Fig 3.

Histologic samples obtained in a 79-year-old woman.

A, Coronal section of the middle portion of the OT shows the cerebral peduncle (CP) (hematoxylin-eosin stain, original magnification ×20) Along the OT, a large 1.5-mm-high space has a pial layer (thin arrow) that lines its inner surface. Vessels (thick arrows) are present in the space, and no necrotic or ischemic changes are visible in the surrounding brain tissue. The histologic features are compatible with those of PV spaces around the anterior commissure shown in B. Small spaces (arrowheads) are present adjacent to the OT.

B, Coronal section at the anterior commissure (AC) and the lower basal ganglia shows multiple PV spaces (hematoxylin-eosin stain, original magnification × 40). Adjacent to the anterior commissure are multiple PV spaces with vessels lined by a pial layer (arrows). No necrotic or ischemic changes are visible in the surrounding brain tissue.