Seborrheic keratoses are superficial, often pigmented, epithelial lesions that are usually verrucous but may occur as smooth papules.
The cause of seborrheic keratosis is unknown, but genetic mutations have been identified in certain types. The lesions commonly occur in middle age and later and most often appear on the trunk or temples. In darker-skinned people, multiple 1- to 3-mm lesions can occur on the cheekbones; this condition is termed dermatosis papulosa nigra.
Seborrheic keratoses vary in size and grow slowly. They may be round or oval and flesh-colored, brown, or black. They usually appear stuck on and may have a verrucous, velvety, waxy, scaling, or crusted surface.
Seborrheic keratoses that are large, multiple, and/or rapidly developing can be a cutaneous paraneoplastic syndrome (Leser-Trélat sign) in patients who have certain cancers (eg, lymphoma, gastrointestinal cancer).
Image provided by Thomas Habif, MD.
DermPics/SCIENCE PHOTO LIBRARY
DermPics/SCIENCE PHOTO LIBRARY
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Diagnosis of Seborrheic Keratoses
Clinical evaluation
Diagnosis of seborrheic keratosis is clinical.
Treatment of Seborrheic Keratoses
Removal only if bothersome
Lesions are not premalignant and need no treatment unless they are irritated, itchy, or cosmetically bothersome.