Metastases to Meningiomas: A Comprehensive Literature Review Including Mediating Proteins

Abstract

Approximately 5–15% of solid tumors metastasizing to the central nervous system metastasize to the leptomeninges. Less common, is metastasis to leptomeningeal meningiomas. These are primarily carcinomas of the breast and lung. Awareness of this phenomenon is critical to the evaluation of meningiomas, especially since the metastases may be the first indication of an occult tumor elsewhere in the body. Lack of clear demarcation between the metastasis and meningioma parenchyma, as well as histological features similar to the meningioma, may hinder recognition. The mechanisms underlying metastases anchoring and spread along the leptomeninges are not established. However, several cell adhesion molecules are thought to contribute to this phenomenon. E cadherin is a cell adhesion molecule present in meningioma cells. Binding to endothelium by adhesion molecules such as ICAM, B1 integrin, P-selectin, PECAM-1, CXCL12 and SDF-1 have also been proposed as part of the mechanisms underlying breast carcinoma metastases. In addition, the leptomeninges and meningiomas express mesothelin that acts as an anchoring protein coupling with mucin-16. Consequently, metastatic tumor cell mucin and mesothelin may also facilitate the anchoring of metastases to meningiomas.

Review of metastasis to meningiomas with case examples

“…This affinity between metastatic tumor cells and the target organ is thought to play a role in invasion and metastasis of the donor cells to the recipient ( Minezaki et al, 2022 ). Our patients had two different subtypes of meningioma (grade 1 and II), but according to a literature review of metastases to meningiomas, there is no increased risk with different meningioma subtypes ( Johnson, 2022 ).…”

“…Meningiomas with metastases are more likely to express hormone receptors and adhesion molecules ( Johnson, 2022 ). Cell adhesion molecules such as ICAM, B1 integrin, PECAM-1, P-selectin, CXCL12, and SDF-1 have also been proposed as part of the mechanism underlying breast carcinoma metastasis, and ICAM expression in meningiomas may also facilitate adhesion of metastases to meningioma blood vessels ( Johnson, 2022 ; Mogere et al, 2024 ). Our immunohistochemical analysis found markers CKAE1/AE3 and PSA in the prostate cancer case, and CKAE1/AE3 and CK7 in the breast cancer case, significance of these in TMM is yet to be clarified.…”