Types of Carcinoma

Carcinoma is a cancer that arises from epithelial tissue cells. These cells are present both in the skin (epidermis) and in the lining of internal organs. Most cancers are of this type. Different types of carcinoma can be classified by their location and stage.

Epithelial tissue cells

The epithelium is a type of tissue, which consists of tightly bound cells without intercellular space. The layer of epithelial cells may be arranged in a single layer or multiple layers. The tissue lacks blood vessels and is separated from the underlying connective tissue by a basal membrane. It lines all external and internal free surfaces of the body, cavities, blood vessels and glands.

  • Morphologically the epithelium can be of the following types: Simple, Stratified and Pseudostratified.
  • The simple epithelium can be further classified on the basis of their appearance: Squamous, Cuboidal and Columnar
  • The stratified epithelium can also be divided into 2 categories: Keratinized and Transitional
  • The epithelium that forms the glands is called glandular epithelium. Glands are of two types: exocrine and endocrine. Mucous cells and serous cells surround the exocrine glands.
  • Carcinomas are named after the type of epithelial cell that they started in and the part of the body that is affected.

Types of carcinoma

On the basis of type of epithelial cell affected:

  • Squamous cell carcinoma
  • Adenocarcinoma
  • Adenosquamous carcinoma
  • Anaplastic carcinoma
  • Large cell carcinoma
  • Small cell carcinoma

On the basis of organs affected and examples of some of the carcinomas in these organs:

Breast:

  • Ductal Carcinoma in situ (non-invasive)
  • Lobular carcinoma in situ (non-invasive)
  • Invasive Ductal Carcinoma
  • Invasive lobular carcinoma
  • Non-invasive Carcinoma

Liver:

 

Lungs

  • Adenocarcinoma
  • Squamous Cell Carcinoma (Epidermoid Carcinoma)
  • Large-cell undifferentiated carcinoma
  • Bronchioalveolar carcinoma

Ovary

  • Surface epithelial-stromal tumor (Adenocarcinoma) or ovarian epithelial carcinoma (which includes serous tumor, endometrioid tumor and mucinous cystadenocarcinoma)
  • Epidermoid (Squamous cell carcinoma)
  • Embryonal carcinoma and choriocarcinoma ( germ cell tumors)

 

 

Kidney

  • Renal adenocarcinoma or hypernephroma
  • Transitional cell carcinoma (renal pelvis)
  • Squamous cell carcinoma
  • Bellini duct carcinoma
  • Clear cell adenocarcinoma
  • Transitional cell carcinoma
  • Carcinoid tumor of the renal pelvis

 

Adrenal

  • Adrenocortical carcinoma

Testes

  • Germ cell carcinoma (Seminoma, Choriocarcinoma, Embryonal carciroma, Teratocarcinoma)
  • Serous carcinoma

Stomach

Intestine

  • Adenocarcinoma (duodenum)

Skin

  • Basal cell carcinoma
  • Squamous cell carcinoma

Details on the types of carcinoma (Terms related to carcinoma)

Carcinoma-in-situ

  • Carcinoma in situ (CIS) is an early form of cancer that involves only the place in which it began and that has not spread or metastasized. The term in situ means “in place.”

Adenocarcinoma

  • An adenocarcinoma is a carcinoma (malignant tumor in epithelium) that originates in glandular tissue.

Squamous cell carcinoma

  • It is a type of carcinoma originating from squamous cells, the flat cells that form the outside layers of the skin, the epidermis. These cells are keratinising i.e., they produce keratin, the horny protein that makes up skin, hair and nails.

Basal Cell Carcinoma

  • Basal cell carcinoma begins in the basal cells — a type of cell within the skin (bottom of epidermis) that produces new skin cells to replace the old ones.

Adenosquamous cell carcinoma

  • It is a carcinoma formed of both adenocarcinoma and squamous cell carcinoma.

Invasive carcinoma

  • Invasive or infiltrating carcinomas describe cancer cells that have metastasized to other locations.

Non-invasive carcinoma

  • It is a type of carcinoma, which did not invade any other tissues and is localized within their original site.

Anaplastic or undifferentiated carcinoma

  • Carcinomas which are formed of different types of cells that originates from epithelial cells lacking distinct histological or cytological features that are generally observed in adenocarcinoma and squamous cell carcinoma. Anaplastic thyroid carcinoma is an example.

Small cell carcinoma

  • These cancer cells are smaller than are normal cells with little cytoplasm. An example is small cell lung cancer.

Large cell carcinoma

  • These cancer cells are larger than are normal cells. They are round or polygonal in shape. An example is lung cancer affecting the bronchioles.

Giant cell carcinoma

  • These cancer cells are very big in size and multinucleated.

Clear cell carcinoma

  • The inside of these cancer cells appears clear. Examples include some kidney, ovarian and uterine cancers.

Spindle cell carcinoma

  • These cancer cells are narrower at both ends than at the center. It resembles connective tissue cancers. Examples include some breast, gastrointestinal, muscle or other soft tissue, and skin cancers.

Sarcomatoid carcinoma

  • This type of carcinoma consists of both spindle and giant cell carcinoma.

Pleomorphic carcinoma 

  • This type of carcinoma contains a mixture of spindle cell and/or giant cell components and adenocarcinoma and/or squamous cell carcinoma (at least 10%).

Carcinosarcoma

  • It is a malignant tumor composed of a mixture of carcinoma and sarcoma 

References

  1. Jules J Berman (2004) Tumor classification: molecular analysis meets Aristotle
  2. BMC Cancer. ; 4: 10.
  3. Jules J Berman (2004) Tumor taxonomy for the developmental classification of neoplasms. BMC Cancer ; 4:88
  4. This article was originally published on September 3, 2012 and last revision and update was 9/4/2015.
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