Laboratory Studies
Laboratory studies should be directed at the pathologic process believed to be responsible for the nasal polyps.
Children with polyposis that is associated with allergic rhinitis should undergo evaluation for their allergies; this may include a serologic radioallergosorbent test (RAST) or some form of allergic skin testing. Mabry et al showed a decrease in the recurrence rate of polyps in children treated with immunotherapy directed at all antigens for which they are allergic, especially molds [10] ; therefore, allergy testing and treatment may be important in treating allergic fungal sinusitis (AFS).
Perform a sweat chloride test or genetic testing for cystic fibrosis (CF) in any child with multiple benign nasal polyps.
A nasal smear for eosinophils may differentiate allergic from nonallergic sinus diseases and indicate whether the child may be responsive to glucocorticoids. The presence of neutrophils may indicate chronic sinusitis.
Imaging Studies
The criterion standard for evaluating nasal lesions, especially nasal polyposis or sinusitis, is a thin-cut (1-3 mm) computed tomography (CT) scan of the maxillofacial area, the sinuses axially, and the coronal plane. A compatible CT scan should be performed if an intraoperative image-guided system is used. Plain film radiography has no significant value after polyps are diagnosed. Magnetic resonance imaging (MRI) is also warranted in patients with possible intracranial involvement or extension of benign nasal polyps.
CT and MRI findings can help diagnose the polyp or polyps; define the extent of the lesion in the nasal cavities, sinuses, and beyond; and narrow the differential diagnosis of an unusual polyp or clinical presentation. CF is associated with a characteristic symmetrical bulging of the lateral nasal walls medially (see the images below).
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 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.
An antral-choanal polyp may show opacified maxillary sinuses with a protruding lesion heading from the maxillary antrum to the choana (see the images below).
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.
A tumor, such as a rhabdomyosarcoma, may show extension of the lesion with invasion of surrounding mucosa (see the images below).
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.
A nasolacrimal duct cyst can show dilation of the nasolacrimal duct (see the images below).
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.
An encephalocele can show expansion of the nasofrontal region (ie, foramen caecum) with herniation of brain or dura.
A glioma can show an isolated nasal lesion that may have a fibrous stalk to the central nervous system (CNS).
Patients with AFS exhibit heterogenous areas in the sinuses on CT and MRI; these areas consist of both the nasal polyposis and the allergic fungal mucin (see the images below). This allergic fungal mucin appears black on MRI and can be confused with the absence of disease.
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 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.
Histologic Findings
Histologically, nasal polyps are characterized by a pseudostratified ciliated columnar epithelium, thickening of the epithelial basement membrane, and few nerve endings. The stroma of nasal polyps is edematous. Vascularization is poor and lacks innervation, except at the base of the polyp. Authors report either hyperplasia of the seromucous glands or almost absent or rare glands when comparing the polyps to the inferior or middle turbinate. Hyperplasia of the gland can cause cystically dilated and degenerated glands containing inspissated mucous.
Eosinophil cells are the most commonly identified inflammatory cell, occurring in 80-90% of polyps. Eosinophils, which are found in the polyps of patients with bronchial asthma and allergy, contain granules with toxic products (eg, leukotrienes, eosinophilic cationic protein, major basophilic protein, platelet-activating factor [PAF], eosinophilic peroxidases, other vasoactive substances and chemotactic factors). These toxic factors are responsible for epithelial lysis, nerve damage, and ciliostasis. Specific granule protein, leukotriene A4, and PAF apparently are responsible for the mucosal swelling and hyperresponsiveness.
Eosinophils in the peripheral blood and in normal nasal mucosa usually last 3 days. In a cell culture of nasal polyps, eosinophils were present at least 12 days. This delayed apoptosis of eosinophils is mediated, in part, by blockage of the Fas receptors, typically with proteases that help begin the process of cell death.
Delayed apoptosis is also mediated by an increase in interleukin (IL)-5, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF) secreted by T cells, which help sustain the eosinophil from death. Glucocorticoids seem to help reduce polyps or polypoid reactions in patients with tissue eosinophilia, possibly, in part, by inhibiting IL-5.
Another inflammatory cell, the neutrophil, occurs in 7% of polyp cases. This type of polyp occurs in association with CF, primary ciliary dyskinesia syndrome, or Young syndrome. These polyps do not respond well to corticosteroids because they lack corticosteroid-sensitive eosinophils. Degranulated mast cells are present. Degranulation presumably occurs in a non–immunoglobulin (Ig) E–mediated fashion. Increased numbers of plasma cells, lymphocytes, and myofibroblasts also occur.
Chemical mediators
The stromata of nasal polyps have numerous mediators, including cytokines, growth factors, adhesion molecules, and immunoglobulins; polyps also contain vasoactive amines, serotonin, prostaglandins [11] , leukotrienes, norepinephrine, kinins, esterases, heparin, and histamine. The level of histamine in nasal polyps is 100-1000 times the level found in the bloodstream.
Cytokines present in polyps include the following:
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IL-1 - Found regularly
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IL-3 - Varies according to study, from absent to intermittent at low levels to regularly present
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IL-4 - Inconsistently detected
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IL-5 - Found regularly; IL-5 is essential for proliferation and differentiation of eosinophils. IL-5 is chemotactic to eosinophils, promotes the migration of eosinophils from the systemic circulation to the polyps, and inhibits eosinophil cell death.
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IL-6 - Same as in controls (no increase)
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IL-8 - Varies, based on study, from undetected to regularly detected; may cause sustained recruitment of leukocytes into nasal polyps and may decrease fibroblastic proliferation
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IL-10 - Same as in controls; no increase regulated on activation, normal T cell expressed and secreted (RANTES); varies, based on study, from same as controls to regularly detected to increased levels interferon gamma; increases in eosinophils, seromucous glands, and epithelium of nasal polyps
Growth factors found in nasal polyps include the following:
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Tumor necrosis factor (TNF)-α and TNF-β - Varies, depending on the study, from same as controls to regularly detected; believed to be from eosinophils
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GM-CSF - mRNA and protein amount varies, based on study, from never to intermittent to present
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Platelet-derived growth factor (PDGF) - Present
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Vascular permeable factors (VPFs) - Present
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Vascular endothelial growth factors (VEGFs) - Present
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Insulinlike growth factor (IGF)-1 - Present
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Stem cell factor - Present
Adhesion molecules include the following:
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Vascular adhesion molecule (VCAM)-1 - Present
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E and P selectin - Present
Immunoglobulins include the following:
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IgG - No increase; same levels as in the middle and inferior turbinate mucosa
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IgA - More in polyps than in the middle and inferior turbinate mucosa, especially IgA1 over IgA2
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IgM - No increase, same as in the middle and inferior turbinate mucosa
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IgD - No increase, same as in the middle and inferior turbinate mucosa
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IgE - Increased levels compared with the middle and inferior turbinate mucosa; same level in patients without allergy as in those with allergy
Staging
In 1993, Lund and Mackay proposed the following three-point system for staging nasal polyps according to endoscopic appearance [12, 13] :
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0 - No polyposis
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1 - Polyps confined to the middle meatus
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2 - Polyps beyond the middle meatus
Subsequently, this system was modified as follows [14, 15] :
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0 - No polyps
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1 - Polyps restricted to the middle meatus
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2 - Polyps extending below the middle turbinate
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3 - Massive polyposis, occluding the entire nasal cavity
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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A 3-month-old infant with hypertelorism and bulging of the nasal dorsum, secondary to encephalocele.
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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.
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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.
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Anterior nasal papilloma arising from the septum. The skin of the nasal vestibule is seen surrounding the papilloma in the center of the image.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Lateral view of a preteenaged child showing infected nasal dermoid. Note the protrusion of the dorsum of the nose.
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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.
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Frontal view of a 5-month-old infant, showing hypertelorism and protrusion in the glabellar region secondary to a small nasal dermoid.
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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.
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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.
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An interoperative view of dermoid removal from a 5-month-old infant.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Nine-year-old girl with allergic fungal sinusitis displaying telecanthus and asymmetrical positioning of her eyes and globes.
