Bladder Paraganglioma: CT and MR Imaging Characteristics in 16 Patients

CT and MR Imaging Features of Bladder Paraganglioma

Abstract

Background. Bladder paraganglioma (BPG) is a rare extra-adrenal pheochromocytoma with variable symptoms and easy to be misdiagnosed and mishandled. The aim of this study was to document the imaging features of BPG using computed tomography (CT) and magnetic resonance imaging (MR).

Patients and methods. We retrospectively enrolled consecutive patients with pathology-proven BPG, who underwent CT or MRI examinations before surgery between October 2009 and October 2017. The clinical characteristics, CT, and MRI features of the patients were described and analyzed.

Results. A total of 16 patients with 16 bladder tumors (median patient age 51 years, 56% female) were included. Among them, 13 patients underwent CT examinations and eight patients underwent MRI examinations preoperatively. Tumor diameters ranged from 1.6−5.4 cm. Most of the tumors grew into the bladder cavity (68.8%) with oval shapes (62.5%) and well-defined margins (87.5%). Intratumor cystic degeneration or necrosis (12.5%) was observed. Two lesions (12.5%) showed peripheral tissue invasion, suggesting malignant BPGs. All 13 lesions (100.0%) imaged with CT exhibited slight hypoattenuation and moderate to marked enhancement. Compared to the gluteus maximus, all lesions showed slight hyperintensity in T2-weighted images, hyperintensity in diffusion-weighted images, hyperintensity in T1-weighted images and a "fast in and slow out" enhanced pattern in contrast-enhanced MRI images.

Conclusions. BPGs are mostly oval-shaped, broadly-based and hypervascular bladder tumors with hypoattenuation on non-contrast CT, T2 hyperintensity, slight T1 hyperintensity compared to the muscle, marked restricted diffusion on DWI. Peripheral tissue invasion can suggest malignancy of the BPGs. All of these features contribute to preoperative decision-making.