The "Scintigraphic Flip": A Visual Warning Sign of Impending Hematologic Toxicity.
Daniel Hueng-Yuan Shen, Kuan-Chieh Chen, I-Hsuan Alan Chen et al.
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Case in brief
A 55-year-old man with metastatic castration-resistant prostate cancer developed increased diffuse marrow uptake and reduced salivary-gland and liver activity on imaging after his second cycle of ¹⁷⁷Lu-PSMA therapy. This redistribution occurred despite improved bone pain, lower analgesic use, and no clinical or laboratory warning signs. It preceded grade III thrombocytopenia and marked anemia, requiring hospitalization for transfusion and supportive care. The patient died.
What made this case unusual
The imaging showed a “scintigraphic flip”: diffuse marrow uptake increased while salivary-gland and liver activity fell, despite symptomatic improvement and no clinical or laboratory warning signs.
Diagnostic / clinical pearl
After ¹⁷⁷Lu-PSMA therapy, a shift toward diffuse marrow uptake on imaging may precede severe hematologic toxicity, even when symptoms and laboratory findings offer no warning.
Why it matters
The authors suggest interval PSMA PET/CT may help detect occult marrow redistribution and support individualized dose adaptation in selected high-risk patients.