Presentation
Symptoms of raised intracranial pressure with fever.
Patient Data
Well-circumscribed, lobulated right frontal mass of low signal on T1, intermediate to low signal on FLAIR, and high signal on T2 with restricted diffusion and thin peripheral enhancing rim of uniform thickness on postcontrast sequences. Perilesional vasogenic edema with mass effect on the midline structures and subfalcine herniation.
Postoperative hemorrhagic area is noted, located posterior to the frontal mass (failed attempts at surgical drainage).
Intact posterior table of the right frontal sinus which may exclude the possibility to direct infection from sinusitis.
Case Discussion
The clinical presentation and the MRI features are most consistent with brain abscess (confirmed at surgery).
When a lesion demonstrates both ring enhancement and central restricted diffusion the differential is very much narrowed, and although brain abscess is by far the most likely diagnosis.