Conversion Hepatectomy After New FP Therapy for Malignant Hepatocellular Neoplasm, Not Otherwise Specified: A Case Report.

[BACKGROUND] Malignant hepatocellular neoplasm, not otherwise specified (HCN, NOS), is a rare primary liver tumor showing overlapping features of hepatoblastoma and hepatocellular carcinoma. Because of its rarity and histopathologic heterogeneity, the optimal treatment strategy for HCN, NOS remains undefined.

[AIM AND METHODS] We report a case of a 20-year-old woman with initially unresectable HCN, NOS, who was treated with hepatic arterial infusion chemotherapy using a fine-powder formulation of cisplatin suspended in Lipiodol combined with continuous 5-fluorouracil administration (New FP). The therapeutic response was assessed radiologically and serologically after each treatment cycle, and the patient subsequently underwent surgical resection after adequate tumor regression.

[RESULTS] After eight cycles of New FP, marked tumor shrinkage and a significant decline in tumor markers were achieved, enabling subsequent systemic chemotherapy according to the SIOPEL-4 regimen. Thereafter, conversion hepatectomy was performed, and histological examination of the resected specimen demonstrated approximately 90% tumor necrosis. The patient has remained disease-free for 20 months after surgery.

[CONCLUSION] This case demonstrates the potential of New FP as an effective hepatic arterial infusion regimen capable of achieving conversion therapy in rare liver malignancies such as HCN, NOS.