Oxaliplatin‐induced portal hypertension manifesting as portosystemic shunt: A case report and review of sinusoidal obstruction syndrome in gastric cancer

A 77-year-old woman with stage IVB gastric adenocarcinoma (cT4N2M1) received 10 cycles of S-1, oxaliplatin, and nivolumab combination chemotherapy. Imaging and biopsy confirmed a complete response. However, thrombocytopenia, mild splenomegaly, and elevated liver enzymes developed following oxaliplatin administration. After the tenth cycle, a contrast-enhanced computed tomography scan revealed a portosystemic shunt. Oxaliplatin was discontinued, but the shunt persisted after 1 year. Balloon-occluded retrograde transvenous obliteration was successfully performed, resulting in the resolution of the shunt. This case highlights the potential for oxaliplatin-induced portal hypertension requiring close monitoring.