This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Pleural mesothelioma is associated with- \nSelect and explain. \nA. Asbestosis, B. Berylliosis, C. Silicosis, D. Bagassosis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Malignant mesothelioma of pleura \n\nMalignant mesothelioma in the thorax arise from either the visceral or the parietal pleura.\nIt is associated with exposure to asbestos.\nSimian virus 40 (SV40) viral DNA has also been associated with malignant mesothelioma. \n\nMorphology\n\nMalignant mesothelioma is a diffuse lesion that spreads widely in the pleural surface and is usually associated with extensive pleural effusion and direct invasion of thoracic structures.\nMalignant mesothelioma may be of following types, depending on the type of mesothelial cells that is present in the tumor.\n\n1. Epithelioid type\n\nMesothelial cells develop as epithelium like lining cells.\nConsists of cuboidal, columnar or flattened cells forming tubular or papillary structures.\nEpithelioid type of mesothelioma resembles adenocarcinoma of lung and can be differentiated from it by following featurs:-\n\n\nPositive staining for mucopolysaccharide.\nLack of staining for carcinoembryonic antigen (CEA).\nStrong staining for keratin.\nPositive staining for calretinin, wilms' tumor 1 susceptibility gene product, cytokeratin 5/6, mesothelin and thrombomodulin.\nPresence of long microvilli and abundant tonofilaments but absent microvillous rootlets and lamellar bodies.\n\n2. Sarcomatoid (mesenchymal type)\n\nMesothelial cells develop as mesenchymal stromal cells.\nThey appear as spindle cell sarcoma, resembling fibrosarcoma.\n\n3. Mixed type (Biphasic type)\n\nContains both epithelioid and sarcomatoid patterns.", 'role': 'assistant'}]