Hyperplasia and hypertrophy of the goblet cells (mucous gland) of the airway are the common pathologic features of chronic bronchitis. Chronic inflammation due to lymphocyte infiltration is seen on microscopy.

• Hallmark features include: hyperplasia (increased number) and hypertrophy (increased size) of the goblet cells (mucous gland) of the airway, resulting in an increase in secretion of mucus, which contributes to the airway obstruction.^[1]
• Narrowing of the airways reduces the rate at which air can flow to and from the air sacs (alveoli) and limits the effectiveness of the lungs.

• On microscopic histopathological analysis, there is infiltration of the airway walls with inflammatory cells, particularly CD8+ T-lymphocytes and neutrophils.^[2] Inflammation is followed by scarring and remodeling that thickens the walls resulting in narrowing of the small airways.