From the Radiopaedia.org reference article on uterine adenomyosis:

Adenomyosis is the pathological presence of endometrial glandular tissue in the context of the myometrium. Adenomyosis may be widespread (most common) or Cullen’s adenomyoma, large nodule fibro glandular with center blood, without capsule.

Adenomyosis, in addition to being responsible for menstrual disorders such as pain and uterine bleeding atypical, can lead to deformation and anomalous uterine growth, resulting in problems of fertility and pregnancy. Processes adenomiotici focal (localized adenomyosis) are individually identified with the term "adenomyoma".