Multiple Pulmonary and Pleural Metastases in Recurrent Intracranial Meningioma with Genetic Changes: Case Report and Review of the Literature

68 Ga-FAPI PET/CT in an Interesting Case of Metastatic Pulmonary Meningioma

ABSTRACT

Meningiomas are one of the major primary CNS tumors. Most meningiomas are benign, but rarely, these metastasize to distant organs, the lungs being the commonest site of metastasis. 18 F-FDG PET/CT has been used to evaluate metastatic pulmonary meningioma. However, 68 Ga-FAPI PET/CT has not yet been evaluated. The present case highlights the 68 Ga-FAPI uptake in metastatic pulmonary meningioma in a postoperated case of left tentorial meningioma presenting with lung masses. Image-guided biopsy from the lung mass was consistent with metastatic meningioma.

Metastatic meningioma: a case series and systematic review

BACKGROUND

Meningiomas are the most common primary intracranial tumor. While the majority of meningiomas are benign, rarely they can metastasize extracranially. There is a need for a more comprehensive review of these patients to improve our understanding of this rare phenomenon and its prevalence globally. Here we describe our institution's experience of patients presenting with metastatic meningiomas. We further perform a systematic review of the existing literature to explore common features of this rare manifestation of meningioma and review the efficacy of current treatments.

METHODS

We performed a retrospective clinical review of all adult patients with metastatic meningioma managed at our institution over the past 20 years, identifying 6 patients. We then performed a systematic review of cases of metastatic meningioma in the literature ranging from the years 1886 to 2022. A descriptive analysis was then conducted on the available data from 1979 onward, focusing on the grade and location of the primary tumor as well as the latency period to, and location of, the metastasis.

RESULTS

In total, we analyzed 155 cases. Fifty-four percent of patients initially presented with a primary meningioma located in the convexity. The most common site of metastasis was the lung. Risk factors associated with a shorter time to metastasis were male sex and a high initial grade of the tumor. Regarding treatment, the addition of chemotherapy was the most common adjunct to the standard management of surgery and radiotherapy. Despite an exhaustive review we were unable to identify effective treatments. The majority of published cases came from centers situated in high-income countries (84%) while only 16% came from lower- and middle-income countries.

CONCLUSIONS

Metastatic meningiomas pose a pertinent, and likely underestimated, clinical challenge within modern neurosurgery. To optimize management, timely identification of these patients is important. More research is needed to explore the mechanisms underlying these tumors to better guide the development of effective screening and management protocols. However, screening of each meningioma patient is not feasible, and at the heart of this challenge is the inability to control the primary disease. Ultimately, a consensus is needed as to how to correctly screen for and manage these patients; genomic and epigenomic approaches could hold the answer to finding druggable targets.

Metastatic grade 1 meningioma lacking genetic abnormalities commonly associated with bad prognosis

AIMS

Meningioma metastasis is a rare event, observed primarily in World Health Organization (WHO) grade 3 tumors, although it has also been reported in WHO grade 1 meningiomas. This study aims at clarifying whether the metastasis of a WHO grade 1 meningioma was associated with genetic abnormalities commonly found in cases that are more aggressive.

METHODS

Using next generation sequencing of a panel of 174 genes, we analyzed the genetic alterations of a WHO grade 1 skull-base meningioma and its paired lung metastases detected 22 years after craniotomy.

RESULTS

Similar to the primary tumor, lung metastases did not show mitoses or histological signs of malignancy. Consistent with their origin from intracranial tumor, they harbored the same genetic alterations as this one. These consisted of the pathogenic mutation p. E17K of AKT1 and variants of unknown significance in NOTCH1 (p. P2133T), SERPINB8 (p. H359Y) and SMARCA4 (p. P277S).

CONCLUSIONS

The E17K AKT1 mutation is frequently found in skull base meningiomas and without prognostic significance. Our findings suggest that metastasis of grade 1 meningiomas is independent of genetic alterations (CDKN2A homozygous deletion, pTERT mutation, or 1p, 9p, 14q and 18q loss of heterozygosity) commonly found in more aggressive tumors.

Pleural metastasis of atypical meningioma: a novel therapeutic approach

Meningiomas are the most common intracranial tumours in adults and they are infrequently associated with a metastasis clinical course. Pleural metastases are extremely rare and no guidelines on a specific treatment have been established. When localized, surgical resection is the mainstay of treatment, but there is a high risk of pleural recurrence. We aimed to describe a novel surgical approach in pleural metastasis of meningiomas. We report the case of a 41-year-old man with the medical history of surgically resected intracranial atypical meningioma. Nine years after diagnosis of atypical meningioma, a CT scan of the chest disclosed 10 pleural implants gathered in the fissure, in the paramediastinal pleura and at the base of the left hemithorax. Surgical resection was decided. Parietal and mediastinal pleura resection with visceral pleural lesions removal were performed. Cytoreductive surgery was associated with intrathoracic hyperthermic chemotherapy. Postoperative course was uneventful and no adjuvant therapy was undertaken. The patient is free of pleural recurrence 12 months post operatively. The present case report suggests that cytoreductive surgery with intrathoracic hyperthermic chemotherapy is feasible and safe in pleural metastasis from meningioma. Prolonged follow-up and prospective studies are mandatory to assess its oncological benefit.