case_images: PMC11291220_01
case_images: (A) Low power view of right breast phyllodes tumor showing cellular leafy fronds composed of benign glands in cellular stroma. (B) High power view of right breast phyllodes tumor showing crowding of atypical stromal cells with frequent mitoses (up to 35 mitoses per 10 high power fields) including atypical forms. Grading is challenging in this case given that all features of malignancy are not identified; however, the overall features favored malignant phyllodes tumor in this case. (C) Core biopsy of left breast showing a fibroepithelial lesion with mild stromal cellularity. (D) Higher power view of left breast core biopsy showing benign glands with small amounts of intervening stroma. The features are compatible with fibroadenoma with some features raising the possibility of tubular adenoma. (E) Excision specimen of left breast lesion showing a well-circumscribed fibroepithelial lesion with clip site changes located on the left of the lesion. (F) Higher power view of left breast excision specimen demonstrates small round glands with variable amounts of mildly cellular stroma, in keeping with fibroadenoma.
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case_images: The pathology report revealed a 3.2 cm malignant phyllodes tumor with positive margins ( Figures 1A, B ). A core biopsy was taken from the largest lesion in the left breast visible on MRI ( Figures 1C, D ). Final pathology agreed that the excised lesion was a benign fibroadenoma ( Figures 1E, F ), indicating a false-positive MRI finding and consequent overtreatment.
case_images: 3D-MIP breast MRI showing bilateral enhancing lesions.
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case_images: T1-weighted imaging sequences. The DCE sequence included a pre-contrast scan and four post-contrast scans. To minimize the enhancement of benign breast parenchyma, the MRI examination was scheduled during the second week of the menstrual cycle. The images displayed multiple enhanced masses bilaterally, classified as bi-rads 4 ( Figure 2 ).
case_images: MLO views of left (A) and right (B) breast acquired with Radialis PET Imager showing no regions of focal 18F-FDG uptake.
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case_images: Positron Emission Mammography Imaging of Suspicious Breast Abnormalities" (research ethics board no. #18-5029). 79 days after the right-sided surgical excision, the patient was assigned to low-dose (37 MBq) FDG-PET breast imaging. 1 hour after injection, images in the craniocaudal (CC) and mediolateral oblique (MLO) views were acquired using the Radialis PET Imager ( Figure 3 ). PET images showed no regions of increased 18F-FDG uptake, suggesting no malignancy in either breast.
case_images: Timeline of the presented case.
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case_images: The timeline of the presented case is shown in  Figure 4 .