The Clinical Characteristics in Children with Sinonasal Inverted Papilloma: A Case Report and Review of the Literature

Abstract

Sinonasal inverted papilloma (SNIP) is one of the most common benign epithelial tumors but rarely occurs in children. The case of a 9-year-old Chinese boy, who presented with a left maxillofacial hump, nasal obstruction, and left nasal cavity and maxillary sinus masses under nasal endoscopy, is reported. The lesion was first diagnosed as a sinonasal tumor. However, to our surprise, the mass was determined to be an inverted papilloma after a detailed histological examination. We retrospectively reported the clinical data of this case and reviewed the relevant literatures on SNIP. This report aims to provide new insights into the clinical characteristics in children with SNIP and improve the understanding of this disease.

Introduction

Sinonasal inverted papilloma (SNIP) is one of the most common benign epithelial tumors, and is common in males aged 50–60 years. ¹ The overall prevalence of SNIP is .6–1.5 cases per 100,000, ² but the incidence is extremely low in children . ¹ The disease commonly occurs unilaterally in the nasal cavity and/or paranasal sinuses, such as the sinonasal and medial wall, ethmoid sinus, and maxillary sinus.^3,4 Additionally, the SNIP is characterized by a strong potential for local destruction, a high recurrence rate and malignancy tendency. ⁵

The clinical symptoms of SNIP are atypical, such as nasal obstruction, anterior and/or posterior rhinorrhea, headache, epistaxis, hyposmia or anosmia, and facial pain. ⁶ Physical examinations by nasal endoscopy typically reveal gray-red lobulated or mulberry-like masses in the nasal cavity and sinus, which are is friable and easily bleed upon palpation. ⁵ Pathological examination is the gold standard for SNIP diagnoses. ⁵ Computerized tomography (CT) and magnetic resonance imaging (MRI) are used as auxiliary imaging examinations to diagnose SNIP.^7,8 The latter is regarded as a complement to the former, which can detect a typical sign of cerebriform circumvolution on T2-weighted images after injecting contrast medium.^5,8 In general, surgical approaches ranging from widely open radical surgery to minimally invasive endonasal surgical resections are the first-line treatments of SNIP.^6,9 However, nasal endoscopic surgery is only suitable for tumors with limited expansion, and external or combined external/endoscopic methods are still required for specific locations. ¹⁰ The success of these methods depends on complete exposure and complete resection of the tumor to reduce recurrence.^10,11

Case report

General information

A 9-years-old Chinese boy presented with a 4-day history of the left maxillofacial hump and nasal obstruction without other clinical symptoms. Physical examination of the ear, nose, and throat (ENT) showed maxillofacial asymmetry and a local bulge of the left palate in the oral cavity (Figure 1A and B). The polypoid tissues filled the left nasal cavity and the left maxillary sinus, which were revealed by the nasal endoscopy. No history of trauma or chronic disease was noted.

Figure 1.

Physical examination of the ear, nose, and throat showed maxillofacial asymmetry (A) and a local bulge of the left palate in the oral cavity (B). Note: The asterisk marked the location of a local bulge of the left palate in the oral cavity.

Imaging examination

CT and MRI scanning were performed and confirmed the presence of the left-sided masses of the nasal cavity and maxillary sinus. An irregular mass was noted along the medial wall of the left maxillary sinus (CT: Figure 2A; MRI: Figure 2B–D). The left maxillary sinus cavity was enlarged. The sinus wall and the local alveolar bone on the left side were compressed and thinned, and the adjacent local soft tissue was slightly compressed. Based on age, sex, history, and clinical presentation, an initial diagnosis of the left sinonasal tumor was made.

Figure 2.

The preoperative presentation of CT imaging (A) and MRI imaging (B–D) showed an irregular mass along the medial wall of the left maxillary sinus.

Surgical treatment

After admission, the routine preoperative examination showed no obvious surgical contraindications. Under general anesthesia, we explored whether the mulberry-like masses in the left nasal cavity and the left maxillary sinus were attached to the medial wall of the maxillary sinus and caused obvious sinonasal stenosis. Thus, we removed the uncinate process and enlarged the left maxillary sinus ostium, and a resection of the left nasal cavity and the left maxillary lesions was conducted under nasal endoscopy. The results of intraoperative freezing were highly indicative of SNIP (Figure 3A). The postoperative pathological diagnosis was consistent with SNIP. Immunohistochemical examination showed that Catenin-B (+), CK5/6 (+), P53 (40%+)and EBER were negative as demonstrated by in situ hybridization (Figure 3B–D). Expression of p16 protein, which is associated with human papillomavirus, was negative in this patient.

Figure 3.

The results of intraoperative freezing (A) and the postoperative pathological examination (B–D).

Follow-up

ENT physical examination showed that the bulge of the left palate in the oral cavity obviously improved compared with the preoperative status (Figure 4A). CT imaging after a 6-month follow-up showed that the left maxillary sinus ostium was significantly enlarged without residual mass (Figure 4B). To date, it has been 18 months after the operation, and no recurrence has been diagnosed.

Figure 4.

The postoperative ear, nose, and throat physical examination (A) and CT imaging after a 6-month follow-up (B). Note: The asterisk marked the location of a local bulge of the left palate in the oral cavity.

Discussion

SNIP is a locally aggressive benign tumor of the nasal cavity and nasal sinus demonstrating a high potential for recurrence and malignancy. ⁵ SNIP is common in middle-aged males, whereas cases have been rarely reported in the pediatric population. ¹ The exact etiology and pathogenic mechanism still remain controversial. Many factors might be associated with this disease, including inflammatory irritation, viral infection, allergic reaction, occupational risk factors.^5,12 Recent studies have demonstrated that human papilloma virus (HPV) and Epstein–Barr virus (EBV) play vital roles in SNIP,^13-15 especially HPV-6, -11, -16, and -18, which are related to the development and recurrence of SNIP. ¹⁶ Thus, the detection of HPV is regarded as a predictor of recurrence. ¹⁷

The presentation of SNIP is mostly unilateral, and rarely bilateral. ⁵ Clinical symptoms of SNIP in the pediatric population, they are similar to those in adults, and no single symptom or sign is statistically associated with SNIP. The main symptoms include nasal obstruction, anterior and/or posterior rhinorrhea, headache, epistaxis, hyposmia or anosmia, and facial pain. ⁶ Similar to adults, the signs and symptoms of SNIP in children are not easily distinguished from other sinonasal tumors. ⁵ Most cases originate from the sinonasal medial wall and represent secondary growth of the maxillary sinus, ethmoidal sinus, or other nasal sinuses. In the present case, the boy was admitted to the hospital with the chief complaints of the left maxillofacial hump and nasal obstruction, which were atypical, general clinical symptoms of SNIP and have been rarely reported thus far. Here, we reported this case to improve the understanding of children with SNIP.

In general, CT and MRI are common auxiliary imaging examinations, and some typical radiological features of SNIP are found on CT or MRI scanning. On the one hand, we used CT to explore alterations including intratumoral calcification and bone bowing, thinning, erosion or local hyperostosis of the sinonasal medial wall.^5,7,18 On the other hand, using MRI, a low-signal nasal/paranasal mass on T1-weighted images was observed, whereas a cerebriform circumvolution on the contrast-enhanced T2-weighted images has been shown to be highly indicative of SNIP.^5,8

In the last decade, an increasing number of SNIP cases have been treated by surgical approaches ranging from widely open radical surgery to minimally invasive endonasal surgical resections.^6,9 In terms of surgery, the critical problem is to identify and remove the attachment site of the tumor. ⁹ In the clinic, surgeons usually classify SNIP according to a staging system (ie, KROUSE) and then develop different surgical plans. According to this staging system, SNIP is classified into four stages to evaluate the preoperative extent and nature of the disease and to compare the safety and efficacy of different surgical approaches. ¹⁹ Lombardi D et al. ¹⁰ performed a retrospective study of 212 adult patients with inverted papilloma (IP) and found that the nasal endoscopic surgery was regarded as the first choice and that the lesions with extensive involvement of the frontal sinus required a combined approach. These results were consistent with other studies.^11,20,21

Additionally, previous studies have reported the different rates of recurrence after surgery. For example, Lombardi D ¹⁰ and his colleagues have observed that the postoperative recurrence rate of 212 adults with IP was 5.7% during a mean follow-up period from 24 to 192 months. Similarly, Filippo Carta ¹¹ has reported that seventy-one adults with IP showed a recurrence rate of 3.3% during a mean follow-up period of 31.6 months. However, inconsistent with the mentioned studies, Jiang ²² et al. recorded a recurrence rate of 8% in adult patients with SNIP in a follow-up period of 2–10 years. Other studies recorded obviously different recurrence rates in patients with SNIP, such as 32% by Sham CL, ²³ 18% by Kaufman MR, ²⁴ and 15.5% by Akkari M. ²⁵ These results may be associated with some risk factors including HPV infection ²⁶ or smoking. ¹⁶ Given the rarity of studies in children with SNIP, continuous reports of the follow-up of the present case are needed. As follow-up time increases, the recurrence rate increases gradually. Thus, long-term follow-up is necessary for patients with SNIP.

Conclusion

SNIP is a benign tumor that is rare in children and accompanied by different clinical symptoms. Preoperative diagnosis is easily confused with other sinonasal tumors in patients with SNIP, ⁵ and pathological examination is the gold standard. In the present case, nasal endoscopic surgery was used to remove the lesions in the left nasal cavity and the left maxillary sinus, which has several advantages, including minimal invasiveness, short operation time, and recovery time. The present case has been followed up for 18 months without recurrence, and the exact therapeutic effect should be reported continuously.