A polyp is an abnormal growth of tissue projecting from a mucous membrane, the inner lining of various organs. The term “pedunculated” describes a specific shape: the growth is attached to the organ wall by a distinct, narrow stalk, or peduncle. This mushroom-like structure contrasts with growths that lie flat against the tissue surface. Understanding their location and cellular makeup helps determine their potential risk and guides removal and follow-up care.
Defining the Peduncle Structure
The defining feature of a pedunculated polyp is its slender stalk, known as the peduncle, which connects the bulk of the growth to the organ wall. This stalk is composed of connective tissue and contains blood vessels supplying the polyp’s head. The appearance is often likened to a small mushroom.
This structure contrasts with a sessile polyp, which lacks a stalk and grows directly from a broad, flat base on the inner lining. Pedunculated polyps are typically easier to spot and remove entirely during an endoscopic procedure. The stalk provides a clear, narrow point for a removal tool to loop around, often allowing the entire growth to be removed in one piece.
Common Locations and Manifestations
Pedunculated polyps can manifest in various parts of the body, but they are most frequently found in the colon and rectum (the large bowel). They can also occur in locations such as the stomach, uterus, nose, or ear canal. The prevalence of polyps in the colon is high, affecting an estimated 25% to 40% of Americans over the age of 50.
Most polyps remain small and do not cause noticeable symptoms. However, larger polyps can lead to detectable signs. In the colon, this might include occult or visible blood in the stool due to irritation or surface bleeding. Significant symptoms can involve a change in bowel habits, such as new-onset constipation or diarrhea. Rarely, a very large polyp can cause a mechanical obstruction or lead to chronic blood loss resulting in iron deficiency anemia. Polyps in the uterus may cause abnormal vaginal bleeding.
Histological Types and Cancer Risk
The most important factor in determining the risk associated with any polyp is its cellular composition, or histology. Polyps are broadly grouped into two main categories: non-neoplastic and neoplastic. Non-neoplastic polyps, such as hyperplastic or inflammatory polyps, are generally considered benign and do not progress to cancer.
Neoplastic polyps, known as adenomas, are considered precancerous and are the growths from which most colorectal cancers arise. Adenomas are classified by microscopic structure into subtypes: tubular, villous, and tubulovillous. Villous adenomas and mixed tubulovillous structures have a higher potential for progression than the more common tubular adenomas. A small percentage of adenomas will eventually become malignant, a process that usually takes years, often around a decade. Finding and removing these adenomas early is the basis of effective cancer prevention, as they account for about 75% of colorectal cancers.
Removal and Surveillance
The standard method for treating a pedunculated polyp is a polypectomy, usually performed during a colonoscopy or other endoscopic examination. The doctor uses a specialized tool, often a thin wire loop called a snare, which is threaded through the endoscope. The snare is carefully looped around the base of the peduncle, severing the polyp from the organ wall.
Heat, known as electrocautery, is frequently applied through the snare wire to ensure a clean cut and seal blood vessels within the stalk, minimizing the risk of bleeding. Once removed, the entire specimen is retrieved and sent to a pathology laboratory for detailed examination. The pathologist’s report on the cellular type and size dictates the necessity and frequency of future follow-up screenings.
If the removed polyp is identified as an adenoma or other type with neoplastic potential, the patient will be placed on an increased surveillance schedule. This typically involves repeat colonoscopies sooner than the standard screening interval. Timing is determined by the number of polyps, their size, and the severity of cellular changes observed. High-risk findings may necessitate a follow-up screening in as little as one to three years.