Pancreatic Ductal Adenocarcinoma and Its Variants: Pearls and Perils

Abstract

Pancreatic ductal adenocarcinoma (PDAC), an epithelial neoplasm derived from the pancreatic ductal tree, is the most common histologic type of pancreatic cancer and accounts for 85%-95% of all solid pancreatic tumors. As a highly lethal malignancy, it is the seventh leading cause of cancer death worldwide and is responsible for more than 300 000 deaths per year. PDAC is highly resistant to current therapies, affording patients a 5-year overall survival rate of only 7.2%. It is characterized histologically by its highly desmoplastic stroma embedding tubular and ductlike structures. On images, it typically manifests as a poorly defined hypoenhancing mass, causing ductal obstruction and vascular involvement. Little is known about the other histologic subtypes of PDAC, mainly because of their rarity and lack of specific patterns of disease manifestation. According to the World Health Organization, these variants include adenosquamous carcinoma, colloid carcinoma, hepatoid carcinoma, medullary carcinoma, signet ring cell carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, and undifferentiated carcinoma. Depending on the subtype, they can confer a better or even worse prognosis than that of conventional PDAC. Thus, awareness of the existence and differentiation of these variants on the basis of imaging and histopathologic characteristics is crucial to guide clinical decision making for optimal treatment and patient management.

Morphologic and Molecular Landscape of Pancreatic Cancer Variants as the Basis of New Therapeutic Strategies for Precision Oncology

“…Nonetheless, these drugs display significant toxicities hence highlighting the urgent need to define precision medicine and improve the patient's OS [152]. Furthermore, as we described before, not all PDAC are similar according to not only histopathological features but also genetic/molecular landscape [100,153]. This classification tragically complicates the design of new clinical trials, given the diversity between each rare histotype, and patients with these variants are not included in new clinical trials.…”

Colloid Carcinoma of the Pancreas with a Series of Radiological and Pathological Studies for Diagnosis: A Case Report

“…Differential diagnoses included both IPMN and MCN when encountering a cystic neoplasm of the pancreas, as was seen in this case. Typical imaging characteristics of IPMN, such as communication between the mass and pancreatic duct, downstream dilatation of the pancreatic duct or intraductal papillary components [ 8 ], were not seen in this case. In terms of MCN, this neoplasm usually presents itself as a single spherical mass with thick septae and peripheral calcifications, typically located at the body and the tail of the pancreas [ 9 ].…”

Targeted-Gene Sequencing and Bioinformatics Analysis of Patients with Pancreatic Mucoepidermoid Carcinoma: A Case Report and Literature Review

“…PDAC encompasses more than 85% of pancreatic cancer. 25 Gene mutations, including carcinogens and tumor suppressors, are a significant pathological process in the initiation and progression of PDAC. The three major tumor suppressors involved in PDAC are TP53, CDKN2A and SMAD4, and RAS is the most well-known oncogene in PDAC.…”