Monday 11 March 2013
Lichen nitidus - "ball in claw" lymphohistiocytic infiltrate with giant cells surrounded by epidermal collarettes
Definition: Lichen nitidus is a chronic inflammatory disease of unknown etiology characterized by 1–2 mm, discrete and uniform, shiny, flat-topped, pale flesh-colored or reddish-brown papules that may appear as hypopigmented against dark skin.
Occasionally, minimal scaling is present or can be induced by rubbing the surface of the papules.
The disease usually affects children and young adults and is painless and usually nonpruritic, although protracted itching may occur in some cases. It is sometimes referred to by dermatologists as "mini lichen planus".
localized granulomatous lymphohistiocytic infiltrate in an expanded dermal papilla
thinning of overlying epidermis
downward extension of the rete ridges at the lateral margin of the infiltrate, producing a typical ’claw clutching a ball’ picture.