Uterine leiomyoma: Clinical sciences

Uterine leiomyomas, also known as fibroids, are benign, solid neoplasms made up of smooth muscle cells and fibroblasts. They can vary in size and location in the uterus, including intramural that are found within the width of the myometrium; submucosal that grow towards the mucosa of the uterus; subserosal that are found near the outer layer or serosa of the uterus; and pedunculated fibroids that grow on a stalk out of the uterine walls, either inside and outside the uterus.

Uterine leiomyomas are very common, and the majority of women have at least one by menopause. They are often asymptomatic, but symptomatic leiomyomas can cause a variety of issues, such as heavy bleeding and pelvic pressure or pain. In fact, leiomyoma is one of the important causes of abnormal uterine bleeding or heavy menstrual bleeding, which can be easily remembered with the mnemonic PALM COEIN. This stands for Polyps, Adenomyosis, Leiomyoma, Malignancy, Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, and Not yet classified. Additionally, leiomyomas can cause infertility in some patients, and depending on their location in the uterus, they can even be associated with recurrent pregnancy loss.

When assessing a patient who presents with a chief concern suggesting they have a uterine leiomyoma, your first step is to obtain a focused history and physical. Patients may report prolonged or heavy menstrual bleeding; anemia; or symptoms of uterine enlargement such as pelvic pressure or pain, urinary frequency, and constipation. While obtaining a history, pay attention to certain risk factors for uterine leiomyomas, such as premenopausal status, a family history of leiomyomas, increasing interval since last birth, hypertension, and obesity. On a physical exam you may note an enlarged uterus or an irregular uterine contour.

Here’s a clinical pearl! Black individuals have a 2 to 3 times higher rate of having uterine leiomyomas compared to white individuals. Due to racial disparities and social determinants of health, black patients also develop leiomyomas earlier and have worse clinical symptoms including higher rates of anemia and larger uteri at the time of diagnosis.

Now, back to your patient! Based on your history and physical exam findings, you should suspect uterine leiomyoma and order a pelvic ultrasound. If there is no evidence of a leiomyoma on ultrasound, you should consider an alternative diagnosis. Since there are multiple types of leiomyomas, ultrasound findings can vary, but generally, you’ll see a smooth and regular myometrial mass.

Let's talk about the different types of leiomyomas. The International Federation of Gynecology and Obstetrics, or FIGO, created a standardized leiomyoma subclassification system that’s used to describe the location of leiomyomas in the uterus. Submucosal leiomyomas are numbered 0 to 2. Category 0 is intracavitary pedunculated, category 1 is less than 50% intramural and category 2 greater than or equal to 50% intramural. Categories 3 and 4 are both intramural but 3 contacts the endometrium. Subserosal leiomyomas are numbered 5 to 7: category 5 is greater than or equal to 50% intramural, category 6 is less than 50% intramural and category 7 is subserosal pedunculated. Category 8 encompasses others, which includes cervical leiomyomas. Keep in mind that you can also have a leiomyoma that prolapses through the cervix!

Here’s another clinical pearl! A standard pelvic ultrasound is a helpful tool, but it can be hard to distinguish all the categories of leiomyomas. A subserosal pedunculated leiomyoma is generally best diagnosed with a pelvic ultrasound, while others need further workup. If you are suspicious of a submucosal leiomyoma, a sonohysterogram can be a useful tool. This is performed by injecting a small amount of saline into the uterine cavity during a transvaginal ultrasound to open up the endometrial cavity and inspect the contours of the endometrium. Hysteroscopy, where a camera is inserted into the endometrial cavity along with saline, can be used to visually diagnose and treat submucosal leiomyomas too. An MRI can be used for surgical planning to map out a large fibroid uterus.

Okay, now that you’ve diagnosed leiomyoma, let's talk about treatment options! The main categories for management are expectant, medical, procedural, and surgical. It's important to discuss all the options with your patient and make a treatment plan based on your patient's goals.