Fig. 5

a Images in a 44-year-old male with ccRCC demonstrate the primary lesion in the left kidney (red arrows) with SUVmax of 3.0, WHO/ISUP grade 2, and left renal vein tumor thrombus (purple arrows) with SUVmax of 2.6 (left image: anterior maximum intensity projection image obtained at ¹⁸F-FDG PET; right upper image: axial fused PET/CT image of primary lesion; right middle image: axial fused PET/CT image of renal vein tumor thrombus; right lower image: H&E result of primary lesion). No distant metastasis was identified. The patient remained in the state of disease-free survival after the radical nephrectomy with tumor thrombectomy with a follow-up of 29 months. b Images in a 64-year-old male with ccRCC demonstrate the primary lesion in the left kidney (red arrows) with SUVmax of 12.1, WHO/ISUP grade 3, and vein tumor thrombus above hepatic veins (purple and green arrows) with SUVmax of 11.5 (left image: anterior maximum intensity projection image obtained at ¹⁸F-FDG PET; right upper image: axial fused PET/CT image of primary lesion; right middle image: axial fused PET/CT image of vein tumor thrombus; right lower image: H&E result of primary lesion). Left lumbar vein tumor thrombus was also observed. The patient progressed after the radical nephrectomy and removal of inferior vena cava thrombus with a follow-up of 3 months