18

Psoriasis (5):

Answer 18

• Accelerated proliferation of skin cells resulting in scaling
• Chronic condition with exacerbations and remissions
• Well-demarcated, erythematous plaques and papules with silver scaling
• Symmetrical
• Auspitz’s sign

Question 19

Auspitz’s sign:

Answer 19

Pinpoint bleeding on removed of scale

Question 20

Psoriasis histologic features (4):

Answer 20

• Downward elongation of rete ridges
• Thinning of overlying stratum granulosum with parakeratosis above
• Aggregates of neutrophils with surrounding spongiosis
• Capillaries in dermal papillae are brought close to the surface

Question 21

Arthritis multilans:

Answer 21

Very destructive form of psoriatic arthritis with significant periarticular bone resorption.

Question 22

Seborrheic dermatitis (4):

Answer 22

• Chronic inflammatory process affecting areas rich in sebaceous glands
• Malassezia furfur
• Yellow greasy scaly patches with surrounding erythema
• Asymptomatic but may be itchy

Question 23

Lichen planus (6):

Answer 23

• Idiopathic inflammatory disorder
• Pruritic, purple, polygonal, planar, papules, plaques
• Most common on wrists and ankles
• Mucous membrane involvement is common
• Wickhams striae
• Koebner phenomenon

Question 24

Wickham’s striae:

Answer 24

Fine reticulated white lines

Question 25

Koebner phenomenon:

Answer 25

Trauma to skin and stress can cause exacerbations

Question 26

Systemic lupus erythematosus:

Answer 26

Multisystem autoimmune disease involving connective tissues and blood vessels

Question 27

Malar rash:

Answer 27

SLE:

- Butterfly rash, erythematous, confluent, macular eruption with clear borders that spares nasolabial folds