The immunoexpression of CD34, Bcl-2, and Ki-67 antigens in sinonasal inverted papillomas

Inverted papilloma is associated with greater radiographic inflammatory disease than other sinonasal malignancy

BACKGROUND

The pathogenesis of inverted papilloma (IP) has not been fully elucidated. However, chronic paranasal sinus inflammation has been anecdotally observed in sites distant from tumor obstruction in IP patients, suggesting an association between inflammation and IP tumorigenesis. This study assesses the association between sinonasal inflammation found in IP and compares this to the level of inflammation observed in other sinonasal tumors.

METHODS

A retrospective chart review was performed identifying patients with unilateral IP. Pertinent clinical data was obtained and comparative analysis of preoperative computed tomography (CT) imaging and histopathology was performed. A sample of unilateral, sinonasal, non-IP and non-squamous cell tumors was used as the control. The Lund-Mackay scoring system was used to assess radiologic sinonasal inflammation both ipsilateral and contralateral to the tumor.

RESULTS

Seventy-one patients were included; 58.9% of patients with IP had evidence of contralateral sinusitis at the time of presentation. In the control group, 26.7% had evidence of contralateral inflammation. When comparing contralateral sinus inflammation between the 2 study groups, the IP patients had significantly higher Lund-Mackay scores than the control group (1.9 vs 0.26, p < 0.001). When comparing ipsilateral sinus inflammation, no significant difference was found in Lund-Mackay scores (5.44 vs 4.00, p < 0.184).

CONCLUSION

In this study, unilateral IPs were associated with a higher level of contralateral sinonasal inflammation when compared to control. This suggests that IP may be associated with inflammation that is independent of obstruction by the tumor. Further studies are needed to better understand the temporal relationship between chronic inflammation and tumorigenesis.

Advances in recurrence and malignant transformation of sinonasal inverted papillomas

Sinonasal inverted papilloma (SIP) is a benign tumor of the nasal cavity and sinus. SIP is characterized by aggressive malignant transformation and a high rate of recurrence. Inadequate removal of the tumor during surgery is one of the most significant contributors to SIP recurrence. A growing body of evidence suggests that molecular alteration in SIP, including human papilloma virus infections, single nucleotide polymorphisms of key genes, deregulation of signaling pathways and immunological changes, may lead to SIP occurrence and malignant transformation. However, the extent to which these molecular mechanisms contribute to SIP pathology and transformation remains unclear due to limited research. Further studies are warranted to elucidate the primary dependent factors that contribute to SIP etiology. The present article reviewed risk factors of progression and recurrence of SIP, including outdoor and industrial occupational exposure, smoking, septal deviation, SIP location, recurrent cases, stage of SIP-associated squamous cell carcinoma and choice of surgical method.

Etiology of sinonasal inverted papilloma: A narrative review

Objective

Sinonasal inverted papilloma (IP) is a benign and uncommon tumor of the nasal cavity and paranasal sinuses with a tendency for recurrence and even malignant transformation. Though the morphology and clinical behavior of this lesion has been well described, its etiology remains controversial.

Methods

Computerized searches were performed in PubMed, Scopus, and Google scholar through May 2015. In this review, etiologic factors including human papilloma virus (HPV), Epstein–Barr virus (EBV), cell cycle related proteins and angiogenic factors, occupational and environmental exposures, and chronic inflammation, will be discussed.

Results

Many studies indicate that HPV has been detected in a significant percentage of IP, while EBV has not been shown to be significantly associated. Certain cell cycle regulatory factors and angiogenic proteins contribute to the dysregulation of proliferation and apoptosis, and facilitate migration and tumor invasion. Occupational exposures, such as welding and organic solvents, have been implicated, and smoking seems more critical to recurrence and dysplasia rather than initial IP occurrence. Chronic inflammation may also have a causative relationship with inverted papilloma, but the mechanism is unclear.

Conclusions

Though etiology of sinonasal IP remains controversial, the studies reviewed here indicate a role for viral infection, cell cycle and angiogenic factors, environmental and occupational exposure, and chronic inflammation. Further study on etiologic factors is necessary for clinical guidance and therapeutic targets.