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Pheochromocytoma: Positive on 131I-MIBG Single-Photon Emission Computed Tomography-Computed Tomography and Negative on 68Ga DOTANOC Positron Emission Tomography-Computed Tomography
Address for correspondence: Dr. Shamim Ahmed Shamim, Department of Nuclear Medicine, Room No. 4, Rajkumari Amritkaur, O. P. D, AIIMS, New Delhi - 110 029, India. E-mail: sashamim2002@yahoo.co.in
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Abstract
Pheochromocytomas are tumors arising from sympathetic lineage-derived cells in adrenal medulla, and 68Ga DOTANOC positron emission tomography-computed tomography (PET-CT) has been found to be superior than 131I MIBG single-photon emission computed tomography-computed tomography (SPECT-CT) for initial localization/diagnosis of the adrenal lesion. We discuss the 68DOTANOC PET-CT and 131I MIBG SPECT-CT findings of a 24-year-old male who presented with clinical and biochemical findings suspicious of pheochromocytoma.
Keywords
DOTANOC
MIBG
pheochromocytoma
positron emission tomography
single-photon emission computed tomography
A 24-year-old male presented with chief complaints of headache and palpitations for the past 4 months. On clinical suspicion of pheochromocytoma, he was advised 68Ga DOTANOC positron emission tomography-computed tomography (PET-CT) which revealed a 1.5 cm × 1.5 cm nodule in the body of right adrenal gland on CT images [Figure 1b solid white arrow] showing no somatostatin receptor expression on PET [Figure 1a and d]. However, his biochemical parameters such as urinary metanephrines, normetanephrines, plasma adrenaline, noradrenaline were 73 μg/24 h, 397.5 μg/24 h, 49.3 pg/ml, and 246 pg/ml, respectively, which prompted the endocrinologist for further evaluation. Subsequently, a 131I MIBG single-photon emission computed tomography-computed tomography (SPECT-CT) was done which showed intense MIBG concentration in the same lesion in the body of right adrenal on SPECT-CT images [Figure 1f solid red arrow] but not on planar images [Figure 1c and e]. The patient underwent right adrenalectomy, and the histopathology was diagnostic of pheochromocytoma. As pheochromocytoma and paragangliomas express high somatostatin expression 68Ga DOTA conjugated peptides that target somatostatin receptors are currently the first-line modality of choice for initial diagnosis of pheochromocytomas and paragangliomas owing to its superior lesion detection rate over other functional imaging modalities.[12345] Other functional imaging tools that are used for detection of pheochromocytomas include 123/131I-MIBG scintigraphy, 18F-Fluorodopa, and 18F-FDG PET-CT. As per the meta-analysis by Han et al., the pooled detection rate of 68Ga-DOTA-conjugated peptides PET was significantly higher than that of 18F-FDOPA PET (80% [95% confidence interval (CI) 69%–88%], P = 0.0003), 18F-FDG PET (74% [95% CI 46%–91%], P < 0.0001), or 123/131I-MIBG scintigraphy (38% [95% CI 20%–59%], P < 0.0001).[6] The peculiarity of our case lies in the fact that despite superior lesion detection rate of DOTA conjugated peptides PET, 68Ga DOTANOC PET-CT does not show any tracer accumulation in the right adrenal body lesion that is visualized on CT but shows MIBG concentration despite it being a comparatively inferior functional modality. As no such case in the literature regarding such behavior of any adrenal lesion suspicious of pheochromocytoma has been reported, the authors advocate the diligent use of 123/131I-MIBG scintigraphy with SPECT CT in the work-up of cases of pheochromocytoma with strong clinical suspicion even if 68Ga-DOTANOC PET-CT results are negative.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- Diagnostic accuracy of (68) Ga-DOTANOC PET/CT imaging in pheochromocytoma. Eur J Nucl Med Mol Imaging. 2014;41:494-504.
- [Google Scholar]
- Functional imaging in phaeochromocytoma and neuroblastoma with 68Ga-DOTA-Tyr 3-octreotide positron emission tomography and 123I-metaiodobenzylguanidine. Eur J Nucl Med Mol Imaging. 2011;38:865-73.
- [Google Scholar]
- 68Ga-DOTA-TATE PET vs. 123I-MIBG in identifying malignant neural crest tumours. Mol Imaging Biol. 2011;13:769-75.
- [Google Scholar]
- 68Ga-DOTANOC PET/CT for baseline evaluation of patients with head and neck paraganglioma. J Nucl Med. 2013;54:841-7.
- [Google Scholar]
- Somatostatin receptor sst1-sst5 expression in normal and neoplastic human tissues using receptor autoradiography with subtype-selective ligands. Eur J Nucl Med. 2001;28:836-46.
- [Google Scholar]
- Performance of 68Ga-DOTA-conjugated somatostatin receptor targeting peptide PET in detection of pheochromocytoma and paraganglioma: A systematic review and meta-analysis. J Nucl Med 2018 pii: jnumed118211706
- [Google Scholar]