Leopardlike PET Pattern and Sarcoidlike Reaction
January 9, 2026
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3 min
5 Key Takeaways
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1
Unique 'leopardlike' pattern on PET/CT suggests SLR rather than cancer progression.
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2
SLRs resemble malignancy but often indicate favorable tumor control.
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3
Notable case: 52-year-old woman on durvalumab therapy.
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4
Lesions resolved with conservative treatment, no steroids.
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5
Importance of biopsy to differentiate SLR from true progression.
A distinctive 'leopardlike' pattern observed in a PET/CT scan led to the diagnosis of a drug-induced sarcoidosislike reaction (SLR) in a 52-year-old woman undergoing immune checkpoint inhibitor therapy, rather than cancer progression. This rare immune-related adverse event usually resembles malignancy but often signals effective tumor control. Following diagnosis, the patient's treatment with durvalumab was stopped, leading to complete resolution of symptoms and imaging abnormalities over three months. Understanding SLRs is crucial for proper management and reducing unnecessary interventions.
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