18 F-FDG Uptake Outperforms 68 Ga-FAP-2286 in Metaplastic Breast Carcinoma.

Metaplastic breast carcinoma is a rare, aggressive malignancy that most commonly exhibits a triple-negative phenotype; its clinical, pathologic, and imaging diagnosis can be challenging, and treatment outcomes and prognosis are generally poor. Here, we report the discrepant imaging findings on 18 F-FDG PET/CT and 68 Ga-FAP-2286 PET/CT in a 47-year-old woman with metaplastic carcinoma of the breast with mesenchymal differentiation and pulmonary and lymph node metastases: tracer uptake in both the primary lesion and metastatic sites was markedly higher on 18 F-FDG PET/CT than on the corresponding 68 Ga-FAP-2286 PET/CT.