Geode

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Geodes, also known as subchondral cysts, are well-defined lytic lesions at the periarticular surfaces. A

Terminology

Geode, meaning a crystal-lined hollow rock, is the preferred term over subchondral cyst, meaning epithelial-lined fluid-filled lesion both of which are absent in these entities 7.

Pathology

Two theories are presented in the formation of geodes in osteoarthritis 7:

  • one theory of geode formation takes place when synovial fluid is oneforced into the subchondral bone due to elevated intra-articular pressure, resulting in a cystic collection of the common differential diagnoses of an epiphyseal lesionjoint fluid
  • another theory is cystic necrosis development post subchondral fracture (lytic).

    Epidemiology

    from vascular insufficiency
Associations

Geodes are seen in a small group of disorders including:

Pathology

Presumably, one method of geode formation takes place when synovial fluid is forced into the subchondral bone, resulting in a cystic collection of joint fluid. Another aetiology is that following a bone contusion, the contused bone forms a cyst.

Treatment and prognosis

They rarely cause problems by themselves but are often misdiagnosed as something more sinister and an unnecessary biopsy of a geode might be performed on the basis of the differential of an epiphyseal lesion.

History and etymology

Geode is a term borrowed from "geology", where it refers to rounded formations in igneous and sedimentary rocks.

Differential diagnosis

Dominate subchondral geodes can be confused with lytic epiphyseal lesion such as 7:

See also

  • -<p><strong>Geodes</strong>, also known as <strong>subchondral cysts</strong>, are well-defined lytic lesions at the periarticular surfaces. A geode is one of the common differential diagnoses of an <a href="/articles/epiphyseal-lesions-differential">epiphyseal lesion</a> (lytic).</p><h4>Epidemiology</h4><h5>Associations</h5><p>Geodes are seen in a small group of disorders including:</p><ul>
  • +<p><strong>Geodes</strong>, also known as <strong>subchondral cysts</strong>, are well-defined lytic lesions at the periarticular surfaces. </p><h4>Terminology</h4><p>Geode, meaning a crystal-lined hollow rock, is the preferred term over subchondral cyst, meaning epithelial-lined fluid-filled lesion both of which are absent in these entities <sup>7</sup>.</p><h4>Pathology</h4><p>Two theories are presented in the formation of geodes in osteoarthritis <sup>7</sup>:</p><ul>
  • +<li>one theory of geode formation takes place when synovial fluid is forced into the subchondral bone due to elevated intra-articular pressure, resulting in a cystic collection of joint fluid</li>
  • +<li>another theory is cystic necrosis development post <a href="/articles/subchondral-fracture">subchondral fracture</a> from vascular insufficiency</li>
  • +</ul><h5>Associations</h5><p>Geodes are seen in a small group of disorders including:</p><ul>
  • -</ul><h4>Pathology</h4><p>Presumably, one method of geode formation takes place when synovial fluid is forced into the subchondral bone, resulting in a cystic collection of joint fluid. Another aetiology is that following a bone contusion, the contused bone forms a cyst.</p><h4>Treatment and prognosis</h4><p>They rarely cause problems by themselves but are often misdiagnosed as something more sinister and an unnecessary biopsy of a geode might be performed on the basis of the differential of an epiphyseal lesion.</p><h4>History and etymology</h4><p><strong>Geode</strong> is a term borrowed from "geology", where it refers to rounded formations in igneous and sedimentary rocks.</p><h4>See also</h4><ul><li><a href="/articles/subchondral-cysts-mnemonic">Subchondral cysts (mnemonic)</a></li></ul>
  • +</ul><h4>Treatment and prognosis</h4><p>They rarely cause problems by themselves but are often misdiagnosed as something more sinister and an unnecessary biopsy of a geode might be performed on the basis of the differential of an epiphyseal lesion.</p><h4>History and etymology</h4><p><strong>Geode</strong> is a term borrowed from "geology", where it refers to rounded formations in igneous and sedimentary rocks.</p><h4>Differential diagnosis</h4><p>Dominate subchondral geodes can be confused with lytic <a href="/articles/epiphyseal-lesions-differential">epiphyseal lesion</a> such as <sup>7</sup>:</p><ul>
  • +<li><a href="/articles/chondroblastoma">chondroblastoma</a></li>
  • +<li><a href="/articles/clear-cell-chondrosarcoma">clear cell chondrosarcoma</a></li>
  • +<li><a href="/articles/giant-cell-tumour-of-bone">giant cell tumour</a></li>
  • +<li><a href="/articles/intraosseous-ganglion">intraosseous ganglion</a></li>
  • +<li><a href="/articles/lytic-bone-metastases">skeletal metastasis</a></li>
  • +</ul><h4>See also</h4><ul><li><a href="/articles/subchondral-cysts-mnemonic">subchondral cysts (mnemonic)</a></li></ul>

References changed:

  • 7. Bancroft L, Peterson J, Kransdorf M. Cysts, Geodes, and Erosions. Radiol Clin North Am. 2004;42(1):73-87. <a href="https://doi.org/10.1016/s0033-8389(03)00165-9">doi:10.1016/s0033-8389(03)00165-9</a>

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