Types of Fibroids

According to their position within the uterine wall, uterine fibroids are classified in four different types:

Subserosal Fibroids

Subserosal Fibroids.png

Subserosal Fibroids are located near the outer layer or serosa of the uterus.

Because they grow more towards the outside of the uterus, small subserosal fibroids are less likely to cause significant symptoms.

Small asymptomatic subserosal fibroids usually do not require any treatment and can be just monitored with regular ultrasounds. Larger fibroids can become symptomatic.

Typical Symptoms of Subserosal Fibroids:

- Heavy menstrual bleeding, caused by the larger size of the uterus.

- Pressure symptoms over nearby organs, most commonly the bladder (increased urinary frequency) and rectum (difficult motions/constipation).

Submucosal Fibroids

Submucosal Fibroids.png

Submucous fibroids grow towards the internal layer or mucosa of the uterus and protrude into the uterine cavity.

They tend to be symptomatic at smaller sizes, the main symptom being heavy and irregular bleeding.

Submucous fibroids are also more likely to impact fertility, both by making it difficult to fall pregnant and by causing miscarriages.

Submucous fibroids can be removed through a hysteroscopy, a very non-invasive method and consideration for removal should be done early, as soon as they are diagnosed.

Intramural Fibroids

Intramural Fibroids.png

Intramural fibroids are located predominantly within the width of the uterine muscle or myometrium.

They tend to behave like subserous fibroids, but depending on their size and position, can cause all the usual symptoms associated with fibroids:

- Heavy bleeding or extended periods

- Bleeding between menstrual cycle

- Pressure syomtoms

- Infertility and miscarriages

Pedunculated Fibroids

Pedunculated Fibroids.png

Pedunculated fibroids are not considered different from the types above, but a variation of subseroral or submucosal fibroids.

They grow on a stalk out of the uterine  walls, outside(subserosal) or inside(submucosal) the uterus.   

Pedunculated subserosal fibroids usually have very mild symptoms unless they are very large. Pedunculated submucosal fibroids on the other hand, can have significant symptoms and very often cause infertility.

This classification of the types of fibroids is not perfect and is limited by the fact that most fibroids are big enough to fall into at least two and sometimes three categories. It helps clinicians make the diagnosis and plan treatment. The treatment is usually based on the predominant aspect of the fibroid, i.e. an intramural fibroid with a significant submucosal portion can be treated by hysteroscopy; an intramural/subserosal fibroid with no submucosal component would require a laparoscopy for removal.