Corpus luteum cyst is a cyst which may develop secondary to inability of corpus luteum to regress after ovulation. The cystic-dilatation of remaining structure gives rise to corpus luteum cyst. Corpus luteum cysts are generally asymptomatic. However, it can cause tenderness and pain during menstruation. Severe pain can occur in case of ovarian torsion. Corpus luteum cysts are diagnosed on transvaginal ultrasound scan. These usually resolves on their own. Reference: https://www.verywellfamily.com/corpus-luteal-cyst-in-pregnancy-2758590 Image via: https://www.researchgate.net/publication/313790741_Gross_and_Histopathological_Study_of_the_Genitalia_in_Goats_1_Ovaries/figures?lo=1