Practice Essentials
Broadly defined, nasal polyps are abnormal lesions that originate from any portion of the nasal mucosa or paranasal sinuses. Polyps are an end result of varying disease processes in the nasal cavities. The most commonly discussed polyps are benign semitransparent nasal lesions that arise from the mucosa of the nasal cavity or from one or more of the paranasal sinuses, often at the outflow tract of the sinuses.
Multiple polyps can occur in children with chronic sinusitis, allergic rhinitis, cystic fibrosis (CF), or allergic fungal sinusitis (AFS). An individual polyp could be an antral-choanal polyp, a benign massive polyp, or any benign or malignant tumor (eg, encephalocele, glioma, hemangioma, papilloma, juvenile nasopharyngeal angiofibroma, rhabdomyosarcoma, lymphoma, neuroblastoma, sarcoma, chordoma, nasopharyngeal carcinoma, inverting papilloma). All children with benign multiple nasal polyposis should be evaluated for CF and asthma. Educating patients about the chronicity of the disease is important to make them aware of the recurrent nature of the problem.
Oral and topical nasal steroid administration is the primary medical therapy for nasal polyposis. Surgical intervention is required for children with multiple benign nasal polyposis or chronic rhinosinusitis in whom maximal medical therapy fails.
Pathophysiology
The pathogenesis of nasal polyposis is unknown. Polyp development has been linked to chronic inflammation, autonomic nervous system dysfunction, and genetic predisposition. Most theories consider polyps to be the ultimate manifestation of chronic inflammation; therefore, conditions leading to chronic inflammation in the nasal cavity can lead to nasal polyps.
The following conditions are associated with multiple benign polyps:
-
Bronchial asthma - In 20-50% of patients with polyps
-
CF - Polyps in 6-44% of patients with CF [1]
-
Allergic rhinitis
-
AFS - Polyps in 85% of patients with AFS
-
Chronic rhinosinusitis
-
Aspirin intolerance - In 8-26% of patients with polyps
-
Alcohol intolerance - In 50% of patients with nasal polyps
-
Churg-Strauss syndrome - Nasal polyps in 50% of patients with Churg-Strauss syndrome
-
Young syndrome (ie, chronic sinusitis, nasal polyposis, azoospermia)
-
Nonallergic rhinitis with eosinophilia syndrome (NARES) - Nasal polyps in 20% of patients with NARES
Most studies suggest that polyps are associated more strongly with nonallergic disease than with allergic disease. Statistically, nasal polyps are more common in patients with nonallergic asthma (13%) than with allergic asthma (5%), and only 0.5% of 3000 atopic individuals have nasal polyps.
Several theories have been postulated to explain the pathogenesis of nasal polyps, though none seems to account fully for all the known facts. Some researchers believe that polyps are an exvagination of the normal nasal or sinus mucosa that fills with edematous stroma; others believe that polyps are a distinct entity arising from the mucosa. On the basis of a review of the literature and several intricate studies of the bioelectric properties of polyps, Bernstein derived a convincing theory regarding the pathogenesis of nasal polyps, building on other theories and information from Tos et al. [2, 3]
In Bernstein's theory, inflammatory changes first occur in the lateral nasal wall or sinus mucosa as the result of viral-bacterial host interactions or secondary to turbulent airflow. In most cases, polyps originate from contact areas of the middle meatus, especially the narrow clefts in the anterior ethmoid region that create turbulent airflow, and particularly when narrowed by mucosal inflammation. Ulceration or prolapse of the submucosa can occur, with reepithelialization and new gland formation.
During this process, a polyp can form from the mucosa because the heightened inflammatory process from epithelial cells, vascular endothelial cells, and fibroblasts affects the bioelectric integrity of the sodium channels at the luminal surface of the respiratory epithelial cell in that section of the nasal mucosa. This response increases sodium absorption, leading to water retention and polyp formation.
Other theories involve vasomotor imbalance or epithelial rupture. The vasomotor imbalance theory postulates that increased vascular permeability and impaired vascular regulation cause detoxification of mast-cell products (eg, histamine). The prolonged effects of these products within the polyp stroma result in marked edema (especially in the polyp pedicle) that is worsened by venous drainage obstruction. This theory is based on the cell-poor stroma of the polyps, which is poorly vascularized and lacks vasoconstrictor innervation.
The epithelial rupture theory suggests that rupture of the epithelium of the nasal mucosa is caused by increased tissue turgor in illness (eg, allergies, infections). This rupture leads to prolapse of the lamina propria mucosa, forming polyps. The defects are possibly enlarged by gravitational effects or venous drainage obstruction, causing the polyps. This theory, though similar to Bernstein's, provides a less convincing explanation for polyp enlargement than the sodium flux theory supported by Bernstein's data. Neither theory completely defines the inflammatory trigger.
Patients with CF have a defective small chloride conductance channel, regulated by cyclic adenosine monophosphate (cAMP), which causes abnormal chloride transport across the apical cell membrane of epithelial cells. The pathogenesis of nasal polyposis in patients with CF could be associated with this defect.
Etiology
As noted (see Pathophysiology), chronic inflammation (from whatever source) apparently plays an initial role in the pathogenesis of nasal polyps. Multiple polyps occur in children with chronic sinusitis, allergic rhinitis, CF, and AFS. An isolated polyp could be an antral-choanal polyp, a benign massive polyp, a nasolacrimal duct cyst, or any of the following congenital lesions or benign or malignant tumors:
-
Nasolacrimal duct cysts
-
Encephaloceles
-
Gliomas
-
Dermoid tumors
-
Hemangiomas
-
Papillomas
-
Juvenile nasopharyngeal angiofibromas
-
Rhabdomyosarcoma
-
Lymphomas
-
Neuroblastomas
-
Sarcomas
-
Chordomas
-
Nasopharyngeal carcinomas
-
Inverting papillomas
All children with benign nasal polyposis should be evaluated for CF and asthma.
Epidemiology
In the United States, the overall incidence of nasal polyps in children is 0.1%; the incidence in children with CF is 6-48%. Among adults, the incidence is 1-4% overall, with a range of 0.2-28%. Worldwide incidence is the same as the incidence in the United States.
Benign multiple nasal polyposis usually manifests in patients older than 20 years and is more common in patients older than 40 years. Nasal polyps are rare in children younger than 10 years. Although the male-to-female ratio is 2-4:1 in adults, the ratio in children is unreported. A review of articles reporting on children whose nasal polyposis required surgery showed apparently equal prevalence in boys and girls, though the data are inconclusive. [4] The reported prevalence is equal in patients with asthma. Nasal polyps occur in all races and social classes.
Prognosis
No significant mortality is associated with nasal polyposis. Morbidity is usually associated with altered quality of life, nasal obstruction, anosmia, chronic sinusitis, headaches, snoring, and postnasal drainage. In certain situations, nasal polyps can alter the craniofacial skeleton because unremoved polyps can extend intracranially and into the orbital vaults.
Polyposis recurrence is common following treatment with medical or surgical therapy if multiple benign polyps are present (see Treatment, Surgical Care). Single large polyps (eg, antral-choanal polyps) are less likely to recur.
Endoscopic sinus surgery appears to improve both olfaction and quality of life in chronic rhinosinusitis patients with nasal polyps. [5, 6] In a study of 58 pediatric patients (< 18 years) with antrochoanal polyps who were treated with functional endoscopic sinus surgery (FESS), Pagella et al reported a recurrence rate of 20.5%. [7]
The literature contains sparse data comparing treatments. Galluzzi et al performed a systematic review (N = 285) aimed at evaluating recurrence rates after different surgical procedures used to treat antrochoanal polyps in children, including FESS, a combined approach (FESS with a transcanine sinusoscopy or mini Caldwell-Luc procedure), the Caldwell-Luc procedure, and simple polypectomy. [8] Recurrence rates were as follows:
-
All types of surgery - 15%
-
FESS - 17.7%
-
Combined approach - 0%
-
Caldwell-Luc procedure - 9.1%
-
Simple polypectomy - 50%
-
Rigid endoscopic view of the left nasal cavity, showing the septum on the left. Polyps with some blood and hemorrhage are on top of them in the center portion. The rim of white from 1 o'clock to 4 o'clock indicates the lateral nasal wall vestibule. The polyps cover the inferior turbinate, which is partially visible at 4 and 5 o'clock.
-
Endoscopic view of the left nasal cavity, showing a polyp protruding from the uncinate process. The middle turbinate is to the left. A suction is visible on top of the inferior portion of the uncinate process and inferior portion of the polyp. The lateral nasal wall is on the far right. The polyp is directly in the center and is pale, glistening, and white.
-
Endoscopic view of the left middle meatus. The septum is on the far left. The middle turbinate is next to the septum on the left. A large, glistening, translucent polyp is visible in the center of the screen next to the middle turbinate. The lateral nasal wall is on the right side of the screen. The inferior turbinate nub posteriorly is in the bottom right hand corner.
-
Rigid endoscopic view of the left nasal cavity, showing the septum on the left, inferior turbinate on the right, middle turbinate superiorly, and antral-choanal polyp among the floor of the nose.
-
Rigid endoscopic view of the left anterior nasal cavity, showing the septum on the left, a suction pushing the inferior turbinate on the right, and the clear antral-choanal polyp at the center of the endoscopic view.
-
Close-up of the middle meatus, showing the stalk of the antral-choanal polyp emanating from the maxillary sinus behind the uncinate process on the bottom right-hand side of the picture. The left side of the picture shows the septum and the middle turbinate being pushed over via suction.
-
Axial CT scan section through the maxillary sinuses showing opacification of the left maxillary sinus with antral-choanal polyp in the posterior nasal cavity and choana exiting from beneath the middle turbinate in the area of the ostiomeatal complex unit. Scale is in centimeters.
-
Coronal CT scan through the anterior sinuses showing opacification of the left maxillary sinus with opacification of the inferior half of the nasal cavity on the left, filled by the antral-choanal polyp. The rest of the sinuses are clear.
-
Coronal CT scan section through the posterior nasopharynx showing the sphenoid sinus superiorly and the antral-choanal polyp filling the nasopharynx in the center of the scan.
-
Oral cavity and oropharyngeal view of antral-choanal polyp filling the posterior oral pharynx and pushing the soft palate anterior and inferiorly. The polyp is visible behind the uvula and the soft palate.
-
Scale is in inches. The left side of the lesion was the portion of the polyp in the nasal cavity. The right was a stalk attached to the medial maxillary wall.
-
Endoscopic view of the left middle meatus, showing the septum on the left, the middle turbinate in the center superiorly, and a large maxillary antrostomy with a curved suction on the right. This is following antral-choanal polyp removal.
-
An anterior endoscopic view of the nasal cavity in a 5-month-old infant. The vestibule is seen in the periphery of the picture. In the center of the picture, the septum is visible to the left, and the inferior turbinate is to the right. These structures are reddish in hue. Some congestion in the nasal cavity is usually present. These are often structures that can be seen only by anterior rhinoscopy. If the area is decongested, the area of the middle meatus can occasionally be seen.
-
A rigid rhinoscopy photograph of the left anterior nasal cavity of a 6-week-old infant. The middle turbinate is superiorly in the midline, and the inferior turbinate is to the right. The septum is to the left.
-
A 3-month-old infant with hypertelorism and bulging of the nasal dorsum, secondary to encephalocele.
-
Interior view of the nose and nasal cavities. To the right of the patient's left nostril, the right nasal cavity has no obstruction. On the left of the picture, a reddish polyp is visible. The reddish mass is a nasal glioma.
-
A close-up view of the right nasal cavity and polyp #5 in a 5-month-old infant. The obstructing reddish polyp is visible. This is an intranasal glioma that was arising from the attachment of the inferior turbinate anteriorly; it was transnasally removed.
-
Anterior nasal papilloma arising from the septum. The skin of the nasal vestibule is seen surrounding the papilloma in the center of the image.
-
Axial MRI scan of the orbits, posterior fossa, and nasal cavity. The solid tumor is seen filling the posterior ethmoid complex, brain stem, cavernous sinuses, and left anterior cranial fossa.
-
Axial CT scan through the orbits and ethmoid sinuses, showing the rhabdomyosarcoma in the same areas, including the posterior ethmoid complex, left middle fossa, and skull base of cavernous sinuses.
-
Rigid endoscopic view of left nasal cavity, showing a polyp in the center of the picture, with extension of the rhabdomyosarcoma. The septum is on the left and the middle turbinate is on the right.
-
Endoscopic view of the left nasal cavity posteriorly, showing a polyp emanating from the sphenoid sinus in the center of the picture and purulence above and below the polyp. On the left is the septum. On the right is the lateral aspect of the middle turbinate.
-
Frontal view of a 2-day-old infant with swelling in the inferior medial canthal area on both sides. The right side appears more prominent on this picture. CT scan showed infected nasal lacrimal duct cysts.
-
Rigid endoscopic view of the left nasal cavity. The septum is on the left, and the lateral nasal wall is on the right. The inferior turbinate is in the center of the picture, and the middle turbinates are visible in the superior midsection of the picture. The nasal lacrimal duct cyst is the yellow dilated lesion underneath the inferior turbinate.
-
Axial CT scan section through the orbit, showing the dilated nasal lacrimal ducts in the medial anterior area compared to the orbits. Scale on the bottom right is in centimeters.
-
Axial CT scan through the inferior nasal cavities, showing the dilated nasal lacrimal duct cysts at the inferior location. Scale on the bottom right is in centimeters. The dilated cysts are in the center of the image.
-
A frontal view of the decompressed nasal lacrimal ducts following surgical marsupialization. Swelling in the inferior medial canthal areas prior to surgery is no longer seen.
-
Lateral view of a preteenaged child showing infected nasal dermoid. Note the protrusion of the dorsum of the nose.
-
Preteenaged boy with infected nasal dermoid. A pith is visible over the superior portion of the swelling between the eyes. Nasal pith is commonly seen with the nasal dermoid.
-
Frontal view of a 5-month-old infant, showing hypertelorism and protrusion in the glabellar region secondary to a small nasal dermoid.
-
Axial CT scan (bony windows) showing a 5-month-old infant with nasal dermoid anterior to the nasal and maxillary bones. No bony dehiscence or bony abnormalities are visible.
-
A coronal MRI scan through the nasal dermoid of a 5-month-old infant. The scale on the left is 2 mm per small bar and 1 cm per tall bar. The arrow points to the lesion. The lesion appears to be approximately 6-7 mm in this dimension.
-
An interoperative view of dermoid removal from a 5-month-old infant.
-
A surgical microdebrider entering the middle meatus. The septum is on the far left. The middle turbinate is in the left center. The surgical microdebrider is on the inferior center. Inferior turbinate is seen on the bottom right. Some blood overlying the ethmoid cavity is noted where polyps were present in the center of the picture.
-
Coronal section through the ethmoid maxillary sinuses and orbits. This is a 2-year-old child with cystic fibrosis, showing complete opacification of the maxillary and ethmoid sinuses. Bulging in the medial maxillary walls is observed.
-
Coronal section showing soft tissue windows rather than bony windows. It indicates the infection by the thick mucus in the maxillary and ethmoid cavities by the heterogeneity of the opacification in the sinuses. Note that the nasal cavity is completely obliterated by polyp disease.
-
A rigid rhinoscopy photograph of the the nasal cavity of a 6-week-old infant taken all the way back into the choanae of the left nasal cavity. The photograph shows the septum on the left, the small adenoids on the posterior superior wall of the nasopharynx in the center, and the eustachian tube orifice on the right.
-
A rigid rhinoscopy photograph taken in the midportion of the left nasal cavity of a 6-week-old infant showing the septum on the left, the inferior turbinate on the right, and the middle turbinate superiorly. The choanae is seen in the dark area in the center.
-
A rigid rhinoscopy photograph taken two thirds of the way back along the floor of the nose of the left nasal cavity of a 6-week-old infant. This photograph shows the septum on the left, the choanae straight ahead, and the posterior portion inferior turbinate to the right.
-
A coronal CT scan section through the orbit to maxillary sinus. The medial maxillary walls bulge medially, which is a typical CT scan view of cystic fibrosis. The ethmoid sinuses have scattered disease.
-
View just inside the nasal vestibule of a fifteen-year-old adolescent boy with allergic fungal sinusitis showing diffused polyposis extending into the anterior nasal cavity and vestibule; the septum is on the right, and the right lateral vestibular wall (nasal ala) is on the left. The polyps are all in the center. The polyps almost hang out of the nasal vestibule.
-
Coronal CT scan showing extensive allergic fungal sinusitis involving the right side with mucocele above the right orbit and expansion of the sinuses on the right.
-
Coronal CT scan showing typical unilateral appearance of allergic sinusitis with hyperintense areas and inhomogeneity of the sinus opacification; the hyperintense areas appear whitish in the center of the allergic mucin.
-
Coronal MRI scan showing expansion of the sinuses with allergic mucin and polypoid disease; the hypointense black areas in the nasal cavities are the actual fungal elements and debris. The density above the right eye is the mucocele. The fungal elements and allergic mucin in allergic fungal sinusitis always look hypointense on MRI scanning and can be mistaken for absence of disease.
-
Fifteen year-old adolescent boy with allergic fungal sinusitis causing right proptosis, telecanthus, and malar flattening; position of his eyes is asymmetrical, and his nasal ala on the right is pushed inferiorly compared with the left.
-
Nine-year-old girl with allergic fungal sinusitis displaying telecanthus and asymmetrical positioning of her eyes and globes.
