False-Positive 68Ga-Fibroblast Activation Protein-Specific Inhibitor Uptake of Benign Lymphoid Tissue in a Patient With Breast Cancer

Clin Nucl Med. 2021 Aug 1;46(8):e433-e435. doi: 10.1097/RLU.0000000000003594.


68Ga-fibroblast activation protein-specific inhibitor (FAPI)-04 PET/CT was performed in a patient with left lower outer quadrant breast cancer who had 18F-FDG PET/CT imaging. 68Ga-FAPI-04 PET/CT showed higher accumulation of radiotracer in primary tumor and axillary lymph nodes than 18F-FDG PET/CT. In addition, focal increased FAPI uptake was observed in another nodular lesion in the lower inner quadrant in the same breast, which was considered malignant. However, Tru-Cut biopsy of this lesion was reported as benign lymphoid tissue. This case showed that all FAPI accumulation in breast tissue should not be interpreted in favor of malignancy; histopathological confirmation is required.

Publication types

  • Case Reports

MeSH terms

  • Biological Transport
  • Breast Neoplasms / diagnostic imaging
  • Breast Neoplasms / metabolism*
  • False Positive Reactions
  • Female
  • Humans
  • Lymphocytes / metabolism*
  • Lymphocytes / pathology
  • Positron Emission Tomography Computed Tomography
  • Quinolines / metabolism*


  • 68Ga-FAPI
  • Quinolines