Abstract:Objective To conduct multiple factors analysis for the consistency of pituitary adenoma so as to guide its preoperative evaluation and to choose appropriate surgical approach. Methods Clinical, image and surgical data of 73 patients with pituitary adenoma were reviewed respectively. The signal ratios of the tumors to white matters in T2 weighted MRI were measured preoperatively. According to the surgical finding, tumor consistency was divided into two types: the soft (50 cases) and the hard (23 cases). Collagen content within the tumors was detected by means of Sirius red stain and the expression of TIMP1 (tissue inhibitors of metalloproteinase1) and TGFβ1 (transforming growth factorβ1) was detected with immunohistochemistry. Results The consistency of pituitary adenoma had no significant relationship with their clinical characteristics such as gender, tumor size, tumor types and their growth way. The signal ratios of the tumors to white matters in T2 weighted MRI were (2.203±0.361) and (1.068±0.204) and collagen contents within the tumors were (8.000±2.475 )% and (29.388±14.772 )% respectively in the soft and hard groups. The difference between two groups was significant(t=6.748, P<0.05). Collagen content was negatively correlated to the signal ratios of the tumors to white matters in T2 weighted MRI (r=-0.787, P<0.05). The expression amounts of TGFβ1 were (0.62±0.23) and (0.28±0.40), and those of TIMP1 were (0.53±0.15) and (0.25±0.17), respectively in the hard and soft groups. Both of them were positively correlated with their collagen content (r=0.781, P<0.05; r=0.46, P<0.05). Conclusion The significant pathological feature is collagen deposition in harden adenomas. TGFβ1 and TIMP1 may play an important role in the formation of consistency of pituitary adenoma. MRI T2 weighted phase of the tumor and white matter signal ratio of the tumor can be used to predict the consistency of adenoma, then to choose appropriate surgical approach.