Carotid body tumors: US evaluation.

The ultrasound (US) findings in 20 patients with 23 carotid-body chemodectomas were reviewed. Twenty-two of 23 tumors could be seen at US; the remaining lesion could not be differentiated from surrounding enlarged lymph nodes resulting from thyroid cancer. The lesions were solid, slightly heterogeneous masses that ranged in size from 1.2 to 5.0 cm and were located within the carotid bifurcation. Pulsed Doppler analysis of blood flow within the tumor mass was possible in eight patients with nine chemodectomas, and low-resistance waveforms were obtained from multiple sites within the mass in all cases. The diagnostic possibility of a chemodectoma has to be considered when a solid mass is detected within the carotid bifurcation. On the basis of these findings, as US diagnosis was possible in 18 of 20 patients in the authors' series. Doppler analysis of the mass to evaluate intratumor blood flow is helpful in differentiating chemodectomas from other solid, nonhypervascular masses.