Targeted Detection of Recurrence and Metastasis in Adrenocortical Carcinoma: A Novel Approach Using 99mTc-FAPI-46 SPECT/CT Imaging.

We present a case of a 73-year-old man with a history of adrenocortical carcinoma (ACC) who underwent multiple surgeries and treatments for recurrent and metastatic lesions. The patient underwent a 99mTc-FAPI-46 scan, which revealed FAPI uptake in all tumoral masses detected on contrast-enhanced CT scans and subsequent laparotomy, with favorable target-to-background ratios. Our experience suggests that 99mTc-FAPI-46 SPECT/CT may be a valuable complementary diagnostic modality for ACC, especially when PET/CT is not available. This case highlights the importance of comprehensive evaluation and consideration of other diagnostic modalities in the management of ACC, given the potential of FAPI-based imaging agents.