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Information

 Bone and Soft-Tissue Disorders

Origin: coalescence of smaller cysts formed by myxomatous degeneration of periarticular connective tissue

Path: capsule of dense fibrous connective tissue

Histo: NO synovial lining (frequent lack of communication with joint, infrequent association with joint / tendon sheath effusion)

Cause: repetitive stress

Location: joint capsule, tendon sheath, ligament, bursa, intraarticular, subchondral intraosseous, periosteal

Prognosis: symptomatic; bone erosion; spontaneous resolution frequent in pediatric cases

DDx: Synovial cyst (differentiation from ganglion cyst radiologically not possible)

Soft-tissue Ganglion  !!navigator!!

= cystic tumorlike lesion usually attached to a tendon sheath

Frequency: 50% of adult wrists

  • asymptomatic / pain
  • uni- / multilocular swelling

Location: periarticular hand, wrist, foot (over dorsum)

Site: arise from tendon, muscle, semilunar cartilage

  • soft-tissue mass with surface bone resorption
  • periosteal new-bone formation
  • arthrography may demonstrate communication with joint / tendon sheath
  • internal septations
  • lobulated configuration with peripheral fluid-filled pseudopodia (“bunch of grapes”)
  • hypointense relative to muscle / hyperintense cyst content (high mucinous content, hemorrhage) on T1WI
  • hyperintense relative to fat on T2WI
  • no enhancement

Prognosis: may resolve spontaneously

Rx: steroid injection may improve symptomatology

Intraosseous Ganglion  !!navigator!!

= benign subchondral radiolucent lesion WITHOUT degenerative arthritis

  • mild localized pain (in 4% of unexplained wrist pain)

Age: middle age

Origin:

  1. mucoid degeneration of intraosseous connective tissue (perhaps due to trauma / ischemia)
  2. penetration of juxtaosseous soft-tissue ganglion (= synovial herniation) into underlying bone (occasionally)

Path: uni- / multilocular cyst surrounded by fibrous lining, containing gelatinous material

Location:

  1. epiphysis of long bone
    1. proximal tibia (at attachment of cruciate ligaments)
    2. medial malleolus
    3. femoral head
    4. carpal bones
  2. subarticular flat bone (acetabulum)
  • well-demarcated solitary 0.6–6 cm lytic lesion
  • sclerotic margin
  • NO communication with joint
  • increased radiotracer uptake on bone scintigraphy (in 10%)

DDx: posttraumatic / degenerative cyst

Periosteal Ganglion  !!navigator!!

= cystic structure with viscid / mucinous contents

Prevalence: 11 cases in literature

Age: 39–50 years; M >F

  • swelling, mild tenderness

Location: long tubular bones of lower extremity

  • cortical erosion / scalloping / reactive bone formation
  • NO intraosseous component (endosteal surface intact)

CT:

  • well-defined soft-tissue mass adjacent to bone cortex with fluid contents

MR:

  • homogeneously isointense compared to muscle on T1WI
  • homogeneously hyperintense compared to fat on T2WI
  • NO internal septations (DDx to soft-tissue ganglion)

DDx: periosteal chondroma without matrix calcification, cortical desmoid, subperiosteal aneurysmal bone cyst, acute subperiosteal hematoma (history of trauma / blood dyscrasia), subperiosteal abscess (involvement of adjacent bone marrow)

Rx: surgical excision (local recurrence possible)

 Outline