Large pelvic soft-tissue mass

Adenomyosis is a medical condition characterized by the growth of cells that build up the inside of the uterus (endometrium) atypically located within the cells that put up the uterine wall (myometrium), as a result, thickening of the uterus occurs. As well as being misplaced in patients with this condition, endometrial tissue is completely functional. [Source: Wikipedia ]