Mucous cysts of the DIPJ

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

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

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

Clinical signs

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

Clinical signs

• Enlarged cyst with attenuated overlying skin

Clinical signs

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

Clinical signs

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

Treatment

• Primarily surgical• Numerous alternative treatment reported in

the past with moderate success:– Intralesional injection - eg. Sodium morrhuate,

triamcinolone– Occlusive flurandrenolone tape

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

Operative technique

• L-shaped / H-shaped / curved incision

• Elliptical excision of attenuated or involved skin

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

Operative technique

• Excison of osteophytes

• Skin closure may require rotation / advancement dorsal skin flap or a full-thickness graft

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

Complications

Residual nail deformitiesStiffnessSkin necrosisRecurrence:

- inadequate excision- ganglion extension to the other side of extensor tendon- persistent underlying arthritic process