Intracranial Angiomatous Meningioma: A Clinicopathological Study of 23 Cases

Abstract

Background: Intracranial angiomatous meningioma (AM) is a rare subtype of meningioma. Here, we investigated the clinical and pathological features of AMs.

Materials and methods: We performed a retrospective study of 23 intracranial AMs verified by postoperative pathology at Huashan Hospital North between 2013 and 2018. Clinical data, radiological and pathological findings, and information on treatment and outcomes were collected and analyzed. Additionally, the literature on intracranial AMs was reviewed.

Results: The sample comprised 13 men and 10 women with AMs. The mean age was 54.2 years, and the mean duration of symptoms was 14.9 months. Headache and epilepsy were the most common symptoms. The most common AMs locations were the cerebral convexity and parasagittal/falx region. The rates of vascular signs, homogeneous enhancement, and peritumoral brain edema (PTBE) on magnetic resonance images were high. Histologically, besides typical meningioma cells, AMs had an abundant vascular component and low Ki-67 index. The extent of PTBE was related to microvessel density (MVD) of tumors, but not to the expression of MMP9 or VEGF. Simpson grade I resection was achieved in 15 cases, and grade II resection was achieved in 7 cases. Twenty-one cases were followed up, and they all had favorable outcomes without recurrence.

Conclusion: AM is a type of meningioma with a rich blood supply and distinct clinical and pathological features. It showed a slight male predominance and was common at the cerebral convexity or parasagittal/falx region. Histologically, it showed benign biological characteristics despite frequent and severe PTBE, and the extent of PTBE was related to MVD of tumors. Simpson I resection is the best treatment, and the prognosis is usually good after total tumor removal, while gamma knife is recommended for small residual tumor.

Keywords: angiomatous meningioma; clinical characteristic; pathohistology; prognosis; radiology.

Figure 1

MRI of a 51-year-old female with AM in the right frontal parafalx region. (A) T1-weighted image showing slight signal hypointensity, a clear arachnoid interface, and obvious vascular signal voids. (B) T2-weighted image showing slight signal hyperintensity, vascular signal voids, and pronounced peritumoral brain edema. (C) Gd-enhanced image showing homogeneous enhancement. (D) Gd-enhanced image showing total absence of the tumor at three months postoperatively.

Figure 2

Representative pathohistological images. (A) Hematoxylin and eosin staining showed numerous blood vessels with intervening tumor cells. Immunohistochemical analysis showed strong EMA positivity of tumor cells (B), strong vimentin positivity of tumor cells (C), strong VEGF positivity of tumor cells (D), strong MMP9 positivity of tumor cells (E), and numerous vascular walls displaying CD34 positivity (F).

Figure 3

Boxes and whiskers graph show that among the IHC score of VEGF (A) and MMP9 (B) and MVD marked with CD34 (C), only MVD marked with CD34 was significantly related to the extent of PTBE (P<0.01) (GraphPad Prism 6.0).