Systemic neo-adjuvant chemotherapy in metastatic colorectal cancer frequently causes morphological lesions involving hepatic microvasculature. Sinusoidal obstruction, complicated by perisinusoidal fibrosis and veno-occlusive lesion of the non-tumoral liver revealed by this study, should be included in the list of the adverse side-effects of colorectal systemic chemotherapy, in particular related to the use of oxaliplatin.

Histological tumor regression of HCRM to chemotherapy corresponds to fibrosis overgrowth and not to increase of necrosis. TRG should be considered when evaluating efficacy of chemotherapy for HCRM. Histological tumor regression was most common among oxaliplatin-treated patients and associated with better clinical outcome.

Pathologists should be aware of the distinctive lesions associated with OX and of their high prevalence. OX-related lesions are less frequent in patients treated with bevacizumab, suggesting that this drug has a preventive effect. Uniform criteria for diagnosis and grading of OX-associated lesions should help to include histological data in the optimal multidisciplinary management of CRLM.

A low preoperative platelet count and high APRI score seem to be the most reliable indicators to predict SOS severity.

Immune checkpoint inhibitors are monoclonal antibodies indicated for an increasing number of malignant diseases. These agents can cause specific side effects, which need to be anticipated while clear patterns of management need to be established. Immune checkpoint inhibitor-mediated gastrointestinal side effects, including diarrhea and colitis, occur in up to 30% of patients. Severe colitis can lead to severe dehydration or intestinal perforation. Endoscopic lesions and histopathological features of immune checkpoint inhibitor-induced colitis are similar to an inflammatory bowel disease (IBD) flare. Patients with immune checkpoint inhibitor-induced diarrhea and colitis are treated with corticosteroids. Infliximab can be used in cases of corticosteroid failure. Rectosigmoïdoscopy or colonoscopy should be performed when severe immune checkpoint inhibitor-induced colitis is suspected, but endoscopic investigations should not delay treatment. Specific patient education as well as co-operation between oncologists and gastroenterologists is essential.