Positive FAPI PET/CT in a Bilateral Mammary Angiosarcoma Patient With Less Impressive FDG PET/CT Images

Abstract

Bilateral primary angiosarcoma of the breast is an extremely rare disease. We describe a case with bilateral angiosarcoma of the breast well visualized on 68Ga-FAPI PET/CT in a 30-year-old woman with a history of right breast–conserving surgery. However, the lesions are less impressive on 18F-FDG PET/CT. No additional findings including lymph node and distant metastases were noted. The patient underwent bilateral mastectomy, and histopathology revealed well-differentiated angiosarcoma that involved bilateral breast parenchyma and the left nipple. Our case illustrates that 68Ga-FAPI PET/CT can be more sensitive in detecting well-differentiated angiosarcoma of the breast.

Comparison of 18F-FDG and 18F-FAPI PET/CT Findings of Signet-Ring Cell Carcinoma of the Stomach

“…Especially, a few reports 10–12 have shown that FAPI PET/CT has much higher sensitivity than FDG PET/CT in the evaluation of signet-ring cell carcinoma. Our case further strengthened the notion that FAPI PET/CT could potentially better than FDG PET/CT in the diagnosis, staging and determining therapy response in a variety of different malignancies 13–23 …”

PET-CT in Clinical Adult Oncology—VI. Primary Cutaneous Cancer, Sarcomas and Neuroendocrine Tumors

“…FDG PET-CT may play a role in the management of leiomyosarcoma. There is evidence that higher degrees of metabolic activity are associated with higher-grade and larger tumors and with worse prognoses [ 72 , 73 , 74 ]. The role of FDG PET-CT in the surveillance and therapeutic assessment of leiomyosarcomas has not yet been established.…”

“…Angiosarcomas of the heart or great vessels often metastasize by hematogenous spread, most particularly to vascular beds downstream from the site of origin ( Figure 18 ). However, some of these tumors are more well-differentiated and can exhibit lower metabolic activity [ 74 ]. FDG PET-CT has been reported to show lower activity with cardiac lymphoma than with cardiac angiosarcoma [ 75 ].…”

Complex Fibroadenoma Mimicking Breast Cancer on 68Ga-FAPI-04 and 18F-FDG PET/CT

“…1-4 68 Ga-FAPI PET/CT has been positive in many primary breast malignancies and may also be positive in many nonmalignant lesions or diseases. [5][6][7][8][9][10][11][12] Although varying levels of FAP positivity are observed in breast cancer, it has been reported that little or no expression is detected in epithelial cells of simple fibroadenoma, benign proliferative breast disease, and normal breast. 13 Similarly, in the study of Lan et al, it was determined that 68 Ga-FAPI-04 PET/CT did not show a significantly higher SUV max than 18 F-FDG PET/CT for all 145 nononcological lesions.…”

“…Fibroadenomas include histological variants that exhibit distinct histological features and variations in their clinicopathological features, including cellular, juvenile, and complex fibroadenomas. Various radiopharmaceuticals have been reported to show varying degrees of uptake in fibroadenoma.1-4 68 Ga-FAPI PET/CT has been positive in many primary breast malignancies and may also be positive in many nonmalignant lesions or diseases [5][6][7][8][9][10][11][12]. Although varying levels of FAP positivity are observed in breast cancer, it has been reported that little or no expression is detected in epithelial cells of simple fibroadenoma, benign proliferative breast disease, and normal breast 13.…”