1.4 Plaque

Plaque.

A palpable, flat-topped, firm, rough, superficial lesion elevated above the skin surface, larger than a papule; papules can coalesce to form plaques.

Colors: if caused by inflammation, then red; if secondary to other deposits, then red, brown or yellow.

Size: > 1 cm (up to 10-20cm).

May appear anywhere on body.

May develop scale or crusts, or ulcerate.

Inflammatory plaques often pruritic.

Psoriasis, sarcoidosis,  plaque stage of mycosis fungoides (cutaneous T-cell lymphoma).

Inflammatory infiltrate, proliferations of cells, deposition of material.