The uterine corpus makes up the majority of the uterus by size and weight. It is the portion of the uterus superior to the internal cervical os bordered laterally by the broad ligaments. The uterine corpus does not include the fallopian tubes, ligamentous structures, cervix, or ovaries. The uterine cavity is a potential space that undergoes remarkable changes over the course of the menstrual cycle and pregnancy. From the inner lining of the uterine cavity moving outward, the corpus is composed of 3 layers: the endometrium, the myometrium, and the serosal layer (perimetrium). This chapter will focus on disorders of the uterine corpus. The normal uterine corpus is outside of the scope of this chapter; however, an understanding of normal anatomy, embryology, physiology, and histology of the corpus is paramount to understanding uterine pathology. These topics are addressed in depth in “Anatomy of the Female Reproductive Tract,” “Embryology of the Urogenital System and Congenital Anomalies,” and “Physiology of Reproduction in Women,” respectively.
Uterine leiomyomas (also referred to fibroids or myomas) are benign monoclonal growths of the smooth muscle cell of the uterine wall. Myomas are the most common tumor of the female reproductive tract, with a prevalence as high as 70–80% in select populations. However, in the United States, rates are not as high. Leiomyomas are found more frequently in the African-American population, with 60% of women having a fibroid uterus by age 50. In Caucasian women, the rate is considerably lower, with 40% of Caucasian women having fibroids by age 50, and of these patients, 70% will have multiple fibroids. Of this large percentage of women with myomas seen on ultrasounds, only 20–50% ever become symptomatic. Despite this, myomas are still the most common reason for hysterectomy in the United States, accounting for almost 40% of the 600,000 hysterectomies annually.
Myomas are associated with a wide range of symptoms depending on their size and location. It is not uncommon for patients to report symptoms of abnormal uterine bleeding (AUB), heavy menstrual bleeding (HMB), dysmenorrhea, dyspareunia with deep penetration, pelvic pressure, infertility, and recurrent pregnancy loss. AUB and HMB are the most common complaints in women with symptomatic myomas. Less frequently, patients have symptoms of mass effect such as difficulty with urination, constipation, and numerous other abdominal complaints due to local compression from large or metastatic fibroids.
Approximately 7–14% of women in the United States have symptomatic uterine fibroids. The incidence of symptomatic cases of fibroids increases with age. As previously noted, the actual occurrence in the United States is around 40–60%, depending on the study population. Furthermore, these benign lesions have significant health care implications, accounting for $5.9 to $34.4 billion annually in in the United States for medical and surgical management. The frequency of leiomyomas and their significant impact on a patient’s ...