Bladder Preservation for Patients With Bladder Paragangliomas: Case Series and Review of the Literature

Bladder paragangliomas: a pictorial review

Bladder paragangliomas (bPGL) are rare neuroendocrine tumors arising from the sympathetic paraganglia present in the bladder wall. Bladder PGLs are typically submucosal or intramural but when subserosal may not be readily visible at cystoscopy. The average size at presentation is 3.9 cm (range 1.0-9.1 cm). When small, bPGL are usually spherical, well-marginated and homogeneous. Larger bPGL are typically more complex with peri- and intra-tumoral neovascularity and central necrosis. On ultrasound, increased color Doppler signal is typical. The increased soft tissue resolution of MRI enables localization of bPGL within the bladder wall more accurately than CT. Restricted diffusion and avid contrast enhancement help differentiate small bPGLs from leiomyomas, which have similar appearances on ultrasound and CT. Nuclear medicine techniques identify bPGLs and their metastases with high specificity, ⁶⁸Ga-DOTATATE PET/CT having largely replaced ¹²³I-mIBG SPECT/CT as the first line functional investigation. Imaging is essential to aid surgical planning, as endoscopic resection is often not possible or incomplete due to tumor location. For patients with advanced disease, ⁶⁸Ga-DOTATATE PET/CT and ¹²³I-mIBG SPECT/CT assess suitability for peptide receptor radionuclide therapy. Up to 63% of bPGL patients have a germline mutation, most commonly in the SDHB subunit gene, increasing their risk of developing pheochromocytomas and further paragangliomas; lifelong annual biochemical and periodic imaging screening from skull base to pelvis is therefore recommended.

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.

An update on adult forms of hereditary pheochromocytomas and paragangliomas

PURPOSE OF REVIEW

Pheochromocytomas and paragangliomas (PPGL) display a strong genetic determinism with 40% of inherited forms. The purpose of this review is to provide an update on current knowledge on adult forms of hereditary PPGL and their management.

RECENT FINDINGS

PPGL are genetically-driven in 70% of cases, with germline and/or somatic mutations identified in more than 20 genes. Although eight new susceptibility genes have recently emerged, mutations on SDHx genes remain the most frequent. In addition to SDHB, mutations in SLC25A11, FH and MDH2 may predispose to a metastatic disease and somatic alterations including TERT and ATRX mutations, and the differential expression on noncoding RNAs are also associated with the occurrence of metastases.The biochemical diagnosis remains the mainstay of functional PPGL and does not differ between hereditary PPGL while the choice of the best nuclear imaging approach is dictated by the tumor type and can be influenced by the presence of a germline mutation (18F-DOPA PET/CT for cluster 2 mutation and Ga-DOTATATE PET/CT for cluster 1 mutation).

SUMMARY

A systematic genetic testing and counselling is recommended for all PPGL patients and should lead to conservative surgery and an adapted follow up, in case of hereditary form.