Nasal polyps with metaplastic ossification: CT and MR imaging findings

Nasal polyps with osseous metaplasia: A misunderstood situation

Osseous metaplasia in nasal polyps is rare but benign. To exclude dangerous lesions, sending the entirety of histological samples is mandatory in cases presenting with clustered densities on CT scan. Microdebrider should not be used for this surgery.

Choanal Polyp with Osseous Metaplasia: Radiological and Therapeutic Management of a Rare Case and a Review of Bone Metaplastic Lesions of Sinonasal Tract

Patient: Female, 51-years-old

Final Diagnosis: Choanal polyp with osseous metaplasia

Symptoms: Nasal obstruction

Medication:—

Clinical Procedure: Combined surgical approach, endoscopic and trans-oral

Specialty: Otolaryngology

Osseous metaplasia of antrochoanal polyp: Case report and radiological-pathological correlation

Osseous metaplasia of inflammatory sinonasal polyp is an extremely rare entity. Correct preoperative diagnosis by noncontrast CT scan is needed to rule out other more common bony neoplasms in paranasal sinuses and for accurate surgical planning. Here, we present a case of 20-year-old patient with an antrochoanal polyp with osseous metaplasia. We describe the lesion and discuss the radiological differential diagnosis thereby providing a brief review of literature of the few published cases worldwide along with histopathological correlation.

Whole-transcriptome sequencing reveals heightened inflammation and defective host defence responses in chronic rhinosinusitis with nasal polyps

INTRODUCTION

The pathways underlying chronic rhinosinusitis with nasal polyps (CRSwNP) are unclear. We conducted genome-wide gene expression analysis to determine pathways and candidate gene sets associated with CRSwNP.

METHODS

We performed whole-transcriptome RNA sequencing on 42 polyp (CRSwNP-NP) and 33 paired nonpolyp inferior turbinate (CRSwNP-IT) tissues from patients with CRSwNP and 28 inferior turbinate samples from non-CRS controls (CS-IT). We analysed the differentially expressed genes (DEGs) and the gene sets that were enriched in functional pathways.

RESULTS

Principal component-informed analysis revealed cilium function and immune regulation as the two main Gene Ontology (GO) categories differentiating CRSwNP patients from controls. We detected 6182 and 1592 DEGs between CRSwNP-NP versus CS-IT and between CRSwNP-NP versus CRSwNP-IT tissues, respectively. Atopy status did not have a major impact on gene expression in various tissues. GO analysis on these DEGs implicated extracellular matrix (ECM) disassembly, O-glycan processing, angiogenesis and host viral response in CRSwNP pathogenesis. Ingenuity Pathway Analysis identified significant enrichment of type 1 interferon signalling and axonal guidance canonical pathways, angiogenesis, and collagen and fibrotic changes in CRSwNP (CRSwNP-NP and CRSwNP-IT) tissues compared with CS-IT. Finally, gene set enrichment analysis implicated sets of genes co-regulated in processes associated with inflammatory response and aberrant cell differentiation in polyp formation.

CONCLUSIONS

Gene signatures involved in defective host defences (including cilia dysfunction and immune dysregulation), inflammation and abnormal metabolism of ECM are implicated in CRSwNP. Functional validation of these gene expression patterns will open opportunities for CRSwNP therapeutic interventions such as biologics and immunomodulators.

Differentiating between benign and malignant sinonasal lesions using dynamic contrast-enhanced MRI and intravoxel incoherent motion

PURPOSE

To explore the value of dynamic contrast-enhanced MRI (DCE-MRI) and intravoxel incoherent motion (IVIM) for distinguishing between benign and malignant sinonasal lesions and investigate the correlations between the two methods.

METHODS AND MATERIALS

Patients with sinonasal lesions (42 benign and 31 malignant) who underwent DCE-MRI and IVIM before confirmation by histopathology were enrolled in this prospective study. Parameters derived from DCE-MRI and IVIM were measured, the optimal cut-off values for differential diagnosis were determined, and the correlations between the two methods were evaluated. Statistical analyses were performed using the Wilcoxon rank sum test, receiver operating characteristic (ROC) curve analysis, and Spearman's rank correlation.

RESULTS

Significantly higher K^trans and K_ep values but lower D and f values were found in malignant lesions than in benign lesions (all p<0.001). There were no significant differences in the V_e and D* values between the two groups. The area under the curve (AUC) of K^trans was significantly higher than those of other parameters. There was no significant difference between the AUCs of DCE-MRI and IVIM with parameters combined (p=0.86). Significant inverse but weak correlations were found between D and K^trans (r=-0.46, p<0.001), f and K^trans (r=-0.41, p<0.001), D and K_ep (r=-0.37, p=0.008), and f and K_ep (r=-0.33, p=0.004).

CONCLUSIONS

DCE-MRI and IVIM can effectively differentiate between benign and malignant sinonasal lesions. IVIM findings correlate with DCE-MRI results and may represent an alternative to DCE-MRI.

Ossifying inverted papilloma and ossifying polyp of the sinonasal tract: comparison of CT and MRI features

AIM

To investigate the key imaging points in distinguishing ossifying inverted papilloma (IP) from polyps.

MATERIALS AND METHODS

The native computed tomography (CT), conventional and enhanced MRI manifestations of 20 ossifying IPs and eight polyps, which were confirmed histopathologically, were retrospectively evaluated by two doctors majoring in head and neck imaging.

RESULTS

A significant difference was detected between the two entities for the involved sites (p<0.05). Although two lesions had similar CT findings, the MRI features differed significantly (p<0.05). Twenty ossifying IPs demonstrated heterogeneously isointense with moderate gadolinium enhancement, and a convoluted "cerebriform" configuration. Seven ossifying polyps revealed low T1 and high T2 signal, with marginal enhancement, and one showed isointense with moderate enhancement. The ossification appeared as oval or striped bone-like high attenuation, which consisted of peripheral hyperattenuating cortical bone and central fat-like attenuation of the medullary cavity. The corresponding MRI findings of the ossifying regions were peripherally low signal and centrally high signal on both T1- and T2-weighted images. The occurrence of two key MRI features of cystic appearance and the "cerebriform" sign were significantly different between two entities (p<0.05).

CONCLUSIONS

CT can better detect intralesional ossification, but MRI is the optimal imaging technique for discriminating between two disease entities.

Diffusion kurtosis imaging for differentiating between the benign and malignant sinonasal lesions

PURPOSE

The study aimed to evaluate diffusion kurtosis imaging (DKI) in the differentiation between benign and malignant sinonasal lesions, and to compare the diagnostic performance of DKI with diffusion weighted imaging (DWI).

MATERIALS AND METHODS

Eight-one patients with solid sinonasal lesions confirmed by surgery and pathology (46 malignant and 35 benign) underwent conventional MRI, DWI, and DKI. DKI was performed employing a 13 extended b-value ranging from 0 to 2500 s/mm² . Apparent diffusion coefficient (ADC) from DWI, kurtosis (K), and diffusion coefficient (D) from DKI were measured and compared between two groups.

RESULTS

ADC and D values were significantly lower in the malignant sinonasal lesions than in the benign sinonasal lesions (1.11 ± 0.41 versus 1.58 ± 0.50 × 10^-3 mm² /s and 1.45 ± 0.36 versus 2.03 ± 0.49 × 10^-3 mm² /s, respectively, both P < 0001). K value was significantly higher in the malignant lesions than in the benign lesions (0.91 ± 0.23 versus 0.57 ± 0.24, P < 0001). The receiver operating characteristic curve analyses yielded a cutoff ADC value of 1.27 × 10^-3 mm² /s for differentiating between benign and malignant lesions, with a sensitivity of 69.6%, a specificity of 77.1% and an accuracy of 74.0%; a cutoff D value of 1.75 × 10^-3 mm² /s, with a sensitivity of 82.6%, a specificity of 77.1% and an accuracy of 80.2%; a cutoff K value of 0.63 with a sensitivity of 95.7%, a specificity of 77.1% and an accuracy of 87.7%. The area under the curve of K value was significantly larger than that of ADC value (0.875 versus 0.762; P < 0.05).

CONCLUSION

K value of DKI demonstrates significantly higher accuracy compared with ADC value for the differentiation between benign and malignant sinonasal lesions. DKI may be a noninvasive method to evaluate the sinonasal lesions.

LEVEL OF EVIDENCE

1 J. MAGN. RESON. IMAGING 2017;45:1446-1454.

Septochoanal Polyp with Metaplastic Ossification Mimicking Sinonasal Tumor: A Case Report

Choanal polyps are a form of nasal polyps that grow toward the choana with a single stalk. Septochoanal polyp is a rare entity that originates from the mucosa of the nasal septum with choanal extension. The most common site of its origin is mainly the superior aspect of the posterior portion of the nasal septum. However, metaplastic ossification is a rare event in nasal polyp and to the best of our knowledge, septochoanal polyp with metaplastic ossification has not been reported in the literature. Herein, we report a case of huge septochoanal polyp with metaplastic ossification obstructing both the nasal cavity and nasopharynx, which was successfully removed via transnasal endoscopic approach.