[A case report of lipoma-like tumor during hepatic arterial infusion chemotherapy].

The patient was a 65-year-old male, who had been performed partial resections of the colon (descending colon cancer and rectal cancer: Stage IIIa). Multiple hepatic metastases were observed 1 year and 10 months after the operation. Hepatic arterial infusion chemotherapy was started, and a complete response for liver metastases had been continuing for 2 years. On the seventh month after the hepatic arterial infusion chemotherapy was started, a lipoma-like tumor of approximately 10 cm was found under the diaphragm on the left side. The tumor was suspected to be a lipoma on imaging and it had a tendency for enlargement. Two years and two months after hepatic arterial infusion chemotherapy was begun, the patient was hospitalized for excision of the tumor. Intraoperative findings indicated that there was a 3.5 cm mass in the greater omentum in addition to the aforementioned tumor under the left diaphragm. Both masses were excised. The histopathological findings showed that the tumor under the left diaphragm was composed of adipose tissue with coagulative necrosis. The existing adipose tissue was thought to have necroses and had become encapsulated. Similar findings were obtained for the mass in the greater omentum. Contrast study using a port system revealed stenosis of hepatic artery and defluxion of contrast medium into splenic artery and inferior phrenic artery. We speculated that the lipoma-like tumor was formed by the angitis with the change of the drug distribution.