What is seborrheic keratosis?

➢ SK are common pigmented epidermal tumors occur most frequently in middle-age or older individuals. ➢ They arise spontaneously and are particularly numerous on the trunk, although the extremities, head, and neck also may be sites of involvement. ➢ Except for cosmetic concerns, SK are usually of little clinical importance. ➢ However, in rare patients hundreds of lesions may appear suddenlyas a paraneoplastic syndrome (sign of Leser-Trelat). ➢ Patients with this presentation may harbor internal malignancies, most commonly gastrointestinal tract carcinomas, which produce growth factors that stimulate epidermal proliferation