Mucous cysts of the DIPJ usually occur in older adults and are associated with osteoarthritis. They contain mucin and form from degeneration of joint structures. Clinically, they appear as nodules near the DIPJ that can cause nail deformities. Treatment involves surgical excision, sometimes with additional procedures like osteophyte removal. Complications include residual deformities, stiffness, skin issues, and recurrence due to incomplete excision or persistent arthritis.

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