UTERINE FIBROIDS (1): WHERE CAN THEY LOCATE?

Dr. Claude Allouche, gynecologist
Ahuza Clinic, Ra'anana
058 726 02 64

A fibroid is a benign tumor affecting the uterine muscle.

Depending on its location in the uterus, there are 3 types of fibroids, from the inside to the outside of the uterine body:
- submucosa.
- intramurals,
- subserosal

1/ Submucosal fibroma (or intra-cavitary fibroma):
It occupies the uterine cavity, grows inside the uterus and is covered by the endometrium (uterine lining).
In English "sub-mucous fibroid"
In Hebrew "shriran soubmukozi" שרירן סובמוקוזי
or "shriran tat-riri" שרירן תת רירי

 He can be:

- pedunculated (presenting an insertion foot)
 
- or sessile (presenting a wide base of implantation).
      * The submucosal component of sessile fibroids can be more or less important.

      *The weaker the submucosal component, the greater their interstitial component (type 0: pure intracavity; type 1: predominantly submucosal; type 2: predominantly interstitial).

2/ Intra-mural fibroma (or interstitial fibroma):
It grows inside the uterine muscle and can lead to the formation of a small bump in the wall of the uterus.
In English "intra-mural fibroid"
In Hebrew "shriran intramourali" שרירן אנטראמורלי
Or "shriran tokh-dofni" שרירן תוך דופני

The majority of fibroids are intramural.

3/ Subserous fibroid: The fibroid protrudes from the outer surface of the uterus and grows into the peritoneal cavity. Subserosal fibroids can be pedunculated (presenting an insertion foot) or sessile (presenting a wide implantation base).

In English: "sub-serous fibroid"
In Hebrew "shriran sub-serous" שרירן סובסרוס
or "shriran tat nesiouvi". שרירן תת נסיובי

4/ Other intrauterine locations:
More rarely, a fibroid can develop in the isthmus or in the cervix.

5/ ectopic locations
Very rarely they can also be localized

- at the level of the supporting ligaments of the uterus (broad ligaments, round ligaments)

- or in the ovaries.

- An international classification of fibroids according to their location in the uterus was created by FIGO in 2011 (International Federation of Gynecology and Obstetrics) in order to adapt surgical treatment if necessary.
Thus fibroids will be classified between 1 and 8 according to their location: (see diagram)

- Submucosa:
 0    Intra-cavity pedicle
 1    < 50% intramural
 2    ≥ 50% intramural

- Intramural or interstitial:
 3     100% intramural, in contact with the endometrium
 4      Intra-mural

- Subserous:
 5      Subserosal, ≥50% intramural
 6      Subserosal, <50% intramural
 7      Pedicled subserosal

- Others
 8      Other, parasite (cervical, round ligament, broad ligament)

- Hybrid (affecting both the endometrium and the serosa)
Two digits separated by a hyphen, the 1st, specifying the relationship with the endometrium, the 2nd with the serosa)

Example: 2-5 Hybrid, class 2 submucosa and class 5 subserous

The size of fibroids is very variable ranging from microscopic to several hundred grams. So is their number.

Indeed, the development of a single fibroid is possible but most often several appear at the same time.

Finally, in the majority of cases, fibroids form a mass within the uterine muscle or sometimes they are only connected to the muscle by a pedicle (pedunculated fibroids).