Microscopic Description -- A 67 Year Old Man in Coma Requiring Prolonged Mechanical Ventilation


The brain showed Alzheimer's Disease changes, diffuse Lewy body disease, slight Wallerian degeneration in the brain stem and multiple recent small infarcts in the left frontal lobe and bilateral basal ganglia. No features of respirator brain were apparent.

In the adenohypophysis a large central area of pallor occupied about 85% of the anterior lobe (Figs. 1 and 2). In this area the cell borders were not recognizable, there was no nuclear staining and using the streptavidin-biotin-peroxidase complex method no immunoreactivity could be detected for the adenohypophysial hormones. However, in several places focal chromogranin and synaptophysin immunopositivity (Fig. 3) was noted indicating that these endocrine markers persisted in the altered area. A peripheral rim of viable adenohypophysial parenchyma consisting of 5-6 rows of adenohypophysial cells (Fig. 2) showed immunopositivity for the pituitary hormones including growth hormone (Fig. 4) and alpha subunit (Fig. 5). An intervening zone was identified which consisted of lymphocytes, large macrophages possessing vacuolated cytoplasm, fibroblasts and occasional leukocytes as demonstrated with a CD 68 immunostain (Fig. 6). Many capillaries were present in this zone growing into the core. Immunostaining for CD-34 (Fig. 7) demonstrated the endothelial lining of the capillaries, which were in many places large, dilated and irregular.

The posterior pituitary showed no histologic abnormalities.


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