99m Tc-FAPI-46 Scintigraphy in Recurrence of Low-Grade Myofibroblastic Sarcoma

Low-grade myofibroblastic sarcoma (LGMFS) is a rare mesenchymal tumor, infrequently found in the abdominal cavity, where it may exhibit more aggressive behavior. This case report presents a 15-year-old boy with LGMFS manifesting as a large abdominal mass. Following neoadjuvant therapy and surgical resection, recurrence was detected via follow-up imaging. We employed 99m Tc-FAPI-46 scintigraphy, representing its first reported application in LGMFS. The FAPI scintigraphy exhibited uptake in all tumoral lesions identified on contrast-enhanced CT scan, underscoring the potential of FAPI in the evaluation of this rare entity.