In oncology

Oncology

Oncology is a branch of medicine that deals with cancer...

, small intestine cancer, also small bowel cancer and cancer of the small bowel, is a cancer

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...

 of the small intestine

Small intestine

The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

. It is relatively rare compared to other gastrointestinal malignancies

Gastrointestinal cancer

Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract, including the esophagus, stomach, biliary system, pancreas, bowels, and anus. The symptoms relate to the organ affected, and can include obstruction , abnormal bleeding, or other associated problems...

 such as gastric cancer (stomach cancer) and colorectal cancer

Colorectal cancer

Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....

.

Small intestine cancer can be subdivided into duodenal cancer

Duodenal cancer

Duodenal cancer is a cancer in the beginning section of the small intestine. It is relatively rare compared to gastric cancer and colorectal cancer. Its histology is usually adenocarcinoma...

 (the first part of the small intestine) and cancer of the jejunum

Jejunum

The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...

 and ileum

Ileum

The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...

 (the later two parts of the small intestine). Duodenal cancer has more in common with stomach cancer

Stomach cancer

Gastric cancer, commonly referred to as stomach cancer, can develop in any part of the stomach and may spread throughout the stomach and to other organs; particularly the esophagus, lungs, lymph nodes, and the liver...

, while cancer of the jejunum and ileum have more in common with colorectal cancer

Colorectal cancer

Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....

.

Several different subtypes of small intestine cancer exist. These include:

• adenocarcinoma
  Adenocarcinoma
  Adenocarcinoma is a cancer of an epithelium that originates in glandular tissue. Epithelial tissue includes, but is not limited to, the surface layer of skin, glands and a variety of other tissue that lines the cavities and organs of the body. Epithelium can be derived embryologically from...
  
  
• gastrointestinal stromal tumor
  Gastrointestinal stromal tumor
  A gastrointestinal stromal tumor is one of the most common mesenchymal tumors of the gastrointestinal tract...
  
  
• lymphoma
  Lymphoma
  Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage...
  
  
• ileal carcinoid tumor

Risk factors

Risk factors for small intestine cancer include:

• Crohn's disease
  Crohn's disease
  Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
  
  
• Celiac disease
• Radiation exposure
  Radiation exposure
  The term radiation exposure commonly has several uses:* Absorption of high-energy ionizing radiation by an object. In living beings a high absorbed dose can lead to radiation poisoning.* Absorption by an object of non-ionizing radiation...
  
  
• Hereditary GI cancer syndromes: familial adenomatous polyposis
  Familial adenomatous polyposis
  Familial adenomatous polyposis is an inherited condition in which numerous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when not treated....
  
  , hereditary nonpolyposis colorectal cancer
  Hereditary nonpolyposis colorectal cancer
  Lynch syndrome is an autosomal dominant genetic condition which has a high risk of colon cancer as well as other cancers including endometrium, ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin...
  
  , Peutz-Jeghers syndrome
  Peutz-Jeghers syndrome
  Peutz–Jeghers syndrome, also known as hereditary intestinal polyposis syndrome, is an autosomal dominant genetic disease characterized by the development of benign hamartomatous polyps in the gastrointestinal tract and hyperpigmented macules on the lips and oral mucosa...
  
  
• Male
  Male
  Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
  
  s are 25% more likely to develop the disease

Benign tumours and conditions that may be mistaken for cancer of the small bowel:

• Hamartoma
  Hamartoma
  A hamartoma is a benign, focal malformation that resembles a neoplasm in the tissue of its origin. This is not a malignant tumor, and it grows at the same rate as the surrounding tissues. It is composed of tissue elements normally found at that site, but which are growing in a disorganized mass...
  
  
• Tuberculosis
  Tuberculosis
  Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...