The isoattenuating pancreatic adenocarcinoma: Review of the literature and critical analysis

•The isoattenuating pancreatic adenocarcinoma is defined as a mass not directly visible on dynamic CT.•88% and 100% of the isoattenuating adenocarcinomas <20 mm and >20 mm are recognized only by secondary imaging findings.•Dynamic MRI can unmask 80% of the isoattenuating pancreatic adenocarcinomas.•EUS-biopsy is not mandatory to be performed before proceeding to surgery.•Isoattenuating adenocarcinoma patients have longer median survival due to the higher rate of well differentiated tumors.

Dynamic CT has a reported sensitivity of as high as 97% in the detection of pancreatic cancer. Consequently, a substantial number of pancreatic tumors can still escape detection. The isoattenuating pancreatic adenocarcinoma is defined as a mass not directly visible on dynamic CT as its attenuation is indistinguishable from the attenuation of the pancreatic parenchyma. 88% and 100% of the isoattenuating adenocarcinomas <20 mm and >20 mm respectively are recognized only by the presence of secondary imaging findings highly suggestive of malignancy. Dynamic MRI can unmask 80% of the isoattenuating pancreatic adenocarcinomas. If MRI fails to unmask the mass, EUS-biopsy is not mandatory to be performed as biopsy proof is not required for solid pancreatic masses suspicious for malignancy before proceeding to surgery. The isoattenuating adenocarcinomas should not be regarded as early cancers as less than one-third of them are stage T1 tumors. After curative intent surgery, isoattenuating pancreatic adenocarcinoma patients have a significantly longer median survival than usual pancreatic adenocarcinoma patients associated with the higher rate of well differentiated tumors among isoattenuating tumors. The more favorable postsurgical survival of the isoattenuating pancreatic adenocarcinoma patients makes it even more imperative to correctly diagnose their cases at a resectable stage.