Case Study: March 2013


  • 25 year old male
  • Cutaneous yellowish papules on neck and axilla
  • Skin biopsy
  • Fig 1 and Fig 2 – H&E
  • Fig 3 – EVG of dermis
  • Fig 4 – Alizarin Red of dermis


  1. What does the skin biopsy show?
  2. What is the diagnosis?
  3. What are the ophthalmic manifestations of this condition?
  4. What is the genetic defect in this condition?
Click to show answers
  1. Curly, frayed basophilic elastic fibres in reticular dermis. Encrusted with calcium
  2. Pseudoxanthoma elasticum (PXE)
  3. Angioid streaks, choroidal neovascular membranes (CRNVM +/- haemorrhage and disciform scarring), RPE atrophy, peau d’orange, choroidal ruptures and retinal haemorrhages (in cases of PXE with trauma), keratoconus
  4. ABCC6 gene cause pseudoxanthoma elasticum. 300 distinct mutations identified in pseudoxanthoma elasticum. Mutations lead to an absent or non-functional MRP6 protein, an acronym for multidrug resistance-associated protein 6