Seborrheic keratosis is one of the most common types of noncancerous (benign) skin growths in older adults. In fact, most people develop at least one seborrheic keratosis at some point in their lives.

The common form of seborrhoeic keratosis has characteristic features:

• Macroscopically:
  • Usually appears as a brown, black or pale growth

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  •  On the face, chest, shoulders or back.
  • The growth has a waxy, scaly, slightly elevated appearance. 
  • Mushroom-shaped
  • Appear singly, but multiple growths are more common.
    
  • Typically, seborrheic keratoses don't become cancerous, but they can look like skin cancer.
  • These skin growths are normally painless and require no treatment.   
• Histologically:
  • hyperplastic epidermis overhanging surrounding skin
  • uniform basal cell overgrowth
  • keratin cysts
  • melanocytes may be present in large numbers giving rise to the variable pigmentation
• Cause:
  Exact cause of seborrheic keratoses isn't known.