Carcinoma in situ (CIS)

MyPathologyReport
November 29, 2023


Carcinoma in situ (CIS) is an early non-invasive type of cancer. CIS starts in a thin layer of tissue called epithelium. Over time, the abnormal cells in CIS can spread beyond the epithelium into the surrounding tissue. This process is called invasion and it signals the transition from CIS to invasive carcinoma (invasive cancer).

Carcinoma in situ

Specific types of carcinoma in situ:

  • Ductal carcinoma in situ: This is a non-invasive type of breast cancer made up of cells normally found in spaces called ducts. Over time it can lead to a type of breast cancer called invasive ductal carcinoma.
  • Lobular carcinoma in situ: This is a non-invasive type of breast cancer made up of cells normally found in small glands called lobules. Over time it can lead to a type of breast cancer called invasive lobular carcinoma.
  • Urothelial carcinoma in situ: This is a non-invasive type of cancer that can arise anywhere along the urinary tract although it is most commonly found in the bladder. Over time it can lead to an invasive type of urinary tract cancer called urothelial carcinoma.
  • Squamous cell carcinoma in situ: This is a very common type of non-invasive cancer of squamous cells. Squamous cell carcinoma in situ can arise in any location where squamous cells are normally found including the skin, lungs, cervix, oral cavity, and throat. Over time it can lead to a type of invasive cancer called squamous cell carcinoma.
  • Adenocarcinoma in situ: This is a non-invasive type of cancer made up of glandular cells. Adenocarcinoma in situ can arise in any location where glandular cells are normally found, however, it is most commonly found in the lungs, stomach, colon, and cervix. Over time it can lead to a type of invasive cancer called adenocarcinoma.

Can a non-invasive cancer spread to other parts of the body?

No. The abnormal cells in carcinoma in situ cannot metastasize (spread) to lymph nodes or distant parts of the body. For this reason, this disease is typically cured through surgery alone.

About this article

Doctors wrote this article to assist you in reading and comprehending your pathology report. Feel free to reach out to us with any questions about this article or your pathology report. To get a comprehensive introduction to your pathology report, read this article.

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