Intraosseous ganglion

Case contributed by Dr Domenico Nicoletti


Knee pain without trauma.

Patient Data

Age: 33
Gender: Female

Round osteolysis with sclerotic margins in the internal femoral condyle


Round osteolysis with sclerotic margins in the medial femoral condyle with small cortical discontinuity. Narrow transition zone.


Osteolysis with septa containing fluid without perilesional edema. No periosteal reaction.

Case Discussion

Intraosseous ganglia localize to the subchondral epiphyseal region of long bones with a predilection for the distal epiphysis of the tibia, in subjects of average age, no sex predilection. The pathogenesis is still linked to hypotheses, none of which are proven:


  1. Theory of fibrous connective tissue metaplasia: in this widely held theory, primitive intramedullary fibroplasia with an abundant mucous secretion results in a cytoplasmic accumulation effect, leading up to a degenerative or cystic stage.
  2. Theory of degeneration of the mucosa: an idiopathic mucoid degeneration of connective intramedullary originated hyaluronic acid producing fibroblasts and histiocytes.
  3. Theory of herniated synovium: ganglion as a product of the herniated synovium from the joint or tendon sheath. This would justify the predilection for the subchondral region, and could be due to a defect or a traumatic tear.
  4. Theory of benign tumor: possible post-surgical recurrence suggests this theory, but becomes less likely as a lasting healing response occurs with the introduction of sclerosing agents in the ganglion.
  5. Theory of synovial residues: with it assumed that the ganglia takes origin from residues of the periarticular tissue that remain in the area after the intramedullary embryonic period of joint development.
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Case information

rID: 48465
Case created: 7th Oct 2016
Last edited: 12th Oct 2016
Inclusion in quiz mode: Included

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