Colorectal polyps and cancer: Pathology review

At the gastroenterology clinic, there is a 63-year-old Caucasian male, named Neil, who's complaining about progressive fatigue and weight loss in the last 6 months. Laboratory findings reveal positive fecal occult blood test and iron-deficiency anemia. At the same time, an 18-year-old Caucasian male, named Brendon came in for a colonoscopy screening. He was concerned after learning that both his grandfather and uncle were diagnosed with colon cancer in their early thirties. His doctor detected more than one hundred polyps on colonoscopy.

Now, both people have some form of colorectal polyps or cancer. But first let’s start with colorectal polyps, which are overgrowths of epithelial cells in the colon or rectum. They are subdivided into non-neoplastic polyps, such as hamartomatous polyps, hyperplastic polyps, inflammatory pseudopolyps, mucosal, and submucosal polyps; and neoplastic polyps, which include adenomatous and serrated polyps.

Hamartomatous polyps are solitary, disorganized masses that contain normal tissue found at the site of the polyp. These polyps can occur sporadically, or in genetically inherited conditions, such as juvenile polyposis syndrome or Peutz-Jeghers syndrome; and they have mild malignant potential.

Next, hyperplastic polyps, are the most common polyps and they are small and typically located in the rectosigmoid region. Usually, these polyps are benign lesions, but in rare cases, they can evolve into serrated polyps, which have malignant potential.

Inflammatory pseudopolyps are multiple benign pseudopolyps that occur during regenerative and healing phases in chronic inflammation, and they are most commonly seen in inflammatory bowel disease.

Mucosal polyps, which are clinically insignificant, are usually small, less than 5mm, and they look similar to surrounding normal mucosa. On the flip side, submucosal polyps can include lipomas, leiomyomas, fibromas, or other lesions.