Nasal polyps are non-cancerous, soft tissue growths that develop within the nasal passages or sinuses. They are the result of chronic inflammation affecting the lining of these air-filled cavities. These outgrowths are generally painless and appear due to prolonged swelling, often associated with conditions like persistent allergies or chronic sinus infections.
The Defining Visual Characteristics
The defining feature of a nasal polyp is its color, which differentiates it from the typical red appearance of inflamed nasal tissue. A polyp is often pale, ranging from a grayish-white to a translucent, slightly yellowish or pink hue. This distinct color results because the growth is made of swollen, fluid-filled tissue, which stretches the surface and reduces the density of visible blood vessels.
The texture of these growths is typically smooth, soft, and shiny, often appearing moist or gelatinous. Unlike other nasal lesions, polyps are non-bleeding and mobile. When small, the growths are frequently described as having a teardrop shape, resembling a pendant drop of fluid.
As polyps grow larger, they often cluster together, taking on a shape that resembles a peeled, seedless grape. This characteristic appearance is an identifier for healthcare providers. Their size can vary significantly, from a few millimeters to several centimeters, and they can expand enough to completely block the nasal passage.
Typical Locations and Growth Patterns
Nasal polyps most frequently originate from the lining of the ethmoid sinuses, which are air cells located between the eyes and the bridge of the nose. From this location, they descend into the nasal cavity, often emerging near the middle meatus, the drainage pathway for the sinuses. Because the underlying inflammation is widespread, polyps commonly develop in clusters and are typically found in both nostrils.
The way a polyp attaches to the nasal lining dictates its growth pattern and mobility. A sessile polyp is a broad-based growth that attaches directly to the tissue without a distinct stalk. Conversely, a pedunculated polyp develops a long, slender stalk, giving it the appearance of a hanging bunch of grapes and allowing it to move more freely.
While most polyps are multiple and arise from the ethmoid region, a specific type known as an antrochoanal polyp typically develops as a single, large growth. This type originates in the maxillary sinus, located behind the cheeks, and extends backward toward the choana—the opening at the back of the nasal cavity. This pattern is more common in children and usually affects only one side of the nose.
How Doctors Confirm the Diagnosis
While a large polyp may sometimes be visible near the front of the nose, most polyps are located deeper within the nasal passages and sinuses, requiring professional visualization. The primary method doctors use to confirm the diagnosis is nasal endoscopy. This procedure involves gently inserting a thin, rigid or flexible tube equipped with a light and a camera into the nostril.
The endoscope allows the physician to navigate past the initial opening and obtain a magnified, real-time view of the growths deep within the nasal cavity and sinus drainage areas. This visualization helps distinguish a true nasal polyp from other conditions, such as swollen turbinates. Turbinates are normal structures that can become enlarged due to allergies or infection, but they are typically red, whereas polyps maintain their characteristic pale, translucent appearance.
In some cases, especially when assessing the extent of the growths or planning treatment, a Computed Tomography (CT) scan may be used. This imaging provides a detailed view of the polyps’ size and exact location within the deeper sinus cavities. Visual confirmation through endoscopy, often combined with imaging, is the standard for an accurate diagnosis.