True Positive 18F-FDG PET/CT and Negative 123I-MIBG SPECT/CT in a Pediatric Patient With Bladder Malignant Paraganglioma

A 10-year-old child presented with episodic headache, diaphoresis, and dizziness during micturition straining, raising clinical suspicion for paraganglioma. 123I-MIBG SPECT/CT revealed no abnormal radiotracer uptake in the bladder mass or enlarged lesions. In contrast, 18F-FDG PET/CT demonstrated increased metabolic activity with marked 18F-FDG uptake in these same regions. Histopathological examination following surgical resection confirmed the diagnosis of malignant paraganglioma with multiple metastases. This case illustrates that bladder paragangliomas may exhibit positive 18F-FDG PET/CT findings despite negative 123I-MIBG SPECT/CT results, highlighting the complementary role of functional imaging modalities in the diagnostic evaluation of bladder paragangliomas.