Study on the etiopathogenesis of multiple spongy necrosis of the pontine base in three autopsy cases.
The etiopathogenesis of multiple spongy necrosis (MSN) of the pontine base was analyzed by examining the spatial relationship with intra- and extrafascicular vascular structures by reconstruction of serial sections of nine lesions from three autopsy cases. All nine lesions in the fascicles were distributed without any spatial relationship to the intrafascicular vessels. Instead, these lesions were distributed in parallel with arterial and venous transverse main branches between the anteromedial and anterolateral groups of the pontine vessels. On the other hand, all lesions in the middle cerebellar peduncle were arranged obliquely along the arterial and venous main trunks of the lateral group vessels with sparing of the perivascular narrow zone of the white matter. Moreover, narrow fascicles, even though located in the dorsomedial region of the pontine base, which is consistently involved in MSN, were spared, and thick transverse and longitudinal fascicles were selectively involved. The marginal zone of fascicles was spared, and focal coagulation necrosis was sometimes found in MSN lesions. Additionally, normal fascicles did not have their own nutritional arteries, and were nourished by arterioles and capillaries from the surrounding pontine gray matter. Neither severe organic stenosis nor occlusion of pontine vessels was found. On the basis of the close topographical relationship of MSN lesions with the pontine vascular architecture in addition to preferential involvement of thick fascicles with sparing of the marginal zone and inclusion of focal coagulation necrosis, it is proposed that the etiopathogenesis of MSN is pontine ischemia on a background of the characteristic parenchymal and vascular architecture of the pontine base. As to the cause of the ischemia, it is proposed that some functional disorder such as arterial vasoconstriction in the pontine base or the vertebrobasilar artery is responsible, rather than organic changes in the vessels.
Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, Japan.
R
R
Okeda
T
T
Kuroiwa
N
N
Funata
Y
Y
Tanoi
D000230:Adenocarcinoma / Q000150:complications / Q000473:pathology; D000368:Aged; D001344:Autopsy; D018287:Carcinoma, Large Cell / Q000150:complications / Q000473:pathology; D002531:Cerebellum / Q000473:pathology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011149:Pons / Q000473:pathology*; D011553:Pseudomyxoma Peritonei / Q000150:complications / Q000473:pathology