Pediatric sellar solitary fibrous tumor/ hemangiopericytoma: A rare case report and review of the literature

Sellar hemangiopericytoma masquerading as pituitary adenoma: an overlooked intriguing case study unveiling a rare surgical conundrum

Hemangiopericytoma (HPC) constitutes less than 1% of all primary central nervous system tumors. It is a vascular neoplasm with potential malignancy that, in rare instances, manifests as a primary lesion within the brain. Typically, it originates from the meninges. Here, we describe an exceptionally uncommon sellar region solitary fibrous tumor/hemangiopericytoma (SFT/HPC) that mimicked a nonfunctional pituitary adenoma.

Introduction and importance

Case presentation

A 54-year-old male was referred to our hospital due to progressive blurred vision in the left eye over the past year. A homogeneous iso-dense extra-axial intrasellar round mass with extension into the suprasellar region, mainly on the left side, along with bony erosion and osteolysis around the sellar region, was observed on a brain computed tomography (CT) scan. Brain magnetic resonance imaging (MRI) revealed a well-defined 251,713 mm mass with iso-signal on T1-weighted images and hypersignal on T2-weighted images, originating from the pituitary gland within the sella turcica. The mass avidly enhanced following Gadolinium injection and adhered to both carotid arteries without vascular compression or invasion. It extended to the suprasellar cistern and compressed the optic chiasm. The diagnosis was nonfunctional pituitary macroadenoma, leading to the decision for Endoscopic Trans-Sphenoidal Surgery (ETSS). A non-sustainable, soft, grayish mass was grossly and totally resected during the operation. Subsequently, there was a significant improvement in visual acuity during the early postoperative period. Histopathologic examination confirmed hemangiopericytoma (WHO grade II).

Conclusion

Due to its malignant nature, hemangiopericytoma should be included in the differential diagnosis of a sellar mass, both from a clinical and morphological perspective.

Intracranial solitary fibrous tumor in a 15-year-old girl: illustrative case

BACKGROUND

Solitary fibrous tumor (SFT) is an infrequent spindle cell tumor derived from mesenchymal tissue, which can manifest in diverse anatomical locations, primarily in the pleural cavity and infrequently in the central nervous system. SFT is predominantly observed in individuals aged between 40 and 50 years old, with a slightly higher occurrence in males than in females.

OBSERVATIONS

This case report describes a female, age 15, who had migraines for 2 months prior to the diagnosis of an intracranial tumor. Computed tomography and magnetic resonance imaging showed a mass located in the right parietooccipital region with surrounding edema and a compressed right lateral ventricle. Neurosurgery was utilized to successfully remove the mass, and single intracranial fibrous tumor (grade I) was identified by postoperative pathological analysis. During an 8-month follow-up period, the patient did not experience any recurrences.

LESSONS

SFT is often misdiagnosed as meningioma because of their similar imaging characteristics. However, identifying the distinctive features of SFT on magnetic resonance imaging can distinguish it from meningioma and help to select appropriate treatment. The complete preoperative imaging data for this case indicated a highly vascularized tumor. Preoperative vascular embolization treatment reduced any difficulties during the subsequent tumor resection and minimized intraoperative bleeding.

Analysis of clinicopathological features and NAB2-STAT6 fusion variants of meningeal solitary fibrous tumor with ectopic salivary gland components in the cerebellopontine angle

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors that can occur at any location. Since the identification of specific NAB2-STAT6 fusion in SFTs, the fusion gene variants, NAB2 exon 4-STAT6 exon 2/3 and NAB2 exon 5/6/7-STAT6 exon 16/17/18, have been reported to be associated with clinicopathological features, and the latter variant is predominant in meningeal SFTs. SFTs developing in the salivary glands are rare, and more rarely, those involving ectopic salivary glands (ESGs) have been reported in the cerebellopontine angle (CPA); however, their characteristics remain not well understood. In this study, we performed a clinicopathological and molecular analysis of 3 cases of meningeal SFT with ESGs. All cases presented with an extra-axial mass in the CPA, which is a rarer location for intracranial ESGs compared to the sellar region. Histologically, except for the presence of ESGs, there was no significant difference between current cases and ordinary SFTs. The ESGs demonstrated no cellular atypia, and although the spindle tumor cells were immunopositive for STAT6, the ESGs were negative in all cases, supporting that the ESGs are non-neoplastic components. In 1 case, ESGs were found only in the primary tumor and disappeared in recurrence/dissemination. Of note, molecular analysis identified NAB2 exon 4-STAT6 exon 2 in all cases. In conclusion, our results suggest that ESGs particularly in the CPA may be associated with SFTs and that meningeal SFTs with ESGs may be associated with the minor fusion variant of NAB2-STAT6 in the intracranial lesions.

Intracranial Solitary Fibrous Tumor of the Skull Base: 2 Cases and Systematic Review of the Literature

BACKGROUND

Intracranial solitary fibrous tumors (ISFTs) are rare neoplasms of mesenchymal origin that originate from the meninges. ISFTs of the skull base can be challenging to treat, as resection can be complicated by skull base anatomy. We present 2 cases of ISFT, the first manifesting with compressive cranial neuropathy from Meckel cave involvement and the second a posterior fossa lesion causing symptomatic hydrocephalus.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed database was queried with title/abstract keywords "intracranial," "solitary fibrous tumor," "hemangiopericytoma," "SFT," and "HPC." Search results were reviewed to exclude cases not involving the skull base. References from all selected articles were reviewed for potential additional cases. Patient demographic and clinical data from 58 identified skull base cases were collected for qualitative synthesis.

RESULTS

Visual disturbances were the most common presenting symptom (30 cases, 52%) followed by headache (22 cases, 38%). The most common site of involvement was the sellar/parasellar region (18 cases, 31%) followed by middle fossa/temporal bone (14 cases, 24%). Resection was performed in 55 cases; gross total resection was reported in 26 cases (45%) and subtotal resection was reported in 21 cases (36%). Tumor recurrence was documented in 15 cases (26%) with median and mean follow-up periods of 16 and 29.9 months, respectively.

CONCLUSIONS

We discuss presentation, imaging, histopathology, and management considerations for ISFTs while highlighting the potentially complex nature of skull base lesions and need for multidisciplinary approach to treatment.