Cerebral Ring Enhancing Lesions: Differential Diagnosis #15

Today's Daily Diff concerns cerebral ring enhancing lesions. The differential for this finding is fairly broad, and can have a significant impact on patient management. Having a brain metastasis is quite different from a resolving hematoma, no? To keep the various entities in mind, think of the phrase DR MAGIC. This is non-sensical, but if you see such a lesion, perhaps think of Magic Johnson having a Toxoplasma abscess, and um, he's a doctor now for some reason...

	Disease	Notes
D	Demyelinating disease
R	Radiation necrosis	Often incomplete C-shaped ring
M	Metastases	Thick, nodular wall
A	Abscess	Marked restriction on DWI; thin wall
G	Glioma	Thick, irregular wall if GBM
I	Infarct	Basal ganglia
C	Contusion	Resolving

Some people add L to the end of the mnemonic for lymphoma as well. Another entity to keep in mind, especially in certain patient populations, is neurocysticercosis, especially if there are other calcified lesions present.