A case report of carotid body tumor with rare thoracic vertebral metastasis and literature review.

BACKGROUND: Malignant carotid body tumor (CBT), a type of carotid body paraganglioma (PGL), is defined by the presence of distant metastasis; histology alone cannot reliably distinguish benign from malignant CBT. We present a 70-year-old female patient who had been suspected of having CBT for more than 10 years without specific treatment, and complained of abdominal pain for 6 months. Contrast-enhanced MRI and CT revealed a T11 vertebral lesion, followed by percutaneous biopsy of the lesion, which showed atypical cell nests. Immunohistochemical staining was positive for CD56, CgA, Syn and S-100, and negative for cytokeratin. A diagnosis of metastatic PGL consistent with malignant CBT was established. The patient received palliative radiotherapy to the T11 vertebra (20 Gy/5 fractions), which was well tolerated without obvious radiation-related adverse reactions. At the 12-month follow-up, the patient remained alive.

CONCLUSION: In this case, a highly suggestive diagnosis of PGL (malignant CBT) with bone metastasis was made based on imaging features, T11 vertebral biopsy, and immunohistochemical results. It provides a reference for radiotherapy in similar clinical settings. For unresectable thoracic vertebral metastases, palliative radiotherapy (20 Gy/5 fractions) can be considered after clinical evaluation.