Scanning electron microscopic observation of the splenic sinus in idiopathic portal hypertension.

Based on analysis of hemodynamic state, it has been assumed that splenic blood flow in idiopathic portal hypertension (IPH) is elevated. The author examined by scanning electron microscopy the sinuses of spleens resected from 3 patients with IPH, as well as from 10 patients with liver cirrhosis and from 3 patients with gastric cancer as controls. In IPH, the arrangement of rod cells of the splenic sinuses was severely disordered, and the slits between rod cells were irregularly enlarged. Rod cells were also deformed and accompanied branching or process formation. The bridges, rod cells which traversed the sinusal lumen, were frequently observed. Decreased resistance in the intrasplenic circulation arising from enlargement of the slits was considered to produce increased splenic blood flow. In liver cirrhosis, the slits tended to close. Slight deformity of rod cells and some bridges were found.