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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.005 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
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 source (direct Gemma or distilled Codex), 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".