Adenomyoma is a tumor (-oma) including components derived from glands (adeno-) and muscle (-my-). It is a type of complex and mixed tumor, and several variants have been described in the medical literature. Uterine adenomyoma, the localized form of uterine adenomyosis, is a tumor composed of endometrial gland tissue and smooth muscle in the myometrium. Adenomyomas containing endometrial glands are also found outside of the uterus, most commonly on the uterine adnexa but can also develop at distant sites outside of the pelvis. Gallbladder adenomyoma, the localized form of adenomyomatosis, is a polypoid tumor in the gallbladder composed of hyperplastic mucosal epithelium and muscularis propria.