4 Dermatopathology

Epidermolytic hyperkeratosis • Coarse, irregular hypergranulosis associated

with disruption of cell membranes • Associated with keratin 1 and 10 mutations

Epidermotropism • Lymphocytes in epidermis with relative

absence of spongiosis: term usually reserved for mycosis fungoides

Erosion • Loss of the epidermis

Exocytosis • Lymphocytes in the epidermis with

associated spongiosis: term usually used when discussing spongiotic dermatitis

Festooning • Papillary dermis retains an undulating pattern

(often used to describe porphyria cutanea tarda)

Flame figure • Collagen encrusted with major basic protein

from eosinophils

Figure 1-12 Epidermolytic hyperkeratosis

Figure 1-13 Epidermotropism, mycosis fungoides

Figure 1-14 Lymphocyte exocytosis, subacute spongiotic dermatitis

a

b

Figure 1-15 Flame figure, Well’s syndrome