Parenchymal lesions in the uterine cavity may be endometrial polyps, uterine fibroids, endometrial cancer and other diseases. It is recommended to consult a doctor in time to find out the cause and treat it under the doctor’s guidance. 1. Endometrial polyps: endometrial polyps are caused by localized overgrowth of endometrial lining, which can be seen as substantial foci in the uterine cavity, manifesting as single or multiple smooth masses protruding from the uterine cavity. 2. Uterine fibroids: a common benign tumor in women, mostly formed by the proliferation of uterine smooth muscle cells. Submucous fibroids can be seen as substantial foci in the uterine cavity with clear boundaries. 3. Endometrial cancer: it is a kind of malignant tumor common in women, manifested by abnormal vaginal discharge or irregular bleeding. Examination of endometrial cancer shows abnormal thickening of endometrium or substantial lesions in the uterine cavity with unclear boundary. If the examination shows parenchymal lesions in the uterine cavity, it is recommended that the patient should consult the doctor in time and improve the relevant examination under the doctor’s guidance for targeted treatment.