[A case of adenomyosis showing multiple large cysts on MR imaging]

Adenomyosis is a condition characterized by benign invasion of the endometrium into the myometrium associated with reactive hypertrophy of the surrounding musculature. The ectopic endometrium in adenomyosis is of the basalis type, and menstrual bleeding is less common than in endometriosis. We report a rare case of adenomyosis that had multiple, large, adenomyotic cysts. These cysts were located in the outer layer of adenomyosis on MR imaging. Pathologic features consisted of blood-filled cysts of 1 cm to 5 cm in maximum diameter of the functioning endometrial type.