Keywords
inverted papilloma - nasal cavity - sphenoid sinus
Introduction
Inverted papilloma is a rare benign tumor of the nasal fossa, which usually originates
from the lateral wall of the nasal cavity. Only 5% of cases have exclusive sinus involvement.
Of the latter cases, the maxillary and ethmoid sinuses are most frequently affected.[1] Primary sphenoid sinus involvement is rare.[2]
[3]
[4]
[5]
[6]
[7] Although this tumor is considered a benign lesion, it has a potentially locally
invasive nature, and it is correlated with bony erosion. It also has a tendency for
local recurrence and an associated malignancy rate of 7 to 15%, with squamous cell
carcinoma being the most common histopathologic type.[1]
[8]
We report a case of inverted nasal papilloma originating in a very unusual location:
the sphenoid sinus. We describe how the patient was managed, including detailed description
of how the lesion was diagnosed and treated. We also report the therapeutic approach
and results of 2-month follow-up.
Literature Review
Inverted papilloma is a rare benign sinonasal tumor, usually arising from the lateral
aspect of nasal wall. It was first described in 1854 by Ward.[9]
[10] It accounts for 0.5 to 4% of nasal tumors, and it is most often seen in the fifth
and sixth decades of life.[11] This tumor presents a characteristic endophytic growth pattern: its Schneiderian
membrane inverts into the underlying stroma.[8] It is also characterized by its potentially invasive nature; 70% of cases have been
found to show evidence of bony erosion on computed tomography (CT) scan at diagnosis.
It has high rates of recurrence, varying from 20 to 47% according to the current literature.[12]
[13]
The characteristic radiographic appearance of inverted papillomas is a unilateral
polypoid lesion occupying the lateral nasal wall and paranasal sinuses.[8] Only 5% of cases demonstrate exclusive sinus involvement, with the maxillary and
ethmoid sinuses being the most commonly affected.[8] Isolated inverted papilloma of the sphenoid sinus is rare. In a recent review of
the English literature, 50 cases were reported.[14] The majority of patients with inverted papilloma present with nasal complaints such
as unilateral nasal obstruction, rhinorrhea, epistaxis, and so on. However, the clinical
presentation of inverted papillomas confined to the sphenoid sinus is often nonspecific
and insidious, with headache being the most common presentation.[14]
For years, the recommended treatment of choice consisted of medial maxillectomy and
en bloc tumor excision through lateral rhinotomy or a midfacial degloving approach.
Nevertheless, recently a more conservative management via a transnasal endoscopic
approach has been advocated by some authors and has produced some good results. There
has been a tendency to consider the exclusive endoscopic approach as the gold standard
treatment for inverted papillomas, even in the more advanced stages of the disease
and inclusive for the treatment of disease recurrences.[15] This technique has remarkably improved throughout the years, presenting a decreased
disease recurrence rate compared with the beginning of its use, and was the one chosen
by us to perform in our patient.[16] The endoscopic technique has shown at least the same effectiveness as the external
traditional approach, avoiding the comorbidities related to the latter one.[17] Some advantages of this technique are better view of the surgical field, lesser
resection of viable tissue, decreased nasal scabbing, and reduced amount of postoperative
bleeding and pain.
Case Report
The patient, a 56-year-old woman, presented to our outpatient clinic with a 2-month
history of frontal headache, occasional otalgia worsened when elevating the head,
and recent forgetfulness. She was at first evaluated by a clinical neurologist and
then submitted to a head magnetic resonance imaging (MRI) scan. A lesion was found
filling and expanding both sphenoid sinuses, extending to the posterior ethmoidal
cells and right sphenoethmoidal recess ([Figs. 1] and [2]). The radiologist described it as a lobulated mass homogenously enhanced by the
contrast media, which was hyperintensive on T2-weighted images and with intermediate
intensity on T1-weighted images. The latter sequence also presented a tenuous hyperintensive
signal on its inner part. Sinus CT showed an opacified sphenoid sinus with apparent
bony integrity ([Fig. 3]).
Fig. 1 Coronal view of head magnetic resonance image reveals a lobulated mass occupying
both sphenoid sinuses enhanced by the contrast media with no unequivocal evidence
of skull base involvement.
Fig. 2 Sagittal view of head magnetic resonance image shows evidence that the lesion might
extend beyond the sphenoid sinus lateral wall toward the skull base, possibly affecting
the cavernous sinus.
Fig. 3 Sinus computed tomography showing a soft tissue mass filling in the sphenoid sinus
extending to the posterior sphenoid with apparent bony integrity.
The patient underwent a sphenoidotomy through a transnasal endoscopic approach, by
means of 0- and 30-degree rigid fibroscopes. A bleeding papillomatous lesion was identified
inside the sphenoid sinus. Biopsy was performed, and a fragment of tissue was sent
for a frozen section analysis. Histopathologic study suggested inverted papilloma
([Fig. 4]). The lesion was meticulously and completely resected through a bilateral sphenoid
sinus endoscopic with de-epithelialization. Postoperatively, the patient did well
and was discharged the next day.
Fig. 4 Resected lesion.
The patient has been followed in the head and neck outpatient clinic for 60 days after
surgery, with no signs of recurrence found upon flexible nasofibroscope examination,
as shown in the picture ([Fig. 5]).
Fig. 5 Two-month postoperative nasofibroscopy.
However, whether this single surgery will be sufficient therapy for our patient in
the years to come remains to be seen. The literature describes most recurrences appearing
between 1 and 11 months after the initial procedure.[3] Although endoscopic sphenoidotomy appeared to be effective in this case, longer
follow-up is necessary to determine whether the disease will recur. Therefore, regular
and close follow-up is necessary in all cases following surgery to remove an inverted
papilloma.
Conclusions
-
Inverted papilloma exclusively involving the sphenoid sinus is a rare entity. Nonspecific
symptomatology and clinical presentation make this kind of tumor a diagnostic and
therapeutic challenge for otolaryngologists. Radiologic examinations, including MRI
and CT scan, are particularly important to identify its characteristics.[14] Endoscopic sphenoidotomy has been the treatment of choice; its effectiveness is
described as at least equal to the traditional external approach although it is associated
with less comorbidities.[18]
-
Close follow-up is required to detect possible recurrences and malignant transformation.
