Extra-axial chordoma

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.

Clinical features

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.

Macroscopic appearances

The tumour is composed of lobules of glistening myxoid tissue.

Histopathology

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.

Immunohistochemistry

 

AE1/AE3

1/11, 2/24

 

MNF116

6/64

Cam5.2

1/11

CK1/10

1/11

CK7

1/71,4

CK19

8/81,4

CK20

0/71,4

EMA

1/11

Brachyury

8/84

Vimentin

1/11

S-100

7/81,4

CEA

0/11

Type IV collagen

0/11

SMA

0/84

   
   

Differential diagnosis

References

1 DiFrancesco LM, Davanzo Castillo CA,Temple WJ. Extra-axial chordoma. Arch Pathol Lab Med 2006; 130:1871-4

2 Hemalatha AL, Srinivasa MR,Parshwanath HA. Parachordoma of tibia--a case report. Indian J Pathol Microbiol 2003; 46:454-5

3 Koh JS, Chung JH, Lee SY, et al. Parachordoma of the tibia: report of a rare case. Pathol Res Pract 2000; 196:269-73

4 Tirabosco Brachyury Expression in Extra-axial Skeletal and Soft Tissue Chordomas: A Marker that Distinguishes Chordoma From Mixed Tumor/Myoepithelioma/Parachordoma in Soft Tissue AJSP 2008;32:572

 

This page last revised 16.4.2008

©SMUHT/PW Bishop