Abstract
Pathogenesis of splenomegaly in idiopathic portal hypertension (IPH) has not sufficiently been elucidated. By hemodynamic studies, it has been clarified that splenic blood flow of IPH is more increased than that of liver cirrhosis.
Histologically, a few papers have been presented about intrasplenic arterial changes in IPH, but correlation between these changes and portal hypertension was not fully revealed. The author morphologically examined arterial system of the spleens, especially that of white pulp, using the spleens resected from 17 cases of IPH, 19 cases of liver cirrhosis and 10 cases of gastric cancer as control.
The results obtained are summarized as follows.
1. In the trabecular arteries of IPH spleens luminal dilatation and intimal lamellar elastosis of hypertensive arteriolopathy were remarkable.
2. Around the central and follicular arteries of IPH spleens formation of cappillary net works accompanied by development of subendothelial elastic fibers was recognized.
3. These blood channels were inflowed from branches of follicular arteries and outflowed directly or via reticular tissue into adjacent sinuses, and these channels were covered with two types of endothelium: most of which resembled sinus lining cells and the others capillary endothelial cells.
4. These findings were observed in spleens of liver cirrhosis, but they were more infrequent and milder as compared with spleens of IPH, and not observed in control cases.
According to these results it was suggested that these newly formed cappillary net works in white pulps of IPH spleens are contributory to collateral pathway from the arterial system of white pulp to splenic sinuses under the conditions of both splenic arterial hypertension and increased splenic blood flow.
