Primary intraosseous meningioma of the calvaria: analysis of the literature and case report

Imaging Features of Primary Intraosseous Meningiomas

OBJECTIVE

To describe the imaging features of primary intraosseous meningiomas (PIMs) to aid an accurate diagnosis.

METHODS

Clinical materials and radiological data for 9 patients with pathologically confirmed PIMs were reviewed comprehensively.

RESULTS

Most lesions involved inner and outer plates of the calvaria and all were relatively well circumscribed. Upon computed tomography, portions of the solid neoplasm were hyperattenuated or isoattenuated. Hyperostosis was found in many lesions, but calcification was seen rarely. On magnetic resonance imaging, most neoplasms were hypointense on T1-weighted images, hyperintense on T2-weighted images, and heterogeneous on fluid-attenuated inversion recovery images. In most cases, the soft tissue of neoplasms showed hyperintense on diffusion-weighted imaging and hypointense on apparent diffusion coefficient. All lesions were obviously enhanced after gadolinium administration. Each patient accepted surgical treatment and recurrence was not observed during follow-up.

CONCLUSIONS

Primary intraosseous meningiomas are very rare tumors that occur usually in later life. They are well-defined and tend to involve the inner and outer plates of the calvaria, with a classic appearance of hyperostosis on computed tomography. Primary intraosseous meningiomas display hypointense on T1-weighted images, hyperintense on T2-weighted images, and hyperattenuated or isoattenuated on computed tomography. Hyperintense on diffusion-weighted imaging, hypointense on apparent diffusion coefficient can also be found. Obvious enhancement supplied additional information for an accurate diagnosis. A neoplasm with these features should raise the suspicion of a PIM.

Bone Invasive Meningioma: Recent Advances and Therapeutic Perspectives

Meningioma is the most common primary neoplasm of the central nervous system (CNS). Generally, these tumors are benign and have a good prognosis. However, treatment can be challenging in cases with aggressive variants and poor prognoses. Among various prognostic factors that have been clinically investigated, bone invasion remains controversial owing to a limited number of assessments. Recent study reported that bone invasion was not associated with WHO grades, progression, or recurrence. Whereas, patients with longer-recurrence tended to have a higher incidence of bone invasion. Furthermore, bone invasion may be a primary preoperative predictor of the extent of surgical resection. Increasing such evidence highlights the potential of translational studies to understand bone invasion as a prognostic factor of meningiomas. Therefore, this mini-review summarizes recent advances in pathophysiology and diagnostic modalities and discusses future research directions and therapeutic strategies for meningiomas with bone invasion.

Primary intraosseous meningioma: an osteosclerotic bone tumour mimicking malignancy

BACKGROUND

Sclerotic tumours of the calvarial bones are rare and may be due to primary and secondary bone tumours as well as extradural tumours of meningeal origin.

CASE PRESENTATION

We report a case of primary intraosseous meningioma (PIM) which arose in the frontal bone of a 63 year old woman who complained of progressive pain and thickening of the right skull. Radiology showed a large osteosclerotic lesion in the right frontal bone. Histology showed an intraosseous lesion containing dense fibrous tissue in which there were scattered cells that expressed epithelial membrane antigen and progesterone receptor. The tumour was partially resected and 3 years after operation has not recurred.

CONCLUSIONS

PIM is a rare tumour which needs to be distinguished from primary/secondary osteosclerotic calvarial bone tumours.

Skull Vault Lesions: A Review

OBJECTIVE

The aim of this article is to describe the imaging features of the most common benign or malignant skull vault lesions, which may be focal, multifocal, or diffuse.

CONCLUSION

Imaging features, in association with the age, history, and clinical symptoms of the patient, make it possible to propose a course of action: simple survey, pathologic confirmation, or complete surgical resection.

Microcystic meningioma of the calvarium: a series of 9 cases and review of the literature

Meningiomas are one of the most common tumors that arise within the central nervous system; they represent up to 30% of all primary intracranial tumors. Extradural meningiomas are rare (<2% of all meningiomas), and most arise within the calvarium. Intraosseous calvarial meningiomas are usually easy to diagnose histologically if they are of the meningothelial type; however, they may cause diagnostic challenges when they manifest as unusual morphologic variants, such as the microcystic type. To address this issue we present a series of 9 cases of calvarial microcystic meningiomas arising in 7 female and 2 male patients; all patients were adults. The tumors had heterogenous findings on imaging studies and ranged in size from 1.1 to 4.3 cm in greatest dimension. The neoplasms were composed predominantly of stellate and spindle cells with long, thin interconnecting cytoplasmic processes arranged in a complex network. The resulting cellular architecture was "sieve-like" in appearance because of the formation of numerous small "cyst-like" spaces interposed between the cytoplasmic processes of the tumor cells. All of the neoplasms expressed the characteristic immunophenotype of meningiomas (EMA, PR positive). Most tumors were resected, and none of these have recurred during a follow-up period of 1 to 83 months (average 17 mo). The morphology of the tumors and their anatomic location generated problems in diagnosis, especially in 6 patients with a history of malignancy and for whom metastatic disease was suspected clinically. Intraosseous microcystic meningioma is uncommon, and this series, the largest reported to date, describes their clinicopathologic findings, biological behavior, and features that facilitate their accurate diagnosis.

[Primary osteolytic intraosseous meningioma of the occipital bone]

Primary intraosseous meningiomas are considered extradural meningiomas when no dural attachment is present. Most of them arise from the cranial bones and can present either as an osteoblastic or an osteolytic lesion. Osteolytic intraosseous meningiomas are the rarest and very few cases have been reported. Given that many of these may develop signs of malignancy, early histological confirmation is important in order to ensure appropriate treatment. The recommended therapy is surgery, with complete resection whenever possible. We present the case of a large primary intraosseous osteolytic meningioma within the occipital bone, which was completely excised five years ago, currently presenting no signs of recurrence.