Lacunes of the human brain are most often considered to represent microinfarcts but several experimental investigations favor the role of edema as an important pathogenetic factor in the formation of lacunes. We have observed 3 cases of Binswanger''s encephalopathy which, apart from typical lacunes, showed edematous lesions most likely representing developing lacunes. These edematous lesions differed from microinfarcts in their fewer number of macrophages, numerous hypertrophic astrocytes, less distinct demarcation from the surrounding tissue and the presence of a surrounding rim of edematous tissue. Our observations are in line with the hypothesis that focal chronic edema is an important pathogenetic factor in the formation of lacunes in Binswanger''s encephalopathy.