Case Report: Gangrene after one dose of investigational stannic pentetate radiopharmaceutical.

Introduction: Bone-seeking radiopharmaceuticals are the treatment of choice with clinical benefits for patients with extensive skeletal metastases, but they can also cause serious radiation-related adverse events (rrAEs). Management of rare and severe radiopharmaceutical rrAEs remains challenging because of incomplete knowledge of their natural history and pathogenetic mechanisms. We report a case of unlikely related gangrene following a protracted hospitalization after one dose of investigational [ Case presentation: An 80-year-old man with innumerable painful skeletal metastases from mCRPC developed anorexia and bilateral ankle edema with serous-draining skin fissures of the left foot, worrisome for uninfected dry gangrene, 24 days after receiving a single administration of Sn-117m-DTPA (710 MBq) in a phase II clinical trial (NCT04616547). Laboratory investigations revealed leukopenia (3,180 ml Conclusion: Gangrene, complicated by leukopenia and sepsis from aspiration pneumonia, is a rarely reported serious adverse event occurring late after a radiopharmaceutical treatment. Given that the window of reversibility for gangrene is narrow, prompt and decisive intervention is warranted. Subtle perturbations in skin integrity after radiopharmaceutical treatment may be more prevalent than realized and should be addressed in both clinical and investigational settings.