Intracranial Primary Malignant Solitary Fibrous Tumor/Hemangiopericytoma Masquerading as Meningioma: Report of a Rare Case

The role of tumor parenchyma and brain cortex signal intensity ratio in differentiating solitary fibrous tumors and meningiomas

BACKGROUND

Solitary fibrous tumors (SFT) and meningiomas (MA) have similar clinical and radiographic presentations but require different treatment approaches and have different prognoses. This emphasizes the importance of a correct preoperative diagnosis of SFT versus MA.

OBJECTIVE

In this study, investigated the differences in imaging characteristics between SFT and MA to improve the accuracy of preoperative imaging diagnosis of SFT.

METHODS

The clinical and imaging data of 26 patients with SFT and 104 patients with MA who were pathologically diagnosed between August 2017 and December 2022, were retrospectively analyzed. The clinical and imaging differences between SFT and MA, as well as between the various pathological grades of SFT, were analyzed.

RESULTS

Age, gender, cystic change, flow void phenomenon, yin-yang sign, lobulation, narrow base, tumor/cortex signal ratio (TCSR) > 1.0 in T1-weighted imaging (T1WI), TCSR ≥ 1.1 in T2-weighted imaging (T2WI), peritumoral edema, and absence of dural tail sign varied between SFT and MA. As per the receiver operating characteristic (ROC) curve analysis, TCSR > 1 in T1WI has the maximum diagnostic accuracy for SFT. Cranial or venous sinus invasion had a positive effect on SFT (Grade III, World Health Organization (WHO) grading).

CONCLUSION

Among the many radiological and clinical distinctions between SFT and MA, TCSR ≥ 1 exhibits the highest predictive efficacy for SFT; while cranial or venous sinus invasion may be a predictor of WHO grade III SFT.

Intracranial Solitary Fibrous Tumor Mimicking Meningioma

Solitary fibrous tumor (SFT) is a clinically rare tumor derived from mesenchymal spindle cells. Central nervous system SFT represents only 0.09% of tumors occurring on the meninges, while intracranial solitary fibrous tumors (ISFT) are even more rare. Due to the similar genetic characteristics it shares with hemangiopericytoma, in 2016, the World Health Organization (WHO) classified it as a single disease called solitary fibrous tumor (SFT)/hemangiopericytoma. We reported a case of a 60-year-old female with an intracranial solitary fibrous tumor (ISFT). The patient's magnetic resonance imaging showed a mass adhering extensively to the dura mater, with adjacent thickening of the meninges and evidence of a meningeal tail sign. These radiologic findings suggested a meningioma. The tumor was surgically removed and sent for pathologic examination, which confirmed that the tumor was consistent with a solitary fibrous tumor(WHO III). Due to its rarity and similarities with meningioma, ISFT is often misdiagnosed as other types of brain tumors. ISFT is poorly understood and poses a diagnostic challenge. Our case report presents several features suggestive of meningioma, but histopathological examination after surgery confirmed the diagnosis of SFT. Knowledge of these tumors is crucial for neurosurgeons to include them in preoperative differential diagnosis.

[Research progress of intraspinal solitary fibrous tumor]

Objective

To review the research progress of intraspinal solitary fibrous tumor (SFT).

Methods

The domestic and foreign researches on intraspinal SFT were extensively reviewed and analyzed from four aspects, including disease origin, pathological and radiological characteristics, diagnosis and differential diagnosis, and treatment and prognosis.

Results

SFT is an interstitial fibroblastic tumor with a low probability of occurrence in the central nervous system, especially in the spinal canal. In 2016, the World Health Organization (WHO) used the joint diagnostic term "SFT/hemangiopericytoma" according to the pathological characteristics of mesenchymal fibroblasts, which can be divided into three levels according to specific characteristics. The diagnosis process of intraspinal SFT is complex and tedious. It has relatively variable imaging manifestations and specific pathological changes of NAB2-STAT6 fusion gene, which often requires differential diagnosis with neurinoma, meningioma, etc. The treatment of SFT is mainly resection, which can be assisted by radiotherapy to improve the prognosis.

Conclusion

Intraspinal SFT is a rare disease. Surgery is still the main treatment. It is recommended to combine preoperative or postoperative radiotherapy. The efficacy of chemotherapy is still unclear. In the future, more studies are expected to establish a systematic diagnosis and treatment strategy for intraspinal SFT.