Bladder paraganglioma in adults: MR appearance in four patients

Purpose: To document the magnetic resonance imaging (MRI) characteristics of paraganglioma of the urinary bladder in adults. Materials and methods: The MRI findings and clinical features of pathologically-proven bladder paraganglioma in four patients (three men, one woman; age range, 39–62 years; mean age, 46.8 years) were reviewed retrospectively. All patients underwent MRI in a 1.5 T instrument. The MRI features of the lesions were analyzed, with emphasis on the size, shape, location, margin, signal intensity, degree of MRI enhancement, and apparent diffusion coefficient (ADC) values. Results: The bladder paragangliomas were located in the posterior vesicle wall (n = 2), in the dome of the bladder wall (n = 1), or the inferoanterior wall (n = 1). On MR images, the tumors were round (n = 1) or oval-shaped (n = 3) and all exhibited well-circumscribed margins and broad-based attachment to the bladder wall. On T1-weighted images, the lesions demonstrated homogeneous hyperintensity (n = 4) compared to the gluteus maximus muscle; while on T2-weighted images, they showed slight hyperintensity (n = 4). On contrast-enhanced MR images, all lesions showed intense enhancement. On diffusion-weighted imaging (DWI), the lesions showed hyperintensity (n = 4) and the mean ADC value was 0.973 × 10−3 mm2/s. Conclusion: Bladder pheochromocytoma appears as a round or oval-shaped intensely enhancing lesion with T1 hyperintensity; these characteristics may facilitate the preoperative determination.