MRI OF POSTERIOR KNEE MASSES

A wide variety of masses may be visualized in the posterior knee. Some are encountered incidentally on MRI obtained for seemingly unrelated symptoms; others are palpable and present for MRI characterization. We describe the appearance, significance and pathophysiology of some of the most common lesions found in the popliteal fossa as well as severa l of the less common entities we have encountered. Thorough understand ing of the appearance and location of the more specific masses should augment precise diagnosis in a majority of cases. In turn, this will e liminate unnecessary additional investigations and enable prompt and a ppropriate treatment.