Cancer unfortunately occurs more frequently in the rectum than any other portion of the intestinal canal. It is found usually in the form of the epithelial, medulla, adenoid and cirrhosis varieties.

The disease does not limit itself to the arms and rectum but is commonly found in the sigmoid, splenetic and hepatic flexes of the colon and cecum. The relative frequency of cancer as given by Cuttle shows that the anus and rectum are the most common seat of the disease as compared with the sigmoid flexible His statistics, given from a collection of 1029 cases, show the occurrence of the disease in the rectum 901 times, and in the sigmoid flexible 128 times. A final comparison as to its relative frequency in the rectum in the sexes; the males are more frequently affected and the prognosis more unfavorable than the females.

Epithelium occurs in the form of the squamous variety, chiefly at the subcutaneous border of the anus, and does not differ materially in appearance or histological from similar growths in the skin or mucous membrane which are covered with squamous epithelium in other portions of the body.

Epithelium begins as a rule in the superficial epithelial or the glands about the anus, but may have its origin in a fissure, ulcer, cicatrix, abrasion, or growth in that region. It may manifest itself as a dry. hard, wart-like nodule or a sharply defined ulcer with firm infiltrated edges. Ordinarily it does not ulcerate until late and assumes the former type. The growth may extend upward, involving and destroying the skin, fascia, muscles or other tissue as it progresses. Commonly squamous epithelium about the anal orifice progresses slowly, causing so little pain or other disturbances at first that the sufferer does not recognize the existence of the growth for months. This may be varied in exceptional cases by the disease progressing rapidly so that the nature of it becomes evident in a short time.

The superficial type does not involve the lymphatics in so short a time as the variety situated higher in the rectum. In some instances when the growth attacks the skin the ulceration extends to the perineum and scrotum, or may extend farther, involving the skin of the surrounding organs. The ulcerated surface may be fissured or assume the appearance of cauliflower excrescences. One of the chief characteristics, however, of the ulcer is the tendency to persist; while healing may take place in some portions the ulceration and cell proliferation continues in another direction. Often there may be a slight healing on one side, with the formation of glistening scars.

Histological, the superficial squamous-celled carcinoma ta are composed of small epithelial cells, which, when of the deep-seated variety, are large, flat, and small. When of the latter variety, the masses of cells extending from the superficial layer into the deeper structures present a concentric arrangement, resembling epithelial coils.

Medulla (Soft Cancer). These growths are characterized by an abundance of epithelial cells, with a slight amount of stoma, poorly supplied with blood vessels and presenting a slight resemblance to brain substance. This type of carcinoma is quite common in the rectum, is of rapid growth and very malignant. It grows so rapidly that it sometimes becomes so large as to completely fill the pelvis. It has a decided tendency to involve the lymphatics early and recur within a short time after operation, when not completely extirpated. The tumor presents the difficulty of demonstrating the stoma on microscopic examination, and is a soft, vascular and juicy tumor, which upon scraping or squeezing expresses what is called "cancer milk" or juice.

Adenoid (Malignant Adenoid). These growths bear a close resemblance to adenoid in the production of gland-like histological formations, which resemble the normal epithelial structures of the bowel. The growth is made up of glandular recesses lined with tall columnar cells similar to those of the Lieberman follicles, and imbedded in a dense connective tissue stoma This form of malignant disease of the rectum is the most difficult with which the surgeon has to contend and is therefore one of the most important of these malignant diseases. During its early stages or incipience this type bears a close resemblance to adenoid, producing a gland-like tumor which very frequently undergoes a transition into carcinomas tissue, and is therefore frequently described as carcinoma

This variety of carcinoma is encountered more often at the anterior and posterior commissionaires than in the lateral walls of the anal canal, originating in the mucous membrane of the tubular glands or the crypts of Lieberman When the connective tissue formation predominates about the tubules it assumes a greater or less degree of permanence. If the epithelial elements predominate the tumor grows more rapidly than when the connective tissue or stoma are in excess. This epithelial or atypical type is most common and the rapid proliferating cell formation completely obliterate the newly-formed tubules.

Progression of cylinder-celled carcinoma takes place either by proliferation of the cancerous elements throughout the entire bulk of the tumor, or by transformation of the healthy mucous membrane into neoplastic tissue at the margin.

The arrangement of the blood vessels and lymphatics around the lower bowel tend to permit the columnar-celled carcinoma-mata to grow more rapidly in the lateral than in the vertical direction and it is apt to encircle the gut in the form of a stricture.

These tumors are hard or soft, depending upon the predominance of the epithelial or connective tissue elements respectively. Ulceration and the breaking down of the tissue takes place from the formation of fistulous sinuses and diminution in the lumen of the bowel. The discharge of blood and broken-down tissue result from abrasions, ulceration, and the sinuses formed about the mass.

Cirrhosis (Hard Cancer). This variety of cancer is the least frequent, less malignant and is slow in its growth. It is composed of a dense, fibrous stoma and epithelial cells, is tough and bears a resemblance to a cartilaginous or raw potato-like material on section. The tumor has few blood vessels in the dense central portion but more in the periphery. The tumor is recognized by the great preponderance of connective tissue, and the relatively small number of epithelial cells contained within the alveolar and the tendency of the cells to undergo degeneration early. Clinically, these tumors appear in the form of a contracting stricture of the rectum, causing very little pain, hemorrhage or discharge. A gradually increasing constipation is the most important symptom. Anemia and sepsis are absent until intestinal obstruction or rupture of the gut supervenes.