Squamous metaplasia is a benign non-cancerous change (metaplasia) of surfacing lining cells (epithelium) to a squamous morphology.
Common sites for squamous metaplasia include the bladder and cervix. Smokers often exhibit squamous metaplasia in the linings of their airways. These changes don't signify a specific disease, but rather usually represent the body's response to stress or irritation. Vitamin A deficiency or overdose can also lead to squamous metaplasia.[1]
In regard to the cervix, squamous metaplasia can sometimes be found in the endocervix, as it is composed of simple columnar epithelium, whereas the ectocervix is composed of stratified squamous non-keratinized epithelium.[2]
Squamous metaplasia may be seen in the context of benign lesions (e.g., atypical polypoid adenomyoma), chronic irritation, or cancer (e.g., endometrioid endometrial carcinoma), as well as pleomorphic adenoma.