Signet Ring Cell Adenocarcinoma Overview

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 tests, which check for signs of cancer in the stool.

Man throwing up in toilet with glass of water in foreground
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Colorectal cancer comes in many forms, including adenocarcinoma, leiomyosarcoma, lymphoma, melanoma, and neuroendocrine tumors. Adenocarcinoma is the most common type of colorectal cancer. Signet ring cell adenocarcinoma is a rare type of adenocarcinoma, accounting for less than 1% of all colon cancers.

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 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.

Other Types of Colorectal Cancer

Symptoms of Colorectal Cancer

Though signet cell adenocarcinomas are aggressive and tend to develop at an earlier age than other types of colorectal cancers, the symptoms are the same:

  • 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 undergo screening tests. It is recommended that average-risk adults undergo colon cancer screening starting at age 45 (and earlier for those with risk factors). Screening includes colonoscopy and tests for blood in the stool. Treatments for colorectal cancer may include surgery, chemotherapy, radiation, or a combination.

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  2. National Cancer Institute. Cellular classification of colon cancer. Updated January 25, 2021.

  3. Khan M, Korphaisarn K, Saif A, Foo WC, Kopetz S. Early-onset signet-ring cell adenocarcinoma of the colon: a case report and review of the literatureCase Reports in Oncological Medicine. 2017;2017:1-7. doi:10.1155/2017/2832180

  4. American Cancer Society. Signs and symptoms of colon cancer. Updated February 8, 2021.

  5. Shaukat A, Kahi CJ, Burke CA, Rabeneck L, Sauer BG, Rex DK. ACG clinical guidelines: colorectal cancer screening 2021Am J Gastroenterol. 2021;116(3):458-479. doi:10.14309/ajg.0000000000001122

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