Cystic meningioma: challenges in the diagnosis

MRI findings of intracranial cystic meningiomas

AIM

To report the magnetic resonance imaging (MRI) features of intracranial cystic meningiomas and compare these features in intra- and peritumoural cyst groups.

MATERIALS AND METHODS

Fourteen cases of peritumoural cystic meningiomas were compared with 18 cases of intratumoural cystic meningiomas. All patients were examined using non-enhanced and contrast-enhanced MRI. Tumour location, tumour size, signal intensity, enhancement characteristics, and cystic changes were assessed. The MRI features were compared between the intra- and peritumoural cyst groups.

RESULTS

Most cystic meningiomas comprised two or more cysts. The solid parts of the tumours showed moderate or marked enhancement after the injection of contrast material. An enhanced cyst wall was found in six out of 14 cases in the peritumoural cyst group, but not in the intratumoural cyst group. Peritumoural cystic meningiomas were predominately located in the cerebral falx, whereas the intratumoural cystic meningiomas were predominantly found in frontal convexity (X(2)=7.434, p=0.024). The cysts were larger in the peritumoural cyst group than in the intratumoural cyst group (t=5.274, p=0.0258). Peritumoural oedema was more commonly found in the intratumoural cyst group (X(2)=6.863, p=0.008). Cystic meningiomas with solid parts located inside the cyst are reported for the first time.

CONCLUSION

Cystic meningiomas, although uncommon, should be differentiated from other cystic intracranial lesions. Peri- and intratumoural cystic meningiomas have distinct MRI features. The present study provides the first report of two lesions with solid parts located inside the cyst, as well as one lesion with a calcified solid nodule and haemorrhage within the cyst.

Atypical Meningioma With Large Cyst-Case Report-

A 29-year-old male presented with loss of consciousness and generalized seizure, followed by right hemiparesis and speech disturbance. Computed tomography and magnetic resonance imaging showed a solid, enhanced tumor with a cyst in the left frontal area with surrounding edema and mild mass effect. The cyst wall was also enhanced. The preoperative diagnosis was cystic falx meningioma. The tumor was totally resected, but most of the cyst wall adhered tightly to the surrounding brain and could not be removed. Histological examination revealed atypical meningioma and tumor cells in the cyst wall. The patient received local radiotherapy to the residual cyst wall with a total dose of 50 Gy.