Bone metastases with “false negative” findings on 18F-FDG PET/CT in patients with angiosarcoma: A case series with literature review

Figure 1.. A 39-year-old woman was diagnosed with angiosarcoma of the breast and underwent mastectomy. One year after the surgery, she noticed worsening right coxalgia. On axial Gd-enhanced magnetic resonance imaging (MRI), multiple bone lesions in bilateral acetabulum (A) and the left ischium (B) (yellow arrows) strongly suggested bone metastases. However, axial fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) showed neither osteolytic destruction nor abnormal uptake around the bilateral acetabulum (C) and the left ischium (D) (yellow arrowheads). Maximum intensity projection also suggested no findings of bone metastases (E).

Figure 2.. Hematoxylin and eosin stained specimen (×400) collected by open biopsy of the left ischiatic lesion revealed irregularly formed vascular channels covered by atypical endothelial cells, which is consistent with the metastasis of primary angiosarcoma of the breast.

Figure 3.. A 37-year-old woman was diagnosed with primary angiosarcoma of the breast and underwent mastectomy. During the postoperative follow-up, although the uptake was covered by the heart in the maximum intensity projection image (A), axial fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) revealed abnormal uptake (SUVmax = 3.1) in the left third intercostal muscle (yellow arrow) (B). Gd-enhanced magnetic resonance imaging (MRI) also showed soft tissue mass in the left intercostal muscle (yellow arrow) in the axial image, suggesting local recurrence (C). Furthermore, axial Gd-enhanced MRI showed a 13-mm (diameter) contrast effect in the sternum (yellow arrow) (E), which suggested bone metastasis. Contrary to these findings, axial 18F-FDG PET/CT showed no uptake or osteolytic destruction in the sternum (D). SUV = standardized uptake value.

Figure 4.. Axial enhanced computed tomography (CT) suggested a 20-mm contrast-impaired area in S5/6 of the liver (yellow arrow). Liver biopsy revealed that this lesion was consistent with angiosarcoma metastasis.

Figure 5.. Sagittal Gd-enhanced magnetic resonance imaging (MRI) showed prolonged contrast effects in the sternum and the fifth thoracic vertebra (yellow arrows), suggesting multiple bone metastases (A). However, sagittal fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) found no uptake or osteolytic destruction (yellow arrowheads), which is inconsistent with the MRI findings (B).