Chordoma in Orthopedic Surgery Differential Diagnoses

Updated: Mar 11, 2019
  • Author: Nagarjun Rao, MD, FRCPath; Chief Editor: Jeffrey A Goldstein, MD  more...
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DDx

Diagnostic Considerations

Chondrosarcoma

Conventional chondrosarcoma is an important differential diagnostic consideration for skull-base chordoma, especially chondroid chordoma. The location, which usually is off of the midline, and the immunohistochemical features (see Histologic Findings) can help distinguish between the two lesions. [5]

Myxoid chondrosarcoma

These lesions are likely to be confused with chordoma based on pathology. The histology of this lesion closely simulates that of chordoma. However, characteristic physaliphorous cells are not observed. Immunohistochemically, the cells are positive for S-100 and negative for cytokeratin (CK) and epithelial membrane antigen (EMA). Clinically, these lesions arise in the extremities (mostly in soft tissue) and rarely involve the axial skeleton.

Metastatic adenocarcinoma

If a chordoma contains large numbers of cells with cytoplasmic vacuoles, it may be confused with metastatic adenocarcinoma. [15]  However, metastatic adenocarcinoma usually lacks physaliphorous cells, and the extracellular mucin is of the neutral epithelial type, compared with the hyaluronidase-resistant sulfated mucopolysaccharide stroma of chordoma.

Myxoid liposarcoma

These tumors possess vacuolated lipoblasts, which may be mistaken for physaliphorous cells. However, they lack the lobular architecture and evenly distributed physaliphorous cells of chordoma. Further, the myxoid stroma in this tumor is hyaluronidase-sensitive nonsulfated mucopolysaccharide. Although both tumors are S-100 positive, myxoid liposarcoma lacks epithelial markers EMA and CK.

Polyvinylpyrrolidone granuloma

Polyvinylpyrrolidone is a high-molecular-weight hydrophilic substance that generally is used as a plasma substitute. Its high molecular weight prevents renal excretion and promotes accumulation within histiocytes, usually at injection sites within soft tissue. The histology of such soft-tissue mass lesions can resemble chordoma, as the bubbly, polyvinylpyrrolidone-laden histiocytes can simulate physaliphorous cells. They stain strongly with a variety of stains, such as Sudan black B and Congo red. The stroma usually lacks the myxoid character of chordoma. Location and the association with injection sites can help distinguish the lesions clinically.

Spinal tumors

Spinal tumors should also be taken into account in the differential diagnosis.