Pathology

1. Sebhorroeic keratosis: benign overgrowth of the basal cell layer of the epidermis
2. Histologically characterised by
   • Hyperkeratosis (thickening of the keratin layer)
   • Acanthosis (thickening of the prickle cell layer)
   • Hyperplasia or the variably pigmented basaloid cells

Approach

• Examine as for any lump

1. Inspection
   • Commonly found on trunk but found anywhere
   • Single or multiple
   • Round or oval in shape
   • "Stuck on" appearance
   • Varying degree of pigmentation - light brown to black
   • Surface appears velvety or warty
   • Can be picked off the skin leaving behind pink skin and one or two surface capillaries that bleed slightly
2. Palpation

Completion

1. Ask about similar lesions elsewhere (sudden onset of multiple seborrhoeic keratoses ias associated with visceral malignancy - known as Leser-Trelat sign)
2. How the lesion affects life
   • Cosmetic
   • Catches on clothes

Treatment

1. Non-surgical
   • Can be left alone as it is a benign condition
2. Surgical
   • Can be shaved or cauterised