A nasal polyp is a mucosal sac filled with inflammatory cells, vessels, edema and / or fibrous tissues. Recently formed glands, changes in epithelial regrowth and presence of edema and eosinophilia are characteristic of the nasal polyps unlike the normal nasal mucosa. Eosinophilia is the most commonly found inflammatory cell in the polyps.
The polyps were observed and recorded even forty centuries ago in Egypt. Since then many developmental strides have been made to understand the polyps better and invent advanced treatments and techniques. For instance, now-a-days, microscopic and endoscopic surgical methods are popularly used to treat nasal polyps.
In the late nineteenth century, scientists suggested that the polyps began from the nasal wall located in the ethmoidal cleft region. Detailed studies of etiology, structure, histopathologic review, autopsy and surgeries of the polyps have revealed some unique features. However, the polyp origin is still a mystery.
Evaluation of functional endoscopic sinus surgery records concludes that the polyps commonly grow from the infundibulum, uncinate process and middle meatal. The second most common place from where polyps originate is the hiatus semilunaris and ethmoidal bulla. Autopsy studies found out that the most of the polyps were linked with ethmoidal clefts and recesses, and were unilateral.
The lifecycle of the polyps begins as solitary and small structures in the osteomeatal regions’ slim channels. Multiple factors initiate nasal polyp formation. The polyp size depends on a number of factors, such as level of edema and inflammation, age and growth rate of polyp. The meatus anatomy, available space and size and number of the existing polyps define its shape. A stalk connects the polyp apex or body to the polyp’s base. The length and thickness of the stalk also vary.
Each polyp consists of numerous tissues. The polyp stroma surrounds the amorphous substance featuring inflammatory cells, glands, blood vessels and fluid. An epithelium layer covers the polyp surface. Both epithelium layer and inflammatory cells may evolve as the polyp develops and grows.
Some nasal polyps may have scores of intraepithelial glands, the pathologic structures. Mucous glands found in the polyps play a crucial role in growth and pathogensis of the polyps. By examining the gland shape, you can decide whether the gland grew within the nasal polyp or in the nasal mucosa, because the glands form when the polyp is still in development and growth stage. As polyp length increases, the gland length also increases.
