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Authors: Dr Charlotte Foster, Anatomical Pathology Registrar, Tauranga, New Zealand; Dr Ben Tallon, Consultant Dermatopathologist, Tauranga, New Zealand. Copy edited by Gus Mitchell. September 2021
Seborrhoeic keratosis is a benign acanthoma comprised of epidermal keratinocytes. Clinically it presents as a sharply demarcated warty plaque with a ‘stuck-on’ appearance and greasy texture.
Seborrhoeic keratosis is a well-demarcated exophytic, flat or, less commonly, endophytic lesion composed of a proliferation of epidermal keratinocytes. Seborrhoeic keratosis can be recognised by a papillomatous architecture, acanthosis, hyperkeratosis, and horn cysts. The hyperkeratosis produces a characteristic loose lamellar stratum corneum. Squamous eddies may be present if particularly acanthotic.
There are multiple distinct histological patterns:
Histological patterns of seborrhoeic keratosis
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