A 25 Year Old Man Complains Of Occasional Blood In Stool

A 25 year old man comes to his primary care physician and complains of seeing blood in his stool occasionally. He has fairly regular and normal bowel habits but he is concerned because he has lost his father at a young age due to colon cancer and his initial symptoms were also blood in stool. He has no other symptoms and is living a healthy life style.
The patient was referred for a colonoscopy which showed the following in the sigmoid colon.

Multiple polyps carpeting the mucosa of the colon.

Based on the history and the above picture what is the most probable diagnosis?
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Familial adenomatous polyposis

Case Discussion:


Familial adenomatous polyposis is an inherited disorder characterized by cancer of the colon and rectum. People with the classic type of familial adenomatous polyposis may develop multiple polyps which are initially benign, as early as in their teenage years. Theses polyps tend to increase with age and become malignant.

Three Variants Of FAP: There are 3 different variant of FAP to occur the FAP and the attenuated FAP are known to occur because of the mutation in APC gene while the third type autosomal recessive FAP is due to MUTHY gene defects. The underlying pathology is a defect in the tumor suppressor genes that help prevent the formation of tumors in the body.

Clinical Features: 
An adenomatous polyp is an area where normal cells that line the inside of the colon begin to make mucus and form a mass inside the intestinal tract. the condition is diagnosed as a classic FAP when there are more than 100 adenomatous polyps inside the colon, along with a family history.
The average age when a patient begins to develop these polyps is around mid teens and by age 35 years they have multiple polyps. If the condition is undiagnosed there is 100% chance of theses polyps to become cancerous. There is also a chance of developing cancer in the stomach and the small intestine. They patients may also develop skin fibromas and bony growths known as osteomas. Some patients may present with blood in stool but it is not always the presenting symptom and the patient may remain asymptomatic for a long time.

Diagnosis: It is important not only to screen the patient but also all the family members who may be asymptomatic but already involved with the disease.
Colonoscopy is usually the diagnostic test of choice.
Genetic testing provides the ultimate diagnosis.

Treatment: depends upon the variant of FAP and the extent of involvement of the gastrointestinal tract. Excision of the involved portions of the colon and rectum are done and in some cases when there are many polyps prophylactic colectomy may be advised before malignant changes take place.
If the condition is detected before malignant changes , prognosis is good without metastasis as the polyps remain confined to the inner wall and intestinal tract.