To review the physiopathology and radiological findings characteristic of the phenomenon of fatty saponification associated with acute pancreatitis. To establish the keys for its differential diagnosis with peritoneal carcinomatosis, due to the similarity of its radiological findings.

In the pathophysiology of acute pancreatitis the release of pancreatic enzymes that are responsible for provoking a secondary systemic response occurs. These include lipolytic enzymes that "self-digest" pancreatic tissue and peripancreatic fat and activate a series of mediating factors of inflammation, mainly macrophages, resulting in an exaggerated inflammatory response. The lysis of the fat cells will cause the release of fatty acids that precipitate with the serum calcium in the form of soap. This is the phenomenon known as fatty saponification and is thought to...

In the imaging diagnosis,ultrasound currently has a limited role in the detection of cholelithiasis (etiological diagnosis), with MRI presenting a similar sensibility but less accessibility. In most acute pancreatitis, with a self-limited course, no further diagnostic tests will be necessary. In the case of severe acute pancreatitis, in which the management of patients will depend directly on the local and distant complications, the modality of choice is CT with intravenous contrast. It is important to recognize the radiological manifestations associated with the phenomenon of fatty...

The fatty saponification associated with acute pancreatitis is a useful concept in the diagnosis and characterization of acute pancreatitis and may predispose to peripancreatic fat necrosis. It is manifested radiologically as scattered nodular lesions that simulate peritoneal carcinomatosis and its radiological differentiation is not always possible. The key to this will be found in the clinical history and the evolution over time of radiological findings, with a tendency to regression in the case of fat saponification versus peritoneal carcinomatosis. However, there are complex cases of...

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