Ch. 7 - Interface dermatitis

Question 1

Lichenoid interface dermatitis

Answer 1

Destruction of basal layer with civatte bodies and sawtooth rete pattern. Hyperkeratosis and hypergranulosis are typically present.

Question 2

Causes of lichenoid interface dermatitis

Answer 2

Lichen planus

Benign lichenoid keratosis

Lichenoid drug eruption

Lichenoid GVHD

Hypertrophic lupus erythematosis

Lichenoid regression of melanocytic lesion

Question 3

Late-phase (burnt out) lichenoid dermatitis

Answer 3

Effacement of the rete with civatte bodies and melanin pigment incontinence (melanoderma)

Question 4

Lichen planus

Answer 4

Lichenoid interface dermatitis with sawtooth rete ridge s and no parakeratosis or eosinophils

Question 5

Lichenoid drug eruption

Answer 5

Lichenoid interface dermatitis with eosinophils and parakeratosis

Question 6

Benign lichenoid keratosis

(early stage?)

Answer 6

Lichenoid interface dermatitis with parakeratosis and solar lentigo at the margin

In early stage, looks vacuolar with lymphocytes in nearly every vacuole.

Question 7

Hypertrophic lupus erythematosus

Answer 7

Lichenoid interface dermatitis with rare parakeratosis and eosinophils, with granular DIF at the basement membrane, also CD123+ dendritic cells adjacent to the epithelium.

Question 8

Lichenoid regression of lentigo maligna

Answer 8

Lichenoid interface dermatitis in an area of heavily sun-damaged skin, sometimes with parakeratosis.

Question 9

Porokeratosis

Answer 9

Cornoid lamellae with lichenoid or psoriasiform zones between.

Question 10

Vacuolar interface dermatitis

Answer 10

Intact but vacuolated basal layer with a rounded rete pattern. Look for lymphocytes in the vacuoles to narrow the differential.

Question 11

Mycosis fungoides

Answer 11

Vacuolar interface dermatitis with atypical CD7- lymphocytes in nearly every vacuole. Little accompanying spongiosis. Epidermal Pautrier microabscesses.

Question 12

Pityriasis lichenoides et varioliformis acuta (PLEVA), Pityriasis lichenoides chronica

Answer 12

Vacuolar interface dermatitis with a lymphocyte in nearly every vacuole. Keratinocyte necrosis and transepidermal elimination of erythrocytes.

Question 13

Lupus erythematosus (non-lichenoid)

Answer 13

Vacuolar interface dermatitis with compact and follicular hyperkeratosis, perivascular/periadnexal lymphocytes. Melanoderma. DIF is negative in early lesions.

Question 14

Dermatomyositis

Answer 14

Similar to lupus erythematosus (vacuolar interface dermatitis with lymphocytes and parakeratosis) but with epidermal atrophy.

Question 15

Lichen striatus

Answer 15

Blaschkoid interface dermatitis, similar to lupus (perivascular and eccrine lymphocytes), but without dermal mucin.

Question 16

Polymorphous light eruption

Answer 16

Can be papulovesicular (spongiotic) or plaque variant (papillary dermal edema and dense perivascular lymphoid infiltrate)

Question 17

Syphilis

Answer 17

Vacuolar interface dermatitis with slender acanthosis. Epidermis can be atrophic with neutrophils in the SC. Endothelial swelling obliterates small vessels.

Question 18

Erythema multiforme

Answer 18

Vacuolar interface dermatitis with necrotic keratinocytes or confluent epidermal necrosis out of proportion to lymphocytes. Later, bulla and re-epithelialization occur.

Question 19

Toxic epidermal necrolysis

Answer 19

Looks identical to erythema multiforme (vacuolar interface dermatitis with epidermal necrosis out of proportion to lymphocytes).

Question 20

Fixed drug eruption

Answer 20

Vacuolar interface dermatitis with polymorphous infiltrate (with eosinophils), papillary dermal fibrosis, and perivascular melanin incontinence.

Question 21

Answer 21

Lichenoid interface dermatitis

Question 22

Answer 22

Lichen planus

Question 23

Answer 23

Lichenoid drug eruption

Question 24

Answer 24

Benign lichenoid keratosis

Question 25

Answer 25

Hypertrophic lupus erythematosus

Question 26

Answer 26

Lichenoid regression of lentigo maligna

Question 27

Answer 27

Porokeratosis

Question 28

Answer 28

Mycosis fungoides

Question 29

Answer 29

Pityriasis lichenoides et varioliformis acuta

Question 30

Answer 30

Pityriasis lichenoides chronica

Question 31

Answer 31

Acute lupus erythematosus

Question 32

Answer 32

Chronic lupus erythematosus

Question 33

Answer 33

Polymorphous light eruption

Question 34

Answer 34

Lichen striatus

Question 35

Answer 35

Dermatomyositis

Question 36

Answer 36

Syphilis

Question 37

Answer 37

Erythema multiforme

Question 38

Answer 38

Fixed drug eruption

Question 39

Answer 39

Graft versus host disease