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Diagnostic Dilemma

Diagnostic Dilemma

A 49-year-old woman presents with increasing constipation. She has noted intermittent bright red blood on the toilet tissue. She denies abdominal pain, anorexia, weight loss, and fever. She has a long history of constipation treated with "natural, herbal remedies." Her medical history is unremarkable. She is taking no other medications. Her surgical history is positive for hysterectomy for fibroids. Her family history is positive for colon cancer in her maternal grandmother.

Physical examination is significant for a lower abdominal scar related to the prior hysterectomy. Fecal occult blood test is negative. Colonoscopy revealed increased pigmentation of the colonic mucosa, diminutive polyps in the sigmoid colon (Figure 1), and an erythematous polyp in the descending colon (Figure 2a). This polyp measured 1 cm. It was removed with snare and cautery. The histologic features are demonstrated in the photomicrograph (Figure 2b).

  1. What kind of polyp is demonstrated in Figure 1, and what is the increased pigmentation?
    a.
     Juvenile polyp
    b. Adenomatus polyp and ischemic discoloration
    c. Hyperplastic polyp and melanosis 
    d. Hyperplastic polyp and ischemic changes
    e. Inflammatory polyp and poor prep
  2.  

  3. What kind of polyp is represented in Figures 2a and 2b, and is it premalignant?
    a.
     Adenomatous, premalignant
    b. Hyperplastic, premalignant
    c. Hyperplastic, not premalignant
    d. Lipoma, not premalignant
    e. Inflammatory, not premalignant

The correct answer to question 1 is c. Hyperplastic polyps are frequently multiple, usually very small, and most commonly located in the distal colon. The endoscopic photograph reveals a 5-mm polyp in the center with multiple smaller polyps surrounding it.

All of the polyps are pigmented, as is the background mucosa. This is typical of melanosis coli. This is an acquired condition related to the use of laxatives containing senna or cascara. The pigment accumulates in macrophages and appears to have no serious deleterious effects.

Of note, the pigment accumulates in hyperplastic but usually not in adenoma-tous polyps. The photograph does not illustrate any evidence of adenomatous, juvenile, or inflammatory polyps. Biopsy is required to confirm the endoscopic suspicion. The prep is good, allowing for appreciation of the melanosis.

The correct answer to question 2 is a. The photograph reveals a typical adenoma on a short stalk. Adenomatous polyps are premalignant, neoplastic lesions. Polypectomy is most appropriate. The photomicrograph reveals colonic mucosa with increased numbers and crowding of glands. Large, hyperchromatic cells that are pseudostratified line these glands.

There was no evidence of carcinoma in this resected polyp. Hyperplastic, lipomatous, and inflammatory polyps are not neoplastic and do not have this endoscopic or histologic appearance.

 
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