Adenomyoma is a tumor ("-oma") including components derived from glands ("adeno-") and muscle ("-my-"). It is a type of complex and mixed tumor.

In obstetrics and gynecology contexts, it is a form of adenomyosis that forms a mass or growth around the tissue of the inner uterus.

Most cases of adenomyosis are non-symptomatic. However, it may present with dysmenorrhea and pelvic pain. In the case of juvenile cystic adenomyoma, laparoscopic enucleation results in a statistically and clinically significant reduction in dysmenorrhea, ease in any chronic pelvic pain, and low risk of recurrence.

Adenomyosis can only be cured definitively with surgical removal of the uterus. As adenomyosis is responsive to reproductive hormones, it reasonably abates following menopause when these hormones decrease. In women in their reproductive years, adenomyosis can typically be managed with the goals to provide pain relief, to restrict progression of the process, and to reduce significant menstrual bleeding.

Broadly speaking, surgical management of adenomyosis is split into two categories: uterine-sparing and non-uterine-sparing procedures. Uterine-sparing procedures are surgical operations that do not include surgical removal of the uterus. Some uterine-sparing procedures have the benefit of improving fertility or retaining the ability to carry a pregnancy to term. In contrast, some uterine-sparing procedures worsen fertility or even result in complete sterility. The impact of each procedure on a woman's fertility is of particular concern and typically guides the selection. Non-uterine-sparing procedures, by definition, include surgical removal of the uterus and consequently they will all result in complete sterility.

Atypical polypoid adenomyoma, abbreviated APA, is a rare uncommon benign tumour of the uterus.

APAs are characterized by glands with abnormal shapes that: (1) often have squamous metaplasia, and (2) are surrounded by benign smooth muscle. Nuclear atypia, if present, is mild.

The microscopic differential diagnosis includes endometrial carcinoma and endocervical adenocarcinoma.