Magnetic resonance imaging of sinonasal malignancies

Intestinal Type Sinonasal Adenocarcinoma: A Clinicopathological Study of 48 Patients With Review of Literature

BACKGROUND

Intestinal type sinonasal adenocarcinoma is a gland forming malignant tumor of sinonasal tract which is histologically and immunohistochemically similar to intestinal type adenocarcinomas. Intestinal type sinonasal adenocarcinoma has a well-recognized etiological association with occupational exposure to wood dusts.

OBJECTIVE

To report the clinicopathological factors of intestinal type sinonasal adenocarcinoma and review the published literature.

METHODS

Forty-eight tumors reported as intestinal type sinonasal adenocarcinoma were retrieved and clinicopathological features were noted.

RESULTS

Age ranged from 22 to 79 (mean 44) years with 36 men and 12 women. Most patients were presented with nasal blockage and difficulty in breathing. Occupational exposure to dust was present in the majority of patients. Tumors were composed of papillae or acini lined by dysplastic intestinal type columnar epithelium with interspersed goblet cells. There were 13 well differentiated (low grade) and 35 poorly differentiated (high-grade) tumors. CDX2 and SATB2 were expressed by the tumor cells in most tumors. Follow-up was available in 24 patients (range 3 months to 10 years). Most of the patients received chemo and/or radiotherapy. Metastases occurred in 19 out of 24 patients. Brain metastases were very common. All patients with metastases died of their disease.

CONCLUSION

Clinical and morphological features in our series were similar to published studies. It is important for pathologists to remember the association of these tumors with occupational exposure to wood dusts and to exclude metastases of intestinal adenocarcinomas when confronted by these tumors in the sinonasal tract.

Alveolar Rhabdomyosarcoma of Nasopharynx and Paranasal Sinuses in Children Diagnosis and Treatment-Review of the Literature and Case Report

Alveolar rhabdomyosarcoma (aRMS) is a rare pediatric malignant tumor with a poor prognosis, particularly when located in the rhinopharynx and sphenoidal floor, which complicates diagnosis and increases the risk of misclassification as benign growths. The specific genotype of aRMS is associated with a worse clinical outcome. In young children, especially those aged 4 to 12 years, rhinopharyngeal masses are often attributed to chronic adenoiditis; however, other benign (e.g., angiofibroma in boys) and malignant tumors may also be present. Initial symptoms frequently include nasal obstruction, muco-purulent nasal discharge, serous otitis media, sinusitis, and epistaxis. Rhabdomyosarcoma is the second most common ENT neoplasm in children, following lymphoma, with an incidence of approximately 6 cases per 1,000,000 annually. This report presents the case of an 8-year-old boy diagnosed with aRMS, accompanied by a literature review. Alveolar rhabdomyosarcoma should be suspected in children presenting with a vegetative tumor in the rhinopharynx or paranasal sinuses. Combined treatment approaches (surgery, radiotherapy, and chemotherapy) should be tailored to tumor characteristics. Neuronavigation-guided functional endoscopic sinus surgery (FESS) is an effective option for achieving complete tumor excision, depending on tumor size and extent. The prognosis remains reserved and is contingent upon accurate evaluation and timely intervention. Rigorous follow-up, including endoscopic and imagistic investigation, is crucial for early detection of recurrences, thereby improving treatment outcomes.

Diagnostic Accuracy of MRI for Orbital and Intracranial Invasion of Sinonasal Malignancies: A Systematic Review and Meta-Analysis

Background/Objectives: In this study, we review the diagnostic accuracy of magnetic resonance imaging (MRI) in detecting orbital and intracranial invasion of sinonasal malignancies (SNMs) using histopathological and surgical evidence as the reference standard. Methods: A systematic search of studies in English was conducted in MEDLINE and Embase, limited to articles published since 1990. We included studies using preoperative MRI to detect the intracranial and orbital invasion of SNMs, with histological or surgical confirmation as the reference standard, and reported patient numbers in each class as required to assess diagnostic accuracy. The outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Heterogeneity was assessed with the Higgins inconsistency test (I2). Results: Seven original articles with 546 subjects were included in the review, with six included in the meta-analysis. The pooled overall accuracy for orbital invasion was higher at 0.88 (95% CI, 0.75-0.94) than that for intracranial invasion at 0.80 (95% CI, 0.76-0.83). The meta-analytic estimates and their 95% confidence intervals were as follows for intracranial/orbital invasion: sensitivity 0.77 (0.69-0.83)/0.71 (0.40-0.90); specificity 0.79 (0.74-0.83)/0.91 (0.78-0.97); PPV 0.76 (0.64-0.85)/0.78 (0.61-0.88); and NPV 0.82 (0.72-0.89)/0.90 (0.63-0.98). Substantial heterogeneity was observed in the Higgins inconsistency test (I2) for orbital invasion (84%, 83%, and 93% for sensitivity, specificity, and NPV, respectively). Conclusions: MRI yielded moderate-to-high diagnostic accuracy for intracranial and orbital invasion, despite some limitations leading to false diagnoses. Loss of the hypointense zone on postcontrast MRI was found to predict dural invasion. Infiltration of the extraconal fat beyond the periorbita was found to be an MRI feature of orbital invasion.

Update from the 5th Edition of the WHO Classification of Nasal, Paranasal, and Skull Base Tumors: Imaging Overview with Histopathologic and Genetic Correlation

Sinonasal and skull base tumors are a heterogeneous group of neoplasms with considerable histologic variation and overlapping imaging features. In 2022, the World Health Organization updated the head and neck tumor classification, further emphasizing the importance of molecular data and genetic alterations in sinonasal neoplasms. The changes include the addition of new entities and discussion of emerging entities, as well as changes to the taxonomy and characterization of tumors. The new classification focuses on entities that develop in these sites either exclusively (eg, olfactory neuroblastoma) or most frequently. Another change includes reduction in the number of categories by creating separate category-specific chapters for soft-tissue, hematolymphoid, and neuroectodermal lesions. In this review, we briefly discuss the various categories in the new classification with a more detailed description of the 2 new entities (SWItch/Sucrose Non-Fermentable complex-deficient sinonasal carcinomas and human papillomavirus-related multiphenotypic sinonasal carcinoma). We also highlight the emerging entities including IDH-mutant sinonasal malignancies and DEK-AFF2 carcinoma, presently classified as sinonasal undifferentiated carcinoma and nonkeratinizing squamous cell carcinoma, respectively.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Malignant and Nonmalignant Sinonasal Tumors

Sinonasal tumors are rare, diverse, complex lesions with overlapping demographic and clinical features. Malignant tumors are more common, with a grave prognosis, and require biopsy for accurate diagnosis. This article briefly reviews the classification of sinonasal tumors and provides imaging examples and imaging characteristics of each clinically important nasal and paranasal mass lesions. Although there are no true pathognomonic imaging features, it is important for the radiologist to have a broad knowledge of the various CT and MR imaging findings that can help narrow the differential diagnosis and aid in early diagnosis and mapping of tumor for treatment planning.

Multi-parametric MRI-based radiomics signature for preoperative prediction of Ki-67 proliferation status in sinonasal malignancies: a two-centre study

OBJECTIVE

To assess the predictive ability of a multi-parametric MRI-based radiomics signature (RS) for the preoperative evaluation of Ki-67 proliferation status in sinonasal malignancies.

METHODS

A total of 128 patients with sinonasal malignancies that underwent multi-parametric MRIs at two medical centres were retrospectively analysed. Data from one medical centre (n = 77) were used to develop the predictive models and data from the other medical centre (n = 51) constitute the test dataset. Clinical data and conventional MRI findings were reviewed to identify significant predictors. Radiomics features were determined using maximum relevance minimum redundancy and least absolute shrinkage and selection operator algorithms. Subsequently, RSs were established using a logistic regression (LR) algorithm. The predictive performance of RSs was assessed using calibration, decision curve analysis (DCA), accuracy, and AUC.

RESULTS

No independent predictors of high Ki-67 proliferation were observed based on clinical data and conventional MRI findings. RS-T1, RS-T2, and RS-T1c (contrast enhancement T1WI) were established based on a single-parametric MRI. RS-Combined (combining T1WI, FS-T2WI, and T1c features) was developed based on multi-parametric MRI and achieved an AUC and accuracy of 0.852 (0.733-0.971) and 86.3%, respectively, on the test dataset. The calibration curve and DCA demonstrated an improved fitness and benefits in clinical practice.

CONCLUSIONS

A multi-parametric MRI-based RS may be used as a non-invasive, dependable, and accurate tool for preoperative evaluation of the Ki-67 proliferation status to overcome the sampling bias in sinonasal malignancies.

KEY POINTS

• Multi-parametric MRI-based radiomics signatures (RSs) are used to preoperatively evaluate the proliferation status of Ki-67 in sinonasal malignancies. • Radiomics features are determined using maximum relevance minimum redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithms. • RSs are established using a logistic regression (LR) algorithm.

Comparison of MRI and CT in the Evaluation of Unilateral Maxillary Sinus Opacification

Objectives

To evaluate the diagnostic performance of MRI compared with CT in differentiating neoplastic from infectious/inflammatory causes of complete unilateral maxillary sinus opacification (UMSO). Although MRI is increasingly used, no studies validate its utility compared to CT or nasal endoscopy in this context.

Methods

A retrospective analysis of 49 patients presenting with complete UMSO to a tertiary referral centre was performed, investigated with both CT and MRI. Two head and neck radiologists independently reviewed each imaging modality and recorded both a final diagnosis and Likert-scale diagnostic certainty score. A consensus radiological diagnosis was determined, stratified into potentially neoplastic or infectious/inflammatory aetiology, and compared with nasal endoscopy and final diagnosis. Diagnostic performance and interoperator agreement for predicting neoplasia were calculated.

Results

Both CT and MRI demonstrated high sensitivity and negative predictive value for neoplasm, although MRI was more specific (79%; 95% CI: 60–92%) than CT (14%; 95% CI: 4–32%), with a higher positive predictive value. MRI was more accurate (88%; 95% CI: 75–95%) than CT (49%; 95% CI: 34–64%) in diagnosing neoplasia. MRI had significantly higher diagnostic certainty Likert scores than CT (p < 0.0001 for both observers). Interobserver agreement was fair for CT (kappa coefficient = 0.327) and excellent for MRI (kappa coefficient = 0.918).

Conclusions

MRI is more specific than CT in characterising UMSO, with greater diagnostic certainty and reproducibility. The additive diagnostic value of MRI complements CT, potentially reducing diagnostic delays in some cases and the need for diagnostic endoscopic sinus surgery in others. We recommend MRI incorporation into the diagnostic pathway for patients with UMSO.

Prognosis of Distant Metastatic Sites in Anterior Skull Base Malignancies

Objective This study aimed to provide information regarding the prognosis of patients presenting with metastatic anterior skull base malignancies based upon histology and site of distant metastasis (DM).

Patients and Methods The National Cancer Database was queried for patients with anterior skull base malignant neoplasms with DM.

Outcomes Prognosis was compared between site of DM and tumor histologies. A multivariable Cox proportional hazards model was used to identify prognostic factors for overall survival (OS).

Results A total of 481 patients were identified. Lung was the most common site of DM (24.9%), followed by bone (22.2%), liver (5.6%), and brain (2.5%). Lung was the most common site for squamous cell carcinoma (SCCa) (28.3%), melanoma (37.7%), and adenoid cystic carcinoma (ACC; 31.4%). The median survival for patients presenting with metastatic disease regardless of tumor histology was 9.0 months (95% confidence interval [CI]: 8.2–10.3), and patients with metastasis to the liver had the best median survival at 15.5 months (95% CI: 10.5–25.6). The median survivals for the most common histologies, SCCa, melanoma, and ACC were 8.2 months (95% CI: 5.5–10.2), 10.5 months (95% CI: 8.7–14.1), and 15.0 months (95% CI: 11.1–61.1), respectively. Multivariable analysis demonstrated worse overall survival (OS) for older patients, higher Charlson-Deyo comorbidity scores, and tumors with higher grade and T stage. Compared with metastasis to bone, lung metastasis had better OS on multivariable analysis (hazard ratio [HR]: 0.70, 95% CI: 0.51–97). Adenoid cystic carcinoma had improved OS compared with SCCa (HR: 0.62, 95% CI: 0.39–99).

Conclusion Tumor histology, metastatic sites, and several disease factors affected prognosis in anterior skull base malignancies with DM.

Self-Made Rapid Prototyping Technique for Orbital Floor Reconstruction: Showcases for Technical Description

BACKGROUND

Restoring the orbital cavity integrity in orbital floor defects is a challenging issue due to the anatomical complexity of the floor's surface. This is a showcase for technical description of a novel "in house" rapid prototyping protocol aimed to customize implant for orbital floor reconstruction.

METHODS

The authors present 4 cases to show our Computer-aided-design and Computer-aided-manufacturing digital workflow. The system was based on a 3D-printed press that; through a virtually designed mold, was used to conform a patient specific titanium mesh for orbital floor reconstruction.

RESULTS

The merging procedure analysis by iPlan Cranial 3.0 (Brainlab, Munich, Germany) highlighted a 0.71 ± 0.23 mm (P <0.05) discrepancy in a point-to-point superimposition between the digital planned reconstruction and the real in vivo result.

CONCLUSIONS

The authors expect that this technique will reduce operative time and cost however further study and larger series may better define the applicability in everyday surgical practice.

Clinical assessment, diagnosis and management of patients with unilateral sinonasal disease

OBJECTIVES

Unilateral sinonasal disease is commonly encountered in practice and represents an issue of major concern since neoplasms may mimic inflammatory conditions. This paper aims to describe the demographic, clinical and radiological patterns of unilateral pathologies and, accordingly, to establish a guiding algorithm for diagnosis and management.

MATERIAL AND METHODS

We conducted a retrospective review of medical records of patients with unilateral sinus opacification on CT scan who underwent endoscopic nasal surgery in our department from January 2011 to December 2017.

RESULTS

Of the 150 patients included, 97(64.7%) and 53(35.3%) had inflammatory and neoplastic pathology, respectively. In the neoplastic group, malignancy was present in 35% of patients. Neoplastic conditions were more common in males (p=0.02) and older patients (56±18 years vs. 38±18, p<.01). Nasal mass or polyp was observed in 56.7% patients. Chronic sinusitis was the most prevalent inflammatory condition, whereas inverted papilloma and osteoma were the most frequent neoplasms. Facial neuralgia, paraesthesia, epistaxis and, on CT scan, superior Lund-Mackay scores, bone remodelling and erosion were significantly more common in neoplastic conditions. Excellent agreement between punch biopsy and postoperative histological results was obtained (k=.883, p<.001).

CONCLUSION

A sequential and careful management of unilateral lesions is mandatory. Based on our experience, we propose that, as routine, physical examination should be complemented with nasal endoscopy, CT scan and punch biopsy, in case of visible mass. Although clinical and radiological information might raise suspicion of some conditions, final diagnosis can only be established with histological examination of the surgical specimen.

Pyogenic granuloma gravidarum: a case in the nasal cavity and the use of MRI as a preoperative surgical aide

Pyogenic granuloma gravidarum is a benign fibrovascular proliferative lesion usually involving the oral gingivae in pregnant patients. While it also occurs, although less frequently, on other oral sites such as lips, tongue and palate, it is relatively unusual to find it in the nasal cavity. Furthermore, lesions normally involute spontaneously after childbirth. For persistent lesions requiring surgical management, imaging has historically been limited to CT. This case is notable not only for its uncommon location but also for its recurrent nature, failure to regress post partum and the use of MRI in the preoperative planning.

Imaging review of the anterior skull base

The anterior skull base (ASB) is intimately associated with the unique soft tissue subtypes of the nasal cavity, paranasal sinuses, orbits, and intracranial compartment. Pathology involving the ASB is rare but the causes are manifold and can be broadly subdivided into those intrinsic to the skull base and processes extending from below or above. Sinonasal pathology is the most commonly encountered and poses significant management challenges that rely heavily on accurate interpretation of the radiological findings. We illustrate the normal anatomy of the ASB and present a cross-sectional imaging review of the pathological entities that may be encountered, focusing on the specific features that will impact on clinical and surgical management.

Optimized imaging of the midface and orbits

A variety of imaging techniques are available for imaging the midface and orbits. This review article describes the different imaging techniques based on the recent literature and discusses their impact on clinical routine imaging. Imaging protocols are presented for different diseases and the different imaging modalities.

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 Approach to Sinonasal Neoplasms

The neoplastic lesions that can be found in the sinonasal space are numerous and varied. This article describes a general approach to narrowing down the differential diagnosis and provides the treating physician sufficient information to choose and deliver the best treatment modality. Computed tomography and MR imaging together provide complete radiologic assessment of sinonasal neoplasms.

Sinonasal Tumors: Computed Tomography and MR Imaging Features

This article describes the computed tomography and MR imaging features of the neoplasms of the sinonasal space. Although a pathologic diagnosis may not always be possible, knowledge of the features may help in narrowing down the differentials and establishing a malignant pathology.

The usefulness of preoperative biopsy in unilateral nasal masses

Unilateral nasal masses are considered suspicious for proliferative diseases. Several tools are routinely used to investigate unilateral lesions such as imaging and nasal biopsy. This study investigated the usefulness of nasal biopsy in predicting the actual nature of unilateral lesions. Preoperative nasal biopsy pathological results were compared with the final pathology obtained during an operation. Forty-six patients with unilateral nasal masses were included in the study group. In 40 patients the final pathology was similar to the preoperative nasal biopsy. In three patients the biopsy specimen was a benign polyp and the final pathology was of an inverted papilloma in two patients and hemangiopericytoma in one patient. In two patients the biopsy specimen was suspicious for an inverted papilloma and the final pathology was a benign polyp. In one patient the biopsy specimen was chordoma and the final pathology was osteosarcoma. The total agreement was 86.9%. The kappa value was 81.2%. Preoperative nasal biopsy is important and useful in evaluating unilateral nasal masses.

A whiff of trouble: tumours of the nasal cavity and their mimics

A range of disease entities can affect the nasal cavity, often presenting with variable and non-specific symptoms. There is considerable overlap between the clinical and radiological features of neoplastic and non-neoplastic entities. The nasal cavity is often included in routine imaging of the brain, middle ear, skull base, and paranasal sinuses and should be included as a critical review area. The definitive diagnosis is in most cases confirmed by histopathological analysis. However, this review highlights the role of imaging in identifying nasal cavity disease, eliciting features of aggressive or indolent behaviour, and helping to narrow the differential diagnosis, thus facilitating a systematic approach when reviewing the nasal cavity.

Clinico-pathological profile of sinonasal masses: An experience in tertiary care hospital of Uttarakhand

Background:

The purpose of this study was to classify various types of non-neoplastic and neoplastic lesions presenting as sinonasal mass and characterize their clinico-pathological profile in a tertiary care center in the state of Uttarakhand.

Materials and Methods:

This was a prospective study where 110 cases of sinonasal masses were included over a period of 12 months. Clinico-pathological study was carried out in these cases. A provisional diagnosis was made after clinical assessment and radiologic investigations, but final diagnosis was made after histopathologic examination.

Observations:

The number of non-neoplastic lesions were more than the neoplastic lesion, 60% versus 40% respectively. In the neoplastic group, 19.8% and 23.76% patients presented with benign and malignant lesion, respectively. The incidence was more predominant in the age group of 11-20 years (22.72%) with male to female ratio of 1.08:1. In our study, among non-neoplastic lesions the occurrence of sinonasal polyps was highest seen in 80.30% cases. In neoplastic lesions, angiofibroma was most common benign lesion seen in 35% cases. Carcinoma nasal cavity was the commonest malignant lesion seen in 45.83% cases. In 3.63% patients, clinical and radiologic diagnosis was not correlated with histopathologic diagnosis. Only two cases required immuno-histocytochemistry to confirm the final diagnosis.

Conclusion:

We concluded that for proper evaluation of a sinonasal mass, clinical, radiologic, and histopathologic evaluation should be carried out conjointly in all the cases. Histopathology always gives a confirmatory diagnosis but in few cases immuno-histocytochemistry becomes the ultimate diagnostic technique for correct and timely intervention.

Evidence-based practice: endoscopic skull base resection for malignancy

Successful outcomes of endoscopic approaches to benign sinonasal tumors have launched interest in expanding its use for sinonasal malignancy. Because of the heterogeneity and rarity of sinonasal malignancy, evidence for clinical outcomes of endoscopic approaches versus traditional craniofacial resection is low. Using the Oxford Center for Evidence-based Medicine guidelines, we present the existing evidence comparing both techniques for a variety of sinonasal malignancies.

Imaging and resectability issues of sinonasal tumors

Sinonasal tumors can invade into the critical structures of the anterior and central skull base. Although the determination of precise tumor histology is difficult with imaging, radiology is important in helping differentiate malignant from benign disease. Imaging helps to map the anatomical extent of intracranial and intraorbital tumor, which has important implications for staging, treatment and prognosis. Imaging also helps to facilitate and plan for craniofacial or endoscopic surgical approaches and radiation planning. This paper will review the locoregional invasion patterns for sinonasal tumors, with emphasis on their imaging features. The authors will discuss the implications for staging, resection potential, choice and details of radiotherapy with or without chemotherapy and prognosis. The imaging assessment of structures and compartments that are critical to the skull base team are highlighted: orbit, cavernous sinus, anterior cranial fossa dura/intracranial tumor, lateral frontal sinus, vascular tumor encasement, perineural tumor spread and tumor effect on the surrounding bony structures.

Intracranial metastases: spectrum of MR imaging findings

Intracranial metastatic lesions arise through a number of routes. Therefore, they can involve any part of the central nervous system and their imaging appearances vary. Magnetic resonance imaging (MRI) plays a key role in lesion detection, lesion delineation, and differentiation of metastases from other intracranial disease processes. This article is a reasoned pictorial review illustrating the many faces of intracranial metastatic lesions based on the location - intra-axial metastases, calvarial metastases, dural metastases, leptomeningeal metastases, secondary invasion of the meninges by metastatic disease involving the calvarium and skull base, direct or perineural intracranial extension of head and neck neoplasm, and other unusual manifestations of intracranial metastases. We also review the role of advanced MRI to distinguish metastases from high-grade gliomas, tumor-mimicking lesions such as brain abscesses, and delayed post-radiation changes in radiosurgically treated patients.

Aggressive inflammatory and neoplastic processes of the paranasal sinuses

Although uncommon, sinonasal malignancies and aggressive inflammatory processes are entities every radiologist will encounter during the evaluation of routine sinus imaging studies. A high index of suspicion is necessary for prompt diagnosis. It is important to consider aggressive inflammatory disease in all patients having routine sinus computed tomography because any delay in diagnosis can adversely affect the patients' care. Magnetic resonance (MR) will often provide a better assessment of the lesion extent, allowing for better surgical treatment. MR is crucial for the accurate assessment of neoplastic lesions. A proficient understanding of the complex anatomy of the region is essential.

Preliminary study on the evaluation of olfactory neuroblastoma using PET/CT

PURPOSE

Because of paucity of data available regarding the utility of PET/CT in the diagnosis and staging of patients with olfactory neuroblastoma (ONB), we retrospectively analyzed the efficacy of PET/CT in 9 patients with ONB.

MATERIALS AND METHODS

Whole-body F-18 FDG PET/CT was performed in 7 patients with newly diagnosed ONB, as well as in 1 patient with recurrence and in 1 patient with remnant tumor. Regional C-11 choline (C-11 CHO) PET/CT was performed in 2 patients with negative F-18 FDG scans. The lesion with intense radiotracer uptake was suggested as positive for tumor and the results of PET/CT were compared with conventional staging examinations.

RESULTS

F-18 FDG PET/CT was positive in 7/9 (77.7%) patients with ONB. In 2 patients with negative F-18 FDG, the lesions were C-11CHO avid. Both the primary tumors and its invasions were clearly delineated by F-18 FDG or C-11 CHO PET/CT. SUVmax of F-18 FDG in the primary tumor was 6.37 ± 4.22 and did not correlate with lesion size (F-18 FDG/size: r = 0.097, P = 0.820). Whole-body F-18 FDG PET/CT detected parapharyngeal and cervical lymph node metastases in 2 patients, lung metastases in 1 patient, liver metastases in 1 patients, and bone metastases in 2 patients. PET/CT altered the stages of 3 of 9 patients with upstaging in 2 patients and downstaging in 1 patient.

CONCLUSIONS

PET/CT may be useful for the diagnosis and staging of ONB.

Complete unilateral maxillary sinus opacity in computed tomography

BACKGROUND/PURPOSE

Unilateral maxillary sinus opacity can be caused by many diseases, but an exact diagnosis is difficult to make. The aim of this study was to describe the pathological conditions and clinical features of patients with unilateral maxillary sinus opacity.

METHODS

From 2004 to 2008, 830 consecutive patients underwent sinus surgery or endonasal endoscopic biopsy at an academic tertiary care center. The preoperative computed tomography (CT) images for these patients were reviewed, and 11 6 patients were identified with complete unilateral maxillary sinus opacification. We then analyzed presenting symptoms, physical examinations, specific CT findings, and pathology.

RESULTS

The most frequent diagnoses were as follows: chronic rhinosinusitis (52.6%), fungus ball (29.3%), antrochoanal polyp (2.6%), benign tumor (10.4%), and malignancy (5.1%). Fungus ball was the most common diagnosis (10/18, 55.6%) in the subgroup of patients with isolated maxillary sinus opacity without disease in the other sinuses. Nasal discharge and foul-smelling breath were more common in inflammatory disease than in neoplastic disease. Neoplastic disease was more likely to present as epistaxis; a polyp or mass revealed by nasal endoscopy; mass effect in the cheek, palate, or gingiva; and bony erosion on CT. Erosion of the maxillary posterolateral wall and extra-sinus extension suggested malignancy.

CONCLUSION

Although unilateral maxillary sinus opacity is usually inflammatory in origin, fungal sinusitis and neoplastic disorder are also likely. A careful history-taking, a thorough head and neck examination including nasal endoscopy, and CT evaluation are all imperative for reaching a correct diagnosis.