Solitary Fibrous Tumors: A Rare Tumor Arising from Ubiquitous Anatomical Locations

Solitary fibrous tumors (SFTs) are uncommon mesenchymal tumors of fibroblastic/myofibroblastic origin that stem from various anatomical sites. Most SFTs are asymptomatic and noticed incidentally by various imaging modalities. Although SFTs were initially identified in the pleura and erroneously considered to originate solely from serosal layers, extrapleural SFTs have been reported more commonly than their pleural counterparts. Imaging features are similar in different anatomical locations and are mainly related to the tumor’s size and collagen content, characteristically displaying low signal intensity on magnetic resonance imaging. Smaller tumors typically exhibit uniform enhancement, yet necrotic regions may become evident as the tumor size increases, resulting in heterogeneous enhancement. Less than 30% of SFTs demonstrate unfavorable clinical outcomes regardless of their histological features, warranting surgery as the preferred treatment with long-term follow-up. In this article, we have reviewed the clinical manifestations and imaging features of SFTs, discussed their differential diagnosis based on anatomical site, and provided diagnostic pearls.