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T. Otsuki
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P3.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 226)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P3.08-006 - NF2 Mutations in Malignant Pleural Mesothelioma Synchronous with Acoustic Neuroma: Disease-Causing Mutation or Chance Effect? (ID 2562)
09:30 - 09:30 | Author(s): T. Otsuki
- Abstract
Background:
Patients with neurofibromatosis type 2 (NF2) are predisposed to schwannomas and meningiomas. Somatic NF2 mutation has also been reported in patients with sporadic schwannomas and a variety of cancers. In particular, approximately 35–40% of patients with malignant pleural mesothelioma (MPM) carry inactivating mutations of NF2. In addition to NF2, BRCA1-associated protein-1 (BAP-1) has also been identified as a key genetic alteration in mesothelioma. Recently, a new familial cancer syndrome associated with germline mutations in BAP1 was proposed, which includes MPM, ocular melanoma, and other cancers. However, NF2 mutations do not usually cause mesothelioma synchronous with schwannoma. We here report two cases of MPM synchronous with vestibular schwannomas and analytical finding on NF2 mutations
Methods:
Case 1 was a 65-year-old man with epithelioid MPM. A unilateral acoustic neuroma was resected in 2010 because the patient experienced progressive hearing loss in the right ear since 2000. In April 2012, right pleural fluid was detected on chest X-ray and a thoracoscopical examination was performed. Epithelioid MPM was diagnosed pathologically. Case 2 was a 72-year-old man with epithelioid MPM synchronous with unilateral acoustic neurinoma. The patient presented with DOE and hearing loss in the left ear that had progressed over the past month. Chest X-ray showed pleural effusion, and a biopsied specimen with thoracoscopy revealed epithelioid MPM. Brain MRI and CT showed a mass that was highly suspected to be acoustic neurinoma between the left cerebellopontine angle and the opening of the internal acoustic meatus. We performed whole-exome sequencing on DNA in tumor tissue and blood and immunohistochemical analysis of NF2 gene encoding protein merlin.
Results:
Both patients were diagnosed with synchronous acoustic neurinoma and epithelioid MPM. NF2 gene mutations were identified in both tumors of MPM and acoustic neurinoma in Case 1. And in Case 2, diagnosis of acoustic neurinoma was depended on typical findings of brain MRI/CT, for which surgical resection was not performed because of advanced stage of MPM. Tumor tissue of MPM in Case 2 showed positive result of NF2 mutation. Both patients had a history of asbestos exposure.
Conclusion:
Although the role of NF2 mutation as a possible disease-causing mutation in MPM and synchronous occurrence with schwannoma remain unclear, both cases showed the possible role of NF2 mutation in asbestos-related neoplasm. We will show the pedigree of the patients’ families.
