Carcinoma: Definition, And Types

Carcinoma Definition

Carcinoma is a type of cancer that begins in the skin or tissues that line or cover internal organs. It can be invasive, meaning it has spread beyond the primary tissue, or in situ, meaning abnormal cells are found only in the place where they first formed and haven’t spread to other parts of the body. Basal cell carcinoma is the most common type of skin cancer.

Types of Carcinoma


Adenocarcinoma is a type of cancer that starts in the glandular tissue, which lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices, and other fluids.

Adenocarcinomas can occur in many organs such as the breast, lung, esophagus, stomach, colon, rectum, pancreas, prostate, uterus, and cervix. Adenocarcinoma can start out as a small polyp or growth that’s usually harmless at first but can turn cancerous.

Adenocarcinomas are diagnosed like other cancer types and are usually detected by taking a biopsy (tissue sample) of the tumor. The treatment recommended for adenocarcinoma depends on the location, size, and type of tumor. It also depends on whether or not cancer has spread to other parts of your body.

There are three main treatments for adenocarcinoma: surgery to remove the tumor; radiation therapy to kill cancer cells; chemotherapy to kill cancer cells or stop them from growing. The prognosis for adenocarcinoma varies depending on the type, location, and stage of cancer. Early detection is important for successful treatment outcomes.

Risk factors for adenocarcinoma include age, family history of cancer, smoking tobacco products (lung), alcohol consumption (esophageal), gastroesophageal reflux disease (GERD) (esophageal), H. pylori infection (gastric), Crohn’s disease or ulcerative colitis (colon).

To reduce your risk of developing adenocarcinoma it is recommended to avoid tobacco products; be physically active; maintain a healthy weight; eat a well-balanced diet; visit your healthcare provider regularly.

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is a common form of skin cancer that develops in the squamous cells that make up the middle and outer layers of the skin.

SCC is the second most common form of skin cancer after basal cell carcinoma. It usually occurs on areas of the skin that have been exposed to natural sunlight or artificial sunlight (such as from tanning beds) over long periods of time.

SCC occurs when DNA damage from exposure to ultraviolet radiation or other damaging agents triggers abnormal changes in the squamous cells. The mutations tell the squamous cells to grow out of control and to invade surrounding tissues, leading to cancerous growth.

SCCs can appear as scaly red patches, open sores, rough, thickened, or wart-like skin, or raised growths with a central depression. At times, SCCs may crust over, itch, or bleed. The lesions most commonly arise in sun-exposed areas of the body such as the face, ears, neck, lips, and backs of hands.

Treatment for SCC depends on various factors such as the size and location of the tumor. Treatment options include surgical removal, radiation therapy, topical medications such as imiquimod cream, and photodynamic therapy. In some cases where SCC has spread beyond its original site, chemotherapy may be used.

Basal Cell Carcinoma

Basal cell carcinoma (BCC) is a type of skin cancer that arises from abnormal, uncontrolled growth of basal cells in the outermost layer of skin (epidermis).

BCC is the most common form of skin cancer and the most frequently occurring form of all cancers, with an estimated 3.6 million cases diagnosed each year in the U.S. alone.

BCC often appears as a slightly transparent bump on the skin, though it can take other forms. It usually occurs on areas of the skin that are exposed to the sun, such as your head and neck.

BCC is serious and should be addressed as soon as possible. When found early, this skin cancer is highly treatable. An early BCC can often be removed during an appointment with a dermatologist.

However, given time to grow, this skin cancer can grow deep, injuring nerves, blood vessels, and anything else in its path. As the cancer cells pile up and form a large tumor, cancer can reach into the bone beneath. This can change the way you look, and for some people, the change may be disfiguring.

The exact cause of BCC may not always be clear but exposure to ultraviolet (UV) radiation from sunlight or indoor tanning is known to trigger changes in basal cells that lead to uncontrolled growth.

Other risk factors include fair skin; blue or green eyes; blond or red hair; a history of sunburns or excessive sun exposure; exposure to radiation; exposure to certain chemicals such as arsenic; a weakened immune system; and having had BCC before.

Anaplastic Carcinoma

Anaplastic thyroid carcinoma, also known as undifferentiated thyroid carcinoma, is a rare and highly aggressive malignant tumor that accounts for 2 to 3 percent of all thyroid gland neoplasms.

It is one of the fastest-growing and most aggressive types of cancer. The cause of anaplastic thyroid cancer is unknown, but it often arises in an unhealthy thyroid or from another type of thyroid cancer.

Anaplastic thyroid cancer can present as a lump or nodule in the neck that grows very quickly and can be visible to the patient or their family and friends.

Most patients with ATC have metastases, particularly in the lung, at diagnosis more than 50% of the time. The survival rate for ATC is reportedly less than 10%, and most patients do not live longer than a few months after diagnosis.

Treatment for anaplastic thyroid cancer is mostly palliative. Surgical resection with adjuvant radiation therapy and chemotherapy may prolong survival somewhat and improve quality of life. However, it is important to note that each patient’s prognosis is individualized, so it’s essential to talk to your doctor if you want information on your prognosis.

Large Cell Carcinoma

Large cell lung cancer is a subtype of non-small cell lung cancer (NSCLC) that can appear in any part of the lung and tends to grow and spread quickly, making it harder to treat.

Large-cell lung cancer is categorized as such by how the cancer cells look under a microscope. The cells do not clearly look like adenocarcinoma or squamous cell lung cancer, and they are distinguished from small cell lung cancer cells by their larger size.

In the past, about 10% of all lung cancers were classified as large cells. However, as more exact ways of diagnosing lung cancer have come into use, this percentage is dropping to possibly as low as 2%.

Large cell carcinoma can be staged using the TNM system. T stands for tumor size and whether it has grown into nearby tissue; N stands for whether cancer has spread to nearby lymph nodes; M stands for whether cancer has metastasized (spread) to other parts of the body.

Treatment options depend on several factors including stage, location, and overall health. Surgery, radiation therapy, chemotherapy, targeted therapy, immunotherapy, or a combination of these may be used to treat large-cell carcinoma.

It is important to note that having additional information about the type of NSCLC is important for choosing treatment options. According to, about 80% to 85% of lung cancers are NSCLC.

The main subtypes of NSCLC are adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. These subtypes start from different types of lung cells but are grouped together as NSCLC because their treatment and prognoses (outlook) are often similar.

Small Cell Carcinoma

Small cell carcinoma is a type of cancer that can appear in various parts of the body, but most often occurs in the lung. It is also known as small-cell lung cancer (SCLC) or oat-cell cancer because the cancer cells may appear to look like oats under a microscope.

Small cell carcinoma grows very rapidly and spreads quickly to other parts of the body. There are two types of small cell lung cancer: small cell carcinoma and combined small cell carcinoma.

Small cell lung cancer is a rare and aggressive illness. Without treatment, most people with small cell lung cancer will die within a few months.

Treatment options for small cell lung cancer include surgery, radiation therapy, chemotherapy, laser therapy, and targeted therapy. The treatment depends on many factors including age, overall health, and cancer stage.

Surgery is not commonly used for treating small-cell lung cancer. In some cases where the tumor has not spread beyond the lungs, surgery may be done to remove part or all of the affected lung.

Symptoms of small cell lung cancer include coughing that doesn’t go away, chest pain that gets worse with deep breathing or coughing, shortness of breath, wheezing, hoarseness, loss of appetite, and weight loss without trying to lose weight.

If you’re showing possible symptoms of lung cancer such as these symptoms mentioned above or have a history of smoking tobacco products talk with your provider about getting screened for lung cancer.

Adenosquamous Carcinoma

Adenosquamous carcinoma is a type of cancer that contains two types of cells: squamous cells and gland-like cells.

It has been associated with more aggressive characteristics when compared to adenocarcinoma in certain cancers. Adenosquamous carcinoma is responsible for 1% to 4% of exocrine forms of pancreatic cancer.

Adenosquamous carcinoma can occur in different parts of the body, including the lung and skin. Diagnosis is made through light microscopy, which shows a combination of gland-like cells and squamous epithelial cells.

On immunohistochemistry, it is typically positive for CK5/6, CK7, and p63 and negative for CK20, p16, and p53. On genetic testing, KRAS and p53 are typically altered.

Treatment options depend on the location and stage of cancer. Surgery may be an option if the cancer is detected early enough. Chemotherapy or radiation therapy may also be used to treat adenosquamous carcinoma.

How Is Carcinoma Diagnosed?

There is no single test that can accurately diagnose cancer. The complete evaluation of a patient usually requires a thorough history and physical examination along with diagnostic testing.

Diagnostic procedures for cancer may include imaging, laboratory tests (including tests for tumor markers), tumor biopsy, endoscopic examination, surgery, or other exams.

Imaging tests used in diagnosing cancer may include a computerized tomography (CT) scan, bone scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, ultrasound, and X-ray among others.

A biopsy is often the only way to tell for sure if you have cancer. During a biopsy, your doctor collects a sample of cells for testing in the laboratory. Lab tests used to diagnose cancer include blood chemistry tests, complete blood count (CBC), cytogenetic analysis, immunophenotyping, and liquid biopsy.

Liquid biopsy is a test done on a sample of blood to look for circulating tumor cells (cells from a cancerous tumor that have entered the bloodstream) in order to help doctors monitor metastatic breast, prostate, and colorectal cancers.

Staging tests and procedures may include imaging tests such as bone scans or X-rays to see if cancer has spread to other parts of the body. Cancer stages are indicated by the numbers 0 through 4 which are often written as Roman numerals 0 through IV. Higher numbers indicate more advanced cancer. For some types of cancer, the cancer stage is indicated using letters or words.

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