colorectal mucinous adenocarcinoma
Friday 15 February 2013
Mucinous adenocarcinoma is defined by >50% of the tumor volume composed of extracellular mucin.
Tumors with a significant mucinous component (>10%) but <50% are usually termed adenocarcinoma with mucinous features or mucinous differentiation.
Mucinous adenocarcinoma typically shows large glandular structures with pools of extracellular mucin.
A variable number of individual tumor cells, including signet ring cells, may be seen.
The prognosis of mucinous adenocarcinoma in comparison with conventional adenocarcinoma has been controversial among different studies.
Many mucinous adenocarcinomas occur in patients with hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome) and thus represent highlevel MSI (MSI-H) tumors. These tumors are expected to behave in a low grade fashion.
In contrast, mucinous adenocarcinomas that are microsatellite stable (MSS) are expected to behave more aggressively, particularly when detected at an advanced stage.