Presentation
Knee pain without trauma.
Patient Data
Age: 33
Gender: Female
From the case:
Intraosseous ganglion
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Round osteolysis with sclerotic margins in the internal femoral condyle
From the case:
Intraosseous ganglion
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Round osteolysis with sclerotic margins in the medial femoral condyle with small cortical discontinuity. Narrow transition zone.
From the case:
Intraosseous ganglion
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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:
- 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.
- Theory of degeneration of the mucosa: an idiopathic mucoid degeneration of connective intramedullary originated hyaluronic acid producing fibroblasts and histiocytes.
- 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.
- 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.
- 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.