Although many BCCs display focal squamatization
, tumors with more-extensive squamous differentiation may be designated as metatypical or keratotic.
Epidermal changes in LP lesions include irregular epidermal hyperplasia with a jagged "sawtooth" appearance, compact hyperkeratosis or orthokeratosis, foci of wedge-shaped hypergranulosis, basilar vacuolar degeneration, slight spongiosis in the spinous layer, and squamatization
. The dermal papillae between the elongated rete ridges are frequently dome shaped .
Histologic sections showed hyperkeratosis, focal epidermal atrophy, basal layer squamatization
and lichenoid infiltration of lymphohistiocytes with a few neutrophils in dermoepidermal junction, also pigment incontinence was prominent (Figure 2a and b).
Their histologic features are distinctive; either they can resemble adenoid cystic carcinoma, with cribriform nests with "punched out" rounded lumina and prominent hyaline basement membrane-like material, or they can resemble basal cell carcinomas of the skin, with variably sized nests, cords, or trabeculae with peripheral palisading of basal cells and central squamatization
of the nests (Figure 2, D and E).