Proximal-type epithelioid sarcoma in pubic region expressing L-type amino acid transporter 1: A case report.

Proximal-type epithelioid sarcoma is an aggressive malignant soft-tissue neoplasm, a "proximal" variant of epithelioid sarcoma, resistant to multimodal therapy and involved in early tumor-related death. Pertinent treatments are, therefore, continually being explored. A 24-year-old woman with nonmetastatic proximal-type epithelioid sarcoma, originating subcutaneously on the right side of the vulva, underwent surgical resection; the lesion recurred, however, leading to death 3 months after the second surgery. Here described is a case of proximal-type epithelioid sarcoma expressing L-type amino acid transporter 1 (LAT1) that transports essential amino acids and p-borono-L-phenylalanine (BPA)-the chemical compound used in boron neutron capture therapy (BNCT)-and is highly expressed in many malignant tumors. Recently, LAT1 has drawn attention, and relevant treatments have been studied-LAT1 inhibitor and BNCT. LAT1 expression in proximal-type epithelioid sarcoma may lead to cogent treatments for the disease.