Small Lesion, Big Impact: EUS Localization and Ablation of a CT-Occult Insulinoma
https://doi.org/10.15605/jafes.041.S1
- Author:
Tharshini Indrajothy
1
;
Vanusha Devaraja
1
;
Goh Qing Ci
1
;
Tay Yang Zet
2
;
Patricia Lee Siow Ping
1
Author Information
1. Hospital Melaka
2. Hospital Kuala Lumpur
- Publication Type:Journal Article
- MeSH:
Insulinoma;
Tomography, X-Ray Computed
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):96-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Insulinoma is a rare functioning pancreatic neuroendocrine
tumor and the most common cause of endogenous
hyperinsulinemic hypoglycemia. Although biochemical
confirmation is usually straightforward, tumor localization may be difficult when lesions are small and not detected
on conventional cross-sectional imaging. In such cases,
endoscopic ultrasound (EUS) plays an important role
in identifying occult lesions and facilitating definitive
treatment.
Case:A 52-year-old female was admitted in April 2025 with
recurrent seizures secondary to hypoglycemia for 3
years, with increasing frequency over time. She fulfilled
Whipple’s triad, with documented capillary glucose of
1.8 mmol/L during an episode and symptom resolution
following glucose administration. A supervised prolonged
fasting test confirmed endogenous hyperinsulinemic
hypoglycemia, with plasma glucose 1.4 mmol/L, insulin 122
pmol/L, and C-peptide 1,010 pmol/L. Short Synacthen test
demonstrated adequate adrenal reserve. Due to persistent
hypoglycemia, she required high-dose diazoxide.
Contrast-enhanced computed tomography abdomen did
not reveal a pancreatic lesion but incidentally detected a
right ovarian teratoma. She underwent total abdominal
hysterectomy and bilateral salpingo-oophorectomy in
June 2025, with histopathology confirming a mature cystic
teratoma without malignancy. However, hypoglycemic
episodes persisted. Further evaluation with EUS in July
2025 identified a highly vascular isoechoic 8 × 8 mm lesion
in the pancreatic body. Fine-needle biopsy confirmed a
well-differentiated neuroendocrine tumor (WHO grade 1)
with Ki-67 index of 2%. She subsequently underwent EUSguided radiofrequency ablation in August 2025. Follow-up
EUS in December 2025 showed post-ablation change, and
her hypoglycemic episodes resolved completely, allowing
diazoxide to be discontinued.
Conclusion:This case highlights the diagnostic challenge of occult
insulinoma in the presence of negative conventional
imaging. EUS was pivotal for tumor localization and tissue
diagnosis, while EUS-guided radiofrequency ablation
provided effective minimally invasive treatment in a
carefully selected patient.
- Full text:2026080416061983261EP_A138.pdf
