Mucous cysts of the DIPJ

2. Mucous cysts of the DIPJ

3. Mucous cyst DIPJ • Ganglion cyst of the DIPJ • Usually occurs between the fifth and seventh decades • Associated with osteophytes or spurring of the DIPJ • Osteoarthritis in other joints

4. Ganglion/Mucous cyst • Single or multiloculated cyst which appears smooth, white & translucent • Wall is made up of compressed collagen fibres and is sparsely lined with flattened cells without evidence of an epithelial or synovial lining • Mucin-filled “clefts” from the capsular attachment of the main cyst interconnect with the adjacent underlying joint via tortuous continuous ducts • Stroma may show tightly packed collagen fibres or sparsely cellular areas with broken fibres and mucin-filled intercellular & extracellular lakes • No inflammatory reaction or mitotic activity has been noted

5. Ganglion/Mucous cyst • Contents of cyst characterized by a highly viscous, clear, sticky, jelly-like mucin made up of glucosamine, albumin, globulin, & high concentrations of hyaluronic acid • Aetiology & pathogenesis remain obscure • Most widely accepted theory - mucoid degeneration associated with degeneration of joint capsule or tendon sheath • Injury & mechanical irritation may stimulate production of hyaluronic acid to form mucin, which may penetrate joint ligaments and capsules and then coalesce to form cyst

6. Clinical signs • Longitudinal grooving of the nail - earliest sign without a visible mass, caused by pressure on the nail matrix

7. Clinical signs • Enlarged cyst with attenuated overlying skin

8. Clinical signs • Cyst (3-5mm) usually lies to one side of the extensor tendon and between the dorsal distal joint crease & the eponychium

9. Clinical signs • Often has Heberden’s nodes and radiographic evidence of osteoarthritic changes in the joint

10. Treatment • Primarily surgical • Numerous alternative treatment reported in the past with moderate success: • Intralesional injection - eg. Sodium morrhuate, triamcinolone • Occlusive flurandrenolone tape

11. Surgical Management • Excision of the cyst alone • Wide excision of the cyst along with surrounding adjacent structures - eg.the overlying skin, osteophyte debridements • Debridement of the DIPJ osteophytes only, without excision of the cyst itself or overlying skin

12. Operative technique • L-shaped / H-shaped / curved incision • Elliptical excision of attenuated or involved skin

13. Operative technique • Cyst mobilized, traced to the joint capsule & excised with the joint capsule • All tissue excised between the extensor tendon & the adjacent collateral ligaments • Insertion of the extensor tendon and the nail matrix must be protected

14. Operative technique • Excison of osteophytes • Skin closure may require rotation / advancement dorsal skin flap or a full-thickness graft

15. Alternative approach • Transverse incision centred over DIPJ • Base of mucous cyst identified & excised while leaving the distal & superficial portion of the cyst intact • Excision of osteophtyes & joint capsule with direct skin closure • Allow several weeks for involution of the remaining cyst

16. Complications Residual nail deformities Stiffness Skin necrosis Recurrence: - inadequate excision - ganglion extension to the other side of extensor tendon - persistent underlying arthritic process