Abstract:

Objective： To investigate the clinicopathological features and prognosis-related factors of the patients with solitary fibrous tumor （SFT）， and to provide the evidence for its pathological diagnosis， clinical treatment and prognosis judgment. Methods The clinicopathological data of 86 patients with SFT who had undergone surgical resection from different systems were collected and divided into low （n=65）， medium （n=14） and high risk groups （n=7） according to the risk classification criteria. The general morphology of tumor was observed，HE staining and immunohistochemical staining were used to detect the morphology of SFT，and the follow-up data of the patients were obtained for the prognosis-related correlation analysis. Kaplan-Meier survival curve method was used to analyze the relationship between single clinicopathological factor in different parts and progression free survival of the patients， and Cox regression analysis was used to analyze the relationships between multiple factors and progression free survival of the patients. Results Of the 86 cases of SFT， 37 were male and 49 were female. There was no significant difference in the gender constituent ratio of the patients with SFT at different sites （P>0.05）. There was no significant difference in the age of patients with SFT at different sites （P>0.05）. There was no significant difference in the distribution of SFT at different sites among low，medium， and high risk groups （P>0.05）. There was significant statistical difference in the tumor diameter at different sites（P<0.01）. The microscope results showed that the shape and arrangement of tumor cells were diverse， and the spindle or oval cells were not arranged structurally in varying density； the characteristic antler like branching vessels and collagen fibers of varying thickness were common；most of the tumor cells were mild in shape and heterotypic， and the mitotic image was not obvious.The immunohistochemiscal staining results showed that the STAT-6 nucleus was diffusely and strongly positive； CD34， Bcl-2 and CD99 were positive in different degrees. A total of 61 cases were followed up for 2－139 months. Among them， 10 cases recurred， and the recurrence rates were 9% in low risk group， 14% in medium risk group， and 28% in high risk group， respectively. The univariate analysis results showed that there was a significant difference in the progression free survival between the patients with mitotic images<4/10 HPF and those with mitotic images ≥ 4/10 HPF （P<0.05）； there were significant differences in the progression free survival between high risk group and low，medium risk groups（P<0.05）. The multivariate analysis results showed that gender， age， tumor diameter and mitotic count were not the independent predictors of progression free survival of the patients （P>0.05）. Conclusion SFT can occur in many organs and systems of human body， and its morphology is diverse. The diameters of tumors in the central nervous system， upper respiratory tract and orbit are significantly smaller than those in female genital tract， abdominal cavity， subcutaneous soft tissue， lung and pleura. STAT-6 is a specific and sensitive index for SFT diagnosis； mitotic images ≥ 4/10 HPF and high risk classification are the risk factors for the progression free survival shortening； multivariate comprehensive analysis of tumor risk classification can not fully reflect the prognosis of the patients.

Key words: Solitary fibrous tumor, Clinicopathological characteristics, Immunohistochemistry, Risk models, Recurrence