Chief Complaint: 65-year-old woman with a loss of appetite, abdominal cramps, constipation, and blood in her stool.

History: Delores Murphy, a 65-year-old white female, was in good health until about 6 weeks ago, when she noted occasional cramps in the left lower quadrant of the abdomen associated with constipation. The episodes of cramping last about 30 minutes each and are most severe in the hour following her meals. She has taken laxatives which have partially relieved her symptoms, but she has had a decreased appetite and 12-pound weight loss over the past four weeks. In addition, she has become increasingly fatigued over this period. When questioned about her bowel habits, she reported bright red blood in her stools and a smaller caliber (i.e. diameter) of stool over the past two weeks.

Physical Examination: She appeared fatigued and distressed. Head and neck exams were normal, as was her thorax. Palpation of the abdomen revealed a 10 x 10 cm mass and tenderness in the left lower quadrant. Percussion over this area revealed a hollow, tympanic sound. Hepatomegaly was noted, and a hard and slightly tender liver edge was felt in the right upper quadrant. Bowel sounds were noticeably reduced. A stool sample was tested with Guaiac paper and was positive for blood.

Questions:

1. Propose an explanation for Delores's:

A. abdominal cramps and left lower quadrant mass:

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B. reduced bowel sounds and smaller-caliber stools:

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C. weight loss and decreased appetite:

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Delores was referred to the radiology department to have an "air-contrast barium enema" procedure which revealed the silhouette of a 3 x 3 x 4 cm polyp in the distal sigmoid colon and a nearly 100% obstruction of the proximal sigmoid colon. The remainder of the large intestine appeared normal.

2. How is an "air-contrast barium enema" performed?

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3. What kinds of information can be gained by performing an air-contrast barium enema?

The suspicious lesions noted on the air-contrast barium enema convinced Delores's physician to examine her sigmoid colon via flexible sigmoidoscopy. During this procedure, biopsies of the polyp and obstructed area were taken and sent to the pathology lab. The obsructed area of the sigmoid colon appeared to be slowly bleeding prior to the biopsy procedure.

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4. What is "flexible sigmoidoscopy"?

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5. Why was it important to biopsy the suspicious lesions?

The report from the pathologist described the polyp as an "adenoma" and the tissue taken from the obstructed area as a "carcinoma".

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6. Define the terms "adenoma" and "carcinoma."

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7. How would the appearance of an adenoma differ from that of a carcinoma under the microscope?

 

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8. Ninety percent of all cancers are carcinomas. Propose an explanation for why such a disproportionately high number of cancers are carcinomas.

Delores is told that she has colon cancer and that the cancer has already metastasized. She is told that her best chance for a cure is via surgery, followed by chemotherapy.

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9. Define the term "metastasis."

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10. Where might a cancer like Delores's metastasize to?

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11. Why do you think Delores's liver edge was hard and tender on physical examination?

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12. A blood sample from Delores revealed iron-deficiency anemia. Propose a cause of this anemia.