What is the characteristic finding in adenomyosis?

Adenomyosis is characterized by the presence of endometrial tissue, which includes glands and stroma, located within the myometrium, the muscular layer of the uterus. This abnormal growth of endometrial cells leads to a thickening of the uterine wall and often results in symptoms such as heavy menstrual bleeding and pelvic pain. The pathological finding of endometrial glands in the myometrium is considered definitive for the diagnosis of adenomyosis.

The irregular shape of the uterus can be associated with conditions like uterine fibroids or structural abnormalities, but in adenomyosis, the uterus may be more diffusely enlarged rather than irregular. In many cases, the uterus is enlarged, so a characteristic finding would not be an unchanged size. Estrogen levels and other hormonal parameters can be influenced by adenomyosis but are not definitive diagnostic criteria like the histological finding of endometrial glands within the myometrium.