Falcine meningioma

Case contributed by Bruno Di Muzio
Diagnosis certain

Presentation

Headaches

Patient Data

Age: 55 years
Gender: Female

CT Brain

ct

Technique: Pre and post-contrast axial images were obtained through the brain, with posterior sagittal and coronal reformations.

Findings: There is a solid, well-defined, and extra-axial tumor involving the mid falx cerebri, which shows to be spontaneously hyperdense, with some minor peripheral calcifications foci, abutting over the adjacent frontal lobes and partially involving the superior sagittal sinus. The lesion express homogeneous and vivid contrast enhancement and cause mild surrounding edema in the adjacent right superior frontal gyrus. It is clear that the lesion goes through the falx.

Remainder brain is unremarkable.

Conclusion: Solid extra-axial tumor involving the mid falx cerebri, which most likely represents a meningioma; Hemangiopericytoma is among the differential diagnosis. Further evaluation with MRI venography is advised to assess possible sinus invasion.

MRI Brain

mri

Technique: Multiplanar, multisequence imaging has been obtained through the brain including post contrast fat saturated images and time-resolved MRA/MRV. Comparison has been made to previous external CT.

Findings: Enhancing extra-axial mass centered on the mid falx and measuring 22 x 33 x 24 mm (AP x ML x SI) has not significantly in size and morphology compared with the prior study.

This abuts the superior sagittal sinus without evidence of invasion. The sinus enhances normally on time-resolved MRA/MRV.

Mild local mass-effect with FLAIR hyperintensity in the adjacent right parenchyma.

No other intra or extra-axial abnormality.

Conclusion: Falcine meningioma without superior sagittal sinus invasion.

The patient was submitted to surgery for the tumor resection.

MICROSCOPIC DESCRIPTION: Sections show a densely sclerotic tumor containing syncytial and spindled tumor cells with pale eosinophilic cytoplasm, oval nuclei with fine granular chromatin and inconspicuous nucleoli. No necrosis or mitoses are seen. No brain tissue is included. There is no evidence of atypia or malignancy.

Immunohistochemically tumor cells stain: EMA+, PgR+, CD99+, BCL2+ and CD34-. The Ki67 proliferation index is approximately 1%.

DIAGNOSIS: Falcine tumor: Meningioma, WHO grade I.

MRI post-surgery

mri

Recent vertex bifrontal craniotomy.

Expected post-surgical changes in the overlying subcutaneous soft tissues.

Thin subjacent extra-axial collection measuring up to 4 mm in depth. At the vertex (at the location of previously demonstrated meningioma) there is a parafalcine surgical cavity containing fluid, blood products, and gas locules.

There is hematoma (a portion of which appears intraparenchymal) with surrounding vasogenic edema in the posterosuperior paramedian right frontal lobe, lateral and inferior to the surgical cavity. Although not directly involved with the hematoma, localized mass effect causes compression of both pre-and post central gyri on the right. In addition, vasogenic edema surrounding the hematoma extends into both pre-and post central gyri.

There is new T2 and FLAIR hyperintensity in the paramedian left frontal lobe at the left lateral margin of the surgical cavity which was not demonstrated on preoperative imaging. There is corresponding high DWI signal with low ADC value. Blood products in the central cavity (seen is high T1 signal on sagittal sequence) may partially account for abnormal appearance on diffusion weighted imaging, however the lateral component of low ADC appears to lie beyond the extent of blood product, and is therefore felt to represent true diffusion restriction. This involves the precentral gyrus close to the vertex.

Although slightly narrowed by local mass effect at the surgical site, the T2 flow-void in the superior sagittal sinus appears preserved. Superior sagittal sinus appears patent on phase contrast venography and enhances normally following contrast administration.

Conclusion:

Changes post resection of parasagittal meningioma.

Partly intraparenchymal hematoma in the right paramedian frontal lobe. Surrounding vasogenic edema and mass-effect involves both pre-and post central gyri on the right.

New FLAIR hyperintensity with diffusion restriction involving the left precentral gyrus. Adjacent blood products account in part for this appearance, but laterally the diffusion restriction is felt to represent postoperative change/ischemia.

Superior sagittal sinus is narrowed but patent.

Case Discussion

This case illustrates a histologically proven falcine meningioma. Falcine and parasagittal meningiomas share the same concern about the superior sagittal sinus involvement, and both locations demand a venography study to make sure if there is or not sinus invasion.

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