Increased 68Ga-FAPI Uptake in Neurofibromatosis in a Patient With Pleomorphic Rhabdomyosarcoma.

A 48-year-old man presented with a painless enlarging mass on his right thigh for 2 months. He had a history of neurofibromatosis. MRI showed a mass in his right thigh. Malignant tumor was suspected. He was enrolled in the clinical trial of 68Ga-FAPI in solid tumors. Multiple increased FAPI uptake was observed in the right thigh mass, lung, and mediastinal lymph nodes, which were confirmed being pleomorphic rhabdomyosarcoma by biopsy. In addition, widespread metabolic activity was also observed in his cutaneous fibroma nodules. This case showed that benign neurofibromatosis can cause FAPI uptake.