SAT-503 False-Positive 68Ga-DOTATATE PET Findings In The Evaluation Of Pheochromocytomas And Paragangliomas: A Case Series
Bibliographic record
Abstract
Abstract Disclosure: S. Leblanc-Savignac: None. C. Cohade: None. F. Mercier: None. H. Olney: None. I. Bourdeau: None. Background: Functional imaging of pheochromocytomas and paragangliomas (PPGLs) using 68Ga-DOTATATE PET has shown high sensibility and specificity. However, we present three cases of suspected PPGLs that turned out to be false positives on DOTATATE PET. Clinical Cases Case 1: A 22-year-old woman known for type 1 neurofibromatosis (17q11.2 deletion) referred for a dense (100 HU), hyperintense, 43 x 31 mm, para-aortic mass found on screening MRI. She presented with occasional headaches and palpitations. DOTATATE-PET showed a left para-aortic mass with moderate uptake (SUV max 9.7). Biochemical testing was normal. With NF1 predisposing to PPGLs, typical para-aortic localization and radiological characteristics, a non-secreting PGL was suspected. The patient underwent surgery, and final pathology came back as: lymph node with histological changes compatible with Castleman disease. Case 2: A 60-year-old male known for metabolic syndrome was found with a 19 x 18 mm hyperdense heterogeneous nodule (150 HU) in the hepatorenal space on a thoracic CT scan. He presented with hot flashes and long-standing anxiety. DOTATATE PET showed strong uptake (SUV max 15.1), suggestive for PGL. Plasma free metanephrine levels were normal. Chromogranin A was slightly elevated at 106,9 ng/ml (N <82 ng/ml). Urine sampling revealed a slight increase of norepinephrine 536 nmol/d (N <475 nmol/d) and dopamine 3200 nmol/d (N <2300 nmol/d). The patient underwent surgery after alpha-blockade. Histological examination revealed a benign tumor corresponding to a hemangioma. Interestingly, exome sequencing of the hemangioma showed a pathogenic variant in the EGLN2 gene c.C1142G, p.A381G, a gene in the hypoxia induced factor 2 family associated with PPGLs and polycythemia, described for the first time in a hemangioma. Case 3: A 54-year-old man was diagnosed in 2016 with metastatic pheochromocytoma for which he underwent left adrenalectomy and nephrectomy, liver thermal ablation and radiotherapy on bone metastasis. He returned in 2023 with a lesion on the left cheek, insomnia and hypertension. DOTATATE-PET showed a 2.0 x 2.4 cm lesion in the left cheek with intense uptake (SUV max 7.1), suspicious for PPGL recurrence. Biochemical testing was normal except for elevated chromogranin A at 153,7 ng/ml (N<104 ng/ml). The patient underwent surgery after alpha-blockade. Pathology returned as high-grade B lymphoproliferative syndrome and chemotherapy was begun. Adding to the 3 presented cases, literature review showed 4 other cases of false positives with 68Ga-DOTATATE for PPGLs with the diagnoses of: solid cancer metastasis (2), focal lesion of fibrous dysplasia (1) and Castleman disease (1). Conclusion: False positive results with 68Ga-DOTATATE PET in the evaluation of PPGLs are rare but possible. A good understanding of their potential causes is essential to improve diagnostic accuracy, particularly in non-secreting tumors. Presentation: Saturday, July 12, 2025
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".