Variable sonographic spectrum of parathyroid adenoma with a novel ultrasound finding: dual concentric echo sign

Aims: To review the detailed gray-scale and Doppler ultrasonography features of histologically proven parathyroid adenomas (PAs) evaluated with high-end ultrasonography devices and to present a novel ultrasonography finding called the dual concentric echo sign in PA with histopathologic correlation which was encountered during detailed analysis. Material and methods: Fifty-six PAs with histopathological result were enrolled. The longest dimension, shape, distance to skin surface, internal echo and Doppler US features obtained with high-end US devices were evaluated. Results: PAs had variable range of shape including oval, irregular, fusiform, lobulated, crescent-shaped, and nodular configuration. In nine patients the lesions were shown to have cystic components and calcifications were seen in four cases. Dual concentric echo sign was detected in 18% PAs. Histological reevaluation of this subgroup demonstrated significantly increased edema (p<0.01), and ectatic vessels (p=0.02) in the central part of the lesion compared to the rest of the PAs. Conclusions: The results of the study led to the conclusion that PAs have variable gray-scale and Doppler findings. Typical sonographic features like ovoid shape, homogeneously hypoechoic pattern may not be present in all PAs. Dual concentric echo sign which is a novel sonographic pattern may be suggestive of a PA.