Comparative analysis of Cutanplast and Spongostan nasal packing after endoscopic sinus surgery: a prospective, randomized, multicenter study.

Commercial gelatin-based packing materials are available under different names and compositions to be used after endoscopic sinus surgery (ESS). The purpose of this study was to investigate the efficacy of Spongostan and Cutanplast nasal packing on patients' subjective symptoms, hemostasis, and wound healing following ESS. One hundred adult patients with chronic sinusitis requiring the same extent of ESS were included. Following surgery, one nasal cavity was packed with Cutanplast and the other one with Spongostan. Patients' subjective symptoms while the packing was in situ, hemostatic properties, degree of remaining amount of packing materials, postoperative wound healing, and the cost of the pack were evaluated. Cutanplast and Spongostan are equally effective in the control of postoperative bleeding following ESS. However, Cutanplast packing was significantly more comfortable than Spongostan for nasal obstruction, postnasal drip, rhinorrhea, and headache. Furthermore, the Cutanplast packing was significantly less painful at all time points. The remaining amount of the pack was significantly lower in the Cutanplast than Spongostan packing. Spongostan packing appears to impair wound healing within the sinus cavities up to 3 months postoperatively. Cutanplast was less expensive than Spongostan as used in this study. Cutanplast may be more useful gelatin-based packing material than Spongostan in terms of efficacy and cost-benefit after ESS.

Endoscopic marsupialization of frontoethmoid mucocele with underlying craniofacial fibrous dysplasia.

Fibrous dysplasia (FD) is a benign progressive fibro-osseous lesion that is rarely associated with mucocele formation. This complication most probably results from the involvement and subsequent occlusion of the recesses of the sinuses by the dysplastic process. The frontoethmoid mucocele associated with FD represents a rare pathology, but it is important to consider this in the differential diagnosis of patients with proptosis, visual disturbance, and bony fronto-orbital swellings. Here, we describe the first case of frontoethmoid mucocele with underlying craniofacial FD, which was successfully treated by wide marsupialization via the transnasal endoscopic approach.

Adipose-derived stem cells ameliorate allergic airway inflammation by inducing regulatory T cells in a mouse model of asthma.

Although several studies have demonstrated that mesenchymal stem cells derived from adipose tissue (ASCs) can ameliorate allergic airway inflammation, the immunomodulatory mechanism of ASCs remains unclear. In this study, we investigated whether regulatory T cells (Tregs) induction is a potential mechanism in immunomodulatory effects of ASCs on allergic airway disease and how these induced Tregs orchestrate allergic inflammation. Intravenous administration of ASCs significantly reduced allergic symptoms and inhibited eosinophilic inflammation. Airway hyperresponsiveness, total immune cell and eosinophils in the bronchoalveolar lavage fluid, mucus production, and serum allergen-specific IgE and IgG1 were significantly reduced after ASCs administration. ASCs significantly inhibited Th2 cytokines (IL-4, IL-5, and IL-13) and enhanced Th1 cytokine (IFN-γ) and regulatory cytokines (IL-10 and TGF-ß) in the bronchoalveolar lavage fluid and lung draining lymph nodes. Furthermore, levels of IDO, TGF-ß, and PGE2 were significantly increased after ASCs administration. Interestingly, this upregulation was accompanied by increased Treg populations. In conclusion, ASCs ameliorated allergic airway inflammation and improved lung function through the induction of Treg expansion. The induction of Treg by ASCs involves the secretion of soluble factors such as IDO, TGF-ß, and PGE2 and Treg might be involved in the downregulation of Th2 cytokines and upregulation of Th1 cytokines production.

Fungal ball within Onodi cell mucocele causing visual loss.

The Onodi cell is a pneumatized posterior ethmoid cell located laterally and superiorly to the sphenoid sinus and closely related to the optic nerve. A mucocele is a benign, expansile, cystlike lesion of the paranasal sinuses that is filled with mucoid secretion. Therefore, optic neuropathy caused by an infected mucocele in an Onodi cell is uncommon. Furthermore, fungal infection superimposed on an Onodi cell mucocele is extremely rare and has not been reported previously. Here, we describe the first case of fungal ball within Onodi cell mucocele causing visual loss, which was completely removed via transnasal endoscopic approach.

The sphenoid sinus: an unusual presentation of a typical carcinoid tumor.

Carcinoid tumors are neuroendocrine tumors that are most commonly found in the gastrointestinal tracts and lungs. They seldom develop in the head and neck area as a primary tumor, and there have been rare reports of them arising in the sinonasal area. We report a case of a 47-year-old woman with a typical carcinoid tumor arising in the sphenoid sinus.

Metastatic renal cell carcinoma of the posterior nasal septum as the first presentation 10 years after nephrectomy.

Metastasis of renal cell carcinoma (RCC) to the head and neck region is infrequent, and metastatic RCC in the nasal cavity and paranasal sinuses is rare. Although there are reported cases of RCC to the paranasal sinuses, isolated metastasis of RCC to the nasal septum is extremely rare. This report describes a case of metastatic RCC of the posterior nasal septum that presented as severe epistaxis in a patient who underwent nephrectomy for RCC 10 years previously.

Inflammation and apoptosis in malignant transformation of sinonasal inverted papilloma: the role of the bridge molecules, cyclooxygenase-2, and nuclear factor κB.

PURPOSE: This study examined the early events in the neoplastic progression of the sinonasal inverted papilloma to squamous cell carcinoma from the viewpoint of chronic inflammation and apoptosis. MATERIALS AND METHODS: In total, 118 archival slides stained with hematoxylin and eosin from 45 patients were graded according to histopathology (grades I-IV). Their representative portions were transferred to a tissue microarray, sections of which were stained immunohistochemically for cyclooxygenase-2, p53, bax, bcl-2, and nuclear factor κB. RESULTS: Cyclooxygenase-2 expression was positively correlated with histopathologic grade, with higher expression in advanced grades. p53s were detected in all cores from advanced grades (III, IV), but not in early grades (I, II). The expressions of nuclear factor κB, bax, and bcl-2 were not correlated with the grade. CONCLUSIONS: A p53 mutation seems be a critical event for the malignant transformation of the sinonasal inverted papilloma. Cyclooxygenase-2-mediated inflammatory signals, activated as a consequence of the p53 mutation, may contribute to promoting the proliferation of the advanced sinonasal inverted papilloma.

Expression of the cysteinyl leukotriene 1 receptor and glucocorticoid receptor-ß in nasal polyps.

The objective of this study was to analyze the expression of cysteinyl leukotriene 1 (CysLT1) receptor and glucocorticoid receptors (GRs) in nasal polyps, and to evaluate the relationship between the expression of CysLT1 receptors and that of GRs. Nasal polyps were taken from 32 patients of chronic rhinosinusitis with nasal polyposis. Samples of middle turbinate from seven healthy subjects were used as controls. Specimens were immunohistochemically stained for CysLT1 receptor, GR-α and GR-ß receptor, and were quantified in the unit area of the tissues. Numbers of CysLT1 receptor-positive cells were much increased in nasal polyps than in middle turbinate (281 ± 67 vs. 157 ± 85 cells/mm(2), P = .01). There was no significant difference in the numbers of GR-α positive cells between nasal polyps and normal turbinate mucosa. GR-ß positive cells were increased in nasal polyps as compared to normal turbinate mucosa (36 ± 8 vs. 19 ± 7 cells/mm(2), P = .03). A significant relationship was found between the expression of CysLT1 receptor and GR-ß in nasal polyps (R = .525, P = .04), whereas there was no significant relationship between the expression of CysLT1 receptor and GR-α in nasal polyps. Our study shows that CysLT1 receptor expression predominates on GR-ß over-expressed polyps. This may suggest the additional effect of CysLT1 receptor antagonist for the treatment of nasal polyposis resistant to steroid alone.

Effectiveness of hemostatic gelatin sponge as a packing material after septoplasty: A prospective, randomized, multicenter study.

OBJECTIVE: Although hemostatic gelatin sponge is a gelatin-based packing material with a powerful hemostatic effect, there were no studies in regard to its efficacy for packing material after septoplasty. The purpose of this study was to investigate the efficacy of hemostatic gelatin sponge nasal packing on patient's subjective symptoms, hemostasis, and wound healing following septoplasty. SUBJECTS AND METHODS: Seventy six adult patients with nasal septum deviation requiring septoplasty were included. Following surgery, one nasal cavity was packed with hemostatic gelatin sponge and the other one with polyvinyl acetate. Patients' subjective symptoms while the packing was in situ, hemostatic properties, patients' pain on removal, degree of bleeding on removal of the packing, time for hemostasis after removal, postoperative wound healing, and the cost of the pack were evaluated. RESULTS: Both packs were equally effective in the control of postoperative bleeding following septoplasty. However, hemostatic gelatin sponge packing was significantly more comfortable while in situ and less painful on removal of the pack. The polyvinyl acetate packing was associated with significantly more bleeding on removal, therefore much time was needed to control hemorrhage. There was no significant difference in the cost of the pack used and outcome of wound healing. CONCLUSION: The use of hemostatic gelatin sponge after septoplasty results in significantly less discomfort and greater patient satisfaction with no adverse reactions when compared with polyvinyl acetate packing. Therefore, hemostatic gelatin sponge may be a useful packing material after septoplasty.

Local Atopy in Childhood Adenotonsillar Hypertrophy.

Background Although the cause of adenotonsillar hypertrophy remains unknown, some studies have shown that allergy may be a risk factor. Purpose This study determined the levels of allergen-specific immunoglobulin E (sIgE) in the adenotonsillar tissues of children with adenotonsillar hypertrophy and evaluated the clinical significance of local atopy in adenotonsillar tissues. Methods We measured 21 types of specific immunoglobulin E in the serum and adenotonsillar tissues of 102 children with adenotonsillar hypertrophy and compared the sensitization patterns of the serum and local tissues. The patients were divided into three groups-atopy, local atopy, and nonatopy-according to the sensitization of serum and adenotonsillar tissues, and the clinical symptoms among the groups were analyzed. Results Seventy-two (70.6%) children with adenotonsillar hypertrophy were sensitized to more than one allergen in the serum and/or adenotonsillar tissue. Thirty (29.4%) children had no IgE positivity to any allergen in both serum and adenotonsillar tissues. Fifty-five (53.9%) were sensitized to at least one allergen in the serum. Seventy (68.6%) were sensitized to at least one allergen in the adenotonsillar tissue. Seventeen (36.2%) of 47 children with specific immunoglobulin E-negative serum had specific immunoglobulin E-positive adenotonsillar tissues. The rate of specific immunoglobulin E was significantly higher in local tissues than in serum. The rate of inhalant allergen specific immunoglobulin E was significantly higher in the adenoids than in the tonsils. However, the rate of food allergen specific immunoglobulin E was significantly higher in the tonsils than adenoids. The lifetime prevalence of asthma and allergic rhinitis, recent symptoms or treatment of allergic rhinitis, and severity of nasal symptoms (rhinorrhea, sneezing, and nasal itching) were significantly higher in children with local atopy than with nonatopy. Conclusions These results confirm that allergic response may be a risk factor for adenotonsillar hypertrophy. Local allergic inflammation may play an important role in childhood adenotonsillar hypertrophy, and local atopy in adenotonsillar tissues can cause respiratory allergic symptoms in children.

Histological and immunological features of non-eosinophilic nasal polyps.

OBJECTIVE: The aim of this study was to investigate the histoimmunological features of non-eosinophilic nasal polyps (NPs). METHODS: Thirty patients with chronic rhinosinusitis and NPs were included in this study. NPs were grouped into eosinophilic and non-eosinophilic types according to the amount of eosinophils in the NPs. The amount of serum total IgE and peripheral blood eosinophils were measured. Basement membrane (BM) thickness was measured, along with the expression of chemokine receptor 5 (CCR5) and chemokine receptor 3 (CCR3) in NP lymphocytes. RESULTS: Non-eosinophilic NPs comprised 66.7% of the total NPs included in this study. The amount of eosinophils in NPs was related to eosinophilia of the peripheral blood, but not to elevated serum IgE. BM was significantly thinner in non-eosinophilic than in eosinophilic NPs. Lymphocytes expressing CCR5 or CCR3 were less frequently found in non-eosinophilic than in eosinophilic NPs. CONCLUSION: Histoimmunological characteristics of non-eosinophilic NPs differ from those of eosinophilic NPs; non-eosinophilic NPs may be featured by thinner BM and fewer CCR5- and CCR3-positive lymphocytes.

Smoking, not human papilloma virus infection, is a risk factor for recurrence of sinonasal inverted papilloma.

BACKGROUND: The recurrence rate of sinonasal inverted papillomas (SNIP) is 15-20%. However, few studies have investigated patient-dependent factors related to recurrence of SNIPs. OBJECTIVE: To analyze risk factors, including human papilloma virus (HPV) infection and smoking, as well as other factors, for recurrence of SNIPs. METHODS: Fifty-four patients who were diagnosed with SNIP and underwent surgery were enrolled: 39 men and 15 women, with the mean age of 54.0 years. Their mean follow-up was 40.6 months. Demographics and information about the history of smoking, previous surgery, tumor extent, follow-up, and recurrence were reviewed retrospectively. Those patients whose tumors were associated with malignant transformation were excluded in this study. HPV detection and genotyping in the tumor specimens were performed with the HPV DNA chip, a polymerase chain reaction-based DNA microarray system. RESULTS: Seven patients (13.0%) had recurrence, with a mean time to recurrence of 39.8 months. Recurrence rates in T1, T2, T3, and T4 of the Krouse staging system were 0% (0/4), 8.3% (2/24), 17.4% (4/23), and 33.3% (1/3), respectively (p > 0.5). Eight patients (14.8%) were positive for HPV DNA. All of these patients belonged to the group without recurrence (p > 0.5). However, recurrence rates according to HPV DNA positivity were not statistically different (0% versus 15.2%). Three (42.9%) in the group with recurrence and four (8.5%) in the group without recurrence were smokers (p < 0.5). CONCLUSION: Smoking was associated with recurrence of SNIP. However, HPV infection is not a recurrence of SNIP risk factor.

A comparison of dexmedetomidine versus propofol during drug-induced sleep endoscopy in sleep apnea patients.

OBJECTIVES/HYPOTHESIS: In this study, we compared the effects of propofol and dexmedetomidine on the upper airway collapse pattern and cardiopulmonary parameters of patients with obstructive sleep apnea (OSA) undergoing drug-induced sleep endoscopy (DISE). STUDY DESIGN: Prospective, single center, observational study MATERIALS AND METHODS: The 50 patients with OSA underwent 30 minutes of DISE on 2 different days, the first time with propofol target-controlled infusion (TCI) and the second time with dexmedetomidine TCI. Both the characteristics of upper airway obstruction and cardiopulmonary parameters in response to the depth of sedation achieved with each drug were evaluated. RESULTS: The results obtained with propofol and dexmedetomidine DISE were in excellent agreement for all sites of obstruction irrespective of the depth of sedation. Although partial or total obstruction at all areas was consistently observed using both drugs, the degree of upper airway narrowing was slightly lower with dexmedetomidine than with propofol. However, the percentage of patients with a greater than 20% change in blood pressure and heart rate compared to baseline was significantly higher in response to propofol than to dexmedetomidine (P = 0.003 and P < 0.001, respectively). Minimal oxygen saturation was significantly lower in DISE with propofol than with dexmedetomidine (P = 0.004). The percentage of patients with oxygen saturation less than 90% or 80% during DISE was significantly higher in response to propofol than to dexmedetomidine (P = 0.032 and P < 0.001, respectively). CONCLUSION: The DISE findings achieved with propofol and dexmedetomidine were in excellent agreement. However, during DISE, dexmedetomidine provided greater hemodynamic stability and less respiratory depression than propofol. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:763-767, 2016.

Inverted papilloma of the maxillary sinus: Surgical approach and long-term results.

BACKGROUND: Inverted papillomas (IP) commonly develop in the maxillary sinus (MS). However, the MS is a complex structure, and all areas in the MS are not easily approachable. OBJECTIVE: This study reviewed our surgical outcome of patients with IPs that originated from the MS in long-term follow-up and suggests appropriate approaches according to the tumor origin. METHODS: Thirty-one patients who were diagnosed with IP that originated from the MS, underwent surgery by a single operator between 1999 and 2011, and had postoperative follow-up of >3 years were enrolled. RESULTS: In all the cases, the endoscopic endonasal approach (EEA) was attempted at first and then canine fossa puncture (CP), canine fossa opening via the Caldwell-Luc approach (CO), and Caldwell-Luc operation (CLO) were added in consecutive order as the occasion demands. Six patients (19.4%) were treated only with EEA, and they had IPs from the superior, posterior, or medial wall. Five (16.1%) were treated with EEA plus CP, which was added for removal of IPs that originated from the lateral wall. Sixteen (51.6%) were treated with EEA plus CO, which was for removal of tumors from the medial, anterior, or inferior wall. Four patients (12.5%) whose IP attached to the whole MS mucosa underwent CLO. Three (9.7%) experienced recurrences, and the mean period to recurrence was 20.7 months. CONCLUSION: The overall recurrence rate was 9.7%. IPs that originated from the lateral wall of the MS can be removed by using CP. When IPs originate from the anterior, inferior, or medial wall of the MS, CO may be needed for the thorough removal of them.

Interleukin-17A-induced inflammation does not influence the development of nasal polyps in murine model.

BACKGROUND: Nasal polyposis associated with chronic rhinosinusitis (CRS) is a chronic inflammatory disease that is characterized by infiltration of many inflammatory cells. Meanwhile, interleukin (IL)-17A is a well-known proinflammatory cytokine that induces both eosinophilic and neutrophilic inflammation. We investigated the role of IL-17A in the development of nasal polyps in the CRS murine model. METHODS: Eosinophilic CRS with nasal polyps was induced by using ovalbumin (OVA) and Staphylococcus aureus enterotoxin B (SEB) in wild-type BALB/c and IL-17A knockout (KO) mice. Histopathologic changes of the sinonasal cavity were evaluated using hematoxylin and eosin, Periodic acid-Schiff, Sirius red, Masson's trichrome, and immunohistochemistry. The levels of total and OVA-specific immunoglobulin Es (IgEs) in sera were measured using enzyme-linked immunosorbent assay. The expression levels of IL-4, IL-5, and interferon-γ (IFN-γ) in the nasal mucosa were assessed by quantitative real-time polymerase chain reaction. RESULTS: Under the IL-17A deficiency, total and OVA-specific IgEs in sera were reduced significantly. Infiltration of both eosinophils and neutrophils into the nasal mucosa, subepithelial fibrosis, and goblet cell count also decreased significantly in IL-17A KO mice treated with both OVA and SEB compared with those in the wild-type counterpart. However, there were no significant differences in the number of polypoid lesions among groups. Meanwhile, IL-4 increased and IFN-γ decreased in the nasal mucosa in IL-17A KO mice treated with both OVA and SEB. CONCLUSION: This study suggests that even though IL-17A plays an important role in both nasal inflammation and remodeling, it does not influence the development of nasal polypoid lesions.

Maxillary sinus retention cysts protruding into the inferior meatus.

Although most of the maxillary sinus retention cysts are asymptomatic, a few of them increase in size and cause symptoms. However, they rarely erode bony walls nor protrude into the inferior meatus. I present 2 cases with maxillary sinus retention cysts protruding into the inferior meatus by making a large defect on the medial wall of the maxillary sinus.

Limited palatal muscle resection with tonsillectomy: a novel palatopharyngoplasty technique for obstructive sleep apnea.

OBJECTIVE: The ideal palatal surgery for obstructive sleep apnea (OSA) and snoring must maintain the airway patency and correct anatomic abnormalities without complications. The purpose of this study was to investigate the efficacy of limited palatal muscle resection (LPMR) to improve OSA severity. SUBJECTS AND METHODS: Twenty-three patients with OSA underwent LPMR. The LPMR was initiated with a bilateral tonsillectomy in patients with tonsil size 2 and 3. The LPMR consisted of partial resection of palatal muscles (levator veli palatini, palatoglossus, and musculus uvulae) with preservation of the uvula and a simple double layer suturing. The retropalatal space and the length of soft palate were evaluated by magnetic resonance imaging. Subjective outcomes using visual analog scales, Epworth Sleepiness Scale, and overnight polysomnography (PSG) data were assessed. RESULTS: Six months after the operation, there was significant symptomatic improvement in snoring, morning headaches, tiredness, and daytime sleepiness. Postoperative magnetic resonance images showed upward and forward movement of uvula and soft palate after LPMR. The length of the soft palate was significantly shortened and the retropalatal space was significantly increased. Postoperative PSG revealed significant improvement in apnea-hypopnea index (AHI) and the total sleep time spent with oxygen saturation below 90%, and reduction in AHI following PMR was found in all patients. Furthermore, no patient experienced velopharyngeal insufficiency, voice changes, and pharyngeal dryness at 6 months follow-up. CONCLUSIONS: The LPMR obtained significant improvement in subjective and objective outcomes in OSA, with preserved pharyngeal function. PMR is an effective and safe technique to treat oropharyngeal obstruction in OSA surgery.

Immunomodulatory Effect of Mesenchymal Stem Cells on T Lymphocyte and Cytokine Expression in Nasal Polyps.

OBJECTIVES: Adipose tissue-derived stem cells (ASCs) have been reported to have immunomodulatory effects in various inflammatory diseases, including asthma and allergic rhinitis, through the induction of T cell anergy. Nasal polyps (NPs) are a chronic inflammatory disease in the nose and paranasal sinus characterized histologically by the infiltration of inflammatory cells, such as eosinophils or lymphocytes. This study was performed to investigate whether ASCs have immunomodulatory effects on T lymphocyte and cytokine expression in eosinophilic NPs. STUDY DESIGN: Basic science experimental study. SETTING: University tertiary care facility. SUBJECTS AND METHODS: NP specimens were obtained from 20 patients with chronic rhinosinusitis and eosinophilic NPs. ASCs were isolated and cultured from the abdominal fat of 15 subjects undergoing intra-abdominal surgery. Infiltrating cells (1 × 10(6)) were isolated from NP tissue and co-cultured with 1 × 10(5) ASCs. To determine whether ASCs affect infiltrating T lymphocyte and cytokine expression in eosinophilic NP, T lymphocyte subsets and cytokine expression were analyzed before and after ASC treatment. RESULTS: ASC treatment significantly decreased the proportions of CD4(+) and CD8(+) T cells. After ASC treatment, Th2 cytokine (interleukin [IL]-4 and IL-5) levels decreased significantly. In contrast, levels of Th1 (interferon-γ and IL-2) and regulatory cytokines (transforming growth factor-ß and IL-10) increased significantly after ASC treatment. CONCLUSIONS: ASCs have immunomodulatory effects in the eosinophilic inflammation of NPs, characterized by down-regulation of activated T lymphocytes and a Th2 immune response. These effects would be expected, over time, to significantly contribute to the control of eosinophilic inflammation and, possibly, growth of eosinophilic NPs.

Prognostic value of metabolic tumor volume as measured by fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography in nasopharyngeal carcinoma.

BACKGROUND: The prognostic value of the tumor burden characterized by the metabolic tumor volume (MTV) remains under investigation in nasopharyngeal carcinoma (NPC). The purpose of this study was to evaluate the prognostic value of the maximum standardized uptake value (SUVmax ) and MTV according to metabolic volume threshold as measured by positron emission tomography (PET)/computed tomography (CT), and other clinical factors, in patients with NPC. METHODS: This study was a retrospective chart review. We evaluated the association of SUVmax , MTV2.5 , MTV3.0 , and other clinical factors with overall survival (OS) using Kaplan-Meier and Cox regression models. (MTV2.5 and MTV3.0 are the volume of hypermetabolic tissue within the regions of gross tumor volumes with a SUV value greater than the threshold values of 2.5 and 3.0, respectively.) RESULTS: Higher MTV2.5 of 31.45 cm(3) and MTV3.0 of 23.01 cm(3) were associated with an increased risk of death (hazard ratio [HR] = 5.028; p = 0.029), although no significant relationship was found between SUVmax and OS. Interestingly, MTV3.0 was associated with OS in both the differentiated and undifferentiated groups, although MTV2.5 was only associated with OS in the undifferentiated group. Among the clinical parameters, only radiotherapy was associated with longer OS (HR = 12.124; p < 0.001). CONCLUSION: The MTV and radiotherapy could be prognostic values associated with OS. Particularly, MTV2.5 and MTV3.0 might be valuable metabolic parameters for predicting long-term survival in patients with NPC. Furthermore, MTV3.0 may be more useful because it can be applied irrespective of pathologic subtype.

Smoking and malignancy in sinonasal inverted papilloma.

OBJECTIVES/HYPOTHESIS: The authors investigated clinical features of squamous cell carcinomas (SCC) arising in sinonasal inverted papillomas (IP) and risk factors responsible for their malignant transformation. STUDY DESIGN: Retrospective analysis. METHODS: In total, 162 patients diagnosed with sinonasal IP and treated between 1998 and 2009 at Pusan National University Hospital were enrolled. Their demographic data, information about previous surgery, smoking history, treatment modalities, follow-up duration, recurrence, and presence of malignancy were reviewed retrospectively. RESULTS: Seventeen patients (10.5%) were diagnosed with SCC arising in sinonasal IPs. Among them, nine (9/162, 5.6%; 9/17, 52.9%) were diagnosed with synchronous malignancies and three (3/162, 1.8%; 3/17, 17.6%) were diagnosed with metachronous malignancies. In five cases (5/162, 3.1%; 5/17, 29.4%), we could not determine whether their malignancies were synchronous or metachronous. Among 53 smokers, 14 (26.4%) had malignant transformation, while only three (2.8%) in 109 nonsmokers had malignant transformation (Odds ratio = 12.7; P < .001). The mean follow-up in the 17 patients with malignancy was 47.0 months. Three patients did not receive surgical treatment and died of progression of SCC. Among the other 14 patients who underwent curative surgeries, four (28.6%) had recurrences, and their mean period to cancer recurrence was 6.3 months. Two of them died of progression of the cancer. Mean survival of the five patients who died was 14.0 months. They all belonged to T4 stage. CONCLUSIONS: Smoking history is associated with malignant transformation of sinonasal IP. It suggests that close follow-up be required in smokers with sinonasal IP in order not to overlook the malignant transformation. LEVEL OF EVIDENCE: 2b.