A polyp is called an overgrowth of tissue that protrudes above the surface of the mucous membranes of hollow organs. This can be the stomach, rectum, uterus and cervix, bladder, larynx, nasopharynx, large intestine. There are several types of polyps, depending on the reasons for their formation: inflammatory, hyperplastic, neoplastic. Inflammatory and hyperplastic ones do not degenerate into malignant tumors, and neoplastic ones can have both malignant and benign nature of tissue growth.
According to their shape, polyps differ into "sessile" (on a wide base) and "on the leg", which holds the polyp in the air. According to the microscopic structure, tubular is distinguished (their cells form tubular structures), villous (the surface of the polyp is covered with thin filamentous villi). There is a mixed combination of two types - tubular-villous.
For the most part, benign polyps are formations less than 1 cm in diameter, which do not cause much concern. Larger polyps can bleed and produce mucus if damaged. It is very likely that new polyps will appear if there is at least one. Inflammatory - formed at the site of inflammation, characteristic of the nasal mucosa and larynx, hyperplastic - appear as a result of excess growth of normal tissue, most often in the stomach, uterus and cervix.
The third type of polyps is the growing atypical cells - neoplastic polyps. Of these, as a rule, malignant tumors are formed that are capable of metastasizing from the site of formation to other organs. The likelihood of spread is higher if the polyp has a villous structure, it does not have a leg, and its diameter is greater than 1 cm. It is believed that cancers of the colon and rectum grow from such polyps.