Chapter 11. TUMORS OF THE LARGE INTESTINE

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ANATOMY OF LARGE INTESTINE (COLON AND RECTUM)

FUNCTIONS OF THE LARGE INTESTINE

Alimentary	Secretory	Absorbing	Motoric
Barrier-protective	Production of B, K vitamines	Excretory	Endocrine

CLASSIFICATION OF DISEASES OF THE COLON AND RECTUM

CANCER OF THE LARGE INTESTINE

Statistical data

Up to 700 thousand cases of cancer of the large intestine are annually revealed in the world, up to 40-50 thousand of them - in Russia. Males and females fall ill with equal frequency. Cancer of the large intestine commonly occurs at the age of 50-75 years. Cancer of the large intestine accounts for about 10% of all oncological diseases.

Congenital, acquired (AIDS).
Diet	High content of meat, animal fats, smoked products in the diet. Low content of cellulose in the food, irregular diet.
Anthropogenic contamination of the environment	Asbest, wood dust.
Genetic factors	Relatives have cancer. Familial diffuse polyposis (of 90-100% malignization).
Benign tumors	Solitary and multiple polyps, villous tumors.
Chronic diseases of the large intestine	Ulcerous colitis, Crohn's disease, diverticulitis.
Immunodefficiency	Congenital, acquired (AIDS).

BENIGN TUMORS OF THE LARGE INTESTINE

A significant part of variable in structure benign tumors of the large intestine is united under the notion "polyps" - small formations growing into the intestinal lumen. They have a wide or thin base ("pedunculated polyps"). Part of them tend to malignization.

Polyps are revealed in 10-12% of proctological patients. Males are affected 2-3 times more frequently. Polyps are revealed in 35-40% of the population above 60 years. Glandular polyps (adenomas) account for 75-85% of benign neoplasms of the large intestine.

Characteristics of common benign neoplasms
Hyperplastic polyps	These represent the focus of the mucous membrane hyperplasia. The colour is almost the same as that of the normal mucous membrane. These polyps have a wide base and may be solitary or multiple. The size is usually not more than 5 mm. Normal structure of the intestinal mucosa and normal glandular structure are present in them but the number of glands is significantly increased.	These polyps do not tend to malignization.
Juvenile polyps	These occur predominantly in children and teenagers. These polyps have a peduncle and a head of spherical shape and cherry colour. Solitary polyps on the rectal mucosa occur most frequently.	Solitary formations do not tend to malignization.
Hamartomas	These represent excessive growth of normal tissues in abnormal amount or in unusual place.	Solitary formations do not tend to malignization.
Fibrous polyps (fibropapillomas)	These are polypoid growths of the connective tissue developing in chronic inflammatory diseases. These polyps are located in the anal canal.	These polyps do not tend to malignization.
Non-epithelial polypoid neoplasms (lymphomas, hemangiomas, leiomyomas, lipomas, etc.)	These usually have a semi-spheric shape and smooth surface. They develop from the corresponding type of tissue.	These polyps do not tend to malignization.
Adenomatous (glandular) polyps	These are observed more frequently than other types (up to 90% of polypoid formations). They have a semispherical shape, smooth surface, wide base. Morphologically they are composed of variable in shape glands, often - of cystically enlarged glands.	These polyps frequently malignize. In polyps larger than 2 cm malignization is up to 50% of cases.
Villous polyp and tumor	It is the formation of a round or oval shape and of pink-red colour. It has a lobular structure resembling a "cauliflower". It is usually localized in the rectum and sigmoid colon. It most commonly occurs in a nodular form - a tumorous node on a wide base with the size up to 5 cm. In the creeping form the tumor spreads alongside the mucous membrane surface, occupying a significant part of the intestinal circumference.	Probability of malignization reaches 90%.

Syndrome of familial adenomatous polyposis	It is a congenital (genetic) disease. It is characterized by formation in the large intestine of a great number (hundreds and thousands) of adenomatous polyps. The average age for diagnosing familial polyposis is 25 years.	Probability of malignization is up to 100%.
Gardner's syndrome	It is a congenital (genetic) disease. It is characterized by combination of multiple polyposis of the large intestine with benign tumors of soft tissues and bones.
Turcot syndrome	It is a congenital (genetic) disease. It is characterized by combination of the alimentary tract polyposis with tumors of the brain.
Peutz - Jeghers syndrome	It is a congenital (genetic) disease. It is characterized by combination of hamarto-matous alimentary tract polyposis with pigment spots on the mucous membranes of the cheeks, around the mouth and on the skin of the palms.	Malignization is unlikely.