## Why option 1 is right The structure marked **A** (saponified calcium soaps) is the pathognomonic histologic hallmark of fat necrosis in acute pancreatitis. The mechanism is well-established: pancreatic lipase escapes into peripancreatic adipose tissue during acute pancreatitis, hydrolyzes triglycerides into free fatty acids (FFAs), and these FFAs immediately bind calcium ions to form insoluble calcium soaps—appearing as chalky white deposits on microscopy. This process consumes circulating calcium, leading to systemic hypocalcemia (as seen in this patient with serum Ca 7.2), which is a poor prognostic sign in Ranson criteria. This is the EXACT mechanism described in Robbins 10e Ch 19 for fat necrosis in acute pancreatitis. ## Why each distractor is wrong - **Option 2**: Pancreatic amylase does not degrade adipocyte glycogen or form calcium phosphate precipitates. Amylase is a carbohydrate-degrading enzyme and plays no role in fat necrosis. This confuses the enzyme involved (lipase, not amylase). - **Option 3**: Pancreatic proteases (trypsin, chymotrypsin) cause coagulative necrosis of pancreatic parenchyma itself, not the specific saponification process in peripancreatic fat. Proteolysis does not explain calcium soap formation. - **Option 4**: Hemorrhage and lipofuscin deposition are features of severe pancreatitis but are not the mechanism of saponification. Lipofuscin is an age-related pigment, not a calcium soap. **High-Yield:** Fat necrosis = lipase + triglycerides → FFAs + calcium → insoluble calcium soaps (chalky white); systemic hypocalcemia is a poor prognostic sign. [cite:Robbins and Cotran Pathologic Basis of Disease, 10th edition, Chapter 19: Pancreas]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.