Isolated extreme gamma-glutamyl transferase elevation as an early indicator of ampullary adenocarcinoma in a young adult: a case report with molecular insights.

Ampullary adenocarcinoma is a rare gastrointestinal malignancy that typically occurs in older populations and characteristically presents with obstructive jaundice. Atypical biochemical presentations in young adults without hyperbilirubinemia are extremely rare and can lead to significant diagnostic delays.

A 37-year-old asymptomatic male presented with a rapid, isolated, and extreme elevation of serum gamma-glutamyl transferase (GGT), surging from 78 U/L to 1793 U/L over 6 months, and an elevated CA19-9 level. Total bilirubin, transaminases, and baseline liver parenchyma remained entirely normal. Abdominal ultrasound followed by high-resolution magnetic resonance cholangiopancreatography (MRCP) revealed extrahepatic biliary dilation and focal thickening at the major duodenal papilla. Based on high radiological suspicion, a multidisciplinary team recommended direct surgical intervention without prior endoscopic ultrasonography (EUS) or biopsy. The patient underwent a curative pancreaticoduodenectomy (Whipple procedure). Histopathology confirmed a 2.8 cm, moderately-to-poorly differentiated ampullary adenocarcinoma of pancreatobiliary origin (pT3aN0M0, R0 resection) with perineural invasion. Molecular profiling demonstrated a KRAS wild-type, BRAF wild-type, microsatellite stable (MSS), and HER2 (2+) equivocal status. Postoperatively, the serum GGT normalized completely to 57 U/L by day 18.

An isolated, rapidly rising GGT can serve as an independent early alert for occult terminal bile duct lesions before full mechanical occlusion and hyperbilirubinemia manifest. Early advanced imaging with MRCP is critical in such atypical presentations. Comprehensive molecular profiling provides additional targetable and prognostic insights for personalized postoperative surveillance.

Not applicable.
Cancer
Care/Management

Authors

Sun Sun, Wu Wu, Lou Lou, Li Li
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