eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2017-08-16 5 8 199 201 10.12691/ajmcr-5-8-1 AJMCR2017581 article Farate A abu.farati@gmail.com 1 Yunusa GH 2 Umar UH 2 Ahmadu MS 2 Mustapha Z 2 Ahidjo A 2 Department of Radiology, University of Maiduguri Teaching Hospital, Maiduguri, Borno State, Nigeria Department of Radiology, Usmanu Danfodio University Teaching Hospital, Sokoto, Sokoto State, Nigeria This report presents the “penumbra sign” of Brodie’s abscess in a 17-year-old boy. The lesion was located in the proximal metaphysis of the left tibia. Histologic and microbiologic confirmation of the diagnosis was made. A “penumbra sign” on non-contrast enhanced T1-weighted magnetic resonance images is a helpful diagnostic sign of Brodie’s abscess. http://pubs.sciepub.com/ajmcr/5/8/1/ajmcr-5-8-1.pdf Brodie's abscess magnetic resonance imaging penumbra sign