Pancreatic metastases are uncommon and are only found in a minority (3-12%) of patients with widespread metastatic disease at autopsy . They account for only 2-5% of all pancreatic malignancies.
Although essentially any primary may eventually deposit in the panaceas the most common primaries encountered include 1-2:
- renal cell carcinoma (RCC): one of commonest of tumours that metastatise to the pancreas
- breast cancer
- lung cancer
- gastric cancer
- colorectal carcinoma (CRC)
Demographics and clinical presentation
Demographics will match those of the primary tumour, but in general will be in elderly patients.
Most pancreatic metastases are asymptomatic and are found incidentally on imaging or at autopsy 1. If particularly large, especially if at the head of the pancreas, then local symptoms may include:
- jaundice: from CBD obstruction
- malabsorption: pancreatic insufficiency
- duodenal/gastric outlet obstruction
- gastrointestinal bleeding
Metastases to the pancreas do not have a predilection for any one part of the gland, and can have a variety of appearances 1,4:
- localised mass: 50-75%
- diffuse involvement: 5-45%
- multiple nodules: 5-15%
In general they tend to be small lesions (0.5-2.0cm) 5.
Metastases appear as solid hypoechogenic masses located within the pancreatic parenchyma 5. Cysts are generally not a feature.
Findings are non-specific, typically demonstrating a well circumscribed mass which is iso- to hypodense relative to normal pancreas on non-contrast scans 1,4. Enhancement is heterogeneous, but tends to be present, homogeneously for smaller lesions, and peripheral in larger lesions, presumably due to central necrosis 1,4. In general, the enhancement pattern resembles that of the primary tumour.
Calcification is rare (again depends on the primary).
Pancreatic ductal obstruction is common for head and body lesions, seen in up to ~40% of cases, and may be associated with CBD obstruction and intrahepatic biliary dilatation 4.
Treatment and prognosis
Treatment is targeted at local symptomatic control, with biliary stents or gastroenteric bypass for obstruction. In general patients are treated with palliative intent, due to widespread metastatic disease.
Resection is usually not an option, except occasionally in the setting of solitary RCC metastasis 1.
Prognosis is universally poor, matching that of the metastatic primary.
- pancreatic ductal adenocarcinoma
- pancreatic islet cell tumours: especially for vascular metastases, e.g. RCC 3
- autoimmune pancreatitis
- cystic neoplasm (cystic pancreatic mass differential diagnosis)
- solid neoplasm
- nonepithelial pancreatic neoplasms
pancreatitis (mnemonic for the causes)
- gallstone pancreatitis
- interstitial oedematous pancreatitis
- necrotising pancreatitis
- haemorrhagic pancreatitis
- revised Atlanta classification of acute pancreatitis
- chronic pancreatitis
- Ascaris-induced pancreatitis
- tropical pancreatitis
- autoimmune pancreatitis
- emphysematous pancreatitis
- hereditary pancreatitis
- pancreatitis associated with cystic fibrosis
- segmental pancreatitis
- acute pancreatitis
- pancreatic atrophy
- pancreatic lipomatosis
- pancreatic trauma
- 1. Scatarige JC, Horton KM, Sheth S et-al. Pancreatic parenchymal metastases: observations on helical CT. AJR Am J Roentgenol. 2001;176 (3): 695-9. AJR Am J Roentgenol (full text) - Pubmed citation
- 2. Charnsangavej C, Whitley NO. Metastases to the pancreas and peripancreatic lymph nodes from carcinoma of the right side of the colon: CT findings in 12 patients. AJR Am J Roentgenol. 1993;160 (1): 49-52. AJR Am J Roentgenol (abstract) - Pubmed citation
- 3. Ng CS, Loyer EM, Iyer RB et-al. Metastases to the pancreas from renal cell carcinoma: findings on three-phase contrast-enhanced helical CT. AJR Am J Roentgenol. 1999;172 (6): 1555-9. AJR Am J Roentgenol (abstract) - Pubmed citation
- 4. Klein KA, Stephens DH, Welch TJ. CT characteristics of metastatic disease of the pancreas. Radiographics. 18 (2): 369-78. Radiographics (abstract) - Pubmed citation
- 5. Wernecke K, Peters PE, Galanski M. Pancreatic metastases: US evaluation. Radiology. 1986;160 (2): 399-402. Radiology (abstract) - Pubmed citation