A lesion is a circumscribed area of tissue damage in the body.
The word 'lesion' is non-specific and does not specify what is causing the problem.
Management of Focal Chondral Lesion in the Knee Joint. Seo S-S, Kim C-W and Jung D-W. Knee Surg Relat Res. 2011 Dec; 23(4): 185–196.