Malignant mesothelioma and central nervous system metastases. Report of two cases, pooled analysis, and systematic review

Management of sarcomatoid Malignant pleural mesothelioma brain metastases with stereotactic radiosurgery: an Illustrative case

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare cancer of the respiratory system that rarely metastasizes to the brain. We report a case of sarcomatoid MPM (SMPM) managed with Stereotactic radiosurgery (SRS) to achieve intracranial tumor control and improve neurological symptoms.

ILLUSTRATIVE CASE

This 67-year-old female patient underwent SRS twice in order to treat a total of 15 brain metastases. One-month follow-up imaging after the first SRS demonstrated local tumor response and seven tumors with symptomatic vasogenic edema that responded to initial corticosteroids followed by bevacizumab. At a three-month follow-up after the first procedure, eight new tumors were detected and required repeat SRS. Although sustained tumor control resulted in improved neurological function, the patient subsequently expired from systemic disease progression 12 months after initial diagnosis and six months after initial SRS for brain metastases despite the concurrent use of systemic immunotherapy and systemic chemotherapy.

CONCLUSIONS

Although SRS provided overall tumor control of metastatic brain disease, further advances in systemic therapies will be needed to improve survival in this aggressive rare cancer.

Incidence and Outcomes of Brain Metastasis in Pleural Mesothelioma in the Era of Immunotherapy

Introduction

Immunotherapy (IO) has reported efficacy in pleural mesothelioma (PM). Brain metastases (BMs) in PM are rare; thus, surveillance brain imaging is not included in the guidelines. We evaluated the incidence of BM by treatment type.

Methods

In this retrospective analysis, patients with PM treated at the University of Pennsylvania between January 1, 2015, and August 31, 2023, were included. Demographic and clinical data were extracted from the medical records. The treatment categories included chemotherapy, single-agent IO, and dual-agent IO. A two-tailed Z score was used to determine a difference in the proportion of BM. Overall survival (OS) was analyzed using the Kaplan-Meier method. Of those with BM, available brain tissue was further analyzed.

Results

In total, 251 patients were included; the median age of the participants was 73 years (range: 35-92 y), 79% were male individuals, 91% were white, and 73% had epithelioid histology. In the study, 102 (40.6%) were treated with chemotherapy, 100 (39.8%) with single-agent IO, and 49 (19.5%) with dual-agent IO. The median OS (mOS) was 21.6 months (95% confidence interval: 17.7-25.5) and did not differ between treatment groups (p = 0.774). A higher proportion of patients treated with IO developed BM than those treated with chemotherapy (6/149 [4%] versus 0/102 [0%]; Z score p = 0.04). The mOS from BM diagnosis was 95 days (range: 16-1025 d). The histomorphology of three patients with available brain tissue were similar to the primary site and reported substantial edema and hemorrhage.

Conclusions

In this retrospective study, clinically significant BM was most prevalent in those exposed to IO and not seen in those receiving chemotherapy despite similar mOS between the groups. Brain imaging should be considered before starting IO in patients with PM.

The Incidence of Distant Metastases in Patients with Pleural Mesothelioma Screened for a Multimodal Approach: How Much Staging Do We Really Need?

Pleural mesothelioma (PM) is a very aggressive malignancy with a poor prognosis. Most patients receive systemic treatment only; however, some patients may benefit from multimodality treatment. A precise staging of patients undergoing multimodal treatment is mandatory. We investigated the pattern of metastasis in a cohort of patients screened for multimodal treatment to define the extent of staging examinations. Additionally, we investigated the occurrence of metastasis during follow-up. We investigated a single-center experience of 545 patients newly diagnosed and/or treated with PM between the years 2010 and 2022. Patients who were treated naïvely and had a whole set of imaging of the brain were included and further analyzed. A total of 54% of all patients with cerebral imaging had an available 18FDG-PET CT scan. We also recorded metastasis during treatment follow-up. There were 110 patients who had a whole set of imaging (CT = 89% and MRI = 11%) of the brain, and 54% of all patients with cerebral imaging had an available 18FDG-PET CT scan. We identified four patients with cerebral metastasis at the time of first diagnosis, which means that 5.4% of the cohort had cerebral metastasis and 13.3% of all patients in the subgroup with complete data of 18FDG-PET CT had distant non-cerebral metastasis. During the longitudinal follow-up, we found 11 patients with newly diagnosed metastases after a median time of 1.6 years (range: 2 months to 3.3 years) after first diagnosis without metastases. Distant metastases are more frequent in mesothelioma patients than previously thought. This implies that extensive staging is needed for patients selected for multimodal treatment, including brain imaging and 18FDG-PET CT.

Brain Metastases With Malignant Peritoneal Mesothelioma: Never Reported Before

Malignant mesothelioma is a very rare diagnosis. Malignant mesotheliomas arise from surface linings of pleura, peritoneal cavity, or tunica vaginalis and pericardium with pleural malignant mesotheliomas being the most common. The incidence of brain metastases has been very low with malignant pleural mesotheliomas, but to date, there have not been any cases reported of brain metastasis with malignant peritoneal mesotheliomas. We present a patient diagnosed with malignant peritoneal mesothelioma and was successfully treated with immunotherapy for over two years but later presented with brain metastases. Although the patient had a surgical resection followed by brain radiation, he died three months after his diagnosis of brain metastases. Immunotherapy has revolutionized the treatment of malignant mesothelioma, and patients are living longer than before. We present this patient to increase awareness of brain metastases with malignant peritoneal mesothelioma. This case also highlights that we need to investigate different treatment options for brain metastases in patients with malignant mesothelioma as conventional treatment options like surgical resection and brain radiation are not very effective.

Rare thoracic cancers: a comprehensive overview of diagnosis and management of small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours

Despite the progress in outcomes seen with immunotherapy in various malignancies, including nonsmall cell lung cancer, the benefits are less in small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours. New effective treatment options are needed, guided via more in-depth insights into the pathophysiology of these rare malignancies. This review comprehensively presents an overview of the clinical presentation, diagnostic tools, staging systems, pathophysiology and treatment options for these rare thoracic cancers. In addition, opportunities for further improvement of therapies are discussed.

Donut sign: a unique radiological sign of cerebral metastasis in malignant mesothelioma

A man in his 70s presented to the emergency department with a 3-day history of confusion and right-facial droop. He was diagnosed with stage IIIB (T4N2M0) malignant mesothelioma 6 months previously for which he was being given palliative chemotherapy. An MRI of the brain demonstrated a left parietal cerebral metastasis with unique radiological characteristics termed 'donut sign'. He underwent a craniotomy and complete macroscopic resection of the lesion with a good postoperative outcome. Mesothelioma cerebral metastases are a rarely reported clinical entity, with only a handful of case reports and case series available. On MRI they often demonstrate a distinctive thick-walled lesion, termed 'donut sign', that may be indicative of the diagnosis. Furthermore, case autopsy series suggest these metastases may be underdiagnosed in the clinical setting due to the dismal prognosis. With newer and more effective neoplastic treatment strategies emerging, there may be a rising incidence of central nervous system metastases in the future.

Haemorrhagic Brain Metastasis From Malignant Pleural Mesothelioma: A Rare Case

Malignant pleural mesothelioma (MPM) typically has a short median survival of only a few months from diagnosis, with death usually due to thoracic disease. This has led to the belief in the past that mesothelioma rarely has distant metastasis, with cerebral metastasis accounting for only 3%. The multiple cases of brain metastasis from MPM recorded so far were discovered after death at autopsy. This report describes a rare case of known malignant mesothelioma with distant haemorrhagic metastasis to the brain, reviews current literature about its metastatic potential to the brain and discusses prognosis and management. We also review the imaging evaluation in known MPM patients with suspected intracranial involvement and describe typical imaging findings of parenchymal brain metastasis on computed tomography (CT) and magnetic resonance imaging (MRI).

Cerebral metastases of malignant mesothelioma

Malignant pleural mesothelioma represents a rare etiology of lung cancer metastasis to the brain. Neurologically symptomatic presentations are extremely rare as these metastatic lesions are detected in the late stages of the disease. Despite many highly heterogenous treatment techniques reported in the literature, overall survival is poor. A 72-year-old male with a history of mesothelioma presented with recurrent episodes of altered mental status, confusion and expressive aphasia. Imaging indicated a large hemorrhagic, enhancing lesion in the anterior left frontal lobe resulting in midline shift of 6 mm. He underwent a left frontal craniotomy for resection, after which he had complete resolution of symptoms. The resected mass was metastatic high-grade malignant mesothelioma. On a 1-month follow-up, new lesions in the bilateral frontal lobes were discovered, and despite undergoing adjuvant stereotactic radiosurgery, the right one grew significantly, causing notable mass effect. The patient successfully underwent a right craniotomy for resection.

Metastasis of Sarcomatoid Malignant Mesothelioma With p16/CDKN2A Deletion Manifested as a Subcutaneous Mass in the Back: A Case Report and Review of Literature

Sarcomatoid malignant mesothelioma (MM) is a rare and aggressive disease, and its diagnosis is challenging. A 60-year-old man presented with a recurrent subcutaneous mass in his right back after the initial resection. A chest computed tomography (CT) scan found right pleural thickening, nodular pleural thickening, pleural effusion, mediastinal, and right infraclavicular lymph nodes enlargement, which indicated a right pleura MM. Immunohistochemical stains of the resected mass showed sarcomatous atypical spindle cells, which were positive for pan-CKs (clone Anti-cytokeratin cocktail AE1/AE3), cytokeratin 5/6 (CK5/6), Wilm's tumor 1, podoplanin, vimentin and programmed death-ligand 1 (PD-L1), and negative for Napsin A, thyroid transcription factor 1, CDX 2, calretinin and desmin, and fluorescent in situ hybridization detected homozygous p16/cyclin-dependent kinase inhibitor 2A (p16/CDKN2A) deletion. The association of the chest CT features and the pathological assessment confirmed metastatic MM in the subcutaneous layer of the back. Moreover, positron emission tomography-CT showed multiple metastases in his brain. He developed massive right pleural effusion and chest tightness soon, and the mass kept growing despite local and systemic treatments. The patient die of pulmonary failure in 3 months.

A case of brain metastasis with pathological transformation of long-surviving malignant pleural mesothelioma: illustrative case

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare cancer, and in 80% of cases the cause is asbestos exposure. In 1972, the World Health Organization (WHO) declared asbestos is a carcinogenic substance. Since then, every developed country has restricted and banned the product. Because of its high heat resistance, asbestos had been widely used as building material for decades. The WHO estimated that approximately 125 million people are exposed to asbestos, and more than 107,000 die from asbestos-related diseases annually. Because of its long incubation period, the number of patients is estimated to keep increasing in the near future.

OBSERVATIONS

The authors report a case of long-surviving MPM with a rushed clinical course after brain metastasis. A 69-year-old woman diagnosed with MPM (epithelial type) 6 years earlier presented with a brain metastasis. The pathological result of the brain metastasis was the sarcomatoid type. This case showed the possibility of subtype transition after long survival.

LESSONS

This article aids in understanding the long-term natural history of MPM and the possibility of epithelial-mesenchymal transition. Neurosurgeons have to be aware of its the natural history and the possibility of brain metastasis.

Radiological evaluation of malignant pleural mesothelioma - defining distant metastatic disease

BACKGROUND

Malignant pleural mesothelioma (MPM) is traditionally characterized by local destructive spread of the pleura and surrounding tissues. Patient outcomes in MPM with distant metastatic dissemination are lacking.

METHODS

In this retrospective study, we reviewed a cohort of 164 MPM patients referred to a Phase I trials unit, aiming to describe identified metastatic sites, and correlate with clinical outcomes.

RESULTS

67% of patients were diagnosed with distant metastatic disease with a high incidence of bone (19%), visceral (14%), contralateral lung (35%) and peritoneal metastases (22%). Peritoneal metastases were more likely in epithelioid versus biphasic/ sarcomatoid MPM (p = 0.015). Overall survival was 23.8 months with no statistical difference in survival between those with distant metastases and those without.

CONCLUSIONS

This report highlights the frequency of distant metastases and encourages further radiological investigations in the presence of symptoms. In particular, given the relatively high incidence of bone metastases, bone imaging should be considered in advanced MPM clinical workflow and trial protocols. The presence of distant metastases does not appear to have prognostic implications under existing treatment paradigms. This cohort of MPM patients gives an indication of patterns of metastatic spread that are likely to become prevalent as prognosis improves with emerging treatment paradigms.

Mesothelium and Malignant Mesothelioma

The mesothelium is an epithelial structure derived from the embryonic mesoderm. It plays an important role in the development of a number of different organs, including the heart, lungs, and intestines. In this publication, we discuss aspects of the development of the mesothelium, where mesothelial structures can be found, and review molecular and cellular characteristics associated with the mesothelium. Furthermore, we discuss the involvement of the mesothelium in a number of disease conditions, in particular in the pathogenesis of mesotheliomas with an emphasis on malignant pleural mesothelioma (MPM)—a primary cancer developing in the pleural cavity.

A systematic review of interventions and outcomes in lung cancer metastases to the spine

Seventy percent of cancer patients will have metastatic bone disease, most commonly in the vertebra. Prognosis of metastatic lung cancer is poor and treatment is mostly palliative. To-date, there is no systematic review on the ideal treatment for lung cancer with spinal metastases in regards to mortality. Literature searches were performed based on PRISMA guidelines for systematic review. Thirty-nine studies comprising 1925 patients treated for spinal metastases of lung cancer met inclusion criteria. All analyses were performed using SAS and SPSS. Data were analyzed for meaningful comparisons of baseline patient characteristics, primary cancer type, metastatic lesion characteristics, treatment modality, and clinical and radiologic outcomes. Significantly greater mean survival length was seen in the non-surgical group (8.5 months, SD 6.6, SEM 0.17) compared to the surgical group (7.5 months, SD 4.5, SEM 0.25; p = 0.013). There was no statistically significant survival difference between different types of primary lung cancer: NSCLC (8.3 months, SD 13.8, SEM 0.91) and SCLC (7.0 months, SD 4.6, SEM 0.46; p = 0.36). Number of vertebral levels involved per lesion also did not exhibit significant difference: single lesion (11.3 months, SD 6.8, SEM 2.2) and multiple lesions (13.8 months, SD 15.7, SEM 3.6; p = 0.64). For patients with symptomatic spinal metastases from lung cancer, non-operative approaches experience significantly better survival outcomes (p = 0.013). Future clinical studies are needed to determine the best treatment algorithm to help maximize outcomes and minimize mortality in metastatic lung cancer.

Metastatic biphasic pleural mesothelioma presenting with cauda equina syndrome

Patient with previous asbestos exposure on a watchful wait and watch regime presents acutely with cauda equina syndrome. Radiological imaging confirmed a mass with direct invasion of the spinal cord. Histology confirmed metastatic pleural mesothelioma.

Proton beam therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare disease with a poor prognosis. Surgical techniques have made incremental improvements over the last few decades while new systemic therapies, including immunotherapies, show promise as potentially effective novel therapies. Radiation therapy has historically been used only in the palliative setting or as adjuvant therapy after extrapleural pneumonectomy, but recent advances in treatment planning and delivery techniques utilizing intensity-modulated radiation therapy and more recently pencil-beam scanning (PBS) proton therapy, have enabled the delivery of radiation therapy as neoadjuvant or adjuvant therapy after an extended pleurectomy and decortication or as definitive therapy for patients with recurrent or unresectable disease. In particular, PBS proton therapy has the potential to deliver high doses of irradiation to the entire effected pleura while significantly reducing doses to nearby organs at risk. This article describes the evolution of radiation therapy for MPM and details how whole-pleural PBS proton therapy is delivered to patients at the Maryland Proton Treatment Center.

Biphasic Malignant Pleural Mesothelioma Masquerading as a Primary Skeletal Tumor

Biphasic malignant pleural mesothelioma is a rare malignant tumor, usually presenting as a pleural-based mass in a patient with history of chronic asbestos exposure. We herein report a case of a 41-year-old man who presented with chest pain and had a chest computed tomography (CT) scan suggestive of a primary skeletal tumor originating from the ribs (chondrosarcoma or osteosarcoma), with no history of asbestos exposure. CT-guided core needle biopsies were diagnosed as malignant sarcomatoid mesothelioma. Surgical resection and chest wall reconstruction were performed, confirming the diagnosis and revealing a secondary histologic component (epithelioid), supporting the diagnosis of biphasic malignant mesothelioma.

Brain metastases in malignant pleural mesothelioma

The brain is a rare site of metastasis in malignant pleural mesothelioma (MPM), and its clinical features and prognosis remain unclear. The aim of this study was to investigate the incidence, prognosis, and risk factors for brain metastases (BM) in MPM patients. Between July 1993 and October 2014, 150 patients with histologically proven MPM were included in this retrospective study. The cumulative incidence of BM was estimated with the Kaplan-Meier method, and differences between groups were analyzed by the log-rank test. Multivariate logistic regression analysis was applied to assess risk factors for BM. The median follow-up time was 11 months (range 0-154.0 months). A total of eight patients (5.3 %) developed BM during the course of their illness. Multivariate analysis identified age <65 years (odds ratio [OR] = 5.83, p = 0.038) and International Mesothelioma Interest Group stage IV (OR = 1.69, p = 0.040) as independent factors related to increased risk of developing BM. The 1-and 2-year cumulative rates of BM were 4.0 % (95 % confidence intervals [CI] 1.4-8.5 %) and 5.3 % (95 % CI 2.3-10.2 %), respectively. Our study showed that the overall survival (OS) of patients with BM was worse than that of patients without BM (median OS 6.5 vs. 11.0 months, p = 0.037). The prognosis for BM in MPM patients is poor. Clinicians should perform careful screening for BM, especially in patients with risk factors.