Imaging description

Colloid (or mucinous) carcinoma of the pancreas is a subtype of pancreatic adenocarcinoma characterized histologically by large pools of extracellular mucin which comprise at least 50% of the tumor volume and which surround central balls of malignant epithelium [1,2]. Colloid carcinoma accounts for 1–3% of invasive pancreatic adenocarcinomas and is commonly found in association with intraductal papillary mucinous neoplasms [3, 4]. At CT, colloid carcinomas may have a well-circumscribed border and low density (Figures 34.1 and 34.2), potentially suggesting a benign or less aggressive cystic process (these findings are not invariable and colloid carcinoma can also be indistinguishable from non-mucinous adenocarcinoma).

Importance

Colloid carcinoma of the pancreas, particularly when it is low density, well circumscribed, and associated with pancreatic ductal dilatation, may be mistaken for benign pathology such as pancreatitis with pseudocyst (Figure 34.2) or intraductal papillary mucinous neoplasm.

Typical clinical scenario

Colloid carcinoma of the pancreas should be considered when a low-density well-circumscribed pancreatic mass with ductal dilatation is seen in a middle-aged or elderly patient, particularly if the patient is known to have intraductal papillary mucinous neoplasm.