Colorectal liver metastases A pathologist’s guide to creating an informative report and improving patient care

Context.—In this era of minimally invasive procedures for diagnosis, prognosis, and treatment, pathologists are at the forefront of analyzing specimens and are expected to make more specific diagnoses, providing additional information from the material they receive. Objective.—To familiarize pathologists with the essential components of surgical pathology reports for colorectal liver metastases (CRLM) resections. Data Sources.—Colorectal cancer is the third most common cancer in the world and the liver is the most frequent site of metastases. Not all patients are candidates for surgery initially and may be treated with neoadjuvant chemotherapy, most commonly with FOLFOX (5-fluoro-uracil/leucovorin and oxaliplatin) and FOLFIRI (5-fluoro-uracil/leucovorin and irinotecan), after which they may become surgical candidates. When CRLM resections are received post neoadjuvant, the pathologist needs to not only report margin status but also report details regarding the tumor’s response to treatment, and should evaluate the nonneoplastic parenchyma for chemotherapy-related injury, such as sinusoidal obstruction syndrome and/or steatohepatitis that may be caused by treatment. If ancillary tests, such as molecular studies (eg, KRAS, BRAF, NRAS, and microsatellite instability), have been previously conducted, these results should be included in the report. If not, they should be ordered for the resection specimen. Conclusions.—In this review, we will describe strategies and practical approaches to maximize the information gained from CRLM resections. A checklist is provided that may be used while signing out these cases to remind pathologists of additional components they may wish to include in their reports to best guide patient management.