Surgical treatment of 186 sinonasal inverted papillomas and analysis of the immunohistochemical and molecular features associated with recurrences.

INTRODUCTION: Inverted papillomas (IP) are benign epithelial tumors with a tendency to be locally invasive and with disposition to recur. The aim of our study is to present the results of IP treatment, considering pathological, immunohistochemical and molecular features of recurrence. MATERIAL AND METHODS: From 1978 to 2020, 186 sinonasal IPs surgeries corresponding to 152 patients were treated in our center. We performed a pathology evaluation of all the recurrent cases reviewing the histological diagnosis, the presence of mixed component other than IP, the koilocytic changes, the p16 over expression and HPV-DNA detection. RESULTS: Overall recurrence rate was 19 % (35/186). The 35 IP recurrences correspond to 22 patients, 9 of whom presented a single recurrence (single recurrence group) while 13 of them presented more than one recurrence (multi-recurrent group). Immunohistochemical analysis showed a higher percentage of p16 overexpression (54 % vs 33 % p = 0.415) and HPV-DNA presence (23 % vs 0 % p = 0.240) in the multi-recurrent group compared with single recurrence group. In addition, the revision showed more IP with exophytic papilloma focus (38 vs 22 % p = 0.648) and a higher proportion of IP with koilocytotic changes (61 % vs 22 % p = 0.099) in the multirecurrent group. There is no significant difference between groups in our results. CONCLUSION: The analysis of our patients may differentiate between two groups with recurrent papillomas. A single recurrence group where the cause of recurrence is probably an anatomical problem related to an incomplete resection, and a second pattern, the multi-recurrence group, where HPV infection may be the main cause of recurrence.

A Large Pleomorphic Adenoma in Nasal Cavity Misdiagnosed as Inverted Papilloma.

Pleomorphic adenoma (PA) is a benign tumor characterized by slow-growing mixed tumors in the craniofacial area. It is relatively common in salivary glands; however, PA of the nasal cavity, which arises in the minor salivary glands, is rare. We present the case of a large PA in the nasal cavity of an adult immunocompetent woman with nasal obstruction and intermittent epistaxis. Based on preoperative radiologic examinations, she was misdiagnosed with an inverted papilloma. Endoscopic resection was performed under general anesthesia. Pathologically, the patient was confirmed to have PA, which has great cellularity and few stromal components. No complications or recurrences during the 1-year follow-up period were observed.

BiZact-Assisted Endoscopic Resection of a Sinonasal Tumor.

The BiZact device, a bipolar electrosurgical scissor designed for tonsillectomy, minimizes thermal tissue damage and seals blood vessels <3 mm in diameter while dividing the soft tissue. This study describes the authors' experience with sinonasal tumor surgery using a BiZact and discusses its clinical utility and advantages. The authors analyzed BiZact-assisted endoscopic sinonasal tumor surgery cases between January 2021 and May 2023. Data were collected on patients' demographics, histopathology, extent of tumor involvement, surgical records, and postoperative medical records. Clinical utility was assessed using the success rate of complete tumor excision, estimated blood loss during surgery, device-related complications, and operation time. A survey of the surgeons' BiZact experience was also conducted. The diagnoses of the 20 patients in this study included squamous cell carcinoma (n = 2), malignant melanoma (n = 1), sarcoma (n = 1), natural killer cell lymphoma (n = 1), inverted papilloma (n = 12), angiofibroma (n = 2), and schwannoma (n = 1). This pilot study demonstrated a shortened operative time, with a median of 0.8 hours and <100 mL of intraoperative blood loss. In addition, no BiZact-related complications were observed. The BiZact device allows efficient sinonasal surgery because it has the unique advantage of one-step sealing and cutting. BiZact-assisted endoscopic sinonasal tumor surgery is a beneficial and safe procedure that reduces blood loss during surgery, shortens the operative time, and minimizes postoperative complications.

Sinonasal inverted papilloma and predictors of health-related quality of life after endonasal endoscopic surgery: A prospective cohort study.

OBJECTIVES: Existing knowledge on health-related quality of life (HRQoL) after surgical removal of sinonasal inverted papilloma (IP) is limited. Moreover, predictors for a better or worse post-operative HRQoL outcome are not known. Our aim was to assess HRQoL in all three health domains (physical, psychological, and social), track its post-operative trajectory, investigate if pre-operative observations could predict distinct post-operative HRQoL outcomes, and evaluate whether physicians' interventions could contribute to improved post-operative HRQoL. DESIGN: Prospective cohort study. SETTING: Tertiary referral hospital. PARTICIPANTS: Seventy-four patients who underwent surgery for an IP were included. They were asked to fill in the Endonasal Endoscopic Sinus and Skull-Base Surgery Questionnaire (EES-Q) pre-operatively, and then 2 weeks, 3 months, and 1 year post-operatively. MAIN OUTCOME MEASURES: Linear mixed models analyses were performed to evaluate the overall post-operative HRQoL and the separate health domains, as well as the impact of specific variables (sex, age, American Society of Anaesthesiologists [ASA] classification, smoker, Krouse staging, pre-operative EES-Q score, type of surgery, and post-operative antibiotics) on HRQoL improvement. RESULTS: The total EES-Q score (p < .001) as well as the physical (p < .001), psychological (p = .049), and the social (p = .002) domains significantly improved post-operatively. ASA classification (p = .049), pre-operative EES-Q score (p < .001) and post-operative antibiotics (p = .036) were significant variables. CONCLUSIONS: Overall HRQoL, as well as each of the three health domains, improved significantly. A higher ASA score, a higher pre-operative EES-Q score, and the administration of post-operative antibiotics were significant predictors for better HRQoL recovery post-operatively. Further research is necessary to confirm these results.

[Inverted papilloma of the nose and paranasal sinuses : Diagnosis, treatment, and malignant transformation]. / Invertiertes Papillom der Nase und Nasennebenhöhlen : Diagnostik, Therapie und maligne Transformation.

Inverted papilloma (IP) are benign tumors that show a locally aggressive behavior, a high rate of recurrence, and a potential for malignant transformation. Specific radiological signs such as hyperostosis at the origin of the IP and convoluted cerebriform patterns, as well as the typical endoscopic aspect, can lead to diagnosis and enable preoperative planning of surgical access and the extent of surgery. Endonasal endoscopic techniques are considered the gold standard and the introduction of extended surgical techniques such as the prelacrimal approach, frontal drillout, or orbital transposition facilitate complete subperiosteal resection with preservation of important physiological structures. There is a risk of synchronous and metachronous squamous cell carcinomas (IP-SCC). Research focuses on radiological criteria to differentiate benign IP from IP-SCC, genetic and epigenetic factors in the process of malignant transformation, and estimation of the risk of IP progressing to IP-SCC.

Clinicopathological predictors of repeated recurrence in sinonasal inverted papilloma.

PURPOSE: To evaluate association between clinical and pathological findings and repeated recurrence in sinonasal inverted papilloma. METHODS: Retrospective cohort study conducted at a tertiary care teaching hospital included all patients operated for inverted papilloma from January 2010 to December 2019. Patients were categorized as primary and recurrent cases. Based on disease status at follow-up, they were subcategorized into 'primary with no recurrence' (PnR), 'primary with recurrence' (PwR), 'recurrent with no further recurrence' (RnR), and 'recurrent with further recurrence' (RwR) groups. Data including demography, clinical, endoscopic and pathological findings were collected and analyzed. RESULTS: Increased incidence of pale appearance of lesion in RnR group (p = 0.017), polypoidal appearance in primary group (p = 0.002) and fibrous appearance in the recurrent group (p = 0.002) were statistically significant. Predominant epithelium was combined respiratory and squamous epithelium in primary and recurrent groups and also in RnR group (p = 0.019), while it was squamous (p = 0.024) in RwR group. Epithelial hyperplasia was more common in primary and RnR groups. Oncocytic change, cystic dilatation, microabscess and squamous metaplasia were seen more in recurrent and RnR groups. Cytoplasmic glycogenation was more in recurrent and RwR groups. Stroma was predominantly edematous in all the groups. CONCLUSIONS: Patients with recurrence are younger and present earlier than those with primary disease. Fleshy appearance and pink/red colour of tumour, lining epithelium being squamous and cytoplasmic glycogenation could be considered as features predicting recurrence. Negative predictors of recurrence of IP include pale appearance of tumour, combined respiratory and squamous epithelium lining and squamous metaplasia.

The implications of concomitant mucosal inflammation on clinical manifestations and outcomes of sinonasal inverted papilloma.

PURPOSE: This study examines the impact of concomitant mucosal inflammation on clinical manifestations and long-term outcomes of Inverted Papilloma (IP). METHODS: This retrospective cohort study was conducted in five tertiary medical centers. The included patients underwent an attachment-oriented surgical resection for IP with a minimum follow-up of 3 years. RESULTS: Of 185 patients with IP, 65 patients (35.1%) had synchronous mucosal inflammation with polypoid changes. The mean age was 56.7 years, and 69% were males. Most tumors originated from the maxillary sinus. Age, gender, Krouse stage, and tumor attachment site did not differ between the mucosal inflammation and IP-only groups. IP recurrence rate was twofold in the patients with mucosal inflammation (15.4% vs. 7.5%, p = 0.092). However, the difference was not significant, with a similar median time to recurrence between the two groups [15.5 (3-36) months vs. 16(6-96) months, p = 0.712]. In revision cases, IP recurred only in patients with mucosal inflammation (19% vs. 0%, p = 0.07). This group had a significantly worse 5-years recurrence-free survival than revision cases without mucosal inflammation (80.6% vs. 100%, p = 0.04). CONCLUSIONS: IP in the setting of mucosal inflammation might be associated with a higher recurrence rate, predominantly after revision surgery. Otolaryngologists should consider this during these patients' diagnosis, surgical planning, and follow-up.

Utility of flexible interventional endoscopy in endoscopic sinus surgery: a case series.

PURPOSE: During endoscopic sinus surgery (ESS), difficult-to-reach pathologies need an extended endoscopic approach or an external approach. We started to use a flexible interventional endoscope (FIE) to evaluate the necessity of those approaches. The study's objective is to describe our experience and define patients who could benefit from this technique. METHODS: We reviewed every patient who benefited from FIE associated with ESS at our tertiary University Hospital between January 2021 and February 2022. RESULTS: During this period, we did 107 ESS, and 14 patients benefited from the FIE, representing 13% of our ESS. The median duration of the flexible endoscopy time was 14 min (4-38 min). We identified three groups of patients who can benefit from the FIE. The first one is for patients with a fungal infection, to control and to clean lateral recesses in a noninvasive manner. The second one is for patients with a pathology of the lateral frontal sinus, to remove the frontoethmoidal cells or mucocele with the biopsy forceps through the working channel. The third group is for patients with inverted papillomas, to precisely identify the insertion and to decide on the most appropriate surgical approach. CONCLUSIONS: In selected cases, using flexible endoscopy during ESS helps decide the optimal surgical approach and sometimes treat the pathology through a limited approach. Prospective studies for each group of patients are needed to confirm the benefit of this new combined procedure.

Extended sphenoidotomy combined with transpterygoid approach for sphenoidal sinus inverted papilloma.

PURPOSE: Inverted papilloma of the sphenoid sinus (IPSS) is a rare tumor with debated surgical management due to its proximity to vital structures. The aim of this manuscript is to highlight the role of a transpterygoid approach (TPA) and pedicle-orientated strategy in case of involvement of critical structures in IPSS and compare it with data from the literature. METHODS: Patients with primary IPSS between January 2000 and June 2021 were included. Pre-operative CT/MRI were analyzed to classify the pneumatization of the SS and predict the insertion point of the inverted papilloma. All patients were treated with a trans-sphenoidal approach which was combined with a TPA in case of lateral insertion point. A systematic search was also performed to summarize the available literature. RESULTS: Twenty-two patients were treated for IPSS. By CT, the SS was categorized with type III pneumatization in 72.8% of cases. Eleven patients (50%) were treated with a TPA with a statistical association with the insertion point on the SS lateral wall (p = 0.01), rather than a SS pneumatization (p = 0.63). The overall success was 95.5% after a mean follow-up of 35.9 months. For the literature, 26 publications were included on 97 patients and described a trans-sphenoidal approach with a success rate of 84.6% after a mean follow-up of 24.5 months. CONCLUSION: IPSS is generally treated with a sphenoidotomy approach, although in selected cases, a TPA should be preferred to expose the whole SS lateral wall though allowing a complete pedicled oriented resection of the tumor.

The choice of endoscopic surgical approach and four steps of operation of inverted papilloma of the maxillary sinus.

OBJECTIVE: The aim of this study was to determine the long-term efficacy of four steps of operation on the treatment of maxillary sinus (MS) inverted papilloma (IP). METHODS: 83 patients who were diagnosed with IP that originated from the MS, underwent four step procedure of attachment sites, including mucosal stripping, periosteum ablation, bone drilling and bone ablation and had postoperative follow-up of 3 years were enrolled. RESULTS: Of the 83 patients, 59 (71.1%) patients were primary surgery and revision surgery in 24 (28.9%), single attachment was in 31(37.3%) patients and multifocal attachments in 52 (62.7%).When the numbers were not mutually exclusive, the most common origin sites of IPs were the medial wall in 54 (37.2%), lateral wall in 29 (20.0%), anterior wall in 18 (12.4%), inferior wall in 22 (15.2%), posterior in 15 (10.3%), and superior wall in 7 (4.8%). Large MMA alone was performed in 5 (6.0%), MMA combined with medial maxillectomy 76 (91.6%), and MMA combined with Caldwell-Luc approach in 2 (2.4%). No major intra- or postoperative complications were observed. The average follow-up was 41 months (range, 37-61 months). CT and endoscope showed that tumor and symptom recurrence occurred in 2 patients (2.41%). In addition, although the opening of antrostomy was closed and CT revealed the uniform soft tissue shadow and hyperostosis of MS in 11(13.3%) patients, they didn't report any symptoms and showed well epithelization of middle meatus mucosa. CONCLUSION: The four steps of operations of attachment sites of MS IP, including mucosal stripping, periosteum ablation, bone drilling and bone ablation, may effectively prevent the recurrence of MS IP.

Quality of life after operative treatment of sinonasal inverted papilloma - a prospective study.

BACKGROUND: Studies assaying morbidity related to sinonasal inverted papilloma (SNIP) and its treatment are lacking. We evaluated how operative treatment of SNIP affects patients' health-related quality of life (HRQoL) and symptoms. METHODS: We prospectively recruited consecutive patients (n=52) operated for SNIP at Helsinki University Hospital, between years 2016 and 2019. In total, 42 patients filled in the 15D, a generic HRQoL instrument and a symptom questionnaire preoperatively and at 1 year and at 2 years postoperatively. The 15D HRQoL scores were compared to those of age- and sex-standardized general population. RESULTS: Patients' mean baseline score for discomfort and symptoms (one of the 15D dimensions) was significantly better compared to general population, but this difference faded postoperatively. Frequency of epistaxis, nasal obstruction, lowered sense of smell, headache, tinnitus and epiphora decreased significantly during follow-up whereas frequency of numbness of the face or mouth increased. Difference in the mean 15D score of the patients compared with general population was insignificant at baseline and at 1 year and at 2 years postoperatively. CONCLUSIONS: Measured by a generic HRQoL questionnaire, the mean score for discomfort and symptoms deteriorated after operative treatment of SNIP. Despite a relief of many symptoms, care should be taken when operating a benign tumour, as surgery may cause morbidity.

Validation of modular endoscopic medial maxillectomies for inverted papilloma of the maxillary sinus.

BACKGROUND: Treatment of inverted papilloma of the maxillary sinus (IPMS) has a lower success rate compared to other IPs. As such, its correct management generally needs trans-nasal endoscopic medial maxillectomy (EMMs) for adequate resection. The aim of this manuscript is to describe outcomes and major prognostic factors of a cohort of patients with IPMS who were treated with EMM. METHODOLOGY: In this multicentric study, patients affected with IPMS and treated with EMMs were included. The site of origin of the IPMS were studied as well as the type of EMM performed. The histological features (IP vs dysplasia), type of mucosal resection (total vs. pedicle oriented), and post-operative complications were analyzed. RESULTS: 310 patients were included (212 primary and 98 recurrent cases). After a mean follow-up of 45.4 months, 15 patients experienced recurrence (4.8%) due to the application of EMMs tailored to the surgical insertion point. Dysplasia was significantly associated with a higher risk of recurrence. The rates of early and late complications were 11.6% and 11.9%, respectively. CONCLUSIONS: IPMS resection via tailored EMM is associated with excellent disease control, thus excluding the systematic use of extended EMMs, which can however be justified in case of dysplastic IPMS given its significant impact on recurrence.

[From the nose to the ear: field cancerization via the Eustachian tube]. / Von der Nase ins Ohr: Feldkanzerisierung über die Tuba auditiva.

We report on the metachronic appearance of an inverted papilloma in the ipsilateral middle ear after resection of an endonasal inverted papilloma and its malignant transformation. After multiple surgical interventions and adjuvant radiation and chemotherapy, there was recurrence with intracerebral growth, which ultimately led to the patient's death 3 years after the initial presentation.

Fluorescence grid analysis for the evaluation of piecemeal surgery in sinonasal inverted papilloma: a proof-of-concept study.

PURPOSE: Local recurrence occurs in ~ 19% of sinonasal inverted papilloma (SNIP) surgeries and is strongly associated with incomplete resection. During surgery, it is technically challenging to visualize and resect all SNIP tissue in this anatomically complex area. Proteins that are overexpressed in SNIP, such as vascular endothelial growth factor (VEGF), may serve as a target for fluorescence molecular imaging to guide surgical removal of SNIP. A proof-of-concept study was performed to investigate if the VEGF-targeted near-infrared fluorescent tracer bevacizumab-800CW specifically localizes in SNIP and whether it could be used as a clinical tool to guide SNIP surgery. METHODS: In five patients diagnosed with SNIP, 10 mg of bevacizumab-800CW was intravenously administered 3 days prior to surgery. Fluorescence molecular imaging was performed in vivo during surgery and ex vivo during the processing of the surgical specimen. Fluorescence signals were correlated with final histopathology and VEGF-A immunohistochemistry. We introduced a fluorescence grid analysis to assess the fluorescence signal in individual tissue fragments, due to the nature of the surgical procedure (i.e., piecemeal resection) allowing the detection of small SNIP residues and location of the tracer ex vivo. RESULTS: In all patients, fluorescence signal was detected in vivo during endoscopic SNIP surgery. Using ex vivo fluorescence grid analysis, we were able to correlate bevacizumab-800CW fluorescence of individual tissue fragments with final histopathology. Fluorescence grid analysis showed substantial variability in mean fluorescence intensity (FImean), with SNIP tissue showing a median FImean of 77.54 (IQR 50.47-112.30) compared to 35.99 (IQR 21.48-57.81) in uninvolved tissue (p < 0.0001), although the diagnostic ability was limited with an area under the curve of 0.78. CONCLUSIONS: A fluorescence grid analysis could serve as a valid method to evaluate fluorescence molecular imaging in piecemeal surgeries. As such, although substantial differences were observed in fluorescence intensities, VEGF-A may not be the ideal target for SNIP surgery. TRIAL REGISTRATION: NCT03925285.

Is intraoperative margin sampling necessary in inverted papilloma resection?

PURPOSE: To explore the association between intraoperative surgical margin sampling by the frozen sections and recurrence in inverted papilloma surgery. METHODS: A multicenter, retrospective study of patients who underwent attachment-oriented IP resection in four tertiary care medical centers with a minimal follow-up of 36 months. RESULTS: The study included 220 surgeries with a mean follow-up period of 49 months (range 36-204). The endoscopic approach was used in all but 4 cases; 73% of procedures were primary. Overall recurrence was 10.45% (n = 23). Squamous cell carcinoma was found in 5 cases (2.2%). Intraoperative margin sampling was obtained in 145 cases. There was no difference in the recurrence rate between frozen section and no-frozen section groups (p = 0.44). Furthermore, margin sampling in various sites of tumor origin, in cases with concomitant nasal polyps (p = 0.53) and in revision cases (p = 0.08) showed no correlation with recurrence. In 26 cases when the surgery was extended following a positive frozen section, there was a significantly higher recurrence rate (OR = 6.94). CONCLUSIONS: According to our results, intraoperative margin sampling did not affect the recurrence rate of IP, and therefore, its routine use should be questioned.

Endoscopic Modified Medial Maxillectomy for Inverted Papilloma of the Maxillary Sinus.

BACKGROUND: Sinonasal inverted papilloma (SNIP) is a benign tumor that can be surgically managed by an endoscopic approach. However, SNIP has a high recurrence rate, mainly due to incomplete resection. AIM: This study aimed to analyze the outcomes of endoscopic modified medial maxillectomy in treating SINP originating from the maxillary sinus. METHODS: The authors retrospectively analyzed 24 patients treated for SNIP via endoscopic modified medial maxillectomy at our institution between August 2014 and June 2019. During surgery, the mucosa involved in the tumor was stripped, and the bone underlying the tumor base was completely excised. Demographic data, surgical technique, location of SNIP attachment, complications, follow-up duration, and recurrence were recorded. RESULTS: Twenty four patients with SNIP were identified (16 males). All patients had Krouse stage-III disease. Eleven patients presented with single attachment and 13 with multiple attachments. None of the patients had any complications during surgery. Four patients had postsurgical facial numbness around the cheek and upper lip. After a mean follow-up of 35.12 ±â€Š14.98 months, no recurrence of SNIP was observed. CONCLUSIONS AND SIGNIFICANCE: Endoscopic modified medial maxillectomy is a safe and effective technique for treating SNIP. Recurrence can be reduced by complete excision of the attachment sites.

Recurrence rates of de-novo versus inverted papilloma-transformed sinonasal squamous cell carcinoma: a meta-analysis.

BACKGROUND: There is a paucity of reporting on recurrence patterns of de-novo sinonasal squamous cell carcinoma (DN-SCC) and inverted-papilloma-transformed sinonasal squamous cell carcinoma (IP-SCC). METHOD: A systematic literature review queried studies comparing recurrence patterns in patients with both DN-SCC and IP-SCC. Primary outcomes included local and regional recurrence and rates of distant metastasis. Of the 595 studies screened, eight were included. RESULTS: Patients with DN-SCC had significantly higher rates of positive margins, advanced T classification (T3/T4), treatment with chemotherapy and radiotherapy. There were no significant differences in local recurrence or regional recurrence. Overall risk of distant metastasis was lower in IP-SCC. DN-SCC, compared to IP-SCC, is more likely to present with advanced TNM classification and have positive margins after surgical resection, which may affect rates of distant metastasis and recurrence. CONCLUSIONS: The findings in this study suggest IP-SCC may be a less aggressive malignancy compared to DN-SCC, with the possibility of a reduced role for adjuvant therapy in IP-SCC. Further studies are required to better understand differences in tumor biology and treatments strategies between IP-SCC and DN-SCC.

A prelacrimal approach technique to overcome the limitation of the narrow lacrimal recess.

PURPOSE: The distance between the anterior wall of the maxillary sinus and the nasolacrimal duct has been classified into three types by Simmen, in which type I (< 3 mm) is the least feasible for a prelacrimal approach. The aim of our study is to present a surgical technique which overcomes the anatomical limitation of the narrow lacrimal recess (type I) in the management of inverted papilloma in the maxillary sinus. METHODS: Case series. RESULTS: Eight patients with type I lacrimal recess underwent surgical resection for inverted papilloma in the maxillary sinus via a prelacrimal approach. The technique is described in detail in the article and essentially involves exposure of the nasolacrimal duct using a diamond burr. Complete tumor excision was achieved in all cases through this access, with no significant intra-operative complications. CONCLUSIONS: This prelacrimal approach technique is safe and effective for the management of inverted papilloma in maxillary sinuses with a type I lacrimal recess configuration.

Temporal bone primary inverted papilloma - Case Report and review of the literature. / Invertiertes Papillom des Felsenbeins ­ Fallbericht und Literaturübersicht.

Inverted papilloma of middle ear is an extremely rare lesion of the respiratory epithelium that normally occurs in the nasal cavity and paranasal sinuses. So far less than 17 cases were described in literature. A 45-year-old patient was admitted in our Department with hearing loss, otorrhea and pulsing tinnitus on the right ear. The clinical examination showed a granulation tissue on the right eardrum. No tumor formation was seen in the nasal cavity. The MRI showed a tissue formation in the tympanic cavity with an extension in the middle cranial fossa. A mastoidectomy with antrotomy and duraplasty was performed. The histological diagnosis was inverted papilloma of the middle ear. In a second step occurred an eradication of the tumor with a subtotal petrosectomy. The etiology of the inverted papilloma of the middle ear is unknown. Our case is so far the 18nd case described.Our experience has shown that the eradication of the tumor with a subtotal petrosectomy resulted as reasonable procedure. A long-term follow-up is suggested in order to detect possible recurrence or malignant transformation.

Prediction of malignant sinonasal inverted papilloma transformation by preoperative computed tomography and magnetic resonance imaging.

BACKGROUND: Accurate preoperative prediction of the malignant transformation of sinonasal inverted papilloma (SNIP) is essential for radical resection of tumours and prevention of recurrence. We here explored the predictive value of preoperative computed tomography (CT) and magnetic resonance imaging (MRI). METHODOLOGY: The study was performed on 268 patients with SNIP with (n = 78) or without (n = 190) coexistent malignant transformation. We used univariate and multivariate logistic regression analysis method to screen for independent risk factors, and established a nomogram model. Finally, using receiver operating characteristic curves, we assessed the diagnostic value of the independent risk factors for malignant transformation of SNIP. RESULTS: We identified bone erosion on CT, change in convoluted cerebriform pattern (CCP) on MRI, and washout-type time intensity curve (TIC) of dynamic contrast-enhanced (DCE)-MRI were independent predictors of malignant transformation of SNIP. The scores of these three independent risk factors from the nomogram model were 10, 7 and 8, respectively. The area under the receiver operating characteristic curve for predicting SNIP malignancy was 0.954 for the nomogram model, 0.826 for bone erosion, 0.776 for washout-type TIC, and 0.810 for CCP mutation. CONCLUSIONS: Of the independent risk factors and related combination identified, the nomogram model based on bone destruction on CT, CCP mutation on MRI, and washout-type TIC of DCE-MRI had the best predictive value for malignant transformation of SNIP.