Features of benign pigmented lesions

• Well defined margin
• Even pigmentation
• Symmetrical
• Not changing over time or changing very slowly

Freckles (ephelis)

• Patchy increase in melanin pigmentation which occurs after UV exposure
• Most common in fair skinned and red heads
• Reflects clumpy distribution of melanocytes
• People with freckles have one defective copy of MC1R gene

Actinic lentigenes

• Also known as 'age' or 'liver' spots
• Flat, well circumscribed patch resulting from exposure to UV radiation, which causes local proliferation of melanocytes and accumulation of melanin within keratinocytes
• Found as groups of similar lesions on sun-exposed sighs, particularly the face, forearm, or the back of the hands
• Often diagnosed based on its clinical appearance; can be clarified by dermoscopy, biopsy can be performed if there is still diagnostic doubt
  • Histology: elongated rete ridges in the epidermis, increase in melanin and basal melanocytes

Melanocytic naevi (common moles)

Congenital melanocytic naevi