A seborrheic keratosis is a non-cancerous benign skin growth that originate in keratinocytes and like liver spots, are seen more often as people age.1 They appear in various colors, from light tan to black, are round or oval-shaped, feel flat or slightly-elevated (like the scab from a healing wound), and range in size from very small to more than 2.5 centimetres (1.0 in) across.2 They can resemble warts1, though they have no viral origins. Because only the top layers of the epidermis are involved, seborrheic keratoses are often described as having a "pasted-on" appearance.
When correctly diagnosed, no treatment is necessary1. There is a small risk of localized infection caused by picking at the lesion. If a growth becomes excessively itchy, or if it is irritated by clothing or jewelry, cryosurgery has been found to be highly effective in their removal.
Causes
Its cause is unclear1; Because they are common on sun-exposed areas, such as the back, arms, face and neck, ultraviolet light might play a role, as may genetics.3 A mutation of a gene coding for a growth factor receptor (FGFR3), has been associated with seborrheic keratosis.4
Etymology
The term "seborrheic keratosis" combines the adjective form of seborrhea5, keratinocyte (referring to the part of the epidermis that produces keratin), and the suffix -osis, meaning abnormal.6
^ Hafner C, Hartmann A, Vogt T (2007). "FGFR3 mutations in epidermal nevi and seborrheic keratoses: lessons from urothelium and skin". J. Invest. Dermatol.127 (7): 1572–3. doi:10.1038/sj.jid.5700772. PMID 17568799.
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