Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma.

OBJECTIVE: To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases. MATERIALS AND METHODS: Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported. RESULTS: Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03). CONCLUSIONS: [68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate. CLINICAL RELEVANCE STATEMENT: In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001). KEY POINTS: • Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Evidence of the Role of Inflammation and the Hormonal Environment in the Pathogenesis of Adrenal Myelolipomas in Congenital Adrenal Hyperplasia.

Adrenal myelolipomas (AML) are composed of mature adipose and hematopoietic components. They represent approximately 3 percent of adrenal tumors and are commonly found in patients with congenital adrenal hyperplasia (CAH). CAH provides a unique environment to explore AML pathogenesis. We aimed to evaluate the role of the immune system and hormones that accumulate in poorly controlled CAH in the development of AML. When compared to normal adrenal tissue, CAH-affected adrenal tissue and myelolipomas showed an increased expression of inflammatory cells (CD68, IL2Rbeta), stem cells (CD117) B cells (IRF4), and adipogenic markers (aP2/FABP4, AdipoQ, PPARγ, Leptin, CideA), and immunostaining showed nodular lymphocytic accumulation. Immunohistochemistry staining revealed a higher density of inflammatory cells (CD20, CD3, CD68) in CAH compared to non-CAH myelolipomas. In vitro RNA-sequencing studies using NCI-H295R adrenocortical cells with exogenous exposure to ACTH, testosterone, and 17-hydroxyprogesterone hormones, showed the differential expression of genes involved in cell cycle progression, phosphorylation, and tumorigenesis. Migration of B-lymphocytes was initiated after the hormonal treatment of adrenocortical cells using the Boyden chamber chemotaxis assay, indicating a possible hormonal influence on triggering inflammation and the development of myelolipomas. These findings demonstrate the important role of inflammation and the hormonal milieu in the development of AML in CAH.

International consensus statement on the diagnosis and management of phaeochromocytoma and paraganglioma in children and adolescents.

Phaeochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumours that arise not only in adulthood but also in childhood and adolescence. Up to 70-80% of childhood PPGL are hereditary, accounting for a higher incidence of metastatic and/or multifocal PPGL in paediatric patients than in adult patients. Key differences in the tumour biology and management, together with rare disease incidence and therapeutic challenges in paediatric compared with adult patients, mandate close expert cross-disciplinary teamwork. Teams should ideally include adult and paediatric endocrinologists, oncologists, cardiologists, surgeons, geneticists, pathologists, radiologists, clinical psychologists and nuclear medicine physicians. Provision of an international Consensus Statement should improve care and outcomes for children and adolescents with these tumours.

Management of phaeochromocytoma and paraganglioma in patients with germline SDHB pathogenic variants: an international expert Consensus statement.

Adult and paediatric patients with pathogenic variants in the gene encoding succinate dehydrogenase (SDH) subunit B (SDHB) often have locally aggressive, recurrent or metastatic phaeochromocytomas and paragangliomas (PPGLs). Furthermore, SDHB PPGLs have the highest rates of disease-specific morbidity and mortality compared with other hereditary PPGLs. PPGLs with SDHB pathogenic variants are often less differentiated and do not produce substantial amounts of catecholamines (in some patients, they produce only dopamine) compared with other hereditary subtypes, which enables these tumours to grow subclinically for a long time. In addition, SDHB pathogenic variants support tumour growth through high levels of the oncometabolite succinate and other mechanisms related to cancer initiation and progression. As a result, pseudohypoxia and upregulation of genes related to the hypoxia signalling pathway occur, promoting the growth, migration, invasiveness and metastasis of cancer cells. These factors, along with a high rate of metastasis, support early surgical intervention and total resection of PPGLs, regardless of the tumour size. The treatment of metastases is challenging and relies on either local or systemic therapies, or sometimes both. This Consensus statement should help guide clinicians in the diagnosis and management of patients with SDHB PPGLs.

Invasive Testing for Preoperative Localization of Parathyroid Tumors.

Context: The identification of parathyroid tumor(s) in patients with persistent/recurrent primary hyperparathyroidism (PHPT) is critical for a successful reoperative surgery. If noninvasive studies (ultrasound, computed tomography, magnetic resonance imaging, sestamibi) fail to conclusively localize the tumor, invasive procedures (arteriography and selective venous sampling) are performed. Objective: To describe our experience with invasive studies for parathyroid tumor localization and provide follow-up data on selective arterial hypocalcemic stimulation with central venous sampling, a technique developed at our center. Methods: We identified patients who underwent preoperative invasive testing for localization of parathyroid tumor from 1991 to 2020. The result of each invasive localization study [arteriogram, hypocalcemic stimulation and selective venous sampling (SVS)] was categorized as true-positive, false-positive, and false-negative based on histology and biochemical outcome. Results: Ninety-four patients with 96 tumor occurrences underwent invasive testing for parathyroid tumor localization. Arteriogram, hypocalcemic stimulation, and SVS accurately localized the tumor in 47 of 94 (50%), 56 of 93 (60%), and 51 of 62 (82%) tumors, respectively. Hypocalcemic stimulation was more likely to correctly localize the tumor when arteriogram showed a blush [37 of 50 (74%) vs 19 of 43 (44%), P = .01]. When both arteriogram and hypocalcemic stimulation yielded concordant positive findings, SVS did not change management in the 18 cases in which all 3 were performed. Twelve patients remained with persistent PHPT; all had recurrent disease with multiple affected glands. Conclusion: Hypocalcemic stimulation is a useful adjunct in patients with PHPT who require invasive localization and can obviate the need for SVS. Clinical Trial number: NCT04969926.