Chordoma

Chordoma is a rare slow-growing malignant neoplasm thought to arise from cellular remnants of the notochord. The evidence for this is the location of the tumors (along the neuraxis), the similar immunohistochemical staining patterns, and the demonstration that notochordal cells are preferentially left behind in the clivus and sacrococcygeal regions when the remainder of the notochord regresses during fetal life.

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Chordomas can arise anywhere along the neuraxis. The two most common locations are cranially at the clivus and at the sacrum.

In the United States, the annual incidence of chordoma is approximately 1 in one million.

There are three histological variants of chordoma: classical, chondroid and dedifferentiated. The histological appearance of classical chordoma is of a lobulated tumor composed of groups of cells separated by fibrous septa. The cells have small round nuclei and abundant vacuolated cytoplasm, sometimes described as physaliferous (resembling a spider's web). Chondroid chordomas histologically show features of both chordoma and chondrosarcoma.

Prognosis and treatment

In one study, the 10-year tumor free survival rate for sacral chordoma was 46%.^[1] Chondroid chordomas appear to have a more indolent clinical course.

Aggressive surgical resection followed by radiation therapy offers the best chance of long-term control.

There are no drugs currently approved to treat chordoma, however chordoma has been shown to have a limited response to the PDGFR inhibitor Imatinib.^[2]

References

1. ^ Fuchs B, Dickey ID, Yaszemski MJ, Inwards CY, Sim FH (2005). "Operative management of sacral chordoma". The Journal of bone and joint surgery. American volume 87 (10): 2211-6. doi:10.2106/JBJS.D.02693. PMID 16203885.
2. ^ Casali PG, Messina A, Stacchiotti S, et al (2004). "Imatinib mesylate in chordoma". Cancer 101 (9): 2086-97. doi:10.1002/cncr.20618. PMID 15372471.