99mTc-FAPI-46 Scintigraphy and Radioligand Therapy With 177Lu-FAPI-2286 in Locally Advanced Epithelioid Sarcoma

Epithelioid sarcoma (ES) is an ultra-rare and aggressive soft tissue malignancy, predominantly affecting the extremities. Scalp involvement in ES is exceedingly uncommon. This case report describes a 25-year-old man diagnosed with a scalp mass confirmed to be ES. Despite undergoing surgical resection and adjuvant chemoradiation, the tumor recurred, causing significant pain and erosion of adjacent bony structures. A multidisciplinary team recommended 99m Tc-FAPI-46 scintigraphy, which demonstrated high uptake in the tumor masses. The patient was subsequently treated with 177 Lu-FAPI-2286 in 4 cycles. Initial cycles showed promising treatment responses; however, disease progression was observed in the final cycle.