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lichen planus

Wednesday 16 June 2004

Definition: Lichen planus has thickened layers epidermis with apoptosis and Civatte bodies in the basal layer, sawtooth rete ridges, and a band of lymphocytes.

Lichen planus causes pruritic erythematous to purple papules on the skin, particularly the flexor surfaces, and the mucous membranes.

It is histologically characterized by: thickening of the epidermis - the stratum corneum (orthokeratosis on the skin, and parakeratosis in the oral form), the stratum granulosum, and the stratum spinosum (acanthosis). The stratum basale / basal layer shows areas of necrosis or apoptosis of the keratinocytes with the formation of Civatte bodies. A sawtooth pattern of the rete ridges is present, and a band of lymphocytes (mostly T cells) is present in the dermis deep to the basal layer. (On histology “lichenoid” refers to a band like inflammatory infiltrate).

Digital cases

- UI:902 - Lichen planus


- hypertrophic lichen planus (HLP)

Differential diagnosis

- lichenoid drug eruption
- lichenoid keratosis
- lichen striatus
- lichen niditus
- lichenoid purpura
- porokeratosis
- lichenoid actinic keratosis