Pathological studies on cerebral amyloid angiopathy, senile plaques and amyloid deposition in visceral organs in aged dogs.

The relationship between cerebral lesions such as amyloid angiopathy or senile plaques and amyloid deposition in the visceral organs were studied in 90 autopsy cases of dogs, 0 to 19-year-old. Cerebral amyloid angiopathy was detected in 28 aged dogs (mean age: 13.7-year-old) and was found mostly in or around the wall of cerebral meningeal arterioles and capillaries of the neocortex. That condition was often accompanied by cerebral hemorrhage in dogs more than 9 years of age. Senile plaques were detected in the neocortex of the brain of 12 dogs (mean age: 13.2-year-old) and classified into 3 subtypes, i.e., "diffuse plaque", "primitive plaque" and "classical plaque". Among those 3 subtypes of senile plaques, amyloid containing plaques were small in number. In the visceral organs of dogs with cerebral amyloid angiopathy, amyloid deposition was found in the vascular walls or connective tissues of small intestines at a high frequency and sometimes in the vascular walls of the heart, lung, liver and thyroid gland as well as in atrioventricular valves. Amyloid in both cerebral and visceral organs was congophilic and showed green birefringence under poralized light even after potassium permanganate oxidation.