Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. By your history and description, possibility of old fibrotic lesion in lung is more likely. This is due to healing. You might be having previous lung infection which heals by time and treatment. In lungs, healing takes place mostly in the form of fibrosis or calcification. Both of them are permanent Scar lesions. They will remain as it is through out the life. No treatment is required hence available for these scars because they are inactive Scar lesions. No need to worry as bronchoscopy is negative for active infection. Hope I have answered your query. Let me know if I can assist you further.