Malignant Dural Solitary Fibrous Tumor; An Exceedingly Rare Entity

Abstract

Abstract Introduction/Objective A solitary fibrous tumor (SFT) is an extremely rare mesenchymal neoplasm, accounting for <1% of all primary CNS tumors. Most SFT is dural-based and occurs predominantly in the fourth to sixth decade of life. Here, we present a case of a dural solitary fibrous tumor. Methods/Case Report A 28-year-old male presented with intermittent throbbing headache, nausea, and vomiting. Imaging revealed a large, well-circumscribed left parafalcine, dural-based multilobulated, solid, and cystic mass. The patient underwent craniotomy with mass resection. Preliminary intraoperative findings were of a spindle cell neoplasm. Histopathologic examination showed hypercellular neoplasm composed of the spindle to ovoid cells with a high nuclear to cytoplasmic ratio and limited intervening stroma arranged in a haphazard pattern with prominent branching staghorn vasculature. Focal areas of necrosis and mitotic counts of 8/10 high power field were also seen. The lesional cells showed focal cytoplasmic CD34 expression and strong STAT6 nuclear expression. Finally, a diagnosis of SFT, haemangiopericytoma phenotype classified as grade 3, was made. Results (if a Case Study enter NA) NA Conclusion Most SFTs are considered clinically benign (grade 1 tumors) with favorable outcomes after complete resection. However, haemangiopericytoma phenotype with hypercellularity, necrosis, and elevated mitotic count (> 4/10 HPF) is known to have an increased risk of local recurrence and rare metastasis, requiring patients to receive adjuvant radiotherapy after resection for longer progression-free survival. Therefore, it is vital to be aware of this entity for optimal management and more active systemic surveillance in patients with high-grade SFT tumors. Our patient is currently doing well post-adjuvant radiotherapy and is under active annual surveillance.