# The First Case Report of a Solitary Pulmonary Metastasis of a Transitional Meningioma and Literature Review

## TL;DR

This paper reports a rare case of a lung metastasis from a meningioma that occurred over 20 years after the initial diagnosis and discusses its molecular features.

## Contribution

The novelty lies in documenting the first known case of a solitary pulmonary metastasis from a low-grade meningioma occurring more than two decades after initial treatment.

## Key findings

- A patient was diagnosed with a solitary lung metastasis over 20 years after initial meningioma treatment.
- Molecular analysis revealed mutations in β2M and ATM genes, potentially contributing to immune evasion and genomic instability.

## Abstract

Extracranial metastases from meningiomas are extremely rare, with an incidence of <1%, and their prognosis is poor. Moreover, there is currently no gold standard for their treatment; therefore, the decision-making process is strictly dependent on multidisciplinary discussions. In this report, we describe the case of a 73-year-old patient who was diagnosed with a solitary lung metastasis more than 20 years after the initial treatment for a low-grade meningioma. Molecular characterization of this metastasis was performed using the Oncomine Comprehensive Assay Plus, which identified multiple functional mutations in the beta2-microglobulin (β2M) and ATM genes, both of which may contribute to immune evasion and genomic instability. A short overview of the literature is also reported. To our knowledge, no previous reports exist on single pulmonary metastasis from low-grade meningioma occurring more than 20 years after diagnosis.