99m Tc-FAPI-46 Scintigraphy in Genital Tract Carcinosarcoma.

A 47-year-old woman presenting with abdominal pain and constipation was diagnosed with high-grade mucinous adenocarcinoma of the genital tract after undergoing extensive surgery. Six months after adjuvant chemotherapy, she developed recurrent symptoms and a large pelvic mass, leading to cytoreductive surgery, which histopathologic evaluation revealed carcinosarcoma. Postsurgery, 99m Tc-FAPI-46 scintigraphy indicated heterogeneous uptake in the tumoral masses and diffuse uptake in peritoneal carcinomatosis, which was not detected on contrast-enhanced CT (CeCT) scan. This case demonstrates the superior diagnostic performance of FAPI-targeted imaging over CeCT in assessing tumor extent in genital tract carcinosarcoma and suggests 177 Lu-FAPI as a potential therapeutic approach.