Molecular imaging and theranostic approaches in pheochromocytoma and paraganglioma

Abstract

Pheochromocytomas and their extra-adrenal counterpart paragangliomas (PGLs; together called PPGLs), belong to the family of neural crest-derived tumors. Given the overexpression of a wide variety of specific targets in PPGLs, it seems that these tumors are optimally suited to be imaged by specific radiopharmaceuticals. Thus, theranostics approaches with somatostatin agonists and antagonists are rapidly evolving in the setting of these tumors and may be considered as the next step in the therapeutic arsenal of metastatic PPGLs.

Keywords: 6-(18F)fluoro-L-3,4-dihydroxyphenylalanine; DOTA-analogues; Gallium-68; Neuroendocrine; Paragangliomas; Positron emission tomography; Somatostatin.

Fig. 1

Molecular imagine and theranostic approaches in pheochromocvtoma and paraganglioma Right sporadic PHEO. a ¹⁸F–FDG PET/CT, b ⁶⁸Ga-DOTATATE PET/CT, c ¹⁸F–FDOPA PET/CT. Scale bar 5 cm. High ⁶⁸Ga-DOTATATE and ¹⁸F–FDOPA tumor uptake with heterogeneous features which contrast with the moderately avidity for ¹⁸F–FDG (arrows). See the high ⁶⁸Ga-DOTATATE uptake by the normal contralateral adrenal gland

Fig. 2

Multifocal MAX-related PHEOs. a, c, e, g Contrast-enhanced CT, b, d, f, h ¹⁸F–FDOPA PET/CT. Bilateral PHEO with multiple lesions within the same glands. Scale bar 5 cm

Fig. 3

Molecular imaging and theranostic approaches in pheochromocvtoma and paraganglioma Metastatic SDHB-related PPGL. Previous history of surgery for PHEOs and extradrenal PGLs. The anterior maximum intensity projection images of ⁶⁸Ga-DOTATATE (a), ¹⁸F–FDG (b), ¹⁸F–FDA (c), and ¹⁸F–FDOPA (d) demonstrates ⁶⁸Ga-DOTATATE and ¹⁸F–FDG identifies similar number of lesions and perform superior than ¹⁸F–FDA and ¹⁸F–FDOPA. The right adrenal recurrent pheochromocytoma (marked by green arrows) is missed on ¹⁸F–FDOPA but identified by other radiotracers. All the scans identify liver lesion in dome of right lobe (red arrows), intensity is low in ¹⁸F–FDA, whereas the liver lesion located in inferior right lobe of liver (black arrows) is missed on ¹⁸F–FDA. The localization of skeletal metastases is similar on ⁶⁸Ga-DOTATATE, ¹⁸F–FDG, and ¹⁸F–FDA whereas it is suboptimal on ¹⁸F–FDOPA