Cases of pheochromocytoma of the urinary bladder are quite rare, accounting for 0.05% of bladder tumors and less than 1% of all pheochromocytomas.1 Pheochromocytomas are clinically important, and functional tumors have been reported by Zhai et al.2 to account for over 63.6% of cases of paraganglioma in the bladder. Clinicians must be vigilant for signs of severe hypertension subsequent to the surgical procedure, which can result in fatal outcomes such as intracranial hemorrhage. Therefore, a preoperative diagnosis is essential to avoid such undesirable outcomes.
Low‐intensity T1‐weighted and high‐intensity T2‐weighted magnetic resonance imaging (MRI) are important diagnostic tools for pheochromocytomas. Additionally, iodine 131 metaiodobenzylguanidine (MIBG) scintigraphy can be used to definitively diagnose the tumor. Other than these imaging modalities, laboratory tests for measuring the concentration of catecholamine or its metabolic products in addition to blood tests or acid urinary collection are helpful diagnostic tools for determining whether the tumor is functional or nonfunctional.
Sugimura et al.3 reported functional paraganglioma of the bladder, which was negative in both radiographic and laboratory examinations. They also noticed that the tumor they were about to incise had some hormonal activity because of the rapid elevation in blood pressure during the transurethral resection of bladder tumor (TURBT). Ceasing the endoscopic procedure was a wise decision. Even though the preoperative MRI scan indicated paraganglioma, the MRI findings were not specific.4 In contrast to MRI, MIBG scintigraphy has high specificity.5 If MIBG scintigraphy and laboratory tests were performed before TURBT and those examinations showed positive results, partial cystectomy could have been selected as the initial treatment. However, in this case, those examinations showed negative results.
Overall, in spite of negative findings of MIBG scintigraphy and laboratory tests, functional paraganglioma cannot be completely ruled out. Therefore, urologists must pay careful attention to perioperative vital signs during TURBT for atypical intravesical tumors, and the procedure must be stopped when a major change in the patients’ condition is observed during the operation.
Conflict of interest
The author declares no conflict of interest.
References
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