Meningioangiomatosis: A rare epileptogenic brain lesion

A previously healthy-seven-year-old boy presented with a ten-day history of generalized tonic-clonic seizures. Physical examination, laboratory studies, and EEG were unremarkable. Brain CT and MRI studies showed an intra-axial, calcified lesion, with surrounding edema, located in the left insular region (Fig. 1, A–D). Imaging features suggested several potential diagnoses such as meningioma, meningioangiomatosis (MA), glioneuronal tumor, glioma, cavernoma, and other vascular pathologies; however, we favored MA as the most likely diagnosis after evaluating typical imaging characteristics of these various pathologies. Therefore, a diagnosis of MA was suggested. Due to the lack of specified guidelines for the management of MA, we discussed with the patient’s guardians the management options we provide for such cases at our institution, including starting with antiepileptic medications with regular follow-ups or proceeding with surgery from the beginning. They opted for the surgical option, and because of the critical location of the lesion (being located in the dominant hemisphere close to critical eloquent areas), we proceeded with an awake craniotomy (also known as awake brain surgery), in which the lesion was fully removed via an en bloc resection. Histopathological evaluation of the resected mass showed marked fibrosis and thickening of the leptomeninges, made up of delicate fibroblasts with nuclei regularly distributed amid fine collagen fibers arranged in various directions, in addition to several areas of calcification along with a number of blood vessels being scattered throughout the lesion (Fig. 1, E). The most prominent finding from the histopathological evaluation was the extensive fibrotic scaffold of the lesion, which was better visualized via Masson’s trichrome staining technique (Fig. 1, E*). Collectively, these findings were typically consistent with the diagnosis of Meningioangiomatosis. Post-operative imaging demonstrated a full clean resection of the mass, with no left-over remnants, and the involved brain area appeared less edematous compared to pre-operative scans (Fig. 1, F). The patient was then followed-up for 12 months, during which; he did not exhibit any seizure activity with clear evidence of achieving 100 % seizure control.

Meningioangiomatosis (MA) is a rare, poorly studied hamartomatous or meningiovascular lesion involving the central nervous system []. MA is generally divided into a sporadic subtype and a neurofibromatosis-associated subtype. A focused clinical examination of our patient did not reveal any Neurofibromatosis (NF)-associated signs or symptoms, and genetic screening for NF mutations revealed a normal variant. Therefore, a diagnosis of sporadic meningioangiomatosis (MA) was made. One of the most common presentations of the sporadic subtype is headache and seizures, which typically occur in children or young individuals []. Besides its rarity, MA poses a major significant radiologic challenge. The main differentials of MA include meningiomas, glioneuronal tumors, gliomas, cavernous malformations, and other vascular pathologies. Meningioma is usually of a pachymeningeal origin, and frequently presents with thickening of the adjacent dura (dural tail sign), rather than as a cortical/subcortical lesion. Gliomas (e.g., oligodendroglioma) and glioneuronal tumors (e.g., ganglioglioma) are intra-axial tumors which may be frequently calcified and thus resemble the appearance of MA. However, a typical oligodendroglioma presents as a mass in the cortex or subcortical white matter with low attenuation on CT, hypointense signal on T1WI, and hyperintense signal on T2WI. Ganglioglioma usually exhibits a variable appearance ranging from a partially cystic lesion with an enhancing mural nodule (∼50 % of cases) to a solid mass expanding the overlying gyrus. Venous vascular malformation or cavernous malformation can involve any brain region, including the cortical/subcortical areas. However, on both T1WI and T2WI, they are usually of a heterogeneous appearance because of the presence of hemorrhage of different ages with a characteristic surrounding hypointense rim on T2WI and GRE images due to hemosiderin deposition. None of these features is evident in this patient’s images, supporting our preliminary diagnosis of MA. The most typical MA’s clinical and imaging scenario is of a young patient with frequent headache and difficult-to-control seizure episodes, who presents with a calcified intra-axial lesion identified on CT with a puzzling nodular appearance on MR imaging. The histopathological hallmarks of MA lesions include a proliferation of small vessels within the cortex, with a concentric perivascular proliferation of the spindle-shaped meningeal cells with extensive fibrosis (perivascular cuffing). Calcification is seen in most cases with MA (∼90 %), and psammoma bodies can be visualized with a scattered pattern in some cases. MA is a slow-growing benign lesion with no malignant potential; therefore, the prognosis is generally excellent following a maximum safe surgical excision, with the ultimate goal being to achieve seizure control for the patient [].

The approval was obtained from the Ethics Committee of Al-Azhar University Hospitals [REF. HSZ-000015236]. The patient’s guardians gave a written informed consent to publish the case and any related data.

M.M. was responsible for the conception of the work, data collection, drafting the article, critical revisions, illustrating the figures, and obtaining approval of the final version of the manuscript. Y.M. contributed by drafting the article, and critical revisions. H.A. contributed by critical revisions of the article. All authors read the final manuscript and were involved in direct patient care.

None declared.

None declared.

The authors would like to thank Dr. Terry C. Burns (Mayo Clinic, USA), Dr. Dyana F. Khalil (Dubai Healthcare City, UAE), Dr. Ahmad A. Ayad (Al-Azhar University Hospitals, Egypt), Dr. Abdou Hamdi (Al-Azhar University Hospitals, Egypt), Dr. Mahmoud Bayoumi (Al-Azhar University Hospitals, Egypt), and Dr. Mohab A. Hasham (Al-Azhar University Hospitals, Egypt) for their valuable assistance in the preparation of this manuscript.