A Case of FDG-Avid but FAPI-Negative Peritoneal Metastatic Gastrointestinal Stromal Tumor.
Linjia Zhou, Shumao Zhang, Wei Liu et al.
✦ AI-curated · Sources linked
Case in brief
An 80-year-old man with a biopsy-confirmed metastatic gastrointestinal stromal tumor underwent both 18F-FDG PET/CT and 68Ga-FAPI PET/CT imaging. The 18F-FDG PET/CT demonstrated significant uptake in perisplenic, right abdominal, and pelvic peritoneal implants, while the 68Ga-FAPI PET/CT revealed negligible uptake in the same areas. This discrepancy highlights the complexities in imaging for GIST.
What made this case unusual
The case is notable for the contrasting results between 18F-FDG PET/CT and 68Ga-FAPI PET/CT, with the latter showing negligible uptake despite the presence of active metastatic disease.
Diagnostic / clinical pearl
Clinicians should be aware that 68Ga-FAPI PET/CT may not always correlate with disease activity in gastrointestinal stromal tumors, as evidenced by this case.
Why it matters
Understanding the limitations of different imaging modalities is crucial for accurate assessment and management of metastatic GIST.