Imaging of neoplasms of the paranasal sinuses

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

Cancer of the Paranasal Sinuses

Sinonasal malignancies rare and pathologically diverse and make up <1% of all malignancies. Due to their anatomical location, they can cause significant morbidity with involvement of surrounding critical structures. They often present at a late stage with insidious onset of symptoms. Treatment of sinonasal malignancies is challenging and they often require a multimodality approach with surgery, radiation, and chemotherapy. Outcomes are poor with 5-year overall survival around 32%, but this varies greatly depending on histologic subtype. There is an urgent need for more randomized controlled trials to better define the appropriate therapeutic regimens and to improve clinical outcomes.

MRI of Sinonasal Malignancies

ABSTRACT

Sinonasal cavity is an important subsite in head and neck tumors. There are a myriad of malignancies that present within this area. Adequate staging for treatment planning requires multimodality evaluation. Magnetic resonance imaging (MRI) forms an important component in the evaluation of sinonasal tumors. We sought to review the most common sinonasal tumors, including sinonasal anatomy, clinical features, and common imaging features. A literature review was performed to evaluate common sinonasal tumors. Owing to the different tissue types within the sinonasal cavity, there are multiple different tumor pathologies within the sinonasal compartment. Most present in adults although some present in the young. Many of these tumor types have imaging overlaps, although some have a characteristic appearance. MRI can aid in soft tissue delineation, evaluation of multicompartmental extension, intracranial spread, and perineural spread. Sinonasal tumors are a heterogeneous group for which soft tissue delineation via MRI forms an important role in ensuring adequate treatment planning to improve outcomes, decreasing morbidity, and improve functional outcomes.

Imaging of sino-nasal inverted papilloma: How can we emphasize the usefulness of the “striated pattern” sign?

Background

Inverted papilloma (IP) is an uncommon sino-nasal neoplasm with potentially distinctive MRI and CT features. The MR “striated” imaging pattern has been reported as a valuable MR imaging feature of IP. The purpose of this study was to validate the usefulness of this sign using detailed criteria of the sign itself.

Results

All imaging findings were described for 16 patients in descriptive pattern. The nasal involvement showed highest prevalence followed by the maxillary sinus. The bony changes include remodeling and defects (n = 6), remodeling only (n = 4), and None (n = 6). Changes were severe 1/10, moderate in 3/10, and mild 5/10. Focal hyperostosis was seen in six. A striated pattern was “diffuse” in all 16 (100%) of the IPs; it followed a certain direction in all 16 patients: divergent (n = 6), convoluted (n = 2), and parallel (n = 8). Divergent growth from focal hyperostosis was seen (n = 4). Visibility of the sign was superior in T2 images (n = 11), superior in enhanced images (n = 3), and equal in both (n = 2).

Conclusions

The striated pattern is a reliable MR imaging feature of sino-nasal IPs. Validity and usefulness of this sign can be emphasized by defining parameters of the signs itself including the following: diffusivity, direction of striations and relation to hyperostosis, and comparing visibility in both T2 and GAD-enhanced images, as well as combining this imaging signature with remolding bony changes < 1.5.

Invasive Sinonasal Lesions: From the Nasal Fossa and Paranasal Sinuses to the Endocranium

The aim of this work is to review the spectrum of sinonasal lesions that extend to the endocranium and to present key points that may narrow the differential diagnosis. The most frequent sinonasal lesions that extend into the endocranium are malignant; however, benign entities are not unusual. Imaging diagnosis is difficult because malignant lesions and benign entities share similar clinical, epidemiologic, and imaging features. Tumor features in relation to bone, intratumor homogeneity and structure, magnetic resonance imaging signal, along with clinical and epidemiologic aspects may allow an appropriate diagnostic focus with important management implications.

A Clinical and Radiological Approach to the Management of Benign Mesenchymal Sinonasal Tumors

PURPOSE

Benign mesenchymal sinonasal neoplasms (BMSN) are rare and histologically heterogeneous. Differential diagnosis, appropriate management, and outcome are still a matter of debate. The aim of this study is to provide evidence for further refinement of assessment and treatment in the future.

PROCEDURES

We retrospectively reviewed data on 93 patients with neuroradiologically verified BMSN treated at our university reference center during the past 22 years.

RESULTS

The most frequent BMSN recorded in our cohort was osteoma of the frontal sinus. Only one-third of the patients affected were symptomatic at initial presentation. The 2 other common fibro-osseous tumor entities, fibrous dysplasia and ossifying fibroma, were confirmed in 12 and 6 patients, respectively. Patients with soft tissue tumor entities such as hemangioma, glomangiopericytoma, angiofibroma, and hamartoma were all symptomatic and underwent surgical resection.

CONCLUSION

Understanding and recognizing the spectrum of appearances of benign mesenchymal sinonasal tumors will improve patient assessment and clinical management. The pathognomonic neuroradiological signs of a particular tumor entity should be actively sought as the neuroradiological features may be the diagnostic clues. Computed tomography and magnetic resonance imaging play complementary roles in identifying the morphological details and locoregional staging of benign mesenchymal sinonasal tumors.

Differentiating Benign from Malignant Sinonasal Lesions: Feasibility of Diffusion Weighted MRI

Introduction  Appearance of nasal masses on routine CT and MRI are not pathognomonic. We utilized the apparent diffusion coefficient (ADC) value obtained from diffusion weighted image (DWI) to detect the differences in the microstructures of tumor and non-tumor tissues.

Objective  The objective of our study was to evaluate the diagnostic role of DWI and ADC values in differentiating between malignant and benign sinonasal lesions and its correlation with histopathological results as the reference standard.

Methods  Patients with nasal and / or paranasal mass underwent CT, MRI, and DWI before any surgical intervention. We used diagnostic sinonasal endoscopy and biopsy to confirm the diagnosis after MRI.

Results  When we used ADC value of (1.2 × 10–3 mm2/s) as a cut-off value for differentiating benign from malignant sinonasal lesions, we achieved 90% accuracy, 100% sensitivity, 88.4% specificity, 77.8% positive predictive value, and 100% negative predictive value. At this cut-off, benign lesions show statistically significant higher ADC value than malignant tumors.

Conclusion  DW MRI and ADC value calculation are promising quantitative methods helping to differentiate between malignant and benign sinonasal lesions. Thus, they are effective methods compared with other conventional methods with short imaging time thus it is recommended to be incorporated into routine evaluations.

Cranial Nerve Schwannomas: Diagnostic Imaging Approach

Schwannomas are benign nerve sheath tumors that may arise along the complex course of the cranial nerves (CNs), anywhere in the head and neck. Sound knowledge of the CN anatomy and imaging features of schwannomas is paramount for making the correct diagnosis. In this article, we review approaches to diagnosing CN schwannomas by describing their imaging characteristics and the associated clinical presentations. Relevant anatomic considerations are highlighted by using illustrative examples and key differential diagnoses categorized according to regions, which include the anterior skull base, orbit, cavernous sinus, basal cisterns, and neck. The clinical presentations associated with CN schwannomas vary and range from no symptoms to symptoms caused by mass effect or CN deficits. Individuals with the inherited disorder neurofibromatosis type 2 are predisposed to multiple schwannomas. When a lesion follows the course of a CN, the radiologist's roles are to confirm the imaging features of schwannoma and exclude appropriate differential considerations. The characteristic imaging features of CN schwannomas reflect their slow growth as benign neoplasms and include circumscribed margins, displacement of local structures, and smooth expansion of osseous foramina. These neoplasms exhibit various degrees of solid enhancement, often with internal cystic spaces on magnetic resonance (MR) and computed tomographic (CT) images and heterogeneous high signal intensity specifically on T2-weighted MR images. Clinical and/or imaging evidence of end-organ compromise of the involved CN may exist and aid in the identification of the nerve of origin. With a detailed understanding of the course of the CNs, the diagnostic features of CN schwannomas, and the correlation between these data and the associated clinical presentations of these tumors, the radiologist can have a key role in the diagnosis of CN schwannomas and the treatment planning for affected patients. (©)RSNA, 2016.

Imaging Appearance of SMARCB1 (INI1)-Deficient Sinonasal Carcinoma: A Newly Described Sinonasal Malignancy

SMARCB1 (INI1)-deficient sinonasal carcinomas were first described in 2014, and this series of 17 cases represents the first imaging description. This tumor is part of a larger group of SMARCB1-deficient neoplasms, characterized by aggressive behavior and a rhabdoid cytopathologic appearance, that affect multiple anatomic sites. Clinical and imaging features overlap considerably with other aggressive sinonasal malignancies such as sinonasal undifferentiated carcinoma, which represents a common initial pathologic diagnosis in this entity. SMARCB1 (INI1)-deficient sinonasal tumors occurred most frequently in the nasoethmoidal region with invasion of the adjacent orbit and anterior cranial fossa. Avid contrast enhancement, intermediate to low T2 signal, and FDG avidity were frequent imaging features. Approximately half of the lesions demonstrated calcification, some with an unusual "hair on end" appearance, suggesting aggressive periosteal reaction.

Endoscopy versus imaging: Analysis of surveillance methods in sinonasal malignancy

BACKGROUND

The purpose of this study was to assess the utility of imaging and endoscopy in posttreatment surveillance of sinonasal malignancies.

METHODS

We conducted a retrospective analysis of primary sinonasal malignancies diagnosed between 2000 and 2014. Posttreatment surveillance included nasal endoscopy and imaging (MRI, CT, and positron emission tomography [PET]/CT). Positive predictive value (PPV), negative predictive value (NPV), specificity, and sensitivity were calculated for each modality and compared.

RESULTS

One hundred nine sinonasal malignancies were identified with 30 recurrences. Endoscopy showed a sensitivity and specificity of 24% and 89%, respectively, whereas imaging was 76% and 90%, respectively. Identifying suspicious symptoms significantly improved the PPV of both endoscopy and imaging. MRI demonstrates the highest PPV when compared with other imaging modalities.

CONCLUSION

Both modalities are necessary in posttreatment surveillance. MRI shows the highest PPV, whereas endoscopy trends toward a higher specificity. PET/CT scans have a high false-positive rate and should be reserved for tumors with a high propensity for distant metastases. © 2016 Wiley Periodicals, Inc. Head Neck 38:1229-1233, 2016.

Long-term radiological findings after endonasal endoscopic approach to the skull base

OBJECTIVE

To study the long-term radiological findings after endonasal endoscopic approach to the skull base.

MATERIAL AND METHODS

Prospective study that included 55 patients who underwent advance endoscopic skull base surgery. All patients were evaluated with MRI before, 3 months and 12 months after surgery. We used the Lund-Mackay staging system for chronic rhinosinusitis to evaluate the paranasal cavities and the sinonasal scoring system to assess sinonasal symptoms.

RESULTS

Seventeen patients (30.9%) underwent extended endonasal approach that required a nasoseptal flap (NSF) for reconstruction of skull base. At baseline the mean total Lund-Mackay score was 0.63 ± 1.2 (range 0-4), and at 3 and 12 months postoperatively the mean scores were 3.5 ± 3.8 (range 0-14) and 2.0 ± 2.5 (range 0-8) respectively. Patients who needed an NSF for reconstruction had a greater Lund-Mackay score (p<0.05). Moreover, NSF is correlated with sinonasal mucosal thickening and fluid retention at 3 months (r=0.45, p<0.01) and 12 months (r=0.4, p<0.01). Total 5-symptom score (T5SS) was similar between both groups at baseline. Patients with extended endoscopic approach reported more smell loss (40.1 ± 26.2; p<0.05) and posterior nasal discharge (49.3 ± 30.1; p<0.05) than TTEA patients (21.6 ± 30.9 and 22.5 ± 27.5 respectively).

CONCLUSIONS

We observed that sinus opacity is still present after one year of advance endoscopic skull base surgery but symptoms seems to return to basal after 12 months of follow-up.

Radiologic Features of Sinonasal Tumors

Imaging evaluation of sinonasal tumors is most often conducted with computed tomography, which excels at identifying the effects of these masses on adjacent osseous structures, and magnetic resonance imaging that is ideal for distinguishing pathologic masses from mucosal thickening and fluid that are common in the sinonasal spaces and depicting extension into the surrounding soft tissues, orbits, and intracranial compartment. Accordingly, the two studies are complementary exams and both are commonly utilized in the assessment of these masses. Less commonly, positron emission tomography can provide additional metabolic evaluation of potential metastatic disease in patients with malignant disease. While these imaging modalities are excellent for the portrayal of an abnormality, there is considerable overlap in the imaging appearance of these tumors and specific imaging manifestations linked to a particular tumor are frequently lacking. Therefore, while the mass may be readily identified, narrowing the differential diagnosis to a single specific entity is rare. Nevertheless, cross-sectional imaging plays an essential role in patient management and valuable guidance for successful biopsy or surgical resection in virtually all cases. This review emphasizes essential imaging manifestations that correlate with sinonasal tumors in general and highlight certain features that may implicate a specific disease process.

Improved performance in differentiating benign from malignant sinonasal tumors using diffusion-weighted combined with dynamic contrast-enhanced magnetic resonance imaging

Background:

Differentiating benign from malignant sinonsal lesions is essential for treatment planning as well as determining the patient's prognosis, but the differentiation is often difficult in clinical practice. The study aimed to determine whether the combination of diffusion-weighted (DW) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can improve the performance in differentiating benign from malignant sinonasal tumors.

Methods:

This retrospective study included 197 consecutive patients with sinonasal tumors (116 malignant tumors and 81 benign tumors). All patients underwent both DW and DCE-MRI in a 3-T magnetic resonance scanner. Two different settings of b values (0,700 and 0,1000 s/mm²) and two different strategies of region of interest (ROI) including whole slice (WS) and partial slice (PS) were used to calculate apparent diffusion coefficients (ADCs). A DW parameter with WS ADCs_b0,1000 and two DCE-MRI parameters (time intensity curve [TIC] and time to peak enhancement [Tpeak]) were finally combined to use in differentiating the benign from the malignant tumors in this study.

Results:

The mean ADCs of malignant sinonasal tumors (WS ADCs_b0,1000 = 1.084 × 10⁻³ mm²/s) were significantly lower than those of benign tumors (WS ADCs_b0,1000 = 1.617 × 10⁻³ mm²/s, P < 0.001). The accuracy using WS ADCs_b0,1000 alone was 83.7% in differentiating the benign from the malignant tumors (85.3% sensitivity, 81.2% specificity, 86.4% positive predictive value [PPV], and 79.5% negative predictive value [NPV]). The accuracy using DCE with Tpeak and TIC alone was 72.1% (69.1% sensitivity, 74.1% specificity, 77.5% PPV, and 65.1% NPV). Using DW-MRI parameter was superior than using DCE parameters in differentiation between benign and malignant sinonasal tumors (P < 0.001). The accuracy was 87.3% (90.5% sensitivity, 82.7% specificity, 88.2% PPV, and 85.9% NPV) using DW-MRI combined with DCE-MRI, which was superior than that using DCE-MRI alone or using DW-MRI alone (both P < 0.001) in differentiating the benign from the malignant tumors.

Conclusions:

Diffusion-weighted combined with DCE-MRI can improve imaging performance in differentiating benign from malignant sinonasal tumors, which has the potential to improve diagnostic accuracy and to provide added value in the management for these tumors.

Imaging for headache: what the neuroradiologist looks for

In this article, computed tomography and magnetic resonance imaging anatomy and pathology of sinus disease is discussed, specifically relating to facial pain, rhinogenic headache, and sinus outflow obstruction. Findings commonly seen in acute, chronic, infectious, and inflammatory sinusitis are illustrated, with additional examples of secondary intracranial and orbital involvement, and more aggressive infectious and neoplastic processes.

Skull base inverted papilloma: a comprehensive review

Skull base inverted papilloma (IP) is an unusual entity for many neurosurgeons. IP is renowned for its high rate of recurrence, its ability to cause local destruction, and its association with malignancy. This paper is a comprehensive review of the reports, studies, and reviews published in the current biomedical literature from 1947 to September 2010 and synthesize this information to focus on its potential invasion to the base of the skull and possible intradural extension. The objective is to familiarize the clinician with the different aspects of this unusual disease. The role of modern diagnostic tools in medical imaging in order to assess clearly the limits of the tumors and to enhance the efficiency and the safety in the choice of a surgical approach is pointed out. The treatment guidelines for IP have undergone a complex evolution that continues today. Radical excision of the tumour is technically difficult and often incomplete. Successful management of IP requires resection of the affected mucosa which could be achieved with open surgery, endoscopic, or combined approach. Radio and chemotherapy were used for certain indications. More optimally research would be a multicenter randomized trials with large size cohorts.

Inflammatory myofibroblastic tumour of the maxillary sinus: CT and MRI findings

AIM

To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of inflammatory myofibroblastic tumours (IMTs) of the maxillary sinus.

MATERIALS AND METHODS

The imaging findings of eight patients with IMTs of the maxillary sinus were reviewed retrospectively. Of the eight patients, four patients underwent unenhanced and contrast-enhanced CT, and one patient underwent unenhanced CT only; three patients underwent unenhanced and contrast-enhanced MRI.

RESULTS

Five cases of IMTs occurred in the left maxillary sinus, while three cases were right-sided. Four cases occupied the entire sinus, and the other four cases only partially occupied the sinus. Unenhanced CT images showed heterogeneous masses in four cases and a homogeneous mass in one case. One of the tumours showed some areas of calcification. T1-weighted MRI images showed isointense lesions. T2-weighted images showed mixed isointense and mild hyperintense lesions. All cases showed bone destruction and had infiltrated into the nasal fossa, orbit, infratemporal fossa, and other adjacent tissues. Seven cases showed mild to moderate heterogeneous enhancement on contrast-enhanced CT or T1-weighted MRI images.

CONCLUSION

IMTs of the maxillary sinus can be characterized as a soft-tissue mass with bony destruction and infiltration of the adjacent tissues, with mild to moderate enhancement after the injection of contrast medium. CT and MRI can help to diagnose IMTs, determine the extent of the lesion and its relationship with adjacent tissues, and thus facilitate the prediction of surgical resectability.

Assessment of nasal and paranasal sinus masses by diffusion-weighted MR imaging

PURPOSE

To assess nasal and paranasal sinus masses by diffusion-weighted echoplanar magnetic resonance imaging (MRI).

PATIENTS AND METHODS

This prospective study included 55 consecutive patients (34 males, 21 females; aged 14-64 years, mean 39 years) with nasal and paranasal sinus masses. All underwent diffusion-weighted MRI using single-shot echoplanar imaging (EPI) with a b factor of 0.500 and 1000 s/mm2. Apparent diffusion coefficient (ADC) maps were constructed, allowing ADC values of the mass to be calculated and correlated with histopathological findings.

RESULTS

The mean ADC value of nasal and paranasal sinus malignant lesions (1.10+/-0.25x10(-3) mm2/s) was significantly different (P=0.001) from that of benign lesions (1.78+/-0.41x10(-3) mm2/s). Also, there was a significant ADC difference between carcinoma and sarcoma (P=0.01) as well as between well differentiated and poorly differentiated malignancies (P=0.005). Using an ADC value of 1.53x10(-3) mm2/s as the threshold value for differentiating malignant from benign lesions, the best result obtained had an accuracy of 93%, sensitivity of 94%, specificity of 92%, a positive predictive value of 92% and negative predictive value of 94%. However, the use of 0.97x10(-3) mm2/s and 1.16x10(-3) mm2/s as threshold values to differentiate carcinomas from sarcomas and poorly differentiated malignancy, respectively, gave the best results.

CONCLUSION

The ADC value is a non-invasive imaging parameter that can be used to assess nasal and paranasal sinus masses, as it can help in the differentiation of malignant tumors from benign lesions, and in the characterization and grading of malignancies.

Imaging lesions of the cavernous sinus

Our aim was to review the imaging findings of relatively common lesions involving the cavernous sinus (CS), such as neoplastic, inflammatory, and vascular ones. The most common are neurogenic tumors and cavernoma. Tumors of the nasopharynx, skull base, and sphenoid sinus may extend to the CS as can perineural and hematogenous metastases. Inflammatory, infective, and granulomatous lesions show linear or nodular enhancement of the meninges of the CS but often have nonspecific MR imaging features. In many of these cases, involvement elsewhere suggests the diagnosis. MR imaging is sensitive for detecting vascular lesions such as carotid cavernous fistulas, aneurysms, and thromboses.

[Role of imaging in the pre-treatment assessment and post-treatment follow-up of sinonasal malignancies]

Malignant sinonasal tumors are the most frequent facial malignancies in adults. Assessment of these tumors requires a multidisciplinary approach and imaging plays a major role to define the precise tumor location, volume and extension and to plan post-treatment follow-up. MRI provides superior differentiation between tumor and surrounding tissues and depiction of intracranial or perineural extension. CT is a useful complement to demonstrate bone erosion or extension into the skull base.

CT versus MR: still a tough decision

CT and MRI are the two most widely used imaging modalities for evaluating head and neck pathology. There is continued controversy in the literature about which modality is superior for imaging different areas of the head and neck. This article summarizes the literature supporting the use of CT, MRI, or both for specific clinical scenarios in otolaryngology. Familiarity with the benefits and potential pitfalls of each modality allows referring physicians and radiologists to tailor imaging regimens to the needs of individual patients.

Paranasal sinus imaging

Endonasal surgery is currently extending its application beyond inflammatory sinonasal lesions to successfully treat both benign and malignant neoplasms. This progression has been possible by the detailed information provided by imaging techniques (CT, MRI and PET). Inflammatory diseases are the "domain" of CT. CT provides excellent details about the thin bony sinonasal walls separating the ethmoid from the anterior skull base and the orbit. Benign and malignant neoplasms are the "domain" of MRI because the tumor is more easily separated from adjacent structures, the periosteal linings (periorbita, dura mater) and perineural spread can be accurately shown. Whereas MRI precisely assess pre-treatment tumor extent, early submucosal local recurrences are difficult to demonstrate because of post-treatment changes of the anatomy and of the signal of treated tissues. Though diffusion-weighted imaging and dynamic contrast-enhanced techniques are promising developments, PET-CT may overcome the limits of morphological MRI.

Role of MR and CT in the paranasal sinuses

This article discusses the benefits and drawbacks of MR imaging and computed tomography as they relate to sinus disease.