Diffuse malignant mesothelioma and synchronous lung cancer: A clinicopathological study of 18 cases

Successful treatment of simultaneous malignant pleural mesothelioma and pulmonary adenocarcinoma: A case report

The present report described the case of a 74-year-old male patient with asbestos exposure whose chest computed tomography revealed a right lower lobe nodule and right pleural effusion. Pleural biopsy led to the diagnosis of epithelial malignant pleural mesothelioma (cT2N0M0, stage IB). Combination therapy with cisplatin + pemetrexed led to the complete remission of malignant pleural mesothelioma; however, the right lower lobe nodule grew in size over time. The patient was subsequently diagnosed with lung adenocarcinoma (cT1aN0M0, stage IA1) by computed tomography-guided biopsy performed 18 months after chemotherapy initiation and achieved remission of lung adenocarcinoma with stereotactic radiotherapy. The patient was alive without recurrence at the 12-month follow-up. The present case illustrated that multiple active regimens are currently available for malignant pleural mesothelioma and lung cancer that can aid in the treatment of complex cases.

The over diagnosis of diffuse mesothelioma: An analysis of 311 cases with recommendations for the avoidance of pitfalls

BACKGROUND

The diagnosis of mesothelioma may be challenging. We investigated a large database of cases in order to determine the frequency with which a diagnosis of mesothelioma was made incorrectly and the most frequent causes of error.

DESIGN

A database including more than 4000 consultation cases of histologically confirmed mesothelioma was examined to identify cases in which mesothelioma was diagnosed by at least one pathologist when the available information pointed towards a different diagnosis.

RESULTS

There were 311 cases misdiagnosed as mesothelioma. The most common category was metastatic carcinoma to the pleura or peritoneum (129 cases: 73 lung carcinomas, 15 renal cell carcinomas). The next most common category was primary lung cancer (111 cases: 55 sarcomatoid carcinoma, 56 pseudomesotheliomatous carcinoma). The third most common category was primary malignancies arising from or near the serosal membranes (33 cases). The fourth most common category was fibrous pleurisy (38 cases). The most common errors were failure to consider important radiographic information regarding the gross distribution of tumor, lack of awareness or consideration of another malignancy, overreliance on certain immunohistochemical results, and failure to perform certain diagnostic histochemical, immunohistochemical, or ultrastructural studies.

CONCLUSIONS

There are a number of diagnostic pitfalls that can lead to the over diagnosis of mesothelioma. Careful attention to clinical and radiographic information as well as performance of appropriate ancillary tests can help to prevent such misdiagnoses. Detailed examples will be presented to assist in the avoidance of these pitfalls with emphasis on the most commonly observed errors.

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.

Malignant mesothelioma without asbestos exposure diagnosed during EGFR-TKI treatment of lung adenocarcinoma: A case report

Synchronous malignant mesothelioma (MM) and lung carcinoma are extremely rare in patients without a history of asbestos exposure and poses tremendous difficulties in clinical management. We report a patient without asbestos exposure diagnosed with MM during EGFR-TKI treatment of lung adenocarcinoma (LUAD), who responded to first-line chemotherapy with pemetrexed plus carboplatin and failed to subsequent systemic therapy. Clinicians should be careful about the possibility of MM comorbidity in LUAD patients whose lesions respond differently to EGFR-TKI, even in those without a history of asbestos exposure.

Genomic profiling of multiple primary cancers including synchronous lung adenocarcinoma and bilateral malignant mesotheliomas: Identification of a novel BAP1 germline variant

We report a case with a rare combination of synchronous lung adenocarcinoma and bilateral malignant pleural mesotheliomas in a 70-year-old male without asbestos exposure. He metachronously developed peritoneal malignant mesothelioma, intrahepatic cholangiocarcinoma, urothelial carcinoma of the bladder and prostatic adenocarcinoma. Immunohistochemistry revealed complete loss of BAP1 expression in all seven lesions. Targeted next generation sequencing using Todai OncoPanel identified a novel germline variant (c.1565_1566del, p.P522Rfs*14) of BAP1. Additionally, different nonsynonymous somatic mutations of BAP1 were identified in four lesions including lung adenocarcinoma, malignant pleural and peritoneal mesotheliomas, and bladder cancer. The remaining two lesions had different somatic mutations in genes other than BAP1. Multiple BAP1-deficient cancers that developed in a single patient suggest the newly identified germline variant of BAP1 gene to be pathogenic and this case expands the clinical spectrum of BAP1-tumor predisposition syndrome. Screening for BAP1 status is highly recommended in cases with a similar combination of cancers.

Metachronous Lung Cancer After Pleurectomy/Decortication

Pleurectomy/decortication is a surgical procedure for malignant pleural mesothelioma (MPM) and has been proposed as an alternative to extrapleural pneumonectomy. We report a second primary lung cancer developing after pleurectomy/decortication for MPM. A 59-year-old man was diagnosed with MPM on the right side and underwent pleurectomy/decortication. Follow-up computed tomography detected a nodule in the right upper lobe that was diagnosed as adenocarcinoma by wedge resection. Lung cancer and MPM are associated with asbestos exposure. However, predicting lung cancer after treatment for MPM is difficult. Careful follow-up of the spared lung is necessary for detecting second primary lung cancer or MPM recurrence.

Malignant Mesothelioma in Individuals With Nonmesothelial Neoplasms

CONTEXT

- Malignant mesothelioma (MM) is a component of the BAP1 tumor predisposition syndrome. Other than in BAP1 familial studies, nonmesothelial neoplasms in individuals with MM has not been comprehensively assessed.

OBJECTIVE

- To assess the spectrum and prevalence of nonmesothelial neoplasms in individuals with MM.

DESIGN

- Individuals with MM and second neoplasms were identified from a database of 3900 MM cases. The expected prevalence of each type of neoplasm was calculated and compared with the actual prevalence in the study population using available Surveillance, Epidemiology, and End Results data and other published data.

RESULTS

- Two hundred seventy nonmesothelial neoplasms were identified in 241 individuals (6% of the study population) with MM. Prostate adenocarcinoma was most common. Non-Hodgkin lymphoma, Hodgkin lymphoma, lung carcinoma, urothelial carcinoma, breast carcinoma, chronic lymphocytic leukemia, clear cell renal cell carcinoma, head and neck squamous cell carcinoma, papillary renal cell carcinoma, multiple myeloma/plasmacytoma, meningioma, pleomorphic undifferentiated sarcoma, chronic myelogenous leukemia, ocular melanoma, hepatocellular carcinoma, liposarcoma, and Wilms tumor all were more prevalent than expected.

CONCLUSIONS

- Nonmesothelial neoplasms are uncommon in individuals with MM, but certain tumor types are increased in prevalence. In an unselected study population with respect to BAP1 status, the prevalence of several tumor types described in BAP1 mutation carriers, including lung carcinoma, clear cell renal cell carcinoma, breast carcinoma, meningioma, pleomorphic undifferentiated sarcoma, and ocular melanoma, was increased.

Successful lung-sparing resection of synchronous pleural mesothelioma and contralateral lung cancer

Background

Malignant pleural mesothelioma (MPM) is an uncommon malignant tumor, and its synchronous occurrence with primary lung cancer is extremely rare. Here, we report the first surgical case of synchronous MPM and contralateral lung adenocarcinoma. Extrapleural pneumonectomy (EPP) combined with surgery for contralateral lung cancer may not be tolerated, and a lung-sparing procedure including pleurectomy/decortication (P/D) can be an alternative to achieve complete resection.

Case presentation

A 69-year-old male with right MPM and lung adenocarcinoma in the left upper lobe presented. Two lesions were judged to be synchronous MPM and lung cancer that were both potentially resectable clinical stage I diseases, and complete resection of both tumors was successfully achieved with right P/D following left upper division segmentectomy.

Conclusions

P/D, not EPP, is a less invasive surgical procedure for MPM with curative intent and can be performed in combination with contralateral lung resection.