Page 4 - DermPath Correlation

Part 4:
Lichenoid pattern -

Lichenoid pattern is a sub group of Interface dermatitis. The other subtype is vacuolar interface
dermatitis. In lichenoid dermatitis there is a band like lymphocytic infiltrate obscuring the dermo
epidermal junction, Squamatisation of the basal cells which form larger keratinocytes with
anpinkish cytoplasm and some dyskeratotic cells and epidermal hyperplasia with saw tooth rete,
hypergranulosis and compact orthokeratosis.

Clinically though various disorders can show this pathology.
Those with mainly a superficial lymphocytic infiltrate include lichenoid keratosis, lichen
nitidus, lichenoid drug reaction, lichen aureus, lichenoid MF, pityriasis lichenoides chronica and
keratosis lichenoides chronica (Nekam's disease)
Those with a deep infiltrate include lichenoid lupus erythematosus, lichen striatus and
PLEVA/lymphomatoid papulosis.

Now most of the disorders above have other histological features that allow them to be diagnosed
easily eg lichen nitidus but lichenoid keratosis, lichenoid drug and Lichen planus can look
histologically indistinguishable. Also lichenoid photodermatitis, pityriasis lichenoides chronica,
Keratosis lichenoides chronica and lichenoid LE can also be difficult to diagnose without clinical
correlation.

Part 5:
Pseudoepitheliomatous hyperplasia

Hyperplasia and acanthosis of the epidermis is seen in certain inflammatory conditions including
hypertrophic lichen planus, hypertrophic lupus erythematosus and in the variant of lichen simplex
chronicus known as prurigo nodularis. The problem arises when a shave biopsy is submitted and