Suburothelial and extrinsic lesions of the urinary bladder: radiologic and pathologic features with emphasis on MR imaging

Abstract

Compared to the more common urothelial lesions, at cystoscopy, suburothelial and extrinsic diseases of the urinary bladder wall often have a non-specific appearance or may be occult. Cross-sectional imaging, in particular MRI, plays an integral role in diagnosis. Mesenchymal tumors have distinct imaging features on MRI. Leiomyomas are characteristically low signal intensity on T2-weighted (T2W) imaging and progressively enhance. Lipomas and lipomatous hypertrophy are diagnosed by the presence of macroscopic fat. Neurofibromas, hemangiomas, and paragangliomas are hyperintense on T2W sequences and hypervascular. Reactive lesions occur in the setting of chronic inflammation and include: nephrogenic adenoma, cystitis cystica, and cystitis glandularis. Imaging findings are commonly non-specific; however, a mass with internal cystic spaces in association with pelvic lipomatosis is suggestive of cystitis glandularis. Urachal anomalies may be complicated by infection or malignancy. Urachal mucinous adenocarcinoma has a poor prognosis and may present as a T2-hyperintense suburothelial/extrinsic mass centered in the bladder dome. Other diseases may extrinsically involve the urinary bladder by hematogenous and peritoneal spread, including infection, endometriosis, and malignancy. A familiarity with suburothelial and extrinsic pathologies of the urinary bladder is critical for the radiologist, who may be the first to suggest these diagnoses.

Inguinal bladder hernia with lipomatosis of the bladder wall: A potential clinical pitfall for cancer

“…An MRI multisequence study by the use of T2W fast/turbo spin echo, fat suppression, inversion recovery and T1W in/ opposed phase imaging techniques offers high diagnostic efficacy in the detection and characterization of adipose lesions of the urinary tract. 6 In this case, surgical exploration confirmed the radiologic suspicion of an IBH composed mostly of fatty tissue. A biopsy was performed to exclude an infiltrating cancer, a possible diagnostic pitfall.…”

“…An MRI multisequence study by the use of T2W fast/turbo spin echo, fat suppression, inversion recovery and T1W in/opposed phase imaging techniques offers high diagnostic efficacy in the detection and characterization of adipose lesions of the urinary tract. 6…”

Imaging manifestations of bladder paraganglioma

“…BPG needs to be distinguished from other tumors of the bladder: (I) Leiomyoma is the most common non-epithelial benign tumor of the bladder, accounting for about 35% of benign tumors of the bladder and 0.5% of all tumors of the bladder (18,19). Leiomyoma is more common in young and middle-aged women.…”

Update on multiparametric MRI of urinary bladder cancer

“…Urachal adenocarcinoma mural invasion is from external to luminal, potentially resulting in a submucosal mass on imaging and at cystoscopy. Mucinous differentiation may be seen in adenocarcinomas, resulting in markedly T 2 W hyperintense signal within the primary mass or nodal metastases, which may distinguish adenocarcinomas from other epithelial malignancies …”

“…Mucinous differentiation may be seen in adenocarcinomas, resulting in markedly T 2 W hyperintense signal within the primary mass or nodal metastases, which may distinguish adenocarcinomas from other epithelial malignancies. 85 Malignant bladder masses may also be secondary to involvement by a nonbladder primary malignancy, either by direct invasion (eg, colonic, rectal, prostatic, or cervical carcinomas) or metastatic disease (eg, lymphoma/leukemia, gastric, melanoma, lung, or breast). 86 The remainder of bladder neoplasms are predominantly accounted for by mesenchymal tumors.…”