From Surf Wiki (app.surf) — the open knowledge base

Seborrheic keratosis

Benign skin tumor originating in keratocytes

Field	Value
name	Seborrheic keratosis
synonyms	Seborrheic verruca, basal cell papilloma, senile wart
image	Seborrheic keratosis on human back.jpg
caption	Multiple seborrheic keratoses on the back of a patient with Leser–Trélat sign
field	Dermatology
diagnosis	Based on clinical examination, skin biopsy
treatment	Electrodesiccation and curettage, cryotherapy

A seborrheic keratosis is a non-cancerous (benign) skin tumour that originates from cells, namely keratinocytes, in the outer layer of the skin called the epidermis. Like liver spots, seborrheic keratoses are seen more often as people age.

The tumours (also called lesions) appear in various colours, from light tan to black. They are round or oval, feel flat or slightly elevated, like the scab from a healing wound, and range in size from very small to more than 2.5 cm across. Sometimes, seborrheic keratosis and basal cell carcinoma occur at the same location. At clinical examination, a differential diagnosis considers warts and melanomas. Because only the top layers of the epidermis are involved, seborrheic keratoses are often described as having a "pasted-on" appearance. Some dermatologists refer to seborrheic keratoses as "seborrheic warts", because they resemble warts, but strictly speaking, the term "warts" refers to lesions that are caused by the human papillomavirus.

Cause

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

Diagnosis

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. 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.

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. To date, the gold standard in the diagnosis of seborrheic keratosis is represented by the histolopathologic analysis of a skin biopsy.

Subtypes

Seborrheic keratoses may be divided into the following types:

Subtype (and alternative names)	Characteristics	Image
Common seborrheic keratosis (basal cell papilloma, solid seborrheic keratosis)	769}}
Reticulated seborrheic keratosis (adenoid seborrheic keratosis)	769}}
author=Rapini, Ronald P.	author2=Bolognia, Jean L.	author3=Jorizzo, Joseph L.	title=Dermatology: 2-Volume Set	publisher=Mosby	location=St. Louis	year=2007	page=1665	isbn=978-1-4160-2999-1}} digitate seborrheic keratosis, hyperkeratotic seborrheic keratosis, serrated seborrheic keratosis, verrucous seborrheic keratosis)	Common. Dull or lackluster surface, and with church-spire-like projections of epidermal cells around collagen seen histologically. Stucco keratoses are often light brown to off-white, and are no larger than a few millimeters in diameter. They are often found on the distal tibia, ankle, and foot.
Clonal seborrheic keratosis	769}}
Irritated seborrheic keratosis (inflamed seborrheic keratosis, basosquamous cell acanthoma)	769}}
Seborrheic keratosis with squamous atypia	770}}
Melanoacanthoma (pigmented seborrheic keratosis)	770}} It involves a proliferation of keratinocytes and melanocytes.
last1=Karadag	first1=AyseSerap	last2=Ozlu	first2=Emin	last3=Uzuncakmak	first3=TugbaKevser	last4=Akdeniz	first4=Necmettin	last5=Cobanoglu	first5=Bengu	last6=Oman	first6=Berkant	title=Inverted follicular keratosis successfully treated with imiquimod	journal=Indian Dermatology Online Journal	volume=7	issue=3	year=2016	pages=177–9	doi=10.4103/2229-5178.182354	pmid=27294052	pmc=4886589	doi-access=free}}	doi=10.1155/2013/752864	pmid=23878739	pmc=3708441	title=Simulators of Squamous Cell Carcinoma of the Skin: Diagnostic Challenges on Small Biopsies and Clinicopathological Correlation	journal=Journal of Skin Cancer	volume=2013	pages=1–10	year=2013	last1=Tan	first1=Kong-Bing	last2=Tan	first2=Sze-Hwa	last3=Aw	first3=Derrick Chen-Wee	last4=Jaffar	first4=Huma	last5=Lim	first5=Thiam-Chye	last6=Lee	first6=Shu-Jin	last7=Lee	first7=Yoke-Sun	doi-access=free }}	[[File:SkinTumors-P6190325.JPG	180px]]

Differential diagnoses

Dermatosis papulosa nigra (DPN) is a condition of many small, benign skin lesions on the face, a condition generally presenting on darker-skinned individuals. DPN is extremely common, affecting up to 30% of black people in the United States.

Treatment

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.

Epidemiology

Seborrheic keratosis is the most common benign skin tumor. Incidence increases with age. There is less prevalence in people with darker skin. In large-cohort studies, all patients aged 50 and older had at least one seborrheic keratosis. 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.

Notes

References

(Aug 2008). "Seborrheic keratosis". Journal der Deutschen Dermatologischen Gesellschaft.
(2003). "Fitzpatrick's Dermatology in General Medicine". McGraw-Hill.
(2006). "Andrews' Diseases of the Skin: Clinical Dermatology". Saunders Elsevier.
(27 August 2021). "Seborrheic Keratosis". [[Cleveland Clinic]].
(18 January 2022). "Seborrheic keratosis". [[Mayo Clinic]].
(2015). "Basal Cell Carcinoma and Seborrheic Keratosis: When Opposites Attract". International Journal of Surgical Pathology.
(May 2006). "Seborrhoeic keratoses with associated lesions: a retrospective analysis of 85 lesions". The Australasian Journal of Dermatology.
(May 2006). "Seborrhoeic keratosis and malignancy: Collision tumour or malignant transformation?". Australasian Journal of Dermatology.
(2014). "Vulvar Seborrheic Keratosis". Journal of Lower Genital Tract Disease.
(2003). "Common benign skin tumors". Am Fam Physician.
(2017-09-01). "Cutaneous malignancies simulating seborrheic keratoses: An underappreciated phenomenon?". Journal of Cutaneous Pathology.
(2018). "A Practical Guide to Skin Cancer". Springer.
{{EMedicine. article. 1056854. Dermatosis Papulosa Nigra
{{EMedicine. article. 1059798. Stucco Keratosis
Rapini, Ronald P.. (2007). "Dermatology: 2-Volume Set". Mosby.
(22 March 2023). "Cutaneous Melanoacanthoma: eMedicine Dermatology".
(2013). "Simulators of Squamous Cell Carcinoma of the Skin: Diagnostic Challenges on Small Biopsies and Clinicopathological Correlation". Journal of Skin Cancer.
(1983). "Dermatosis papulosa nigra". Cutis.
"Seborrheic keratoses". American Academy of Dermatology.
Zhang, Ru-Zhi. (2011). "Seborrheic keratoses in five elderly patients: An appearance of raindrops and streams". Indian Journal of Dermatology.
(September 1997). "The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency?". Br J Dermatol.
(Jun 2000). "The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant?". Arch Dermatol.

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

epidermal-nevi,-neoplasms,-and-cysts dermal-and-subcutaneous-growths

Want to explore this topic further?

Ask Mako anything about Seborrheic keratosis — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report