Seborrheic keratosis

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

of a seborrheic keratosis (H&E stain, scanning magnification) 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: 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. ==Treatment==

Medical reasons for removing seborrheic keratoses include irritation and bleeding. They may also be removed for cosmetic reasons. ==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. == See also ==