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Deep neural network (DNN) -based object detectors have achieved remarkable success, but recent research has revealed their vulnerability to backdoor attacks. The attacks cause the poisoned model to output results normally on benign images, but outputs results specified by the attacker on images inserted with a trigger. Although backdoor attacks have been extensively investigated on image classification tasks, their exploration in object detection tasks remains limited. With the increasing application of object detectors in safety-sensitive fields such as autonomous driving, backdoor attacks on object detection tasks may have serious consequences. Currently, strategies for object disappearance attack scenarios exhibit certain limitations. First, these strategies typically exhibit a one-to-one correspondence, implying that the insertion of one trigger can only result in the disappearance of one object. Second, these strategies typically necessitate the attacker’s knowledge of the object’s precise location information to achieve its disappearance, thereby rendering real-time insertion of triggers unfeasible. Finally, these strategies exhibit diminished attack success rates when applied to two-stage detectors. The paper presents a global object disappearance attack scenario and proposes a simple, covert, and highly effective attack strategy. Experimental evaluations are conducted on four widely-used object detection models (Yolov5s, Yolov8s, Faster R-CNN, and Libra R-CNN) using two benchmark datasets (PASCAL VOC $07+12$ and MS COCO2017) to validate the effectiveness of the proposed strategy. The results demonstrate that the success rate of this attack strategy exceeds 96%, while the poison rate is only 10%.

Polypoid lesions in the uterus are very common. There are a lot of benign lesions and malignant tumor should be considered. Adenosarcoma, one of the differential diagnoses, is a rare mixed epithelial and mesenchymal tumor consisting of benign epithelial components and sarcoma stroma. Here, we present a case of atypical adenosarcoma that has never been reported. This tumor was composed of benign endometrial epithelium and hyperplastic stroma with extensive bizarre stromal cells. But the cleft-like spaces and papillary stomal fronds which were the typical histological images of adenosarcoma were absent. These stomal cells, including bizarre cells, were positive for vimentin, CD10, ER, PR, cyclin D1 and P16 but were immunonegative for caldesmon. Furthermore, this tumor harbored amplification of MDM2, as revealed by fluorescence in situ hybridization testing (FISH) and next-generation DNA sequencing (NGS).