Synonyms in a broader sense
Uterus myomatosus, intramural myoma, subserous myoma, submucous myoma
Definition
A myoma is a benign tumor that originates from the muscle layer of the uterus.
Frequency
It is estimated that approximately one in three women over the age of 30 is affected by a myoma. They are the most common benign tumors of the uterus – less than 0.5% of all myomas are malignant.
Cause
A definitive cause for the tumor formation could not be determined so far. However, it has been proven that the muscle cells are stimulated by the female sex hormone estrogen and therefore only reappear at childbearing age, i.e. between puberty and menopause (see also our topic on menopause). The structure of the uterus (S. Anatomy of the uterus) is divided into three layers: The inner cavity is lined by mucous membrane (mucosa), while the uterus is covered from the outside by a connective tissue skin (serosa).
Between these two layers lies the muscle layer, in which a myoma can occur. According to this nomenclature, the direction of spread of a myoma is divided into three forms:
- In so-called intramural growth (lat. : intra- inside, mura- the wall) the tumor spreads only within the thick muscle layer.
This type of growth occurs most frequently.
- The subserous (Latin: sub-lower, serosa-the connective tissue skin) myoma is characterized by an outward growth direction, towards the covering connective tissue skin. There is a risk that adjacent structures such as the ureters or vessels adjacent to the uterus may be pinched off.
- Submucous (lat. : sub -under, mucosa-the mucous membrane) growth is accompanied by an inward spread of the myoma towards the cavity of the uterus.
This form of growth is rather rare, but is particularly noticeable at an early stage due to bleeding anomalies.
Furthermore, all forms of myoma can change over time. This includes, for example, cavity formation (cystic remodeling) or hardening (calcification). Especially in the case of submucous myomas, there is a risk of ascending infections from the vagina due to their growth in the direction of the uterine cavity.
A subserous myoma is a parasitic myoma that grows into the peritoneum and is subsequently supplied with blood by the peritoneum. In all forms of growth, a so-called stalk formation is possible. In this case the actual tumor is only attached to its site of origin by a kind of connective tissue stalk. There is always the danger that, by rotating around its own axis, the vessels supplying the tumor are pinched off in the stalk, resulting in cell death within the myoma. In the so-called uterus myomatosus, the uterus is penetrated by numerous tumors, which usually leads to massive symptoms.
