[Autopsy findings of pontine lesions in the elderly]

The characteristics of multiple spongy necrosis of the basis pontis (MSN), central pontine myelinolysis (CPM), and cerebrovascular disease (CVD) of the pons developing in the elderly have not been fully clarified. We therefore studied 305 patients (aged 60-107, mean: 83.9) autopsied in Nagoya City Kohseiin Geriatric Hospital. MSN was found in four patients (1.3%). The major histologic finding was multiple necrosis of the basis pontis, characterized by loss of myelin and axons, no reactive astrocytes or inflammatory cells were found. Small foci of spongy necrosis appeared to unite with each other to form larger lesions. The central basis pontis was weakly stained by Klüver-Barrera stain in 15 patients, which suggested the presence of CPM. However, the diagnosis was only confirmed in one patient, (by the myelinolysis, loss of oligodendroglia, infiltration of macrophages, and reactive astrocytosis). With regard to CVD, none of the 305 patients had macroscopic pontine hemorrhage, but histologically small and old hemorrhagic lesions were found in 15. These lesions were associated with hypertensive or arteriosclerotic changes in the pontine vessels. Pontine infarction was evident in 77 patients (25.2%). In most lesions (74%) the area of infarction was smaller than 1 mm2. In 27 of the 74 patients with lacunar or microscopic infarcts, the pontine infarcts were found in areas where the blood was supplied through the short circumferential branch.