Signet Ring Cell Adenocarcinoma of the Colon and Rectum

An Overview of the Signet Ring Cell Form of Adenocarcinoma

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Signet ring cell adenocarcinoma of the colon and rectum is a common colorectal cancer. Colorectal cancer is the third most common type of cancer in men and women in the United States. Deaths from colorectal cancer have decreased with the use of colonoscopies and fecal occult blood tests, which check for blood in the stool.

Colorectal cancer comes in many forms, including adenocarcinoma, leiomyosarcoma, lymphoma, melanoma and neuroendocrine tumors.

Adenocarcinoma is the most common type of colorectal cancer and has two subtypes, signet ring cell and mucinous. This article discusses signet ring cell adenocarcinoma.

What is an adenocarcinoma? 

"Adeno-" is a prefix that means "gland." In general, glands secrete things and are classified as endocrine or exocrine. Endocrine glands secrete things into the bloodstream, like hormones. Exocrine glands secrete things that go outside of the body, like mucus and sweat.

A carcinoma is a malignant tumor that starts in epithelial tissue. Put the two words together and you get "adenocarcinoma," which means a malignant tumor in epithelial tissue, specifically in a gland.

The term "signet ring cell" describes the appearance of the cancer. To look at cancer cells under a microscope, you have to stain and dehydrate them. Because signet ring cell adenocarcinomas have so much fat in them, once they're dehydrated, the nucleus gets pushed all the way over to one side.

This makes the cell look kind of like a ring under the microscope.

Signet ring cell adenocarcinomas are considered more aggressive than regular adenocarcinomas and are harder to successfully treat. The signet ring cell form is very uncommon and accounts for about 0.1 percent of all adenocarcinomas.

Other Types of Colorectal Cancer:

Symptoms of Colorectal Cancer

Symptoms of colorectal cancer include

  • Diarrhea or constipation
  • A feeling that your bowel does not empty completely
  • Blood (either bright red or very dark) in your stool
  • Stools that are narrower than usual
  • Frequent gas pains or cramps, or feeling full or bloated
  • Weight loss with no known reason
  • Fatigue
  • Nausea or vomiting

Because you may not have symptoms at first, it's important to have screening tests. Everyone over 50 should get screened. Tests include colonoscopy and tests for blood in the stool. Treatments for colorectal cancer include surgery, chemotherapy, radiation, or a combination. 


Buetow, Peter and Buck, James. "Colorectal Adenocarcinoma." RadioGraphics 15.1 (Jan. 1995). Archives of the AFIP. 5 Jul. 2006 []. An Overview of the Signet Ring Cell Form of Adenocarcinoma

National Cancer Institute.

U.S. National Library of Medicine. MedLine Plus.

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