Background: This study aims to emphasize the features that should be considered in the follow-up of patients with solitary fibrous tumors by analyzing the clinical and pathological parameters that are effective in the prognosis.

Methods: In this study, 53 patients (28 males, 25 females; mean age: 56.2±5 years; range, 24 to 76 years) diagnosed with solitary fibrous tumor and operated on between 2009 and 2023 were retrospectively examined. The patients included in the study were followed for at least one year. Patients with complete clinical and pathological data records were included in the study. Survival and recurrence rates were analyzed in relation to clinical and pathological parameters.

Results: The median follow-up was 44.9 months. Eight (15%) patients underwent anatomic resection, 23 (35.8%) patients underwent wedge resection, five (5.6%) patients underwent total pleurectomy, 26 (41.5%) patients underwent mass excision, and three (1.8%) underwent mass excision and chest wall resection. Survival analyses were conducted using the Kaplan-Meier method. Overall survival and disease-free survival were calculated in months from the date of surgery until the date of death or recurrence, respectively. Low mitotic rate was found to be a significant independent predictor of reduced mortality (odds ratio [OR]=0.46, 95% confidence interval [CI]: 0.243-0.877, p=0.018), indicating better survival outcomes in patients with low mitotic activity. In contrast, low Ki-67 expression was not a statistically significant predictor (OR=0.9, 95% CI: 0.880-1.116, p=0.885). Pleomorphism was strongly associated with increased mortality (OR=10.0, 95% CI: 1.316-76.081, p=0.026), highlighting the importance of pleomorphism as an important prognostic marker. Necrosis, although not statistically significant (OR=6.3, 95% CI: 0.497-79,123, p=0.156), showed a trend indicating worse outcomes. Similarly, CD34 negativity showed a trend in favor of mortality (OR=3.5, 95% CI: 0.429-28.990, p=0.241.

Conclusion: Solitary fibrous tumors are generally benign and have low recurrence and high survival rates. However, the recurrence rate is higher in malignant solitary fibrous tumors. According to the results of our study, high mitosis rate and pleomorphism are important independent predictors of increased mortality in solitary fibrous tumors. These findings emphasize the importance of detailed histopathological examination in prognostic evaluation.

Keywords : Mitotic count, pleomorphism, prognostic factors, solitary fibrous tumor, survival, recurrence