Alert at 26 MG/DL: A Rare Presentation of Insulinoma in the Pancreatic Uncinate Process

Insulinoma is the most common functional pancreatic neuroendocrine tumor (incidence < 4/million/year), yet diagnosis is frequently delayed by years due to nonspecific symptoms mimicking neurological conditions. Uncinate process location adds surgical complexity from proximity to the main pancreatic duct and superior mesenteric vessels. This case highlights the value of early biochemical investigation and anatomy-driven surgical planning. Clinical evaluation and biochemical workup were performed at Barleti University Polyclinic, Tirana. Endogenous hyperinsulinemia was confirmed by simultaneous fasting measurement of glucose, insulin, C-peptide, and cortisol per established thresholds. Tumor localization was performed with contrast-enhanced abdominal magnetic resonance imaging (MRI) at Villa Maria Hospital, Tirana (T1/T2, DWI/ADC, dynamic post-contrast). Surgical strategy was decided by a multidisciplinary team. The specimen underwent histopathological and immunohistochemical analysis (Ki-67/MIB-1, Chromogranin A, Synaptophysin, Congo Red) per World Health Organization (WHO) 2022 classification. A 33-year-old woman with a two-year history of recurrent hypoglycemic episodes presented with fasting glucose 26 mg/dL, insulin 26.3 µU/mL, and C-peptide 3.64 ng/mL, confirming endogenous hyperinsulinemia; cortisol was normal, excluding adrenal insufficiency. MRI identified a 20 × 16.7 mm hypervascular lesion in the uncinate process with arterial enhancement and delayed washout. Proximity to the main pancreatic duct and superior mesenteric vessels precluded safe enucleation; pancreaticoduodenectomy (Whipple procedure) was performed without complications, with discharge on day seven and normalized glycemia. Histopathology (Biopsy 13777/25) confirmed a well-differentiated pancreatic neuroendocrine tumor, WHO Grade 1, Ki-67 < 2%, Chromogranin A and Synaptophysin positive, clear resection margins (R0), and no lymph node involvement (pN0). Measuring insulin and C peptide alongside glucose during any hypoglycemic episode is a simple step that can prevent diagnostic delay. When insulinoma arises in the uncinate process, enucleation may be unsafe regardless of tumor size; pancreaticoduodenectomy is the guideline-consistent, curative alternative. The G1, R0, pN0 outcome is associated with 5-year survival of 94–100%, underscoring the importance of timely and complete
surgical resection.