Detection of Pancreatic Carcinoma in a patient presenting with Acute Pancreatitis

History

A middle-aged man presented with acute epigastric pain. An abdominal CT was performed and showed streaks of fat around the body and tail of the pancreas, consistent with acute pancreatitis. Additional findings included a somewhat bulky pancreas head without any focal hypodensities.

The patient was referred for an FDG PET/CT scan which revealed an intensely FDG-avid lesion (SUV 8.7) at the head of the pancreas and diffuse low-grade FDG uptake was noted at the body and tail of the pancreas. The level of FDG uptake at the body and tail of the pancreas appeared consistent with acute pancreatitis. CT also showed slight thickening of the tail of the pancreas. The FDG-avid mass in the pancreas head was biopsied secondary to laparotomy and, on frozen section, confirmed to be adenocarcinoma of the pancreas.

Fig 1. FDG PET image of the abdomen showing high uptake in the head of the pancreas

Comments

Pancreatic cancer coexisting with or causing acute pancreatitis is rare.

FDG PET has been used to characterize indeterminate masses of the pancreas and is regarded to be of value in screening for pancreatic malignancy in at-risk patients, especially with Chronic Pancreatitis (EJNM Jan 2005-Marietta et al). This study found FDG PET to be 91% sensitive and 87% specific for detection of pancreatic malignancy in a setting of chronic pancreatitis.

Fig 2. CT, FDG PET and PET/CT fusion image — transaxial section at the level of the body and tail of pancreas

Fig 3. CT, FDG PET and PET/CT fusion image — transaxial section at the level of the pancreatic head

This presented case, previously unreported detection of pancreatic cancer in a patient with acute pancreatitis, demonstrates the clinical value PET/CT hybrid imaging provides. Acute inflammation of the pancreas is itself associated with high FDG accumulation, evident in the pancreas body and tail (see images below). However, the associated malignant pancreatic tumor located in the head is conspicuous because of the very high FDG uptake (SUV of 8.3), reflecting the aggressive nature of the adenocarcinoma.

Although CT demonstrates slight enlargement of the pancreatic head, it is not diagnostic by itself. In this case, FDG PET/CT is critical to diagnose the associated cancer, which otherwise would have been left untreated in the context of an acute pancreatitis episode.

Case study and images

courtesy Dr. David Ng & Dr. Anthony Goh – Dept. of Nuclear Medicine Singapore General Hospital Singapore. Study acquired on – Biograph LSO PET/CT system. Dr. Partha Ghosh
Clinical Marketing Manager
Asia Pacific Nuclear Medicine Group
Siemens Medical Solutions
Singapore

Fig 4. CT, FDG PET and PET/CT fusion image — transaxial section at the level of the pancreatic head