Psoriasis vs Lichen planus (histologic findings)
PSORIASIS
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acanthosis( overgrowth of the stratum spinosum) (with clubbed rete ridges),
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keratinocyte hyperproliferation,
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**parakeratosis **** (retention of nuclei in stratum corneum).
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usually presents with chronic erythematous plaques with silvery scales on the extensor surfaces of the knees and elbows, scalp, or neck.
LICHEN PLANUS :
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Chronic hyperkeratosis (thickening of stratum corneum), nooo **parakeratosis ****
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lymphocytic infiltrates at the dermoepidermal junction**
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thickened stratum granulosum with sawtooth rete ridges***
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eosinophilic colloid bodies in the papillary dermis
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pruritic, purple/pink, polygonal papules and plaques