Brain metastases in malignant pleural mesothelioma

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).

When the Diagnosis of Mesothelioma Challenges Textbooks and Guidelines

The diagnosis of malignant mesothelioma (MPM) does not pose difficulties when presenting with usual clinico-radiologic features and morphology. Pathology textbooks and national/international guidelines generally describe the findings of classic MPM, underlining common clinical presentation, the gold standard of sampling techniques, usual morphologic variants, immunohistochemical results of several positive and negative primary antibodies in the differential diagnosis, and the role of novel molecular markers. Nevertheless, MPM often does not follow the golden rules in routine practice, while the literature generally does not sufficiently emphasize unusual features of its manifestation. This gap may potentially create problems for patients in sustaining a difficult diagnosis of MPM in clinical practice and during legal disputes. Indeed, the guidelines accidentally tend to favor the job of lawyers and pathologists defending asbestos-producing industries against patients suffering from MPM characterized by uncommon features. The current review is aimed at underlining the wide spectrum of clinical and radiological presentation of MPM, the possibility to consistently use cytology for diagnostic intent, the aberrant immunohistochemical expression using so-called specific negative and positive primary antibodies, and finally proposing some alternative and more unbiased approaches to the diagnosis of MPM.

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.

Impressive clinical response to anti-PD-1 therapy in epithelioid mesothelioma with high clonal PD-L1 expression and EML4-ALK rearrangement

OBJECTIVES

Treatment options for malignant pleural mesothelioma (MPM) are limited but some studies on immune checkpoint inhibitors (ICIs) in MPM have reported antitumor activity. Very little is known about immune-related predictive factors.

MATERIALS AND METHODS

Here we report the case of a 45-year-old woman presenting with dyspnea and evidence of pleural effusion. She was diagnosed with malignant epithelioid pleural mesothelioma with brain metastasis and peritoneal carcinosis, refractory to initial standard chemotherapy treatment. Because of high PDL1 expression (100 %), she was treated with the anti-PD1 agent, pembrolizumab.

RESULTS

Chemotherapy with cisplatin and pemetrexed was started, imaging studies showing stable disease after 3 treatment cycles. The patient underwent pleural decortication but rapidly progressed and thus started chemotherapy with carboplatin and gemcitabine. After 2 cycles she experienced seizures caused by a brain metastasis. This secondary lesion was surgically removed and confirmed as a metastasis from mesothelioma. Samples from both the primary tumor and the metastasis were molecularly characterized, the pleural sample proving ALK-positive and the brain sample, ALK-negative. PD-L1 was positive in 10 % of tumor cells in the pleural biopsy and 100 % in the brain lesion. Next generation sequencing analysis was negative for both samples. It was decided to start alectinib. Disease progression (peritoneal carcinosis and liver metastases) was documented after one month followed by complete bowel obstruction and recurrence in the site of the brain surgery. Alectinib was stopped and supportive care begun with parenteral nutrition via nasogastric tube. Pembrolizumab was started and after 15 days the patient's condition had significantly improved, enabling recanalization and restoration of enteral nutrition. Imaging displayed complete response of the brain metastasis, peritoneal carcinosis, bone lesions and mediastinal nodal metastases. A partial response was documented in the pleural and pulmonary nodules, with stable liver metastases. The patient is still undergoing immunotherapy and has no cancer-related symptoms.

CONCLUSIONS

Our findings indicate that the use of immunotherapy in MPM warrants further investigation. Furthermore, the impressive clinical response obtained by our patient suggests that immune checkpoint inhibitors could help in the management of the disease after the failure of other treatments.

Prognostic and predictive factors in patients with brain metastases from solid tumors: A review of published nomograms

OBJECTIVE

To review published nomograms that predict endpoints such as overall survival (OS) or risk of intracranial relapse in patients with brain metastases from solid tumors.

METHODS

The methods and results of nomogram studies identified by a systematic search were extracted and compared, stratified by endpoint predicted by the respective nomograms. In particular, validation strategies (external/internal), concordance indices (cut-off 0.75) and comparisons to older models were analyzed.

RESULTS

Six publications reported on prediction of OS. Most of these analyses focused on one particular primary tumor site, e.g., breast cancer or hepatocellular carcinoma, while the largest study included different primary tumor sites. The median number of patients was 244. Three of six studies included external validation cohorts. With few exceptions, concordance indices <0.75 were reported. In all studies reporting this endpoint, the nomogram outperformed older prognostic scores. Two nomograms focused on development of new brain metastases after radiosurgery (one externally validated), one on survival free from salvage whole brain radiotherapy (WBRT) after radiosurgery, and one on neurologic and non-neurologic death in patients receiving radiosurgery after WBRT failure. All concordance indices of these 4 nomograms were <0.70.

CONCLUSION

Taking into account concordance indices and comparisons to older prognostic models, the most promising, externally validated nomograms are the breast cancer and the non-small cell lung cancer nomogram predicting OS, and the distant brain failure after radiosurgery nomogram. Additional validation studies as well as continuous monitoring of the models' performance appear necessary to ensure their clinical applicability in the present era of rapidly changing treatment paradigms.

Primary Spinal Malignant Mesothelioma: A Case Report and Literature Review

BACKGROUND

Malignant mesotheliomas are aggressive and rapidly fatal neoplasms arising from the mesothelial cells. The most common sites of origin are the pleural and peritoneal cavities; the pericardium and the tunica vaginalis are infrequently involved, and malignant mesothelioma in the spinal canal is extremely rare. Here we report a case of primary spinal malignant mesothelioma. We also report the results of a literature search conducted in PubMed with specific key terms, inclusion criteria, and exclusion criteria, with a comparison of elected case studies and case series, and statistical analysis as appropriate.

CASE DESCRIPTION

A 35-year-old man presented with a 3-month history of swelling and pain in the left lower extremity. Neurologic examination revealed a loss of sensation below the L5 dermatome. Magnetic resonance imaging (MRI) showed a mass at the L4-5 level. A diagnosis of schwannoma was suspected, and surgical resection was performed. Histopathological findings were consistent with sarcomatoid malignant mesothelioma. Thoracic and whole-abdomen computed tomography yielded normal results. The patient refused adjuvant radiotherapy or chemotherapy. Positron emission tomography-computed tomography performed at 3 months postoperatively showed no abnormality. At 8 months postoperatively, the patient developed back pain and difficulty with defecation; MRI demonstrated tumor recurrence. During a second operation, invasion of the vertebra and cauda equina was noted. A subtotal resection was achieved, and the pain was partially alleviated. Two months later, the patient succumbed to a traffic accident.

CONCLUSIONS

Spinal malignant mesothelioma is an extremely rare but highly aggressive entity. Preoperative identification is challenging, and definitive diagnosis depends on histopathological evidence. Surgical resection can help relieve the symptoms, but the overall prognosis is poor.

Systemically Administered RNAi Molecule Sensitizes Malignant Pleural Mesotheliomal Cells to Pemetrexed Therapy

Pemetrexed (PMX) is a key drug for the management of malignant pleural mesothelioma (MPM). However, its therapeutic efficacy is cruelly restricted in many clinical settings by the overexpression of thymidylate synthase (TS) gene. Recently, we emphasized the efficacy of locally administered shRNA designed against TS gene in enhancing the cytotoxic effect of PMX against orthotopically implanted MPM cells in tumor xenograft tumor model. Herein, we explored the efficiency of systemic, rather than local, delivery of TS RNAi molecule in sensitizing MPM cells to the cytotoxic effect of PMX. We here designed a PEG-coated TS shRNA-lipoplex (PEG-coated TS shRNA-lipoplex) for systemic injection. PEG modification efficiently delivered TS shRNA in the lipoplex to tumor tissue following intravenous administration as indicated by a significant suppression of TS expression level in tumor tissue. In addition, the combined treatment of PMX with systemic injection of PEG-coated TS shRNA-lipoplex exerted a potent antitumor activity in a s.c. xenograft tumor model, compared to a single treatment with either PMX or PEG-coated TS shRNA-lipoplex. Metastasis, or the spread, of mesothelioma substantially dedicates the effectiveness of treatment options. The systemic, in addition to local, delivery of tumor targeted anti-TS RNAi system we propose in this study might be an effective option to extend the clinical utility of PMX in treating malignant mesothelioma.