Derivation and characterization of an extra-axial chordoma cell line (EACH-1) from a scapular tumor.
BACKGROUND
Extra-axial chordomas are rare low-grade malignant tumors thought to arise from notochordal remnants in the extra-axial skeleton. Few studies have been done on this neoplasm because of its rarity. In addition, there is a lack of a good in vitro model on which to perform more characterization.


METHODS
We describe a twenty-eight-year-old man with a mass in the right scapula. Cytomorphology and immunohistochemistry, including brachyury staining, were used to formulate the final diagnosis. A fragment of the tumor was placed in culture, and cells obtained were injected subcutaneously in an immunocompromised mouse. From the tumor developed in mice, a cell line has been derived and characterized by fluorescence-activated cell-sorting analysis, karyotyping, clonogenicity, and cell and tumor growth curves.


RESULTS
Cytomorphology on the tumor showed nests of round cells with vacuoles and also physaliferous-like cells with uniform nuclei. Immunochemistry revealed a tumor positive for vimentin, moderately positive for S-100 and cytokeratin AE1/AE3, weakly positive for epithelial membrane antigen, and negative for p63 and cytokeratin (CK)-7. Further analysis revealed the tumor was diffusely and strongly positive for brachyury. The cell line derived from the tumor showed rapid doubling-time, a strong expression of mesenchymal cell surface markers, a karyotype of diploid or hypotetraploid clones with numerous chromosomal aberrations, and the ability to form colonies without attachment and to form tumors in immunocompromised mice.


CONCLUSIONS
The diagnosis of the extra-axial chordoma is difficult but can be resolved by the detection of a strong brachyury expression. In addition, the derivation of a human extra-axial chordoma cell line could be a useful tool for the basic research of this rare neoplasm.
DeComas
Amalia M
AM
Ochsner Medical Center, New Orleans, LA 70121, USA.
Penfornis
Patrice
P
Harris
Michael R
MR
Meyer
Mark S
MS
Pochampally
Radhika R
RR
D000328:Adult; D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D002817:Chordoma / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D008297:Male; D051379:Mice; D019042:Muscle Neoplasms / Q000175:diagnosis / Q000601:surgery*; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D012540:Scapula / Q000473:pathology*