The “Double-Peak” Pattern of Pituitary Adenoma Intrasellar Pressure and Its Effects on the Microvascular Structure

Abstract

The purpose of the present study was to investigate the relationship between the intrasellar pressure (ISP) and the microvascular structure of pituitary adenomas. We retrospectively analyzed the ISP in 66 patients with pituitary adenomas. The corresponding microvascular structure was obtained using immunohistochemistry and analyzed for its correlation with the ISP. The average ISP was 25.89 ± 8.27 mm Hg, and the ISP was not related to the size of the adenoma (Pearson correlation coefficient, 0.103; P= 0.415). The ISPs of adenomas with different Knosp grades were significantly different (P < 0.05). From grade 0 to grade 4, at first, the ISP increased with the Knosp grade and reached the first peak at grade 2. It then decreased at grade 3 and increased again at grade 4, showing a "double-peak" pattern. The minimal diameter and perimeter of the microvessels and the vessel-covered area percentage were positively related to the ISP. When these parameters were compared among the adenomas of different Knosp grades, they also exhibited a "double-peak" pattern. In the present study, we found that with the increase in pituitary adenoma size and invasion of the surrounding tissues, the ISP of pituitary adenomas showed a "double-peak" pattern. The ISP and certain parameters of the microvascular structure are related, because the microvasculature adaptively changes its structure in response to the changing ISP to ensure a sufficient blood supply to the adenoma. The specific mechanism of this phenomenon requires further study.