<prompt> All are true regarding mesothelioma except?Bilaterally symmetricalAssociated with asbestos exposureHistopathalogy shows biphasic patternOccurs in late middle age  <response>: Malignant mesothelioma is MC tumor of the pleura In 20 of malignant mesotheliomas, the tumor arises from peritoneum Exposure to asbestos is the major known risk factor More common in males, most common after 40 years of age. Three types: Epithelial, sarcomatous, and biphasic Epithelial types are associated with a more favorable prognosisPathophysiology Physical characteristics of specific fibers referred to as serpentine or amphibole have been shown to be important. Serpentine fibers: Large and curly, not able to travel beyond larger airways. Straight amphibole fibers: In particular the crocidoliteQ fibers navigate distally into the pulmonary parenchyma, most clearly associated with mesotheliomas. Latency period between asbestos exposure and the development of mesothelioma is at least 20 years. Multicentric tumor with multiple pleura-based nodules coalescing to form sheets of tumor but not bilaterally symmetrical Natural history of the disease in untreated patients culminates in death due to local extension.Clinical Features Most patients present with dyspnea and chest pain. Over 90 have a pleural effusion.Diagnosis Results of thoracentesis are diagnostic in 10 of patients. Chest X-ray: Pleural effusion, generalized pleural thickening and shrunken hemithorax. Thoracoscopy or open pleural biopsy with special staining of tumor samples is required to differentiate mesotheliomas from adenocarcinomas.Management No effective therapy Treatment options: Supportive care only, surgical resection, and multimodality approaches using a combination of surgery, chemotherapy, and radiation therapy. 