The prevalence of double primary prostate and bladder cancer is not uncommon. Though both share a common pathway of malignant transformation, they bear to differ in the case of 2-[18F]FDG PET/CT and ­[68Ga]Ga-PSMA uptake. We present a case of double primary cancer involving the bladder and prostate, where the prostatic primary showed intense [68Ga]GaPSMA uptake with non-avid skeletal and pulmonary metastases, which showed intense 2-[18F]FDG uptake, thus showing discordance due to different clonal origins.

In this case report, we present the clinical management of a 52-year-old female patient with a recurrent right temporo-parietal glioblastoma multiforme (GBM). The patient presented with symptoms of headache and loss of balance and recurrence on magnetic resonance imaging (MRI). To evaluate the fibroblast activation protein inhibitor (FAPi) expression in the recurrent lesion, an exploratory ­[68Ga]Ga-DOTA.SA.FAPi PET/CT scan was performed. The imaging results revealed FAPi expression in the lesion located in the right temporo-parietal region. Based on the findings of FAPi expression, the patient underwent[177 Lu]Lu-DOTAGA.Glu.(FAPi)2 treatment. After completing two cycles of ­[177 Lu]Lu-DOTAGA.Glu.(FAPi)2 therapy, afollow-u [68Ga]Ga-DOTA.SA.FAPi PET/CT scan was conducted. The post-treatment imaging showed a significant reduction in FAPi uptake and regression in the size of the lesion, as well as a decrease in perilesional edema, as observed on the MRI. Furthermore, the patient experienced an improvement in symptoms and performance status. These results suggesttha [68Ga]Ga-DOTA.SA.FAPi monomer imaging and ­[177 Lu]Lu-DOTAGA.Glu.(FAPi)2 dimer therapeutics hold promisefor patients with recurrent GBM when other standard-line therapeutic options have been exhausted. This case highlights the potential of using FAPi-based theranostics in the management of recurrent GBM, providing a potential avenue for personalized treatment in patients who have limited treatment options available.