Key Points about Cloacogenic Carcinoma

  • Cloacogenic carcinoma is a rare type of anal cancer that develops in people whose cloacal membrane is still intact.
  • This condition occurs twice as often in women than in men.
  • Doctors use biopsy, imaging tests and physical exam to diagnose cloacogenic carcinoma.
  • Treatment for cloacogenic carcinoma may include surgery, chemotherapy, targeted therapy and/or radiation therapy.


Anal cancer is cancer that begins in the tissue of the anal canal, which is the short tube through which stool leaves your body. Cloacogenic carcinoma is a very rare type of anal cancer, making up just 2 to 3 percent of anorectal carcinomas.

Cloacogenic carcinoma develops from a piece of the cloacal membrane (thin skin from the development of the urinary and reproductive organs that normally disappears before birth) that remains from fetal development. People who still have the cloacal membrane are at risk for developing this type of anal cancer.

Cloacogenic carcinoma causes

Anal cancer is caused by mutations (changes) to the DNA of the cells of the anal canal.

Cloacogenic carcinoma risk factors

The following factors may increase your risk for developing cloacogenic carcinoma:

  • Being a smoker
  • Being age 50 or older
  • Being female
  • Being the recipient of anal sex
  • Having human papillomavirus, or HPV
  • Having multiple sex partners throughout your lifetime
  • Taking immunosuppressant medications, such as after undergoing organ transplant

Cloacogenic carcinoma symptoms

Signs and symptoms of cloacogenic carcinoma can include:

  • Bleeding from the rectum or anus
  • Itchy sensation in the anus
  • Mass or growth inside the anal canal that can be felt
  • Pain in the anus

Cloacogenic carcinoma diagnosis

Your oncologist may use one or more of the following tests to diagnose this condition:

  • Physical exam – your doctor will perform a complete physical exam, including asking questions about your health history, your symptoms and related risk factors.
  • Biopsy – in this test, your doctor removes a biopsy (small tissue sample) from the suspicious area. This sample is sent to the laboratory, where a specialist closely checks the biopsy for abnormalities.
  • Computerized tomography (CT) scan – this type of imaging test provides a 3D image of the inside of the body that your doctor can use to determine if there is any cancer present. Your doctor may use a CT scan to determine if cancer has spread beyond the anal canal, as well as to stage the cancer.
  • Magnetic resonance imaging (MRI) – this type of imaging test uses high-powered magnets to create detailed images of the inside of your body. Your doctor can closely examine these images to look for any areas that could indicate cancer. Your doctor may use MRI to determine if cancer has spread beyond the anal canal, as well as to stage the cancer.
  • Ultrasound – this type of imaging test uses sound waves to create images of the inside of your body. Your doctor can closely examine ultrasound images to look for any areas that could indicate cancer.

Cloacogenic carcinoma treatments

Depending on your personal health history, the extent of the cloacogenic carcinoma and other factors, your oncologist may recommend one or more of the following treatment options:

  • Combination of chemotherapy and radiation therapy – in most cases, anal cancer is initially treated using a combination of these two treatments. In chemotherapy, medication is used to destroy cancerous cells. Chemotherapy can be taken via an oral (by mouth) pill or intravenously (through a vein). Radiation therapy uses high-powered energy beams to destroy cancerous cells.
  • Surgery – if your cloacogenic carcinoma is early-stage or if it has not been responsive to chemotherapy and radiation therapy, your doctor may recommend a surgical procedure to remove the cancerous area. Your surgeon will work to preserve as much surrounding healthy tissue as possible. 

When should I seek care?

If you experience any of these symptoms, start by voicing your concerns and symptoms to your primary care provider. From there, your doctor may suggest seeing an oncologist for more specialized treatment.

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