Imaging Characteristics of a Bladder Wall Paraganglioma

The Vital Role of 131I-MIBG in Localization of Paraganglioma at Unusual Sites

Paragangliomas (PGLs) are extra-adrenal neuroendocrine tumors. PGL of the urinary bladder are very rare and commonly present with features of hypertensive crisis, headache, syncope, and other symptoms of sympathetic excess. A few of these tumors are silent at the presentation. Here, we report a case of a urinary bladder PGL, presenting with lower abdominal pain.

Paraganglioma (pheochromocytoma) of the urinary bladder: A systematic review with a diagnostic, management and treatment algorithm

Introduction:

Paraganglioma of the urinary bladder is a rare but well-documented tumour. Herein, we provide the largest, comprehensive systematic review of the literature and aim to increase familiarity with this rare but significant neoplasm.

Methods:

A systematic review of the literature was conducted on the NCBI PubMed database. The search criteria were not limited to any specific years or languages. There were 418 articles between January 1953 and August 2020, of which 255 case reports were selected.

Results:

Paragangliomas of the urinary bladder most commonly occurred in Caucasians in the fifth decade of life, most commonly presenting with haematuria and variations of ‘micturition attacks’. Eighty percent of tumours were functionally active. The mucosa was normal in 91% of patients. In all, 25% of tumours were treated with transurethral resection alone, 65% had partial cystectomy and 5% had radical cystectomy. Alpha-blockers were administered pre-operatively in 38% of patients and the risk of intra-operative hypertensive crisis was over three times greater in those who did not receive an alpha-blocker. The tumour was confined to the bladder in 75% of cases. Metastasis occurred in 20% of cases, most commonly to iliac nodes. The mean follow-up time was 26.5 months. In cases that documented follow-up, 18.6% had recurrence, most commonly in lymph nodes and bone.

Conclusion:

All patients presenting with micturition attacks or haematuria with a computed tomography showing an enhancing, well-defined submucosal bladder lesion and/or cystoscopy showing a lesion with normal overlying mucosa should be worked up for a possible paraganglioma of the urinary bladder.

Level of evidence:

Not applicable

Site-based performance of 131I-MIBG imaging and 99mTc-HYNIC-TOC scintigraphy in the detection of nonmetastatic extra-adrenal paraganglioma

OBJECTIVES

This study aimed to evaluate the performance of 131I-metaiodobenzylguanidine (MIBG) imaging to detect nonmetastatic extra-adrenal paragangliomas at their respective sites (abdominal vs. thoracic vs. head and neck vs. urinary bladder), and compare it with that of 99mTc-hydrazinonicotinyl-tyr3-octreotide (HYNIC-TOC) scintigraphy.

METHODS

We retrospectively analyzed 235 patients with nonmetastatic extra-adrenal paragangliomas who underwent preoperative 131I-MIBG imaging or 99mTc-HYNIC-TOC scintigraphy. Of all 235 patients, 145 patients underwent both imaging procedures, 16 patients 131I-MIBG imaging only and 74 patients 99mTc-HYNIC-TOC scintigraphy only.

RESULTS

The overall sensitivity of 131I-MIBG and 99mTc-HYNIC-TOC imaging to detect extra-adrenal paragangliomas regardless of tumor sites was 75.8% (122/161) and 67.6% (148/219), respectively (P = 0.082). However, when stratified by tumor sites, 131I-MIBG imaging showed a significant improvement in the detection of extra-adrenal abdominal paragangliomas with a sensitivity of 90.3% (103/114), which was significantly higher than that of 99mTc-HYNIC-TOC scintigraphy (67.6% (96/142); P = 0.000). In addition, the intensity of tracer uptake in the extra-adrenal abdominal paragangliomas with 131I-MIBG imaging was evidently higher than with 99mTc-HYNIC-TOC scintigraphy. The sensitivity of 131I-MIBG imaging and 99mTc-HYNIC-TOC scintigraphy to detect urinary bladder, head and neck, and thoracic paragangliomas were 18.7 vs. 18.5% (P = 1.000); 17.4% vs. 84.6% (P = 0.000) and 60% vs. 94.4% (P = 0.030), respectively.

CONCLUSIONS

131I-MIBG imaging could become the first-line investigation modality in patients with extra-adrenal abdominal paragangliomas. However, 99mTc-HYNIC-TOC scintigraphy has high sensitivity and is superior to 131I-MIBG imaging for detecting head & neck and thoracic paraganglioma. Both 131I-MIBG imaging and 99mTc-HYNIC-TOC scintigraphy have poor performance for detecting urinary bladder paragangliomas.

Bladder Paraganglioma: Three Cases Report and Literature Review

BACKGROUND

Bladder paraganglioma (BPG) is one of the rare neuroendocrine neoplasms that develops from neural crest cells. It categorizes into functional and non-functional types based on the catecholamines secretion. Currently, functional BPG is predicted in advance based on signs and symptoms of catecholamine excess, such as hypertension and "micturition attacks". However, it is often overlooked because of its rareness. Misdiagnosis of a functional tumor may increase the risk of surgical intervention.

CASE PRESENTATION

We reported 3 cases of BPG that they were admitted to the hospital due to abdominal pain or gross hematuria. Computed tomography (CT) scans showed space-occupying lesions in the bladders with diameters less than 3cm. There were no typical catecholamine excess symptoms before surgical intervention. Postoperative pathology confirmed BPG after removal of the tumor. We also analyze 69 cases of BPG that has been reported and found that 78.0% cases were functional among the tumors larger than 3cm.

CONCLUSION

Bladder tumors larger than 3cm in diameter can serve as an additional predictor of functional BPG. Patients who are suspected should undergo magnetic resonance imaging (MRI) scans, 123/131 metaiodobenzylguanidine (MIBG) scan, and have their catecholamine levels tested. Once the diagnosis is confirmed, patients should be started on fluid replacement therapy and adrenergic blockade to abate the disorders associated with catecholamine excess.

Imaging of Bladder Cancer: Standard Applications and Future Trends

The evolution in imaging has had an increasing role in the diagnosis, staging and follow up of bladder cancer. Conventional cystoscopy is crucial in the diagnosis of bladder cancer. However, a cystoscopic procedure cannot always depict carcinoma in situ (CIS) or differentiate benign from malignant tumors prior to biopsy. This review will discuss the standard application, novel imaging modalities and their additive role in patients with bladder cancer. Staging can be performed with CT, but distinguishing between T1 and T2 BCa (bladder cancer) cannot be assessed. MRI can distinguish muscle-invasive from non-muscle-invasive tumors with accurate local staging. Vesical Imaging-Reporting and Data System (VI-RADS) score is a new diagnostic modality used for the prediction of tumor aggressiveness and therapeutic response. Bone scintigraphy is recommended in patients with muscle-invasive BCa with suspected bony metastases. CT shows low sensitivity for nodal staging; however, PET (Positron Emission Tomography)/CT is superior and highly recommended for restaging and determining therapeutic effect. PET/MRI is a new imaging technique in bladder cancer imaging and its role is promising. Texture analysis has shown significant steps in discriminating low-grade from high-grade bladder cancer. Radiomics could be a reliable method for quantitative assessment of the muscle invasion of bladder cancer.

Recent advances in pediatric bladder malignancies

Urothelial pediatric neoplasms are relatively rare. Papillary urothelial neoplasms of low malignant potential (PUNLMPs) and rhabdomyosarcoma (RMS) are the most common bladder malignancies in the pediatric population. Clinical presentation encompasses macroscopic hematuria or lower urinary tract symptoms (or both) or is detected incidentally at imaging. Tumors arising from the bladder can originate from any of its four histological layers (urothelium, lamina propria, detrusor, and adventitia) and are divided into tumors that have an epithelial origin (arising from the urothelium) and those that have a non-epithelial origin (mesenchymal neoplasms). RMS is the most common malignant tumor of the urinary bladder in children younger than 10 years. Deriving from the embryonic mesenchymal cell, the histopathologic subtypes of RMS are embryonal RMS (>90%) and alveolar histology (<10%). Pre-treatment imaging should be carried out by computed tomography (CT) or at present is more likely with magnetic resonance imaging of the pelvis. Chest CT and bone scintigraphy are used to screen for metastases. In selected cases, a positron emission tomography scan may be recommended to evaluate suspicious lesions. The current prognostic classification considers age, histologic subtype, tumor site, size, and extent (nodal or distant metastases). Staging is based on pre-operative findings, group is based on intra-operative findings and pathology, and risk stratification is derived from both stage and group data. Pre-operative chemotherapy is the most common first-line intervention for bladder/prostate RMS, before surgery or radiation therapy. Collaborative groups such as the Soft Tissue Sarcoma Committee of the Children’s Oncology Group and the European Pediatric Soft Tissue Sarcoma Study Group endorse this therapy. PUNLMPs are generally solitary, small (1–2 cm), non-invasive lesions that do not metastasize. Therapy is usually limited to a transurethral resection of the bladder tumor. About 35% are recurrent and around 10% of them increase in size if they are not treated.

Bladder cancer and its mimics: a sonographic pictorial review with CT/MR and histologic correlation

Bladder cancer is the most common cancer of the urinary system and often presents with hematuria. Despite its relatively high incidence, bladder cancer is often under-recognized sonographically. Moreover, even when bladder abnormalities are identified, numerous other entities may mimic the appearance of bladder cancer. Given the incidence and prevalence of bladder cancer, it is important to recognize its variable appearance sonographically and distinguish it from its common mimics. We review the sonographic appearance of bladder cancer and its mimics, providing correlative CT/MR imaging as well as pathology. We stress the importance and advantage of ultrasound as a dynamic imaging modality, with the ability to optimize distinguishing bladder cancer from similar-appearing entities.

Multifocal Urinary Bladder Paragangliomas With Negative 68Ga-DOTATATE Uptake and Positive 123I-MIBG Uptake

We report a case of an adult male patient with multifocal urinary bladder paragangliomas, which were negative on Ga-DOTATATE PET/CT scan, but positive on I-MIBG SPECT/CT scan. While the Ga-DOTA analog PET/CT exhibits superior performance in diagnosis and staging of pheochromocytoma and paraganglioma, our case demonstrates negative somatostatin receptor expression in this rare entity and indicates that I-MIBG SPECT/CT still plays a vital role in characterization of bladder paraganglioma.