The patient is a 31-year-old woman, currently 33 weeks pregnant. She was referred to our hospital due to fetal growth retardation. Transabdominal ultrasonography revealed an 8-cm spherical mass within the placenta. The next step is to undergo an MRI examination to confirm the diagnosis, following which a treatment strategy will be decided upon. If the lesion is determined to be benign and can be managed with regular follow-ups, what specific findings would be observed on the MRI?