Solitary Fibrous Tumor (SFT)
Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that can arise from the meninges (dura). It closely resembles meningioma on imaging; distinction is made by pathological and molecular analysis. The NAB2::STAT6 gene fusion is the molecular hallmark of the disease.
Останнє оновлення: 2026-06-06
Definition
Solitary fibrous tumor, first described in 1931 in the pleura, is a mesenchymal tumor that can occur in many parts of the body. Intracranial SFT accounts for less than 1% of all intracranial tumors; about 90% of cases are dura-based. It usually grows slowly and is mostly benign, but can behave in a locally aggressive manner and rarely metastasize.
Classification and Molecular Features
In the WHO classification of central nervous system tumors, SFT is graded 1-3 according to histologic features; mitotic count, necrosis and cellularity determine the grade. The molecular hallmark is the NAB2::STAT6 fusion, formed by the joining of the NAB2 and STAT6 genes on chromosome 12. Nuclear STAT6 staining, a surrogate marker of this fusion, is the immunohistochemical feature that distinguishes SFT from meningioma (STAT6-negative).
Symptoms
Symptoms depend on the location and size of the mass. Chronic, localized headache is most common; convexity tumors may cause seizures. Mass effect can produce focal neurological signs (weakness, sensory loss), visual disturbances and personality changes. Because of slow growth it may remain asymptomatic for a long time and is sometimes found incidentally. Rarely, IGF-2 secretion by the tumor can cause hypoglycemia (Doege-Potter syndrome).
Diagnosis
Contrast-enhanced brain MRI is the gold standard. SFT appears as a dura-based, avidly and homogeneously enhancing mass resembling meningioma; however, it contains prominent vascular flow-voids and fibrous bands and, unlike meningioma, does not cause bony thickening (hyperostosis). Owing to its high vascularity, blood volume is high on perfusion MRI; angiography may be performed for preoperative embolization planning in large, vascular tumors. Definitive diagnosis is made by pathology and immunohistochemistry (nuclear STAT6 positive, CD34 positive).
Treatment
The mainstay of treatment is total surgical resection; removal of the tumor with its dura and, where necessary, the adjacent bone (Simpson grade 1-2) minimizes recurrence risk. Because of high vascularity, preoperative embolization reduces bleeding risk in large tumors. Adjuvant radiotherapy is considered when complete resection is not achieved or in high-grade cases; stereotactic radiosurgery is an option for small, residual or recurrent lesions. In advanced or metastatic disease, antiangiogenic targeted therapies (e.g., pazopanib) may be used; conventional chemotherapy has limited efficacy.
Prognosis and Follow-up
Prognosis after total resection is generally good with high long-term survival; recurrence and metastasis risk increase with higher grade. Because recurrence risk is highest in the first 5 years, regular MRI follow-up is required; in malignant SFT, metastasis screening with chest-abdomen imaging is recommended. The variant of the NAB2::STAT6 fusion has been linked to outcome and may help guide the intensity of follow-up. Outcomes are individual and none can be guaranteed.
Джерела
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:820-828.
- Osborn AG, Hedlund GL, Salzman KL. Osborn's Brain: Imaging, Pathology, and Anatomy. 2nd ed. Elsevier; 2018:685-687.
- Louis DN, et al. The 2021 WHO Classification of Tumors of the Central Nervous System. Neuro Oncol. 2021.
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