Primary Malignant Melanoma of the Colon: Symptoms, Risk Factors, Diagnosis, Treatment and Prognosis

Primary Malignant Melanoma of the Colon: Symptoms, Risk Factors, Diagnosis, Treatment and Prognosis
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Primary Malignant Melanoma of the Colon

Primary malignant melanoma of the colon is very rare. In most instances melanomas of the colon are metastatic meaning the melanoma spread from a different origin. Early detection is key to successful treatment.

Signs and Symptoms

Signs and symptoms of primary malignant melanoma include:

Rectal bleeding

Blood in the stool

Unexplained weight loss

Abdominal cramps that are persistent

A change in bowel habits that lasts for more than a few weeks

Risk Factors

The median age of patients diagnosed with primary malignant melanoma of the colon is age 60. Family history can play a roll. If the patient has a history of colorectal polyps it puts them at greater risk for developing colon cancer. Lifestyle choices can put patient’s at risk for colon cancer as well such as smoking, obesity and use of alcohol. It is difficult to assess risk factors due to the fact these cases occur so rarely.


If any of the above symptoms occur it is important to see a physician right away. As with any melanoma, early detection is key to treatment. Colon cancer can be diagnosed a number of ways. Your physician may perform a test known as a colonoscopy. A colonoscopy is done as an outpatient and requires no hospital overnight stay. It involves a physician using a long slender tube attached to a camera to view the patient’s entire colon and rectum. If the physician sees any suspicious areas they can obtain biopsies to determine if the areas are cancerous.

Physician’s can also use CAT scans to view the colon and look for suspicious areas. Another form of x-ray used to diagnose colon cancer is a barium enema. This involves the patient receiving barium dye in the form of an enema. The barium creates a silhouette of the colon and rectum so the physician can identify masses if they are present.


There are several treatment options for malignant melanoma of the colon. Surgery can be performed to remove the cancerous tissue. This treatment is the one physicians utilize most often. Chemotherapy may be used alone or in conjunction with surgery. Chemotherapy is typically employed if the melanoma has metastasized. Chemotherapy uses strong drugs to kill cancer cells. Radiation therapy may also be used alone or with surgery. Radiation uses energy sources such as x-rays in a powerful way to shrink tumors and may be used in conjunction with chemotherapy as well.


The prognosis for primary melanoma of the colon is better than most mucosal melanomas. Due to the fact primary malignant melanomas are so rare it is assumed that the prognosis is similar to that of melanomas of the colon. The survival rate for melanomas of the colon are:

Overall mortality 47 percent with one and five year survival rates of 60 percent and 33 percent.


Primary malignant melanoma of the colon can be treated in many ways. It is important to see a physician if any of the symptoms develop especially if risk factors are present. The patient’s physician will design a treatment plan suitable for their case if the diagnosis of melanoma of the colon is confirmed.


Mayo Clinic:


American Cancer Society:

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