Carcinoma of the pancreatic head and its ultrasound appearances have been discussed in a previously published case [click here to view it].
This case is discussed here to highlight certain features that suggest that it is a malignant process, rather than a mass forming focal pancreatitis [its closest differential].
- A focal hypoechoic mass – is seen in both conditions. Calcifications within a mass are more common with pancreatitis.
- Main pancreatic duct dilatation – is regular in a carcinoma [as is seen in this case], while irregularly beaded dilatation of the duct is more typical for pancreatitis.
- Vascularity of the mass – pancreatic malignant masses are relatively avascular, while inflammatory mass is iso or hypervascular as compared to the pancreatic parenchyma.
- Remainder of the pancreatic parenchyma - normal with a carcinoma [as is seen in this case] or may be atrophic; however in focal pancreatitis, the remainder of the pancreatic body often exhibits inhomogeneous echotexture, altered echogenicity and presence of calcifications or pseudocysts.
Peripancreatic vessel invasion is an obvious pointer of a malignant process. Presence of hepatic and lymph nodal metastases also favors malignancy. Difficulty may arise if a carcinoma is superimposed on chronic pancreatitis, necessitating the use of other modalities. Ultrasound directed FNA biopsy can also be performed to establish histopathological diagnosis.
In the patient illustrated here, a biliary stent was placed in the common bile duct following ERCP to decompress the system and relieve the patient’s jaundice. In certain cases, where endoscopy guided stent placement is not possible, ultrasound guided percutaneous biliary drainage can be performed. In patients with hilar biliary obstruction, external - internal drainage catheters can be placed. In the palliative treatment of advanced pancreatic malignancies, the mainstay of treatment is to keep the system decompressed via the placement of biliary stents. One of the common complications that occur in such a scenario is stent blockage. Intraductal ultrasound in conjunction with EUS is an upcoming modality that can be used to monitor the growth of tumor into the duct and stent.