A cystic mass in the left adnexal region is 3 mm (millimeters) larger in two months and is not serious if the cyst is less than 4 to 5 centimeters. Most of the cystic masses in the left adnexal area are benign changes, which are common benign pelvic swellings, with physiologic and pathologic changes. Physiologic changes are mainly manifested as corpus luteum cysts, most of which are relatively small and usually disappear on their own after menstruation and do not require treatment. If the left adnexal cystic mass has existed for a long time, and the mass is not big, it can be treated without treatment, and regular ultrasound review can be done. The left adnexal cystic mass has increased by 3mm in two months, and the time of the examination is also related to a certain degree, and it is recommended that ultrasound be done in 3-7 days after menstruation is clean, and the conclusions will be more accurate. The left adnexal cystic mass needs to go to the hospital for regular checkups and closely observe the progress of the mass.