Squamous metaplasia refers to benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 (non-cancerous

Cancer

Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

) changes in the epithelial

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 linings of certain organ

Organ (anatomy)

In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...

s within the body. These cells assume a more squamous morphology. Common sites for squamous metaplasia include the bladder

Urinary bladder

The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

 and cervix

Cervix

The cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...

. 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

Vitamin A

Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...

 deficiency can lead to squamous metaplasia.

In regards to the cervix, squamous metaplasia can sometimes be found in the ectocervix, as it is composed of squamous epithelium

Squamous epithelium

In anatomy, squamous epithelium is an epithelium characterised by its most superficial layer consisting of flat, scale-like cells called squamous epithelial cells...

, whereas the endocervix is composed of columnar epithelium. Squamous metaplasia in the cervix are susceptible to dysplasia

Dysplasia

Dysplasia , is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process...

 (precancerous changes), which is why a smear test can be performed to monitor changes.