Intestinal Tumors and Carcinomas:

Intestinal tumors may be associated with various risk factors, contributing to the development of distinct forms of these tumors. Key risk factors include:

  1. High-Fat Diets
  2. Crohn’s Disease
  3. Celiac Disease
  4. Intestinal Polyps

It’s important to note that having one of these risk factors doesn’t guarantee the development of intestinal cancer, and the absence of these factors doesn’t rule out the possibility of its occurrence. If you have concerns, it is advisable to consult with your family physician or gastroenterologist.

There are four primary types of intestinal tumors, each classified differently:

  1. Adenocarcinoma
  2. Gastrointestinal Carcinoid Tumors
  3. Lymphomas
  4. Sarcomas

Additionally, if you undergo a procedure to remove an intestinal tumor, especially if a significant portion of the bowel is removed, there is a risk of developing Short Bowel Syndrome (SBS). Regular follow-ups and consultations with healthcare professionals are recommended in such cases.


Adenocarcinomas account for approximately 30% to 40% of cancers in the small intestine. Originating from the cells lining the intestine, this type of cancer is believed to follow a development pattern similar to colorectal cancer. It typically initiates as a small benign growth known as a polyp, which can evolve into cancer over time. The majority of small intestinal cancers manifest in the duodenum, with fewer cases in the jejunum and ileum.

A notable location for cancer in the duodenum is the small opening that enters into the first portion of the small intestine. This is the area where the pancreatic and bile ducts release their secretions into the intestine. However it should be noted that due to its close association with the pancreas, it is managed as if it were pancreatic cancer.

Gastrointestinal Carcinoid Tumors

Gastrointestinal (GI) Carcinoid tumors originate from cells of the diffuse neuroendocrine system. This system comprises cells that share characteristics with both nerve cells and hormone-producing endocrine cells. Unlike forming a distinct organ like the adrenal or thyroid glands, these cells are dispersed throughout organs such as the esophagus, stomach, pancreas, intestines, and lungs. The digestive system, being extensive, harbors more neuroendocrine cells than any other part of the body, potentially explaining why carcinoid tumors predominantly initiate in the digestive system.

Neuroendocrine cells play a role in regulating the release of digestive juices and the speed of food movement in the GI tract. Additionally, they may influence the growth of other types of cells in the digestive system.

Similar to many cells in the body, neuroendocrine cells in the GI tract can undergo changes that lead to excessive growth and the formation of tumors. These tumors are referred to as neuroendocrine tumors (NET) and neuroendocrine cancers. While previously all abnormal growths of neuroendocrine cells were termed carcinoids, the World Health Organization (WHO) reclassified them in 2000 into neuroendocrine tumors and neuroendocrine cancers.

Neuroendocrine tumors appear benign but may have the potential to spread to other parts of the body. Neuroendocrine cancers, on the other hand, represent abnormal growths of neuroendocrine cells capable of spreading to distant areas.

Neuroendocrine cancers, also known as neuroendocrine carcinomas, can be categorized based on the microscopic appearance of the cells. Well-differentiated cancers have cells that do not exhibit significant abnormalities and tend to be less aggressive, growing and spreading slowly. These tumors may closely resemble benign neuroendocrine tumors when examined under a microscope. In contrast, poorly differentiated cancers have cells that appear highly abnormal, signifying greater aggressiveness with rapid growth and spread. Confirmation that a mass is a neuroendocrine cancer (rather than a benign tumor) may sometimes only occur when it spreads to other organs or tissues.


Lymphomas occurring in the small bowel can either be primary, originating from the small bowel lymph tissue, or secondary to a systemic lymphoma. The small bowel comprises the duodenum, jejunum, and ileum, with lymphomas potentially affecting any of these sections or the colon.

This relatively uncommon cancer is typically a non-Hodgkin’s type that initiates in the lymph tissue of the small intestine. The lymph tissue plays a crucial role in the body’s immune system, aiding in the fight against infections. Malignant lymphoma is rarely identified as a solitary lesion.

For additional information on General Lymphomas, you can refer to the American Cancer Society


Typically, leiomyosarcoma is the predominant type of malignant sarcoma found in the small intestine, particularly in the smooth muscle lining of the ileum—the final segment of the small intestine. Liposarcoma and angiosarcoma are less common occurrences in the small intestine. For more information, click here.


Children’s Hospital of Pittsburgh: Intestinal Diseases


American Cancer Society