A rare case of meningioangiomatosis

A four-year-old boy was brought to the hospital with recurrent episodes of focal left seizures since one and half years of age. Antiepileptic medications were started for the same. He had breakthrough seizures on medications, and hence MRI was advised.

On MRI, there was a large diffuse ill-defined lesion showing hypointense signal on T1 and T2W images involving the right high frontoparietal region, centrum semiovale and corona radiata (Figures 1,2). Few well-defined T1/T2 hyperintense ovoid/ round areas were seen in the lesion suggestive of late subacute hematomas. (Figures 1b,2)

On post-contrast scans, there was gyriform enhancement involving cortex and subcortical white matter. (Figures 3a)

Extensive blooming was seen on SWI (susceptibility weighted imaging) images. (Figures 3b)

On the FLAIR sequence, the lesion was hypointense due to calcifications and haemorrhage. (Figures 4)

The lesion show gyriform hyperdensity on CT images with areas of calcification.(Figure 5 a, b). No perilesional oedema or mass effect on adjacent ventricle was seen.

Background

Meningioangiomatosis is a rare, benign, hamartomatous lesion of the leptomeninges that was initially described by Worcester-Drought et al. in 1937 as an atypical, incomplete manifestation of neurofibromatosis type 2 [1]. Since then, multiple cases have been reported in patients who did not have neurofibromatosis.

Clinical Perspective

Headaches and seizures are the most common clinical presentation, with seizures being the predominant clinical problem in most patients [2,3,4]. The majority of those affected are children and young adults [2,3,4].

Imaging Perspective

The lesions are typically cortical based, and the frontal and the temporal lobes are most commonly involved [3].

On CT

• Majority of the lesions appear hypodense, though they can be hyperdense or of mixed attenuation[2].
• Calcifications are seen in 90% of cases in CT, and it is a strong indicator of meningioangiomatosis [2,3].

On MRI

• Meningioangiomatosis is commonly hypointense on T1, hyperintense on T2 weighted imaging[2,3,4].
• There is susceptibility artifact in half of the cases on susceptibility-weighted imaging (SWI) [2].
• Gyriform hyperintensity on T2-fluid attenuated inversion recovery (FLAIR) sequence has been reported to be the most prominent characteristic on MR imaging [4].
• Though less common, significant number of the lesions exhibit at least some edema and mass effect[2]. 
• Various types of enhancement patterns ranging from mild to strong and even no enhancement are seen, but some enhancement is seen in up to 80% of cases[3,4].
• The lesions in meningioangiomatosis can assume different morphologies on imaging; for example, it can be gyriform or associated with a cystic component [2].

Outcome

Meningioangiomatosis is a benign slow-growing tumour. Surgical resection is the typical treatment strategy[3,4]. Main goal of surgical resection is to achieve seizure control for the patient[3].

Take-Home Message / Teaching Points

There are variable imaging features of meningioangiomatosis and it is a difficult diagnosis on imaging. It should be one of the differentials in a young patient with seizures and headaches.