A follicular cyst is a fluid-filled sac that forms on the ovary during the menstrual cycle. It develops when a follicle, which normally releases an egg, fails to do so and continues to grow. These cysts are usually benign and often resolve on their own within a few menstrual cycles. Most follicular cysts do not cause symptoms, but some may lead to pelvic pain or discomfort. They are commonly detected during routine pelvic exams or imaging tests. While they typically do not require treatment, monitoring may be necessary to ensure they do not cause complications.