Submucosal fibroids: what are they, symptoms and treatment

• Submucosal fibroids are uterine fibroids that form in the innermost layer of the uterus.
• The symptoms of submucous fibroids are the most severe in terms of vaginal bleeding due to their location.
• To remove symptomatic submucous fibroids, the most commonly used surgical technique is surgical hysteroscopy.

Uterine fibroids are benign tumours that form in the uterus, most of which cause a series of characteristic symptoms. 

There are different types of fibroids depending on the layer of the uterus where they form: subserosal fibroids are those that form under the outermost layer of the uterus (serous layer); intramural fibroids are those that form in the wall of the uterus, the intermediate layer; and submucosal fibroids are those that form under the mucous membrane that lines the inside of the uterus.

Submucous fibroids are the type of uterine fibroid that presents the most serious and important symptoms of all those that can occur, although it must be said that it is also the least common. The following is key information for understanding submucous fibroids.

The endometrium is the innermost layer of the uterus. This mucous layer grows during each menstrual period with the intention of harbouring the embryo that would form if the woman were to become pregnant. 

When this does not happen, the endometrium sheds and sheds, producing the bleeding known as menstruation, leaving only a thin mucous layer of endometrium that will grow again during the next menstrual cycle.

As mentioned briefly in the previous section, submucosal fibroids are the type of fibroid that causes the most severe haemorrhagic symptoms compared to the others. These include a prolongation of the woman's menstrual cycles, an increase in the intensity and quantity of bleeding, as well as the appearance of these haemorrhages during intermenstrual periods.

Because of this abnormal bleeding, it is common for some patients to suffer from chronic anaemia or iron deficiency anaemia due to blood loss.

Similarly, infertility is a common, but not obligatory, symptom in women who have uterine fibroids, whether submucous or otherwise. 

This is mainly due to the anatomical, content and functional alterations that the uterus undergoes as a result of these benign tumours, preventing the gametes (sperm and egg) from joining, the zygote (egg fertilised by a sperm) from clinging to the walls of the uterus or sufficient blood from reaching the uterus, among other things.

Submucosal fibroids are not really classified by size, as they are usually classified according to the amount of uterus they occupy. 

The following is Labastida's classification of fibroids:

• Type 1: Pedunculated fibroids: they are attached to the uterus only by a stalk.
• Type 2: Sessile fibroids: in this case, they are attached to the uterus by a much wider base than pedunculated fibroids.
• Type 3: Fibroids that occupy 1/3 of the volume of the interior of the uterus.
• Type 4: Fibroids that occupy 50% of the volume of the interior of the uterus.
• Type 5: Fibroids that occupy at least 2/3 of the volume of the interior of the uterus.

Depending on the size of the submucosal fibroids, the surgeon will choose one or another surgical technique to perform the removal or, if they do not cause symptoms, in the case of submucous fibroids it is rare that they are asymptomatic, the surgeon may proceed to wait until the problems begin.

There is also another type of classification of submucous myomas in which, depending on the amount of uterine cavity occupied by the submucous myoma, it can be divided into 3 grades:

• Grade 0: In this grade, the submucous myoma occupies more than 75% of the uterine cavity.
• Grade 1: Fibroids occupy between 50% and 75% of the uterine cavity.
• Grade 2: These types of fibroids are those that occupy less than 50% of the uterine cavity.

Submucosal fibroids are usually removed using surgical hysteroscopy, as they form under and grow into the uterine cavity, it is easier, more comfortable and safer to remove them using a hysteroscope with a resectoscope through a vaginal approach.

This surgical hysteroscopy allows the surgeon to remove symptomatic submucosal fibroids with an outpatient operation in most cases, requiring only spinal anaesthesia and sedation. 

Sometimes the operation is carried out in the doctor's surgery itself, but at Operarme, for example, we always perform the operation in the operating theatre to ensure maximum safety and avoid possible infections.