logo Benign non-melanocytic skin lesions

Skin lesions

Benign non-melanocytic skin lesions

Objectives

  • Identify and describe common congenital and acquired non-melanocytic skin lesions

Key points

  • Naevi consist of clusters of epidermal or dermal cells with numerous clinical variants.
  • Seborrhoeic keratoses (basal cell papillomas) appear as stuck-on warty plaques and are very common in those over 40 years of age.
  • Epidermoid cysts are walled-off cavities filled with keratin and are derived from the hair follicle unit.
  • Syringomas are sweat duct tumours most often presenting as skin-coloured papules on the eyelids.
  • Dermatofibromas are firm dermal papules caused by a proliferation of fibroblasts.
  • Skin tags are pedunculated papillomas filled with loose collagen.
  • Keloids are scars with excessive bands of collagen.
  • Lipomas are due to a proliferation of adipose tissue and present as soft subcutaneous nodules.
  • Neurofibromas are spindle cell tumours and present as soft to firm dermal nodules.
  • Vascular tumours in babies may be proliferative haemangiomas, which usually resolve, or vascular malformations including port wine stain and lymphangioma circumscriptum.
  • Pyogenic granulomas are formed of granulation tissue (vascular proliferation with inflammatory infiltrate).

Common benign non-melanocytic tumours are described on DermNet.

Keratinocytic lesions

Adnexal tumours

Deeper tumours

Vascular tumours