Orthopedic Oncology cases chordoma

A 52-year-old female is referred from her primary care physician’s office. She has had vague lower back pain and constipation for the last 8 months, and over the past month she has experienced pain and tingling that radiates into her perineum. She has a history of a lumbar disc herniation when she was 20 years old and was in a motor vehicle collision. She was treated with microdiscectomy and has been asymptomatic since that time. Her primary care physician ordered an MRI and refers her for concerning findings on this imaging (Fig. 8–36).

 

 

Figure 8–36

 

After appropriate workup, she obtains a needle biopsy of the lesion performed under image guidance. Biopsy specimens are shown in Figure 8–37A and B. What is the most likely diagnosis?

1. Metastatic adenocarcinoma

2. Metastatic renal cell carcinoma

3. Chondrosarcoma

4. Chordoma

 

 

 

Figure 8–37 A

 

 

 

Figure 8–37 B

 

Discussion

The correct answer is (D). The imaging and histology displayed are consistent with chordoma, which is a slow-growing malignant bone tumor arising from notochordal nests and occurring in the spinal axis. Specifically, they arise in the base of the skull or in the sacrum. The histopathologic findings of myxoid and cartilaginous regions, with bubbly physaliferous cells that are distinguished by their abundant cytoplasm, are all suggestive of this diagnosis.

Which of the following statements is true regarding the immunohistochemical staining of chordoma and chondrosarcoma?

1. They both stain positively with S100, but chordoma stains with cytokeratin while chondrosarcoma does not

2. They both stain positively with cytokeratin, but chordoma stains with S100 while chondrosarcoma does not

3. They both stain positively with S100, but chondrosarcoma stains with cytokeratin while chordoma does not

4. They both stain positively with cytokeratin, but chondrosarcoma stains with cytokeratin while chordoma does not

Discussion

The correct answer is (A). Both of these lesions stain positively with S100, but cytokeratin is a valuable staining study to perform because it differentiates chordoma (which stains strongly positively) from chondrosarcoma (which does not stain with cytokeratin).

Which of the following immunohistochemical stains are specific for chordoma?

1. S100

2. CD34

3. Neurofibromin

4. Brachyury

 

Discussion

The correct answer is (D). Brachyury is an immunohistochemical test which helps confirm the diagnosis of chordoma. Brachyury staining is only positive in notochordal cell–derived tumors. The remaining stains are not specific for chordoma.

 

Objectives: Did you learn...?

 

 

Imaging and clinical features of chordoma? Histologic features of chordoma?