Paraganglioma of Urinary Bladder: An Uncommon Entity in Uropathology

Magnetic resonance imaging of bladder pheochromocytomas: a review

Bladder pheochromocytomas (PCCs) are rare tumors that account for 0.06% of all bladder tumors and makeup 1% of all PCCs. Most PCCs are functional, and they secrete catecholamines that lead to clinical symptoms such as paroxysmal hypertension, headaches, palpitations, and sweating. However, some are nonfunctional and asymptomatic and are hence difficult to diagnose. Cystoscopy and biopsy should not be performed when bladder PCCs are suspected. They may provoke a hypertensive crisis if preventative antiadrenergic blockers are not administered prior to the procedure. The diagnostic workup begins with obtaining blood or urine catecholamine and catecholamine metabolite values to make a presumptive diagnosis of bladder PCC. Computed tomography (C.T.) and magnetic resonance imaging (MRI) are then used to localize and stage the tumor for surgical resection. MRI, due to its superior soft tissue resolution and the ability to use multiparametric MRI (mpMRI) to differentiate between layers of the bladder wall and from other bladder masses, is the optimal imaging modality to detect extra-adrenal bladder PCCs and determine locoregional staging. Once antiadrenergic medications are given, the tumor is resected, and the diagnosis is confirmed histologically. However, the differential diagnosis of bladder PCC often gets overlooked, leading to surgical resection in the absence of antiadrenergic medications, increasing the chances of a fatal hypertensive crisis. This makes MRI an essential diagnostic tool for staging bladder PCCs before surgery. This review discusses the indications for MRI in bladder PCCs and describes findings from these tumors on various MRI sequences and when to use them. We also discuss how MRI can differentiate bladder PCCs from other bladder neoplasms.

Spontaneous Retroperitoneal Bleeding as a Complication of Unusual Renal Paraganglioma

Spontaneous retroperitoneal bleeding is a rare occurrence that might have catastrophic implications. We present a 58-year-old male with a 4-day history of progressively worsening left-sided flank pain due to retroperitoneal hemorrhage from a nonfunctional renal paraganglioma. Abdominal contrast CT scan was helpful in locating the tumor, estimating tumor size and extent of bleeding, visualizing the interaction between the tumor and the surroundings, and ruling out any potential metastasis; however, it lacked specificity in identifying the origin of the mass, needing histologic investigation for a conclusive diagnosis. MRI was not available at our center. We report a rare case of spontaneous retroperitoneal bleeding as a complication of an unusual nonfunctional renal paraganglioma, which was initially misdiagnosed as renal cell carcinoma but later confirmed by postoperative histopathology.

Functional Bladder Paraganglioma as an Incidental Finding During Infertility Workup

Bladder paragangliomas (PGLs) are extremely rare catecholamine-producing neuroendocrine tumors. They arise more frequently in the trigone and have unpredictable depth and behavior. Most cases typically present with a well-defined set of symptoms triggered by micturition or bladder overdistension. Besides long-term follow-up, they are usually managed by either transurethral resection (TUR) or partial cystectomy (PC). However, about 25% of all documented cases do not manifest clinically, raising both diagnosis and management challenges. This report describes an unusual case of a misdiagnosed, functional PGL arising on the bladder dome, which was fortuitously detected in a 21-year-old female during a fertility workup. Owing to its hypervascular nature and submucosal location, bladder PGL was suspected on ultrasound and CT findings and successfully diagnosed before surgery through biochemical confirmation. It was managed by cystoscopy-guided laparoscopic partial cystectomy (LPC) with good oncological and urinary outcomes, as well as no compromise of her fertility potential. To our best knowledge, this is the first case to be incidentally detected on transvaginal ultrasound during evaluation for infertility. This case also stresses the importance of considering PGL in the differential diagnosis of atypical bladder tumors, as well as conservative management through simultaneous laparoscopy and cystoscopy, when approaching young patients with large functional PGL.