Seborrheic Keratosis or Seborrheic Verrucas

A seborrheic keratosis (also known as “Seborrheic verruca,” “Senile keratosis,” and “Senile wart” [1,2]  is a noncancerous benign skin growth that originates in keratinocytes. Like liver spots, seborrheic keratoses are seen more often as people age.[3] In fact they are sometimes humorously referred to as the “barnacles of old age”. [1]

They appear in various colors, 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 centimetres (1.0 in) across.[4] They can resemble warts[3], though they have no viral origins. They can also resemble melanoma skin cancer, though they are unrelated to melanoma as well.

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”, however these lesions are usually not associated with HPV, and therefore such nomenclature should be discouraged.

* 1 Classification
* 2 Variances of Seborrheic Keratosis
o 2.1 Dermatosis Papulosis Nigra
o 2.2 Stucco Keratosis
* 3 Diagnosis
* 4 Treatment
* 5 Cause
* 6 Etymology
* 7 References
* 8 External links

Classification

Seborrheic keratoses may be divided into the following types:[1]

* Common seborrheic keratosis (Basal cell papilloma, Solid seborrheic keratosis)
* Reticulated seborrheic keratosis (Adenoid seborrheic keratosis)
* Stucco keratosis (Digitate seborrheic keratosis, Hyperkeratotic seborrheic keratosis, Serrated seborrheic keratosis, Verrucous seborrheic keratosis)
* Clonal seborrheic keratosis
* Irritated seborrheic keratosis (Basosquamous cell acanthoma, Inflamed seborrheic keratosis)
* Seborrheic keratosis with squamous atypia
* Melanoacanthoma (Pigmented seborrheic keratosis)
* Dermatosis papulosa nigra

Also see:

* The sign of Leser-Trélat
Variances of Seborrheic Keratosis or Dermatosis Papulosis Nigra

Often are small papules. Pinpoint to a few millimeters in size. More commonly found in dark-skinned persons.[5]

Stucco Keratosis

Often are light brown to off-white. Pinpoint to a few millimeters in size. Often found on the distal tibia, ankle, and foot.[6]

Diagnosis

Visual diagnosis is made by the “stuck on” appearance, horny pearls or cysts embedded in the structure. Darkly pigmented lesions can be hard to distinguish from nodular melanomas. [7] If in doubt, a skin biopsy should be performed. 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. On the penis and genital skin, differentiation between condylomas and seborrheic keratoses can be difficult and may require a skin biopsy.

Treatment

When correctly diagnosed, no treatment is necessary[3]. There is a small risk of localized infection caused by picking at the lesion. If a growth becomes excessively itchy or is irritated by clothing or jewelry, it can be removed by cryosurgery.  Small lesions can be treated with light electrocautery. Larger lesions can be treated with electrodessication and curettage, shave excision, or cryotherapy. When correctly performed, removal of seborrheic keratoses will not cause much visible scarring except in darkly colored persons.

Cause

The cause of seborrheic keratosis is unclear[3]. Because they are common on sun-exposed areas such as the back, arms, face, and neck, ultraviolet light may play a role, as may genetics.[8] A mutation of a gene coding for a growth factor receptor, (FGFR3), has been associated with seborrheic keratosis.[9]

Etymology
The term “seborrheic keratosis” combines the adjective form of seborrhea[10], keratinocyte (referring to the part of the epidermis that produces keratin), and the suffix -osis, meaning abnormal.[11]

References

1. ^ a b Freedberg, et. al. (2003). Fitzpatrick’s Dermatology in General Medicine. (6th ed.). McGraw-Hill. ISBN 0071380760.
2. ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews’ Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921

-0.
3. ^ a b c d Moles, Freckles, Skin Tags, Benign Lentigines, and Seborrheic Keratoses from the Cleveland Clinic website
4. ^ Seborrheic keratosis: Symptoms, from the Mayo Clinic website
5. ^ http://www.emedicine.com/derm/topic99.htm
6. ^ http://www.emedicine.com/derm/TOPIC407.HTM
7. ^ http://www.dermadoctor.com/article_Seborrheic-Keratoses_91.html
8. ^ Seborrheic keratosis: Causes, from the Mayo Clinic website
9. ^ 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.
10. ^ Seborrheic, from Merriam-Webster’s online medical dictionary
11. ^ Suffix “-osis” from the Merriam-Webster website

Types and Causes of Warts

A wart (also known as verruca) is generally a small, rough tumor, typically on hands and feet but often other locations, that can resemble a cauliflower or a solid blister. Warts are common, and are caused by a viral infection, specifically by the human papillomavirus (HPV) and are contagious when in contact with the skin of an infected person. It is also possible to get warts from using towels or other objects used by an infected person. They typically disappear after a few months but can last for years and can recur.

Warts are caused by a virus called human papilloma virus or HPV. There are approximately 100 strains of human papilloma viruses. Type 1, 2, and 3 causes most of the common warts. Type 1 is associated with deep plantar (sole of the feet) and palmar warts (palm of the hand). Type 2 causes common warts, filiform warts, plantar warts, mosaic plantar warts. Type 3 causes plane warts, or commonly known as flat warts. Anogenital warts are caused by types 6, 11, 16, 18, 30, 31, 33, 34, 35, 39, 40 and others. HPV types 6 and 11 cause about 90% of genital warts cases. HPV types 16 and 18 currently cause about 70% of cervical cancer cases, and also cause some vulvar, vaginal, penile and anal cancers. Gardasil, a vaccine for HPV is designed to prevent infection with HPV types 16, 18, 6, and 11; it is claimed to prevent infections to other strains of anogenital warts through cross protection against other types of HPVs. HPV is associated with oral cancer, laryngeal cancers, tracheal and lung cancers.

Types of wart

A range of different types of wart has been identified, varying in shape and site affected, as well as the type of human papillomavirus involved. These include

• Common wart (Verruca vulgaris), a raised wart with roughened surface, most common on hands and knees;
• Flat wart (Verruca plana), a small, smooth flattened wart, flesh coloured, which can occur in large numbers; most common on the face, neck, hands, wrists and knees;
• Filiform or digitate wart, a thread- or finger-like wart, most common on the face, especially near the eyelids and lips;
• Plantar wart (verruca, Verruca pedis), a hard sometimes painful lump, often with multiple black specks in the center; usually only found on pressure points on the soles of the feet;
• Mosaic wart, a group of tightly clustered plantar-type warts, commonly on the hands or soles of the feet;
• Genital wart (venereal wart, Condyloma acuminatum, Verruca acuminata), a wart that occurs on the genitalia.