15 YEARS OF PARAGANGLIOMA: Imaging and imaging-based treatment of pheochromocytoma and paraganglioma

Abstract

Although anatomic imaging to assess the precise localization of pheochromocytomas/ paragangliomas (PHEOs/PGLs) is unavoidable before any surgical intervention on these tumors, functional imaging is becoming an inseparable portion of the imaging algorithm for these tumors. This review article presents applications of the most up-to-date functional imaging modalities and image-based treatment to PHEOs/PGLs patients. Functional imaging techniques provide whole-body localization (number of tumors present along with metastatic deposits) together with genetic-specific imaging approaches to PHEOs/PGLs, thus enabling highly specific and sensitive PHEO/PGL detection and delineation that now greatly impact the management of patients. Radionuclide imaging techniques also play a crucial role in the prediction of possible radioactive treatment options for PHEO/PGL. In contrast to previous imaging algorithms used for either assessement of these patients or their follow-up, endocrinologists, surgeons, oncologists, pediatricians, and other specialists require functional imaging before any therapeutic plan is outlined to the patient, and follow-up, especially in patients with metastatic disease, is based on the periodic use of functional imaging, often reducing or substituting for anatomical imaging. In similar specific indications, this will be further powered by using PET/MR in the assessment of these tumors. In the near future, it is expected that PHEO/PGL patients will benefit even more from an assessement of the functional characteristics of these tumors and new imaging-based treatment options. Finally, due to the use of new targeting moieties, gene-targeted radiotherapeutics and nanobodiesbased theranostic approaches are expected to become a reality in the near future.

18F-FDOPA PET/CT Uptake Parameters Correlate with Catecholamine Secretion in Human Pheochromocytomas

“…Finally, there were only a small number of mutated PHEO and a limited representation of specific mutations due to their relative rarity in our series, which also constitutes a limitation of this study. As such, only sporadic PHEO were used in the amperometric analysis, because mutated PHEO do not have the same pattern of 18 F-FDO-PA uptake [7]. Nevertheless, other experiments will have to be performed on this subgroup of patients to confirm or disprove these data.…”

“…18 F-FDOPA positron emission tomography/computed tomography ( 18 F-FDOPA PET/CT) has both high sensitivity and high specificity for the characterization of these tumors, especially in cases of small hereditary PHEO [6,7]. The principle of 18 F-FDOPA PET/CT is based on the property of neuroendocrine tumor cells to take up L-DO-PA via the neutral amino acid transporter system L (LAT1 or LAT2), to decarboxylate it into dopamine thanks to amino acid decarboxylase, and to eventually store amino acids (such as DOPA) and their biogenic amines in vesicles [8].…”

Leptomeningeal dissemination of a low-grade lumbar paraganglioma: case report

“…It is possible that gene-targeted radiotherapeutics and other novel targeting moieties will be employed in the future. 21 Further studies are warranted to assess treatment outcomes in patients with this uncharacteristic modality of disease metastasis, with comparison of current treatment protocols and newly-developed models as they become available. We also wish to emphasize the important utility of 18 F-FDOPA scans in the diagnosis of unresectable, small-sized disease where biopsy is not feasible.…”

Radiological diagnosis of perinephric pathology: pictorial essay 2015

“…PCCs appear hypointense or iso-intense on T1-weighted imaging and markedly hyperintense on T2-weighted images. CT imaging will show a soft tissue density that enhances markedly with contrast administration, often showing areas of calcification or central necrosis [88, 89] (Fig. 19).…”

“…19). When morphological imaging and biochemical investigations of lesions are indeterminate, functional imaging utilising meta-iodobenzylguanide ( 123 I-MIBG) can achieve specificity of up to 99% and sensitivity of 77–90% in the diagnosis of PCC, and remains the most important nuclear imagining tool currently in service [89]. It is important to consider paraganglioma in appropriate cases, especially if biopsy is planned, as biopsy may lead to a catecholamine crisis characterised by headache, hypertension, sweating, haemodynamic compromise and even death.…”