sequential changes in host tracheas consisted of hyperplasia with complete loss of mucociliary epithelium , squamous metaplasia , intense mononuclear infiltration , reestablishment of mucocillary epithelium ( during the course of nhmi administration ) except for focal areas of hyperkeratotic squamous metaplasia or marked dystrophic changes , and finally , papillomas , polyps , and invasive squamous cell carcinomas .
C0014609
epithelium
C0007137
squamous cell carcinomas