Mucous Cyst

Outpouching of synovial fluid from DIP caused by early OA

Aetiology

  • Higher incidence in females
  • 40-60 years

Clinical presentation

  • Raised swelling of DIP/PIP joint or just distal to the joint (between joint crease and nail plate)
  • Painful
  • Always on the radial/ulnar side of the midline
  • Can fluctuate in size
  • Initially quite small but can increase in size and cause thinning of the skin
  • If the skin becomes very thin it can rupture and produce discharge
  • If it becomes particularly large it can deform the nail and cause a ridge
notion image

Management

  • May be left alone - majority of cysts will completely disappear over time
  • In patients with particularly deep/cracked nail ridges, or those who are constantly discharging, consider exision
    • Often needs advancement/rotation flap if larger