1 INTRODUCTION
Pheochromocytomas are tumors originating from the chromaffin cells of the sympathetic adrenomedullary axis, characterized by autonomous production of catecholamines, most often adrenaline and/or noradrenaline[
1]. The paraganglion is characterized by the presence of granular deposits in main cells containing neurotransmitter substances, which govern local levels of excitation within the autonomic nervous system[
2].
Bladder paragangliomas are rare neoplasms, accounting for less than 0.06% of all bladder tumors. They are commonly located in the bladder trigone or near the ureteral orifices, followed by the dome and lateral walls[
3]. They are classified as malignant tumors due to their infiltrative capacity, but histopathological findings suggest a relatively benign course[
4].
Based on this context, the aim of this study is to highlight the relevance of the occurrence of a rare case of paraganglioma in the bladder wall within urological medical practice and to discuss the respective diagnosis and treatment, thereby aiding in the follow‐up of new cases of this pathology.
2 CASE PRESENTATION
The patient was a 72‐year‐old retired man with hypertension. Following the administration of Losartan and Amlodipine, the patient exhibited moderate blood pressure and was asymptomatic.
The patient was referred to urology due to the incidental finding of a bladder mass on prostate ultrasound, which showed a 25‐g prostate with a 2.3‐cm lesion on the left lateral wall of the bladder.
The patient reported frequent episodes of headache and tachycardia, which were associated with an anxious condition. He had irregular follow‐ups with the psychiatry team, and was continuously using diazepam and risperidone. He denied hematuria and visual alterations.
The patient also underwent laboratory tests, which yielded unchanged results for the complete blood count, urea, creatinine, sodium, potassium, coagulogram, prostate‐specific antigen, urine analysis, and urine culture.
The measurement of urinary metanephrines was carried out preoperatively and demonstrated values within the normal limit, meaning that alpha blockade was not performed.
A computed tomography (CT) scan of the chest, abdomen, and pelvis was performed on April 11, 2023. The results showed a well‐defined nodular lesion in the left posterior bladder wall with invasion of the left ureter (Figure 1).
On March 17, 2023, the patient underwent transurethral resection of bladder with a finding of a nodular vesicular lesion with an extrinsic aspect to the mucosa on the left lateral wall, pedunculated, without signs of vegetation or lesion of the bladder mucosa.
Anatomopathological investigation revealed the presence of a poorly differentiated invasive neoplasm in the bladder wall with infiltration of the lamina propria. The immunohistochemical analysis showed the presence of bladder wall paraganglioma with invasion of the muscle layer.
A surgical approach on June 16, 2023, identified a suprameatal lesion on the left, adhered to the distal ureter. Partial cystectomy was performed, including removal of the lesion and distal ureterectomy on the left. Ureteral reimplantation was carried out using the Taguchi technique.
Anatomopathological results showed an epithelioid neoplasm located in the bladder wall, compatible with neuroendocrine neoplasia, with a hypothesis of paraganglioma moderately differentiated by the grading system for adrenal phaeochromocytoma and paraganglioma (GAPP).
GAPP is characterized by assessing the degree of malignancy of pheochromocytoma and paraganglioma. Catecholamine phenotypes are analyzed, and finally, malignancy is classified as low‐risk, intermediate‐risk, or high‐risk of metastasis. Thus, the prediction of patient survival is based on the degree of risk. Histological classification is based on a scoring system consisting of six parameters (risk factors for metastasis): histological pattern, cellularity, comedonecrosis, capsular/vascular invasion, Ki67 staining index, and catecholamine phenotype, with a total of 10 possible points. A score of 3–6 is considered moderately differentiated and has a 5‐year survival rate of 67%[
5].
The patient maintains asymptomatic outpatient oncological follow‐up with adequate blood pressure levels without the use of antihypertensive drugs, and control tests do not show secondary lesions.
3 DISCUSSION
The first case of bladder paraganglioma was described by Zimmerman, Biron, and Macmohon in 1953[
6]. Ninety percent of pheochromocytomas arise in the adrenal medulla, and extra‐adrenal tumors occur in 10%–20% of all cases[
2].
The symptoms of bladder paraganglioma consist of voiding syndrome, characterized by headache (48.1%), tachycardia (43.4%), hypertension (54.7%), hematuria (47.2%) and visual changes, occurring in 47%–77% of patients[
7,
8].
Biochemical and imaging tests are required for diagnostic suspicion, with urine measurement of catecholamines, vanillylmandelic acid (VMA) and metanephrines being the most sensitive form. Most functioning paragangliomas secrete noradrenaline exclusively or as the predominant catecholamine[
3].
Localization studies, such as ultrasonography (USG), excretory urography, cystoscopy, CT, magnetic resonance imaging (MRI), and iodine‐131 metaiodobenzylguanidine (I‐131 MIBG) scintigraphy, are expensive and not always specific, but they are relevant diagnostic techniques[
7].
Cystoscopy shows a submucosal mass in more than 80% of patients, either in the trigone or dome of the bladder, unlike most transitional cell tumors of the bladder that involve the mucosa[
2,
6].
Ultrasound and CT are noninvasive, nonspecific exams, with the advantage of better visualization of lesions smaller than 1 cm. CT is useful for detecting adrenal tumors and MRI for bladder juxtavesical tumors. MRI may be superior to CT, but experience with this method is limited[
3,
7]. Scintigraphy using the radiopharmaceutical I‐131 MIBG has been used as a method for identifying tumors originating from chromaffin tissues, both adrenal and extra‐adrenal[
2,
3,
6].
I‐131 MIBG has a molecular structure similar to noradrenaline and its incorporation into chromaffin tissue occurs through a mechanism similar to that observed with neurotransmitters or hormones. The use of this radiopharmaceutical is valuable for diagnosing thoracic localizations, a site rarely identified by CT, and for the follow‐up of some malignant paragangliomas. The I‐131 MIBG uptake method is considered to be the most specific (95%) for the diagnosis of functioning paragangliomas, and can detect multiple or small tumors, whether metastatic or recurrent disease. It is also the most sensitive method (85%). The role of I‐131 MIBG scintigraphy in nonfunctioning tumors is unknown[
3,
7].
The management of bladder paraganglioma is surgical, either by means of transurethral resection, total or partial cystectomy[
6]. In the literature, the most commonly used treatments were partial cystectomy (73; 68.9%), TURP (21; 19.8%) and radical cystectomy (12; 11.3%)[
8].
In the case described, the diagnosis was made through anatomopathological analysis with material collected in cystoscopy. As with most of the cases found in the literature, the patient underwent surgical resection—partial cystectomy, requiring ureterectomy due to involvement of the left ureter.
In preoperative preparation, alpha‐blockers are used and, if necessary, beta‐blockers along with strict hydration to avoid hypotension after tumor removal. Postoperative hypertensive crisis can be controlled with phentolamine or sodium nitroprusside[
6].
In this case, the patient had regular blood pressure control with the two antihypertensive drugs previously used, and there was no need for alpha‐blockers or beta‐blockers. The patient remained stable during the surgical procedure, with no hypertensive peaks. In outpatient follow‐up, the use of antihypertensive drugs was discontinued due to 24‐h ambulatory blood pressure measurement tests showing normal blood pressure.
The prognosis of bladder paraganglioma is not well known due to the small number of cases and their segmentation[
3].
4 CONCLUSION
It can be concluded that bladder paraganglioma, despite being a rare bladder neoplasm, requires adequate diagnostic and therapeutic methods for the proper management of the patient. Initially, imaging tests such as ultrasounds and CT scans can be used, followed by cystoscopy with visualization and biopsy of the lesion or laboratory tests with urine dosage of catecholamines, VMA and metanephrines. These tests are more sensitive but are not always available.
The classic clinical picture of bladder paraganglioma consists of voiding syndrome, which includes headache, tachycardia, hematuria, and visual alterations, and is present in almost half of the patients.
Treatment is based on resection of the lesion, and the need for alpha‐blockers or beta‐blockers should be evaluated to avoid hypertensive peaks during the surgical procedure.
In addition, it is of paramount importance to maintain clinical follow‐up of the patient, although the prognosis is not yet well defined due to the small number of cases found in the literature.
However, due to the fact that there are few cases reported and discussed in the literature, it can be concluded that this study is extremely important, as it could help, in different ways, future conduct when urologists are faced with rare cases of bladder paraganglioma.
2024 The Author(s). UroPrecision published by John Wiley & Sons Australia, Ltd on behalf of Higher Education Press.
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