Recent advances in the understanding of colorectal carcinogenesis have resulted in the need to modify many of our previously held ideas about diagnosing seemingly "simple" polyps and "straightforward" colon cancers. With the elucidation of relevant pathways, terminology has changed and become more complicated. Assessment of prognostic and predictive factors is becoming part of the pathologist's role as many centers move toward a personalized medicine approach. In order to keep up with increasing demands for more sophisticated information, a basic understanding of the molecular underpinnings of colorectal neoplasia is essential.

This course will focus on colorectal polyps and carcinoma. Emphasis will be placed on the morphologic findings, diagnostic criteria, evolving terminology, and differential diagnosis in colorectal polyps, polyposis syndromes, and carcinoma. The role of ancillary studies including immunohistochemical and molecular testing will be discussed, including their relevance in the "modern" surgical pathology report. A case study format will be utilized.

Topics to be discussed include the following: 1) Microsatellite unstable colorectal carcinomas including Lynch syndrome and sporadic colorectal carcinoma; 2) Serrated polyps, including those occurring in the hyperplastic polyposis syndrome, and their differential diagnosis; 3) Metastatic colorectal carcinoma with a discussion of the immunohistochemical evaluation of poorly differentiated tumors and the significance of K-ras mutation analysis; 4) Hamartomatous and juvenile polyps and polyposis syndromes and sporadic morphologic counterparts.

Upon completion of the course, participants will be able to: 1) understand the microsatellite unstable (MSI-H) pathway to colorectal neoplasia and to know the morphologic and immunohistochemical features of MSI-H carcinomas and their precursors and the terminology of the serrated neoplasia pathway; 2) understand the immunohistochemical workup of a poorly differentiated tumor; 3) know the diagnostic, prognostic, and therapeutic implications of MSI testing/MMR protein immunohistochemistry, BRAF mutation analysis, KRAS mutation analysis; and 4) recognize various hamartomatous and juvenile polyps of the colon and their potential diagnostic implications regarding familial cancer syndromes.

The course is designed for residents, fellows, and general pathologists, as well as those with an interest in GI pathology. Virtual slides and still images, along with histories, will be posted on the USCAP website for review by pre-registrants prior to the meeting. All participants will also receive a syllabus with comprehensive reference list and a CD with representative histological images will be mailed after the meeting.

(New Course) This course may be used for CME credits or SAM's credits.