Metastatic paraganglioma treatment options are limited. Peptide receptor radionuclide therapy (PRRT) has been introduced as a novel management option for metastatic neuroendocrine tumors demonstrating safety, efficacy, and increased quality of life.We present two cases of marked progression of metastatic paraganglioma following initial partial response to PRRT. Given their positivity on ⁶⁸Ga-DOTATATE PET/CT and ¹¹¹In-octreotide SPECT, they underwent PRRT. Imaging following treatment revealed significant improvement in size and intensity, with some foci nearly completely resolved in one patient, and disease regression with a decrease in the number and size of bone and liver lesions in the second patient.Within months, repeat imaging in both patients revealed extensive metastatic disease with new lesions, which eventually lead to their deaths. The mechanism for rapid disease progression after partial response is not well understood, although it could be related to initially high Ki-67 levels or ¹⁸F-FDG PET/CT SUV(max) values. However, naturally rapid disease progression despite PRRT response cannot be excluded. This finding warrants the importance of proper patient counseling along with early and accurate pre-PRRT assessment, taking into consideration the above potential risk factors for therapy response in order to personalize treatment regimens and achieve maximum patient benefit.
Counseling ; Disease Progression ; Humans ; Liver ; Neuroendocrine Tumors ; Paraganglioma ; Positron-Emission Tomography and Computed Tomography ; Receptors, Peptide ; Risk Factors ; Tomography, Emission-Computed, Single-Photon

Metastatic paraganglioma treatment options are limited. Peptide receptor radionuclide therapy (PRRT) has been introduced as a novel management option for metastatic neuroendocrine tumors demonstrating safety, efficacy, and increased quality of life.We present two cases of marked progression of metastatic paraganglioma following initial partial response to PRRT. Given their positivity on ⁶⁸Ga-DOTATATE PET/CT and ¹¹¹In-octreotide SPECT, they underwent PRRT. Imaging following treatment revealed significant improvement in size and intensity, with some foci nearly completely resolved in one patient, and disease regression with a decrease in the number and size of bone and liver lesions in the second patient.Within months, repeat imaging in both patients revealed extensive metastatic disease with new lesions, which eventually lead to their deaths. The mechanism for rapid disease progression after partial response is not well understood, although it could be related to initially high Ki-67 levels or ¹⁸F-FDG PET/CT SUV(max) values. However, naturally rapid disease progression despite PRRT response cannot be excluded. This finding warrants the importance of proper patient counseling along with early and accurate pre-PRRT assessment, taking into consideration the above potential risk factors for therapy response in order to personalize treatment regimens and achieve maximum patient benefit.

A 36-year-old male patient initially presented with hypertension, tinnitus, bilateral carotid masses, a right jugular foramen, and a periaortic arch mass with an elevated plasma dopamine level but an otherwise normal biochemical profile. On surveillance MRI 4 years after initial presentation, he was found to have a 2.2-cm T2 hyperintense lesion with arterial enhancement adjacent to the gallbladder, which demonstrated avidity on ⁶⁸Ga-DOTATATE PET/CTand retrospectively on ¹⁸F-FDOPA PET/CT but was nonavid on ¹⁸F-FDG PET/CT. Biochemical work-up including plasma catecholamines, metanephrines, and chromogranin A levels were found to be within normal limits. This lesion was surgically resected and was confirmed to be a paraganglioma (PGL) originating from the gallbladder wall on histopathology. Pheochromocytoma (PHEO) and PGL are rare tumors of the autonomic nervous system. Succinate dehydrogenase subunit D (SDHD) pathogenic variants of the succinate dehydrogenase complex are usually involved in parasympathetic, extra-adrenal, multifocal head, and neck PGLs. We report an unusual location of PGL in the gallbladder associated with SDHD mutation which could present as a potential pitfall on ¹⁸F-FDOPA PET/CT as its normal excretion occurs through biliary system and gallbladder. This case highlights the superiority of ⁶⁸Ga-DOTATATE in comparison to ¹⁸F-FDOPA and ¹⁸F-FDG in the detection of SDHD-related parasympathetic PGL.ClinicalTrials.gov Identifier: NCT00004847.
Adult ; Autonomic Nervous System ; Biliary Tract ; Catecholamines ; Chromogranin A ; Dopamine ; Gallbladder ; Head ; Humans ; Hypertension ; Magnetic Resonance Imaging ; Male ; Neck ; Paraganglioma ; Pheochromocytoma ; Plasma ; Positron-Emission Tomography and Computed Tomography ; Retrospective Studies ; Succinate Dehydrogenase ; Tinnitus

Although rare, a metastatic renal cell carcinoma could present with 68Ga-DOTATATE avidity. A 66-year-old man with von Hippel-Lindau syndrome (VHL) presented with 68Ga-DOTATATE uptake in the pancreatic head, splenic hilar region, and multiple osseous sites, including the right lateral portion of the T9 vertebrae. Biopsy of the T9 lesion confirmed metastatic renal cell carcinoma. Various VHL-associated cancers may display 68Ga-DOTATATE avidity, which can change and guide clinical decisions for the patient.

A 36-year-old male patient initially presented with hypertension, tinnitus, bilateral carotid masses, a right jugular foramen, and a periaortic arch mass with an elevated plasma dopamine level but an otherwise normal biochemical profile. On surveillance MRI 4 years after initial presentation, he was found to have a 2.2-cm T2 hyperintense lesion with arterial enhancement adjacent to the gallbladder, which demonstrated avidity on ⁶⁸Ga-DOTATATE PET/CTand retrospectively on ¹⁸F-FDOPA PET/CT but was nonavid on ¹⁸F-FDG PET/CT. Biochemical work-up including plasma catecholamines, metanephrines, and chromogranin A levels were found to be within normal limits. This lesion was surgically resected and was confirmed to be a paraganglioma (PGL) originating from the gallbladder wall on histopathology. Pheochromocytoma (PHEO) and PGL are rare tumors of the autonomic nervous system. Succinate dehydrogenase subunit D (SDHD) pathogenic variants of the succinate dehydrogenase complex are usually involved in parasympathetic, extra-adrenal, multifocal head, and neck PGLs. We report an unusual location of PGL in the gallbladder associated with SDHD mutation which could present as a potential pitfall on ¹⁸F-FDOPA PET/CT as its normal excretion occurs through biliary system and gallbladder. This case highlights the superiority of ⁶⁸Ga-DOTATATE in comparison to ¹⁸F-FDOPA and ¹⁸F-FDG in the detection of SDHD-related parasympathetic PGL.ClinicalTrials.gov Identifier: NCT00004847.

We describe an unusual case of a 42-year-old female with an unresectable succinate dehydrogenase subunit B (SDHB)-related pterygopalatine fossa paraganglioma. She underwent somatostatin receptor imaging with 68Ga-DOTA(0)-Tyr(3)-octreotate (68Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT), which showed uptake in the above mentioned tumor. Hence, the patient was started on octreotide, a cold somatostatin analog, and responded with tumor stabilization and improvement of clinical symptoms for 36 months since initiation of octreotide therapy. This case demonstrates the role of 68Ga-DOTATATE PET/CT in diagnostic localization and its subsequent role in treatment using cold somatostatin analog as a potential choice of therapy in the management of paraganglioma in an unusual location with limited therapeutic options.