Squamous cell carcinoma

In medicine, squamous cell carcinoma (SCC) is a form of cancer of the carcinoma type that may occur in many different organs, including the skin, lips, mouth, esophagus, urinary bladder, prostate, lungs, vagina, and cervix. It is a malignant tumor of squamous epithelium (epithelium that shows squamous cell differentiation).

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Terminology

  A carcinoma can be characterized as either in situ (confined to the original site) or invasive, depending on whether the cancer invades underlying tissues; only invasive cancers are able to spread to other organs and cause metastasis.

Sites

Skin

Squamous cell carcinoma is the second most common cancer of the skin (after basal cell carcinoma but more common than melanoma). It usually occurs in areas exposed to the sun, and can generally be treated by excision only. Sunlight exposure and immunosuppression are risk factors for SCC of the skin. The risk of metastasis is larger than with basal cell carcinoma.

Head and neck cancer

  Most cases of head and neck cancer (cancer of the mouth, nasal cavity, throat and associated structures) are due to squamous cell carcinoma. Symptoms may include a poorly healing mouth ulcer, a hoarse voice or other persistent problems in the area. Treatment is usually with surgery (which may be extensive) and radiotherapy. Risk factors include smoking and alcohol consumption.

Esophagus

Esophageal cancer may be due to either SCC or adenocarcinoma. SCCs tend to occur closer to the mouth, while adenocarcinomas occur closer to the stomach. Dysphagia (difficulty swallowing, solids worse than liquids) and odynophagia are common initial symptoms. If the disease is localized, esophagectomy may offer the possibility of a cure. If the disease has spread, chemotherapy and radiotherapy are commonly used.

Lung

When associated with the lung, it often causes ectopic production of parathyroid hormone-related protein (PTHrP), resulting in hypercalcemia.

Prostate

When associated with the prostate, squamous cell carcinoma is very aggressive in nature. It is difficult to detect as there is no increase in prostate specific antigen levels seen; meaning that the cancer is often diagnosed at an advanced stage.

Vagina and cervix

Vaginal squamous cell carcinoma spreads slowly and usually stays near the vagina, but may spread to the lungs and liver. This is the most common type of vaginal cancer.

Related conditions

• Keratoacanthoma is a low-grade malignancy of the skin. It originates in the pilo-sebaceous glands, and is similar in clincal presentation and microscopic analysis to squamous cell carcinoma, except that it contains a central keratin plug. Statistically, it is less likely to become invasive than squamous cell carcinoma.
• Bowen's disease is a sunlight-induced skin disease, and is considered to be an early form of squamous cell carcinoma.
• Marjolin's ulcer is a type of squamous cell carcinoma that arises from an non-healing ulcer or burn wound.