[A Case That in Most Part of the Metastatic Liver Tumor Fell into Spontaneous Necrosis after Surgery of Rectal Cancer]

We present a case of a 74-year-old woman treated with maintenance dialysis for chronic renal failure. She had undergone intravascular treatment of lower limb arteriosclerosis obliterans 3 times. Low anterior resection was performed for rectal cancer StageⅡ, but adjuvant chemotherapy was not administered after the operation. S5/S6 partial hepatectomy was performed after confirming a liver metastatic recurrence 7 months after the first operation. Tumor pathology examination of the resected specimen revealed necrosis in most parts of the specimen. Residual primary lesion similar to adenocarcinoma tissue was found only in a small part of the specimen. Artery wall embolism and recanalization image with cholesterol crystals indicated a Grison's lesion, which was considered to have likely developed into tumor necrosis from the embolization. Spontaneous regression of a malignant tumor is a rare condition found 1 case in 6-10 ten thousand cases. In hepatocellular carcinoma, secondary tumor infarction from tumor invasion and tumor thrombus may occur. The present case was a metastatic liver cancer, in which the cholesterol crystal embolism possibly reached the tumor necrosis. The suggested cause of the cholesterol crystal embolism in this case was intravascular treatment related.