Answer:
Ecchordosis physaliphora
Discussion:
Tumours of the notochord are unusual for a variety of reasons. As the axial skeleton develops, the notochord becomes incorporated into the vertebral column along most of its length and ultimately contributes to the formation of the nucleus pulposus of the intervertebral disk. However, at the two poles of the skeleton—the dorsum sellae and the sacrococcygeal region—the fate of the notochord is more variable and correlates with the presence of aberrant notochordal tissue in later life.
Multiple studies have shown the presence of non-neoplastic notochordal remnants in adults in an extraosseous location primarily around the spheno-occipital region. With an autopsy incidence of 2%, they take the form of small soft tissue nodules which are translucent and gelatinous in consistency, and histologically similar to the embryonal notochord containing physaliferous cells. They have been variously described as “ectopic notochordal rests”, “ecchondrosis physaliphora spheno-occipitalis”, “ecchordosis physaliphora spheno-occipitalis” and “benign chordoma”.
They have also been found in the sacro- coccygeal region, and very rarely in the vertebrae where they were given the designation of “ecchordosis physaliphora vertebralis”.
References:
1. Imaging of Bone Tumors and Tumor-Like Lesions Techniques and Applications by A. M. Davies ∙ M. Sundaram ∙ S. L. J. James
2. Retroclival Ecchordosis Physaliphora: MRImaging and Review of the Literature AJNR Am J Neuroradiol 25:1851–1855, Nov/Dec 2004
Ecchordosis physaliphora
Discussion:
Tumours of the notochord are unusual for a variety of reasons. As the axial skeleton develops, the notochord becomes incorporated into the vertebral column along most of its length and ultimately contributes to the formation of the nucleus pulposus of the intervertebral disk. However, at the two poles of the skeleton—the dorsum sellae and the sacrococcygeal region—the fate of the notochord is more variable and correlates with the presence of aberrant notochordal tissue in later life.
Multiple studies have shown the presence of non-neoplastic notochordal remnants in adults in an extraosseous location primarily around the spheno-occipital region. With an autopsy incidence of 2%, they take the form of small soft tissue nodules which are translucent and gelatinous in consistency, and histologically similar to the embryonal notochord containing physaliferous cells. They have been variously described as “ectopic notochordal rests”, “ecchondrosis physaliphora spheno-occipitalis”, “ecchordosis physaliphora spheno-occipitalis” and “benign chordoma”.
They have also been found in the sacro- coccygeal region, and very rarely in the vertebrae where they were given the designation of “ecchordosis physaliphora vertebralis”.
References:
1. Imaging of Bone Tumors and Tumor-Like Lesions Techniques and Applications by A. M. Davies ∙ M. Sundaram ∙ S. L. J. James
2. Retroclival Ecchordosis Physaliphora: MRImaging and Review of the Literature AJNR Am J Neuroradiol 25:1851–1855, Nov/Dec 2004