We describe the case of 74-year-old-male, previously treated with fronto-parietal craniotomy due to primary glioblastoma multiforme (GBM), followed by concurrent radiation therapy (RT) and temozolomide (TMZ) chemotherapy. Magnetic resonance imaging (MRI) of the brain, at 1 month after completing RT + TMZ, depicted partial response. Three months later, the patient was submitted to a further brain MRI, that resulted doubtful for therapy induced changes (i.e., pseudoprogression). The patient, who had been previously treated with prostatectomy for prostate cancer (PC), underwent a positron emission tomography/computed tomography (PET/CT) scan with 18F-choline for PC biochemical recurrence. 18F-choline whole body PET/CT resulted negative for PC relapse, while segmental brain PET, co-registered with MRI, demonstrated increased tracer uptake corresponding to tumor boundaries. In order to solve differential diagnosis between pseudoprogression and GBM recurrence, brain PET/CT with 18F-L-dihydroxy-phenil-alanine ( 18F-DOPA) was subsequently performed: fused axial PET/MRI images showed increased 18F-DOPA incorporation in the peri-tumoral edema, but not in tumor boundaries, consistent with the suspicion of GBM pseudoprogression, as then confirmed by clinical and radiological follow-up.

223Ra-dichloride is a bone-seeking targeted alpha (α)-emitting approved for bone metastases in prostate cancer. Here, we report a case of therapy-related acute promyelocytic leukemia (t-APL) following administration of 223Ra, showing some evidence of a causative relationship. A patient with metastatic prostate cancer received therapy with 223Ra, with 6 injections of the radiopharmaceutical at a standard dose of 55 kBq/kg at 4-week intervals for a cumulative administered activity of 26.3 MBq. PET/CT with 18F-methylcholine repeated 1 month after the conclusion of 223Ra was negative. After 8 months, he developed pancytopenia and we made a diagnosis of therapy-related acute promyelocytic leukemia (t-APL). We then studied the genomic locations of the breakpoints in the PML and RARA genes, which were at nucleotide positions 1708-09 of PML intron 3, respectively, outside the previously reported Topo II-associated hotspot region. t-APL was cured with all-trans-retinoic acid (ATRA) and arsenic trioxide. The type of PML/RARA rearrangement we identified, in absence of other myelotoxic treatments, is suggestive of a possible direct causal relationship with exposure to 223Ra and warrants further investigations.