Definition
An extremely rare tumour arising within the extra-axial skeleton, identical to the more common axial chordoma. The latter are thought to arise from remnants of notochord: it is difficult to explain those arising away from the axial skeleton on this basis.
This is a tumour of adults, with a wide age range. The tumour has been reported to arise in the pubic ramus1, tibia2,3,4, femur4, rib4, metatarsal4 and ulna4.
The tumour is composed of lobules of glistening myxoid tissue.
Cells occur single and in cords within a myxoid matrix. These foci form lobules are separated by fibrous septa. The cells vary in size, including large multivacuolated "physaliphorous" cells. Nuclei are small. Mitotic activity is absent or scant. Epithelioid, spindle and glomeruloid cells are absent. Cartilaginous differentiation is absent or focal.
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1/11, 2/24 |
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|
6/64 |
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|
1/11 |
|||
|
1/11 |
|||
|
1/71,4 |
|||
|
8/81,4 |
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|
0/71,4 |
|||
|
1/11 |
|||
|
8/84 |
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|
1/11 |
|||
|
7/81,4 |
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|
0/11 |
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|
0/11 |
|||
|
0/84 |
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Metastatic axial chordoma
Parachordoma, a tumour of soft tissues.
Myxoid chrondrosarcoma, most commonly a tumour of deep soft tissues. Physaliferous cells are lacking. It is negative for cytokeratins.
Metastatic carcinoma
Metastatic melanoma
©SMUHT/PW Bishop