Extensive Emphysematous Necrotising Pancreatitis Presenting With Cullen's Sign Despite a Normal Serum Amylase Level

Emphysematous necrotising pancreatitis is a rare and life-threatening form of acute pancreatitis characterised by infected pancreatic necrosis with gas formation and a high risk of systemic complications. We report the case of a man presenting with a seven-day history of constipation, progressive abdominal distension, vomiting, and systemic deterioration, with periumbilical discoloration consistent with Cullen's sign. Despite a normal serum amylase level, contrast-enhanced CT demonstrated extensive necrosis involving the neck and mid-body of the pancreas, gas locules within the peripancreatic region, and an acute necrotic collection in the lesser sac, consistent with emphysematous necrotising pancreatitis. His condition progressed despite supportive treatment, with interval imaging showing enlarging loculated intra-abdominal collections, mesenteric oedema, and vascular narrowing, and his course was further complicated by respiratory failure requiring intubation and probable aspiration pneumonia. This case highlights that severe necrotising pancreatitis may present with atypical biochemical findings and emphasises the importance of clinical suspicion, early cross-sectional imaging, serial reassessment, and multidisciplinary intensive care management.