Non-meningothelial meningeal tumours with meningioangiomatosis-like pattern of spread

A comprehensive histomolecular characterization of meningioangiomatosis: Further evidence for a precursor neoplastic lesion

Meningioangiomatosis (MAM) remains a poorly understood lesion responsible for epileptic disease. In the past, MAM was primarily described in the context of neurofibromatosis type 2 before being mainly reported sporadically. Moreover, the malformative or tumoral nature is still debated. Because a subset of MAM are associated with meningiomas, some authors argue that MAM corresponds to an infiltration pattern of these tumors. For these reasons, MAM has not been added to the World Health Organization (WHO) Classification of Central Nervous System Tumors as a specific entity. In the present study, we characterized a series of pure MAM (n = 7) and MAM associated with meningiomas (n = 4) using histopathology, immunohistochemistry, genetic (fluorescent in situ and DNA sequencing analyses), and epigenetic (DNA-methylation profiling) data. We evidenced two distinct morphological patterns: MAM with a fibroblastic-like pattern having few lesional cells, and MAM with a more cellular pattern. A subset was associated with the genetic alterations previously reported in meningiomas (such as a KMT2C mutation and a hemizygous deletion of chromosome 22q including the NF2 gene). The DNA-methylation profile, using a t-distributed stochastic neighbor embedding analysis, evidenced that MAM (pure or associated with meningiomas) clustered in a separate group from pediatric meningiomas. The present results seem to suggest that MAM represents a neoplastic lesion and encourage the further study of similar additional series so that it may be included in a future WHO classification.

Encephalic meningioangiomatosis in a dog with high-grade undefined glioma

Meningioangiomatosis (MA) is a rare proliferative meningovascular disorder that affects mainly the cerebral cortex, brainstem and spinal cord of humans and animals and can coexist with other proliferative disorders. A 7.5-year-old male Brazilian Campeiro Bulldog died after a convulsive crisis and cardiorespiratory arrest. At necropsy, a firm, white mass involving the piriform and right occipital lobes was seen. Histologically, the mass consisted of two morphologically distinct entities that collided: a congenital malformation characterized by a proliferation of meningothelial cells around blood vessels, within the perivascular spaces; and a neoplasm composed of two cell populations with astrocytic and oligodendrocytic differentiation. Meningothelial cells and neoplastic glial cells immunolabelled for vimentin. This first reported case of encephalic MA with a high-grade undefined glioma in a dog was confirmed through clinical signs, pathological and immunohistochemical findings.

Meningioangiomatosis Combined with Calcifying Pseudoneoplasms of Neuraxis

Meningioangiomatosis (MA) is a rare hamartomatous or meningovascular lesion involving the central nervous system, and is sometimes associated with intracranial meningiomas. Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare, slow-growing benign tumor-like lesions that can occur anywhere along the neuraxis. Here, we report a rare case of MA combined with CAPNON. A 31-year-old woman was admitted to our hospital because of a high-density mass in the left frontal lobe, detected by computed tomography (CT) during a physical examination. She had a 3-year history of obsessive-compulsive disorder. We describe the imaging, histopathological, and molecular characteristics of the patient. To our knowledge, this is the first report describing MA combined with CAPNON. We reviewed the literature on MA and CAPNON over the last decade and summarized the points for differential diagnosis and treatment. It is difficult to preoperatively distinguish between MA and CAPNON. However, this coexisting condition should be considered when intra-axial calcification lesions are observed on radiological imaging. Accurate diagnosis and appropriate treatment are likely to benefit this patient group.

Meningioangiomatosis: A review of the variable manifestations and complex pathophysiology

Meningioangiomatosis (MA) is a rare, complex and heterogeneous disease of meningovascular proliferation that is found primarily in the leptomeninges and cerebral cortex but can involve subcortical white matter and other brain regions such as the cerebellum and deep gray matter. MA may be found in pediatric or adult populations and may be sporadic or neurofibromatosis-associated. The presentation of MA is highly variable: it may be associated with other neurological diseases; clinically presents on a spectrum from asymptomatic to seizures or focal deficits; radiologically presents with multifocal, tumor-like, or cystic lesions, or may appear normal; and pathologically may have cellular or vascular predominance. In this article, we review the various manifestations of MA including neurofibromatosis-associated MA, multifocal MA, cystic MA, and MA associated with meningioma, other brain tumors, focal cortical dysplasia, neurodegenerative changes, and post-radiation changes. The treatment of MA is also reviewed. While the pathogenesis of MA remains elusive, we discuss the proposed theories such as developmental, dysplastic, hamartomatous or reactive ethology in given variants. It is important for physicians to be aware of MA as more research on this complex entity is needed and timely diagnosis may benefit outcomes in patients with MA.