Gross endometrium is a thickened and unevenly echogenic endometrium seen on ultrasound. This condition usually occurs in perimenopausal women with irregular menstruation. This is because of irregular shedding of the endometrium, or incomplete shedding of the endometrium, resulting in coexistence of the proliferative and secretory phases of the endometrium, resulting in uneven echogenicity of the endometrium on imaging. There are also endometrial polyps, which can also show abnormal endometrial echogenicity in the uterine cavity under ultrasound. In addition, after a medication abortion or an induced abortion, an uneven echogenic mass is seen in the uterine cavity on review. This is usually due to abnormal echogenicity of the endometrium caused by the accumulation of blood in the uterine cavity or residual detrusor tissue. Most of these patients have menstrual irregularities and irregular vaginal bleeding, which require appropriate treatment depending on the patient’s condition.