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': "Histopatholoty of a lung cancer shows 'clara cells' probable diagnosis is ? \nSelect and explain. \nA. Squamous cell cancer, B. Bronchio alveolar cancer, C. Large cell cancer, D. Papillary carcinoma", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' i.e., Brochioalveolar carcinoma Bronchioloalveolar carcinoma o It is a histological type of adenocarcinoma. o It occurs in the pulmonary parenchyma in the terminal bronchioloalveolar pattern. o The tumor is almost always in the peripheral poion of the lung. o More often it occurs as multiple diffuse nodules that sometimes coalesce to produce a pneumonia - like consolidation. o The key feature of bronchioloaveolar carcinomas is their growth along preexisting structures without destruction of the alveolar architecture. This growth pattern has been termed "lepidic" an allusion to the neoplastic cells resembling butterflies sitting on a fence. o Stromal, vascular or pleural invasion is characteristically absent. o Bronchioloalveolar carcinoma consists mucin secreting bronchiolar cells, clara cells, or rarely type II pneumocytes. o These tend to have aerogenous spread and patient usually dies of suffocation (not by metastatic spread). o Bronchioloalveolar carcinoma has two subtypes ? (i) Nonmucinous --> Rare aerogenous spread and therefore amenable to surgical resection. (ii) Mucinous --> Tend to spread aerogenously, forming satellite tumors.', 'role': 'assistant'}]