What does marrow edema or focal osseous lesion mean on an mri?

Marrow edema: means abnormal fluid or swelling in the bone marrow. This is a nonspecific finding in and of itself, and can be due to numerous causes spanning the mundane to the malignant. Focal osseous lesion is also a generic descriptor of a focal abnormality of bone. It doesn't imply either benign or malignant. You need to talk to your doctor about it,