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Case report
Sinonasal inverted schneiderian papilloma presenting as a large intraoral lesion
  1. Kumar Nilesh1,
  2. Srijon Mukherji2,
  3. Sujata R Kanetkar3 and
  4. Aaditee Vande4
  1. 1Oral & Maxillofacial surgery, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra, India
  2. 2Calcutta Institute of Maxillofacial Surgery and Research, Kolkata, India
  3. 3Department of Pathology, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra, India
  4. 4Department of Prosthodontics, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra, India
  1. Correspondence to Dr Kumar Nilesh; drkumarnilesh{at}


Sinonasal inverted schneiderian papilloma (ISP) is a rare tumour, which almost exclusively arises from the mucosa lining, the nasal cavity and the paranasal sinuses. The tumour in its early stages presents as an asymptomatic mass, which may be discovered during routine examination. Large lesions usually measure a few millimetres to centimetres in size and show symptoms such as nasal blockade, recurrent sinusitis, postnasal drip, anosmia, epistaxis, facial pain and headache. Lesion presenting as a large oral mass is extremely rare and may cause diagnostic dilemma, resulting in misdiagnosis. This report describes a rare case of ISP presenting as large intraoral lesion, with wide area of facial skeletal involvement. Diagnosis and management of the pathology has also been highlighted.

  • dentistry and oral medicine
  • surgery
  • head and neck surgery
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Inverted schneiderian papilloma (ISP) is a benign tumour of epithelial origin, which arises from respiratory mucosa that lines the nasal cavity and paranasal sinuses. It is rare and accounts for 0.5%–4% of all sinonasal neoplasms.1 Clinically, it presents as a mass lesion contained within the nasal cavity or paranasal sinus. Early-stage lesion is asymptomatic and may get diagnosed serendipitously during routine examination. As the lesion grows, it may cause symptoms, which include nasal obstruction, postnasal drip, hyposmia or anosmia, rhinorrhea, headache, facial pain and epistaxis.2 ISP is locally aggressive, with high recurrence rate and risk of malignant transformation. This paper reports a case of sinonasal ISP presenting as a large mass in the oral cavity. The tumour was treated by wide excision through extraoral approach. Reconstruction was done using combination of iliac graft, titanium mesh, split thickness skin graft and oral prosthesis.

Case presentation

A 46-year-old man presented to oral surgery clinic with chief complaint of painless intraoral mass, associated with progressive difficulty in speech and swallowing since the past 6 months. There was no contributing medical history. The patient gave a history of sequential extraction of multiple mobile teeth in the right maxillary region 2 years ago. The patient did not give history of tobacco smoking or other deleterious oral habits. On clinical examination, no gross facial swelling was seen. Intraoral examination revealed large soft tissue growth, occupying the right half of oral cavity (figure 1A). Mucosa overlying the growth appeared normal, but was friable and readily bled on palpation. Intranasal inspection using nasal speculum showed no obvious nasal growth. No history of epistaxis, anosmia or postnasal drip was reported.

Figure 1

Clinical presentation of lesion as large mucosal mass (A), axial section of CT showing osteolytic lesion involving right half of maxilla (B) and three-dimensional stereolithographic model showing wide area ok mid-face skeletal resorption (C).


For further evaluation, CT was advised. CT images revealed osteolytic lesion causing wide area of bone destruction involving the right maxilla (figure 1B). Entire right maxillary sinus was obliterated. A three-dimensional (3D) stereolithography model was fabricated from the data available from the CT imaging, which confirmed the findings of large area of destruction of the right mid-face skeleton, involving maxilla, zygomatic bone, infraorbital rim and the lateral nasal wall (figure 1C).

Differential diagnosis

Based on the clinical presentation and imaging findings, a working diagnosis of locally aggressive oral or sinonasal tumour was made. The differential diagnosis included oral carcinoma, sinonasal carcinoma and sinonasal carcinoma ex-papilloma. Incision biopsy was planned and executed under local anaesthesia. Histopathology reveals hyperplastic ribbons and islands of squamous and ciliated respiratory epithelium covered with an intact basement membrane growing into underlying stroma. Epithelial transmigration of neutrophils was seen. Koilocytic change was also noted (figure 2A–D). There was no evidence of dysplasia, mitoses or pleomorphism. Mucous cells were not seen in the lesion. Based on the finding of microscopic study, diagnosis of ISP was made.

Figure 2

Photomicrographs showing hyperplastic ribbons and islands of epithelium (squamous and ciliated respiratory epithelium) enclosed by basement membrane growing into underlying stroma (H&E stain, ×100 magnification) (A), epithelial transmigration of neutrophils (H&E stain, ×400 magnification) (B,C), squamous epithelium with koilocytic changes (H&E stain, ×400 magnification) (D).


After diagnosis of ISP, the patient was prepared for wide excision of the lesion under general anaesthesia after due of the ethical committee. 3D stereolithography model was used for surgical planning. Wax block was adapted over the 3D model (to mimic the bone graft) and titanium mesh was preadapted for reconstruction of the zygomatic prominence and orbital floor (figure 3A). Oral impression of upper arch was made using alginate impression material and a surgical obturator was fabricated. Under general anaesthesia, extended Weber-Ferguson’s incision was used to access the lesion (figure 3B). After elevation of the skin flap, the lesion was dissected from its base, which was apparently arising from the lateral wall of right nasal cavity (figure 3C). After adequate exposure, complete excision of the lesion was done in toto (figure 3D,E). The surgical bed after removal of lesion showed smooth margins of surrounding bone, suggestive of pressure resorption from the mass lesion. The excised gross specimen was a pink-white firm polypoid soft tissue, which was partly covered by intact mucosa (figure 3E). The excised tissue was then submitted for histopathological evaluation. Cortico-cancellous iliac bone graft was harvested. The bone graft was used to reconstruct the zygoma and orbital floor. After insetting the graft, it was fixed with precontoured titanium mesh and screws (figure 3F). The defect was lined with split thickness skin graft and the surgical obturator was placed securing the skin graft in place (figure 3G). Closure of skin flap was done in layers (figure 3H).

Figure 3

Intraoperative images showing three-dimensional stereolithography model used for surgical planning (A), use of extended Weber-Ferguson’s incision for access to the lesion (B), tumour attached to lateral nasal wall (C), surgical site after removal of lesion (D), excised lesion (E), reconstruction of zygoma and orbital floor (F), split thickness skin graft and the surgical obturator in place (G) and closure (H).

Histopathological evaluation of the excised specimen revealed ribbons and islands of squamous and ciliated respiratory epithelium with intact basement membrane. The epithelial lining showed multiple folds into the underlying connective tissue with prominent neutrophil infiltration. The overall findings were consistent with incision biopsy and were confirmatory for ISP. The interface between tumour and adjacent normal bone showed abrupt transition, without any evidence of infiltration. Sufficient sampling of the submitted specimen was done to rule out carcinoma ex-papilloma. No evidence of atypical mitosis, dysplasia, bone invasion, pleomorphism, dyskeratosis or perineural invasion was found on thorough sequential evaluation of the specimen.

Outcome and follow-up

The patient had an uneventful postoperative recovery and was kept on periodic follow-up schedule. At 3 years of follow-up, the patient showed satisfactory healing with no symptoms of relapse or evidence of recurrence (figure 4).

Figure 4

Clinical photograph at 3 years of follow-up.


ISP was first described by Ward, in year 1854.3 They are rare benign tumours accounting for 0.5%–4% of all sinonasal neoplasms.1 ISP arises from the schneiderian membrane of the paranasal sinuses or the mucosal lining of nasal cavity. Reportedly, the most commonly involved sites are lateral nasal wall and maxillary sinus.4 The WHO (2005) classified sinonasal schneiderian papilloma into inverted, oncocytic and exophytic type.5 ISP is the most common of the three variants of sinonasal schneiderian papilloma.6 Features that distinguish ISP from other sinonasal tumours include local aggressive growth, chance of malignant transformation and relatively high rate of recurrence.

Aetiology of ISP remains controversial. Causative agents that have been commonly implicated include smoking, allergy and occupational exposures. Although smoking is considered as an important risk factor, its role in tumour initiation has been refuted by various case–control studies. Comparative clinical studies by Deitmer and Wiener7 and Sham et al8 showed no significant association between smokers and incidence of ISP. However, positive association has been found between smoking and higher risk of recurrence and malignant transformation of ISP.9 10 In the present report, the patient did not have a history of smoking. Occupational/industrial exposures from construction, textile, printing, papermaking and electronic industries have also been described as contributory factors for ISP.8 The role of inflammation in the pathogenesis of ISP is not clearly understood. Allergic rhinitis and chronic inflammatory changes are common in lateral nasal wall and maxillary sinus, from where ISP commonly originates. Inflammatory changes are known to be associated with ISP. Significant epithelial transmigration of neutrophils was seen on histopathological evaluation of the specimen in the present case. A retrospective analysis of histopathological features of schneiderian papilloma showed that inflammatory cell population was significantly greater in ISP, as compared with the other two forms of schneiderian papillomas.11 The role of human papillomavirus (HPV) in ISP has been widely studied. While HPV has been associated with high potential of malignant transformation and increased risk of recurrence, a number of recent studies have presented conflicting evidences.12 A recent study by Rooper et al13 showed that transcriptionally active high-risk HPV does not play significant role in either development or malignant transformation of ISP.

ISP is common in men, with a reported male-to-female ratio of 3.4:1.3 Small and early lesions are asymptomatic and in 4%–23% cases are serendipitously diagnosed during routine evaluation.14 The clinical signs of ISP are non-specific and include nasal congestion, rhinorrhea, epistaxis, headache, hyposmia or anosmia and facial pain.2 ISP is usually limited to nasal cavity and/or paranasal sinuses and is assessed by endoscopic examination. It clinically appears as a reddish-grey lobulated tumour and is typically described as having ‘raspberry appearance’. Lesion involving larger parts of nasal cavity and paranasal sinuses is relatively uncommon. Kamath et al reported a case of ISP presenting as nasal mass with extension into the oropharynx.15 ISP involving left nasal cavity and all the left paranasal sinuses along with temporal and orbital extension was reported by Ibrahim et al.16 Both the cases were partly associated with carcinoma in situ and malignant transformation. Large ISP without histological evidence of dysplasia, involving entire left nasal cavity, maxillary sinus and part of ethmoidal sinus, was reported by Jayakody et al in a paediatric patient.17 Such presentation of ISP is rare and may lead to misdiagnosis.

As there is no pathognomonic clinical feature of ISP, histopathologic assessment is essential for definitive diagnosis. Microscopically, the lesion is characterised by thick ciliated or columnar epithelium, which is inserted into the underlying connective tissue.18 The extensive epithelial invasion into the underlying stroma may possibly explain the propensity of widespread involvement in cases of large lesions. The reported case presented as a large intraoral mass, causing difficulty in speech and swallowing. Such presentation being rare and should be sequentially investigated to rule out other pathologies. The differential diagnosis included oral carcinoma, sinonasal carcinoma and sinonasal carcinoma ex-papilloma. Invasive carcinoma was ruled out because of the presence of ribbons covered with intact basement membrane and bland nuclei. Whereas, sinonasal carcinoma ex-papilloma was ruled out by sequential sampling of the excised specimen, which did not show atypical mitosis, dysplasia, bone invasion, pleomorphism, dyskeratosis or perineural invasion.

Imaging of extensive ISP is indicated to evaluate the extent of spread and involvement of vital anatomical structures. Both CT and MRI have been used for this purpose.15–17 On CT, ISP appears as homogeneous isodense lesion. Calcifications have been seen in about 20% cases.19 In a review of 61 cases of ISP, approximately 23 (37%) patients showed bony erosion on CT scan.20 This case presented as large homogeneous mass causing complete obliteration of maxillary sinus along with extensive bone erosion, involving maxilla, lateral nasal wall, zygoma and orbital skeleton.

Surgery involving wide excision of the lesion remains the mainstay for management of ISP. Wide excision eliminates the pathology, relieves the symptoms produced by mass lesion and provides specimen for histopathological confirmation. Endoscopy assisted resection of ISP was first described by Waitz and Wigand and by Kamel in year 1992.21 22 Endoscopic approach is usually used to access lesions, which are localised within the nasal cavity and/or the paranasal sinuses. Extraoral approach may be required for extensive pathologies, as success of surgery is dependent on wide exposure and complete resection of tumour from its insertion point. In the present report, surgical approach through Weber Ferguson’s incision with infraorbital skin crease extension was used. The exposure allowed good visibility for complete removal of the pathology as well as reconstruction of the mid-face defect. 3D stereolithography model allowed better understanding and visualisation of the pathology as well as provided model for presurgical work-up and preadaptation of the titanium mesh, thus reducing the operating time. The rate of recurrence of ISP after its surgical management ranges from 0% to 50%.23–25 The wide variation in the reported recurrence rate is possibly due to differences in size and extent of lesions, degree of aggressiveness and malignant transformation. Hence, long-term follow-up is critical. It is important to detect recurrence early to enable prompt treatment, especially for those cases associated with malignant changes. There were no clinical signs of recurrence in the reported case and the patient was disease free at 3 years of follow-up.

Patient’s perspective

I was extremely disturbed with the disease that had grown in my mouth and was the cause of many problems to me, including difficulty to speak clearly and eat. It was not only affecting my day to day work, but had also stopped mixing up with people. I had visited few physicians and was advised referral to higher centre for management. When I was told that big part of the face and mouth is going to be subjected to surgery for removal of the disease, it further compounded my apprehension. But with proper counselling and description that the defect left will be carefully reconstructed gave me some confidence. I was informed that the disease was very rare; however, surgical management would give the adequate clearance and disease-free life to me. The surgery though had caused significant concern in my mind, passed smoothly. My face looked normal except for the stitch marks that were faintly visible, and to be honest I was ok with it! It was emphasised on me to have regular follow-up for a long time and possibly for lifetime, which I have been religiously following.

Learning points

  • Inverted schneiderian papilloma (ISP) is a rare neoplasms and account for 0.5%–4% of all sinonasal neoplasms.

  • Clinically, ISP presents as well-localised lesion within nasal cavity or paranasal sinus. It may be asymptomatic or present with non-specific symptoms of mass lesion including nasal obstruction, postnasal drip, hyposmia or anosmia, rhinorrhea, headache, facial pain and epistaxis. Large lesion is commonly associated with malignant changes.

  • This paper reports a case of ISP presenting as a huge oral mucosal mass. Such rare presentation can result in misdiagnosis and delay execution of appropriate treatment plan.

  • Due to known aggressive nature of lesion with potential of malignant transformation and high recurrence rate, the lesion was approached through extraoral incision and surgically treated with wide excision. The patient was disease free at 3 years of follow-up.


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  • Contributors KN was involved in the concept, design, literature search, data acquisition, manuscript preparation, review and editing. SM was involved in literature search and manuscript preparation. SRK and AV were involved in final drafting of manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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