You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A 45 year old, HIV positive patient presents with features of pneumonia. Characteristic histopathological features suggesting pneumocystis carinii pneumonia is: and explain in detail?
Answer is B (Eosinophilic Alveolar Exudate): The most characteristic histoputhological feature of pneumocystis carinii pneumonia in adults is predominantly alveolar, foamy vacuoloted, eosinophilic exudates. Interstitial pneumonitis is usually mild and shows infiltration with PML and mononuclear cells.