Evaluation of Sonographic Features for Patients with Urinary Bladder Paraganglioma: A Comparison with Patients with Urothelial Carcinoma

The goals of the work described here were to analyze the ultrasonographic characteristics of urinary bladder paraganglioma and to evaluate the use of ultrasonography (US) in diagnosis. Ten patients with bladder paraganglioma (3 males, 7 females) and 51 patients with urothelial carcinoma (37 males, 14 females) were enrolled. Ultrasonographic characteristics as well as clinical features were analyzed. Patients with urothelial carcinoma were significantly older than those with paraganglioma (62.9 y vs. 48.1 y, p = 0.001). The patients with paraganglioma had higher average systolic blood pressure than those with urothelial carcinoma (146.7 mm Hg vs. 130.7 mm Hg, p = 0.012). All bladder paragangliomas were solitary, and 40% were located on the dome. There was a statistically significant difference in location of lesions between the bladder paraganglioma and urothelial carcinoma groups (p = 0.014). The longest diameters in 80% of the bladder paragangliomas were in the range 1.1-3.0 cm; 60% were hypoechoic, and 40% were located in the submucosa of the bladder. Color Doppler revealed that 40% of the bladder paragangliomas were highly vascular. One patient with paraganglioma and four patients with urothelial carcinoma underwent contrast-enhanced ultrasound, which revealed rapid contrast enhancement and slow wash-out, with a non-enhanced area. Contrast-enhanced ultrasound of urothelial carcinomas revealed rapid homogeneous enhancement and variable wash-out patterns. Pre-operative ultrasonography detected all neoplasms of the urinary bladder in the 10 patients with pathologically confirmed paraganglioma, but made the correct diagnosis in only 2 cases (20%). Although there is overlap in US findings among different diseases, solitary, submucosal masses arising on the dome may be the key US imaging characteristic for bladder paraganglioma.