Imaging Studies
Preoperative radiographic assessment of sinonasal papillomas (SPs) plays an important role in determining extension of the disease and involvement of adjacent structures; hence, choosing the appropriate approach is important.
CT scanning
Coronal and axial contrast-enhanced computed tomography (CT) scanning is considered the study of choice for assessing intranasal lesions.
As many as 75% of patients with SPs have evidence of various degrees of bone destruction. These may include thinning, remodeling, erosion, and (less commonly) sclerotic bony changes. The presence of bone destruction alone does not indicate dedifferentiation into malignancy from the SP. CT scanning is more precise than conventional radiography for identifying the areas of bony erosion.
With CT scanning, differentiating a papillomatous lesion from inspissated mucous, mucoperiosteal thickening, or polyps that result from the obstruction of a sinus drainage pathway is sometimes difficult.
MRI
MRI is an alternative study that is superior to CT scanning in distinguishing papillomas from inflammation and for providing better delineation of the lesions in contrast to surrounding soft tissue.
SPs have a heterogeneous appearance on MRI.
On T1-weighted images, sinonasal papillomas appear slightly hyperintense to muscle; however, on T2-weighted images, SPs have intermediate signal intensity.
A convoluted cerebriform pattern on T2 and enhanced T1-weighted MRI scans for inverted papillomas may be potentially distinctive in 80% of cases, according to Ojiri et al. [14, 15]
Inflammatory polyps and inspissated material in the sinuses secondary to obstruction by the papilloma are hyperintense on T2-weighted images.
Because of the findings listed above, MRI can more accurately define the true extent of the lesion and can help in treatment planning.
Diagnostic Procedures
See the list below:
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Biopsy is the most important diagnostic tool when a sinonasal papilloma is suspected.
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If intracranial pathology may be manifesting in the sinonasal cavity (ie, encephalocele, meningocele, meningoencephalocele), perform imaging studies before biopsy.
Histologic Findings
SPs can be divided into 3 histologic subtypes: inverted, fungiform, and cylindrical (columnar). Inverted papillomas have an endophytic growth pattern found almost exclusively on the lateral nasal wall; these account for 47% of all cases of SPs. On the contrary, fungiform papillomas constitute approximately 50% of sinonasal SPs and have an exophytic type of growth. They are found mainly on the nasal septum. Cylindrical papillomas are the rarest type (3-5%) and are also called oncocytic SPs.
On gross examination, SPs originate from a narrow or broad-based stalk. Sinonasal papillomas have an irregular, friable appearance and bleed easily. On microscopy, the fungiform type is mainly composed of thick squamous epithelium and, less frequently, respiratory epithelium arranged in papillary fronds with exophytic type of growth. By comparison, the inverted type, which has an endophytic or inverted growth pattern, consists of thickened squamous epithelium admixed with mucocytes and intraepithelial mucous cysts. The cylindrical papilloma is composed of multilayered epithelium with an eosinophilic cytoplasm among which intraepithelial mucin cysts are identified.
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Sagittal illustration of transnasal endoscopic medial maxillectomy (TEMM) shows the resected lateral nasal wall. Note the cavity of the maxillary sinus (M), resected ethmoid sinuses (E), nasolacrimal duct (NLD), sphenopalatine artery (SPA), and tumor (T).
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Superior cut in transnasal endoscopic medial maxillectomy (TEMM) going through the anterior ethmoids (AE) along the ethmoid roof. Central circle shows the endoscopic view and the semitranslucent peripheral circle is the bird's-eye view to show the context. Image shows the middle turbinate (MT), nasolacrimal duct (NLD), Tumor (T), nasal septum (S), and inferior turbinate (IT).
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Inferior incision in transnasal endoscopic medial maxillectomy (TEMM) through the mucosa and soft tissue to expose the bone for osteotomy. Broken line illustrates the position of the inferior osteotomy. Image shows the nasal floor (NF), septum (S), the anterior head of inferior turbinate (IT), nasolacrimal duct (NLD)), and tumor (T).
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Anterior mucosal incision and osteotomy in transnasal endoscopic medial maxillectomy (TEMM) connecting the superior and the inferior cuts. Bony nasolacrimal duct is osteotomized to expose the duct (NLD). Image shows the nasal floor (NF), inferior turbinate (IT), septum (S), ethmoid sinuses (ES), and tumor (T).
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Posterior cuts in transnasal endoscopic medial maxillectomy (TEMM). The nasolacrimal duct (NLD) is transected to allow medialization of the lateral nasal wall and to expose the maxillary sinus. Posterior cuts are completed in the maxillary sinus. The sphenopalatine artery is exposed. Semitranslucent bird's-eye view illustrates the ethmoid sinuses (ES) along with the lateral nasal wall that is medialized with the tumor (T). Image also shows the ethmoid roof (ER), nasal floor (NF), and sphenoid ostium (SO).
