Machado I, Morales GN, Cruz J, et al. - Clinical, pathological, and molecular data of 28 patients with histologically verified solitary fibrous tumors (SFTs, a rare type of mesenchymal lesion in which specific clinicopathologic factors have been associated with a patient outcome) having at least one pathological factor correlated with aggressive behavior were involved in order to recognize pathological adverse factors—implications for risk stratification and classification. Histopathologically, all tumors exhibited hypercellularity, 11 had ≥ 4 mitoses/10 HPF, and 12 explicated necrosis. Dedifferentiation was witnessed in three tumors. In all cases, STAT6 was positive. In 14, 18, 21, and 46% of the SFT, Desmin, p16, INSM1, and HTER, immunoexpressions, respectively, were recognized. The NAB2/STAT6 gene fusion was identified in 16 tumors. Following a median follow-up of 34 months, 32.0% recurred, 32.1% metastasized, and 35.7% died of the disease. In almost half the tumors, TERT mutations were identified. Tumors with TP53 mutations or with TP53 and TERT promoter mutations were almost always classified as high risk, and the patients developed metastases and/or died of the disease. Tumors with intermediate-risk and TERT mutation had a more unfortunate evolution. SFTs with adverse pathological parameters were not always correlated to a poor outcome, hence verifying the inconstant clinical behavior of SFT. The inclusion of molecular factors (TP53 and TERT promoter status) may give new prognostic indicators for future risk stratification systems, particularly in the intermediate-risk group.