Oral cancer or mouth cancer, a type of head and neck cancer, is any cancerous tissue growth located in the oral cavity. It may arise as a primary lesion originating in any of the tissues in the mouth, by metastasis from a distant site of origin, or by extension from a neighboring anatomic structure, such as the nasal cavity. Alternatively, the oral cancers may originate in any of the tissues of the mouth, and may be of varied histologic types: teratoma, adenocarcinoma derived from a major or minor salivary gland, lymphoma from tonsillar or other lymphoid tissue, or melanoma from the pigment-producing cells of the oral mucosa. There are several types of oral cancers, but around 90% are squamous cell carcinomas, originating in the tissues that line the mouth and lips. Oral or mouth cancer most commonly involves the tongue. It may also occur on the floor of the mouth, cheek lining, gingiva (gums), lips, or palate (roof of the mouth). Most oral cancers look very similar under the microscope and are called squamous cell carcinoma, but less commonly other types of oral cancer occur, such as Kaposi’s sarcoma.
Types of Oral Cancer
Squamous cell carcinoma: More than 90% of cancers that occur in the oral cavity and oropharynx are squamous cell carcinoma. Normally, the throat and mouth are lined with so-called squamous cells, which are flat and arranged in a scale-like way. Squamous cell carcinoma means that some squamous cells are abnormal.
Verrucous carcinoma: About 5% of all oral cavity tumors are verrucous carcinoma, which is a type of very slow-growing cancer made up of squamous cells. This type of oral cancer rarely spreads to other parts of the body, but can invade the tissue surrounding the site of origin.
Minor salivary gland carcinomas: This category includes several kinds of oral cancer that can develop on the minor salivary glands, which are found throughout the lining of the mouth and throat. These types include adenoid cystic carcinoma, mucoepidermoid carcinoma, and polymorphous low-grade adenocarcinoma.
Lymphomas:Oral cancers that develop in lymph tissue, which is part of the immune system, are known as lymphomas. The tonsils and base of the tongue both contain lymphoid tissue. See our pages on Hodgkin lymphoma and non-Hodgkin lymphoma for cancer information related to lymphomas in the oral cavity.
Benign oral cavity and oropharyngeal tumors: Several types of non-cancerous tumors and tumor-like conditions can arise in the oral cavity and oropharynx. Sometimes, these conditions may develop into cancer. For this reason, benign tumors, which usually don’t recur, are often surgically removed.
Leukoplakia and erythroplakia: These non-cancerous conditions mean that there are certain types of abnormal cells in the mouth or throat. With leukoplakia, a white area can be seen, and with erythroplakia, there is a red area, flat or slightly raised, that often bleeds when scraped. Both conditions may be precancerous; that is, they can develop into different types of cancer. When these conditions occur, a biopsy or other test is done to determine whether the cells are cancerous.
Most leukoplakia is benign: About 25% of cases of leukoplakia are either cancerous when first discovered or become precancerous. Erythroplakia is usually more serious, with about 70% of cases cancerous either at the time of diagnosis or later.
Comments
Post a Comment