Mucinous cystadenomas are benign tumors that occur in the ovary, and are mainly named after the accumulation of large amounts of mucus secreted by the cells within the adenoma into a capsule. This condition often affects women between the ages of 40 and 70. Mucinous cystadenomas account for about 20% of ovarian tumors, and upon anatomical examination they are found to have a smooth surface and contain an immune fluid inside, appearing as a couch paste or jelly-like consistency. Very few of them are malignant, and most of them are benign. The adnexal area can be visualized by ultrasound imaging, and the presence of a well-defined oval or round echogenic area with smooth margins is diagnostic of the disease. If the tumor is found to be large or has malignant features, early diagnosis and treatment is required. Mucinous cystadenomas are mostly benign and should be treated promptly after discovery, with a generally good prognosis.