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II./3.7.: Differential diagnosis
Adenomyosis leads to a differential dignostic problem if the uterine myoma is examined. However, the affected age group is older compared to the population of the myomatous patients. If befalls in a maternal (reproductive) aged female, infertility is also common. Occurance in infancy is also possible, thus ovarial function is not necessary to the development and persistance of adenomyosis (heritable?, developmental disorder?). Endometrial islands develop in the smooth muscle wall of the uterus which infiltrate the smooth muscle (the endometrial islands will be transplantated such as the endometriosis, but not in the abdominal cavity). After all, the rare cooccurence of the two diseases (adenomyosis and endometriosis) goes against this causal theory. Anglo-Saxon terminology: intramyometric cystic adenomyosis.
Symptoms can be parallel to the menstrual cycle:
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- dysmenorrhoea (uterine contraction pain – because of the wall infiltration),
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- however, symptoms might be independent of the cycle: metrorrhagia.
Accompanying polyp is not uncommon. Thickening of the real endometrium can be also accompanied. Its forms: diffuse and focal.
According to its localisation:
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- Submucous: muscle fibers infiltrated mucosa touches the endometrium directly.
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- Intramural: the deeply, in the uterine muscle localised uterine mucosal islands are distinct from the real endometrium.
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- External adenomyosis: endometrial islands are located under the peritoneal covering of the uterus. External adenomyosis can be caused by the adhesions of the adjacent peritoneum which is hard like a cartilage („frozen pelvis”) , and severe complains and symptoms are accompanied. The hormonal cycle is followed, remnants of cystic degeneration or bleedings can be included.
US-image: myomatosis develops mainly in the dorsal uterine wall, and thickens that. So much hyporeflective (smooth muscle part) as the myoma, but myomatosis is not circumscribed by virtue of its infiltrative nature, it has no capsule (pseudocapsule). Myomatosis often shows heterogeneous echoreflectivity: the endometrial islands are more echogeneous compared to the smooth muscle. Small cystic dilatation of the glandulae, hemorrhages are visible. Color Doppler technique also helps in the differentiation from the myomas.
The spatial resolution of CT is excellent, however, tissue differentiation ability is in the focus of imaging (!): the differentiation of the infiltrating mucosal islands in the uterine wall is the aim, and attenuation differences are less effective in CT imaging for that.
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Therefore, MRI is the best imaging method in adenomyosis. MRI is very trustworthy regarding its sensitivity and specificity. MRI image: similarly to the myoma – adenomyosis is usually hypointense compared to its environment, but it is not circumscribed. The junctional zone is often widened, high signal intense nodules can be included on T1/T2, similarly to the myometrium (cystic dilatation of heterotopic glandular islands – possibly dotted with the varied signal intensity of hemoglobin decomposition products). The myometrium might look striated (invasion of the basal endometrium). The focal type is hypointense on both T1 and T2, weakly circumscribed, no space occupying effect is present, it might osculate into the sorrounding structures, and it thickens the uterine wall only by its weight (mostly dorsal wall).
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