Differential diagnoses - Benign skin lesions

Diagnose a cyst, ganglion, lipoma and dermatofibroma. Dr Nigel Stollery highlights the differences in presentation

Epidermoid cyst


  • Occurs more commonly in hair-bearing areas
  • Lesion varies in size from a few millimetres to many centimetres
  • Punctum may be visible
  • Secondary bacterial infection may occur
  • Contents can usually be expressed
  • Contains sebum which has characteristic odour
  • Multiple lesions may be present


  • Treatment not always required
  • Excision can be undertaken, but recurrence may occur
  • Secondary infection may require oral antibiotics



  • Fluid-filled cyst that may fluctuate in size
  • Occurs over joints
  • Common at any age
  • Firm to the touch, but not bony hard
  • -Radiolucent


  • Typically ruptures after trauma
  • Aspiration with a large-bore needle possible
  • Recurrence common
  • In persistent cases, surgical excision can be undertaken



  • Common on limbs
  • Occurs secondary to foreign body, such as an insect bite or ingrowing hair
  • Typically dimples when pinched
  • May be pigmented
  • A malignant variant, dermatofibrosarcoma protuberans, is very rare


  • Treatment usually not required
  • Rarely resolves without treatment
  • If treatment is necessary, formal excision is the treatment of choice



  • Occurs anywhere on the body
  • May be multiple and some can be very large
  • Located below the skin with normal skin overlying
  • Smooth but irregular surface
  • Non-tender and often asymptomatic


  • Treatment not usually required for smaller lesions
  • Excision is treatment of choice
  • Recurrence may occur
  • Dr Stollery is a GP in Kibworth, Leicestershire

This is an updated version of an article that was first published in January 2014.

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