Seborrheic keratosis

The cause of seborrheic keratosis is not known. The only definitive association is that its prevalence increases with age.

File:Seborrheic keratosis (1).jpg of a seborrheic keratosis (H&E stain, scanning magnification)]]

File:Seborrheic keratosis closup.jpg

Visual diagnosis is made by the "stuck on" appearance, horny pearls or cysts embedded in the structure. Darkly pigmented lesions can be challenging to distinguish from nodular melanomas.{{cite journal |vauthors=Luba MC, Bangs SA, Mohler AM, Stulberg DL |title=Common benign skin tumors |journal=Am Fam Physician |volume=67 |issue=4 |pages=729–738 |date=2003 |pmid=12613727 |url=https://www.aafp.org/pubs/afp/issues/2003/0215/p729.html |quote=§Seborrheic Keratosis: ... Differentiating between seborrheic keratoses and melanomas is a challenge. Both have variable dark colors, the potential for large size, and irregularity.}} Furthermore, thin seborrheic keratoses on facial skin can be very difficult to differentiate from lentigo maligna even with dermatoscopy. Clinically, epidermal nevi are similar to seborrheic keratoses in appearance. Epidermal nevi are usually present at or near birth. Condylomas and warts can clinically resemble seborrheic keratoses, and dermatoscopy can be helpful to differentiate them. On the penis and genital skin, condylomas and seborrheic keratoses can be difficult to differentiate, even on biopsy.{{citation needed|date=May 2019}}

A study examining over 4,000 biopsied skin lesions identified clinically as seborrheic keratoses showed 3.1% were malignancies. Two-thirds of those were squamous cell carcinoma.{{Cite journal|last1=Chen|first1=Tiffany Y.|last2=Morrison|first2=Annie O.|last3=Cockerell|first3=Clay J.|date=2017-09-01|title=Cutaneous malignancies simulating seborrheic keratoses: An underappreciated phenomenon?|journal=Journal of Cutaneous Pathology |volume=44|issue=9|pages=747–8|doi=10.1111/cup.12975|pmid=28589622|s2cid=11350866 }} To date, the gold standard in the diagnosis of seborrheic keratosis is represented by the histolopathologic analysis of a skin biopsy.{{cite book |last1=Hanlon |first1=Allison |title=A Practical Guide to Skin Cancer |date=2018 |publisher=Springer |isbn=9783319749037 |page=80 |url=https://books.google.com/books?id=UbtaDwAAQBAJ&q=Seborrheic+keratosis+skin+biopsy+gold+standard&pg=PA80 |access-date=22 September 2018 |language=en}}

Seborrheic keratoses may be divided into the following types:{{EMedicine|article|1056854|Dermatosis Papulosa Nigra}}{{EMedicine|article|1059798|Stucco Keratosis}}

Dermatosis papulosa nigra (DPN) is a condition of many small, benign skin lesions on the face, a condition generally presenting on darker-skinned individuals.{{rp|638–9}} DPN is extremely common, affecting up to 30% of black people in the United States.{{cite journal |vauthors=Grimes PE, Arora S, Minus HR, Kenney JA Jr |title=Dermatosis papulosa nigra |journal=Cutis |date=1983 |volume=32 |issue=4 |pages=385–6, 392 |pmid=6226495}}

Medical reasons for removing seborrheic keratoses include irritation and bleeding. They may also be removed for cosmetic reasons. Generally, lesions can be treated with electrodesiccation and curettage, or cryosurgery. When correctly performed, removal of seborrheic keratoses will not cause much visible scarring.{{cite web |title=Seborrheic keratoses |url=https://www.aad.org/public/diseases/bumps-and-growths/seborrheic-keratoses#treatment |publisher=American Academy of Dermatology |access-date=22 September 2018}}

Seborrheic keratosis is the most common benign skin tumor. Incidence increases with age. There is less prevalence in people with darker skin.{{cite journal|author=Zhang, Ru-Zhi|author2=Zhu, Wen-Yuan|title=Seborrheic keratoses in five elderly patients: An appearance of raindrops and streams|journal=Indian Journal of Dermatology|date=2011|volume=56|issue = 4|pages=432–434|doi=10.4103/0019-5154.84754|pmid=21965858|pmc=3179013 |doi-access=free }} In large-cohort studies, all patients aged 50 and older had at least one seborrheic keratosis.{{cite journal |vauthors=Yeatman JM, Kilkenny M, Marks R | date = September 1997 | title = The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency? | journal = Br J Dermatol | volume = 137 | issue = 3| pages = 411–4 | doi=10.1111/j.1365-2133.1997.tb03748.x| pmid = 9349339 }} Onset is usually in middle age, although they are common in younger patients too, as they are found in 12% of 15-year-olds to 25-year-olds, which makes the term "senile keratosis" a misnomer.{{cite journal |vauthors=Gill D, Dorevitch A, Marks R | date = Jun 2000 | title = The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant? | journal = Arch Dermatol | volume = 136 | issue = 6| pages = 759–62 | doi=10.1001/archderm.136.6.759| pmid = 10871940 | doi-access = free }}

• The sign of Leser-Trélat

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{{Commons category|Seborrheic keratosis}}

{{Medical resources

| DiseasesDB = 29386

| ICD10 = {{ICD10|L|82||l|80}}

| ICD9 = {{ICD9|702.1}}

| ICDO =

| OMIM = 182000

| MedlinePlus = 000884

| eMedicineSubj = derm

| eMedicineTopic = 397

| MeshID = D017492

}}

{{Diseases of the skin and appendages by morphology}}

{{Cutaneous ketatosis, ulcer, atrophy, necrobiosis, and vasculitis}}

{{Skin tumors, epidermis}}

{{DEFAULTSORT:Seborrheic Keratosis}}

Category:Epidermal nevi, neoplasms, and cysts

Category:Dermal and subcutaneous growths