Postpartum degeneration of adenomyosis with diffuse cyst‐like changes and localized hemorrhage detected by sequential magnetic resonance imaging

Imaging and histological changes occurring in adenomyosis due to pregnancy are unclear. A 38‐year‐old nulliparous woman presented with dysmenorrhea and infertility. Pelvic magnetic resonance imaging (MRI) showed diffuse‐type adenomyosis. Following pregnancy by in vitro fertilization, she was hospitalized at 23 weeks of gestation due to fetal growth restriction and subsequently diagnosed with preeclampsia. A second MRI performed due to an elevated inflammatory response at 31 weeks of gestation detected no obvious degenerative findings. An emergency cesarean section was performed at 33 weeks of gestation because of nonreassuring fetal status. On postpartum day 2, she showed uterine tenderness with a dramatically elevated inflammatory response. A third MRI showed cyst‐like degenerations with hemorrhagic changes without abscess. By postpartum day 7, she was quickly relieved and discharged from the hospital. A fourth MRI at postpartum month 4 confirmed the disappearance of degenerations. This is the first report of imaging findings of early postpartum degeneration of adenomyosis.