Gastrointestinal Pathology II Case Studies


CASE 4: Tubular Adenoma


Clinical History:

A 45-year-old man was found to have a stool positive for occult blood during a routine physical examination. A colonoscopy was performed and a 1.3 cm diameter polypoid lesion on a short stalk was found in the descending colon, along with a smaller 0.5 cm polyp in the sigmoid region (image 4.1). Both were resected. The gross photograph shows another case of a patient with several of these lesions (image 4.2). Another patient with a different gross appearance is shown in image 4.3. The low power microscopic view of the polyps is seen in image 4.4 and the high power appearance in image 4.5.
  1. What is the diagnosis?

    2. These are benign tubular adenomas (adenomatous polyps).

  2. This is thought to be a precursor for what lesion?

    3. Adenomas of the colon are thought to be precursors for colonic adenocarcinoma. Polyps larger than 2 cm have a greater chance for containing an adenocarcinoma. Over time, more genetic mutational "hits" in genes such as APC, SMAD4, and p53 occur in the neoplasm to drive transformation to malignancy.

  3. Name a syndrome in which the patient has hundreds of these polyps (A gross photograph of such a patient is shown in image 4.4).

    4. The syndrome is familial polyposis coli, with an autosomal dominant inheritance pattern. Colectomy is performed to prevent development of adenocarcinomas.

  4. Name a syndrome that not only has hundreds of these polyps, but also has osteomas, desmoids, and other extracolonic manifestations.

    5. The syndrome is Gardner syndrome, demonstrating pleiotropy (multiple tissues involved by the genetic condition). There is an autosomal dominant inheritance pattern, but with variable expression. These patients are also at risk for development of gastrointestinal tract adenocarcinomas.