Non-Hodgkin's lymphoma of the nasopharynx: CT and MR imaging

A nodular type of mantle cell lymphoma in the nasopharynx

Mantle cell lymphoma (MCL) is a subtype of B-cell lymphoma derived from CD5-positive antigen-naïve pre-germinal center B-cells within the mantle zone that surrounds normal germinal center follicles. MCL comprises approximately 5 to 10% of all lymphomas. Tonsil is the most common location of MCL in the head and neck region, followed by the nasopharynx. Primary MCL involving the nasopharynx is extremely rare. Its clinical course is very aggressive with frequent relapses after conventional chemotherapy. It always presents as a protruding mass on the mucosal lining of the pharyngeal cavity. Here, we report a new nodular type of MCL in the nasopharynx. Endoscopically, this case showed multiple nodular lesions of primary MCL on the nasopharyngeal mucosa. This unique finding has not been reported yet in the English literature. These lesions should be differentiated from simple pharyngeal infections or benign lymphoid hyperplasia in the nasopharynx.

Synthetic MRI and diffusion-weighted imaging for differentiating nasopharyngeal lymphoma from nasopharyngeal carcinoma: combination with morphological features

OBJECTIVES

To investigate the feasibility of synthetic MRI (syMRI), diffusion-weighted imaging (DWI), and their combination with morphological features for differentiating nasopharyngeal lymphoma (NPL) from nasopharyngeal carcinoma (NPC).

METHODS

Sixty-nine patients with nasopharyngeal tumours (NPL, n = 22; NPC, n = 47) who underwent syMRI and DWI were retrospectively enrolled between October 2020 and May 2022. syMRI and DWI quantitative parameters (T1, T2, PD, ADC) and morphological features were obtained. Diagnostic performance was assessed by independent sample t-test, chi-square test, logistic regression analysis, receiver operating characteristic curve (ROC), and DeLong test.

RESULTS

NPL has significantly lower T2, PD, and ADC values compared to NPC (all P < .05), whereas no significant difference was found in T1 value between these two entities (P > .05). The morphological features of tumour type, skull-base involvement, Waldeyer ring involvement, and lymph nodes involvement region were significantly different between NPL and NPC (all P < .05). The syMRI (T2 + PD) model has better diagnostic efficacy, with AUC, sensitivity, specificity, and accuracy of 0.875, 77.27%, 89.36%, and 85.51%. Compared with syMRI model, syMRI + Morph (PD + Waldeyer ring involvement + lymph nodes involvement region), syMRI + DWI (T2 + PD + ADC), and syMRI + DWI + Morph (PD + ADC + skull-base involvement + Waldeyer ring involvement) models can further improve the diagnostic efficiency (all P < .05). Furthermore, syMRI + DWI + Morph model has excellent diagnostic performance, with AUC, sensitivity, specificity, and accuracy of 0.986, 95.47%, 97.87%, and 97.10%, respectively.

CONCLUSION

syMRI and DWI quantitative parameters were helpful in discriminating NPL from NPC. syMRI + DWI + Morph model has the excellent diagnostic efficiency in differentiating these two entities.

ADVANCES IN KNOWLEDGE

syMRI + DWI + morphological feature method can differentiate NPL from NPC with excellent diagnostic performance.

Artificial intelligence for diagnosis and prognosis prediction of natural killer/T cell lymphoma using magnetic resonance imaging

Accurate diagnosis and prognosis prediction are conducive to early intervention and improvement of medical care for natural killer/T cell lymphoma (NKTCL). Artificial intelligence (AI)-based systems are developed based on nasopharynx magnetic resonance imaging. The diagnostic systems achieve areas under the curve of 0.905-0.960 in detecting malignant nasopharyngeal lesions and distinguishing NKTCL from nasopharyngeal carcinoma in independent validation datasets. In comparison to human radiologists, the diagnostic systems show higher accuracies than resident radiologists and comparable ones to senior radiologists. The prognostic system shows promising performance in predicting survival outcomes of NKTCL and outperforms several clinical models. For patients with early-stage NKTCL, only the high-risk group benefits from early radiotherapy (hazard ratio = 0.414 vs. late radiotherapy; 95% confidence interval, 0.190-0.900, p = 0.022), while progression-free survival does not differ in the low-risk group. In conclusion, AI-based systems show potential in assisting accurate diagnosis and prognosis prediction and may contribute to therapeutic optimization for NKTCL.

Diagnosis of skull-base invasion by nasopharyngeal tumors on CT with a deep-learning approach

PURPOSE

To develop a convolutional neural network (CNN) model to diagnose skull-base invasion by nasopharyngeal malignancies in CT images and evaluate the model's diagnostic performance.

MATERIALS AND METHODS

We divided 100 malignant nasopharyngeal tumor lesions into a training (n = 70) and a test (n = 30) dataset. Two head/neck radiologists reviewed CT and MRI images and determined the positive/negative skull-base invasion status of each case (training dataset: 29 invasion-positive and 41 invasion-negative; test dataset: 13 invasion-positive and 17 invasion-negative). Preprocessing involved extracting continuous slices of the nasopharynx and clivus. The preprocessed training dataset was used for transfer learning with Residual Neural Networks 50 to create a diagnostic CNN model, which was then tested on the preprocessed test dataset to determine the invasion status and model performance. Original CT images from the test dataset were reviewed by a radiologist with extensive head/neck imaging experience (senior reader: SR) and another less-experienced radiologist (junior reader: JR). Gradient-weighted class activation maps (Grad-CAMs) were created to visualize the explainability of the invasion status classification.

RESULTS

The CNN model's diagnostic accuracy was 0.973, significantly higher than those of the two radiologists (SR: 0.838; JR: 0.595). Receiver operating characteristic curve analysis gave an area under the curve of 0.953 for the CNN model (versus 0.832 and 0.617 for SR and JR; both p < 0.05). The Grad-CAMs suggested that the invasion-negative cases were present predominantly in bone marrow, while the invasion-positive cases exhibited osteosclerosis and nasopharyngeal masses.

CONCLUSIONS

This CNN technique would be useful for CT-based diagnosis of skull-base invasion by nasopharyngeal malignancies.

Nasopharyngeal Chordoma: A Case Report

Chordoma is a rare malignant neoplasm arising from remnants of primitive notochord. The most common location for chordoma is in the sacrum. This case presents a 10-year-old medically free male who came to the ENT clinic with the impression of adenoid hypertrophy. After further investigations, including imaging and biopsy, it was found to be a nasopharyngeal chordoma. Our aim, in this case, is to increase the suspension of differential diagnosis of nasopharyngeal masses other than adenoid hypertrophy. In addition, it highlights the importance of imaging in the evaluation of nasopharyngeal masses.

Image findings of anti-neutrophil cytoplasmic antibody-associated vasculitis involving the skull base

AIM

To investigate computed tomography (CT) and magnetic resonance imaging (MRI) features of skull bases involving anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV).

MATERIALS AND METHODS

A retrospective review was undertaken to identify an institutional historical cohort of 17 patients with confirmed AAV who underwent CT or MRI and had skull base involvement between 2002 and 2021. Two radiologists reviewed the extent and features of the lesions, bone changes, and other MRI findings.

RESULTS

A total of 17 patients (12 men; mean age ± standard deviation, 46.5 ± 17.1 years) were selected. AAV presented as infiltrative lesions with involvement at various sites. Most cases involved the paranasal sinuses (PNS; 88%, 15/17), nasopharynx (88%, 15/17), pterygopalatine fossa (82%, 14/17), and parapharyngeal space (82%, 14/17), frequently accompanied by mucosal irregularity of the PNS and nasopharynx (71%, 12/17). Central skull base and temporal bone involvement were seen in 53% (9/17) and 38% (6/16) of cases, respectively. On T1-weighted imaging (WI) and T2WI MRI, all lesions (15/15) showed predominant signal iso-intensity to grey matter.

CONCLUSIONS

Although radiological findings of AAV are non-specific and skull base involvement is less common, AAV may be considered if infiltrative lesions predominantly involving the PNS, nasopharynx, pterygopalatine fossa, and parapharyngeal space with combined bone changes of skull base are seen.

A CT-based radiomics nomogram for differentiation of squamous cell carcinoma and non-Hodgkin's lymphoma of the palatine tonsil

OBJECTIVES

Accurate preoperative differentiation between squamous cell carcinoma (SCC) and non-Hodgkin's lymphoma (NHL) in the palatine tonsil is crucial because of their different treatment. This study aimed to construct and validate a contrast-enhanced CT (CECT)-based radiomics nomogram for preoperative differentiation of SCC and NHL in the palatine tonsil.

METHODS

This study enrolled 135 patients with a pathological diagnosis of SCC or NHL from two clinical centers, who were divided into training (n = 94; SCC = 50, NHL = 44) and external validation sets (n = 41; SCC = 22, NHL = 19). A radiomics signature was constructed from radiomics features extracted from routine CECT images and a radiomics score (Rad-score) was calculated. A clinical model was established using demographic features and CT findings. The independent clinical factors and Rad-score were combined to construct a radiomics nomogram. Performance of the clinical model, radiomics signature, and nomogram was assessed using receiver operating characteristics analysis and decision curve analysis.

RESULTS

Eleven features were finally selected to construct the radiomics signature. The radiomics nomogram incorporating gender, mean CECT value, and radiomics signature showed better predictive value for differentiating SCC from NHL than the clinical model for training (AUC, 0.919 vs. 0.801, p = 0.004) and validation (AUC, 0.876 vs. 0.703, p = 0.029) sets. Decision curve analysis demonstrated that the radiomics nomogram was more clinically useful than the clinical model.

CONCLUSIONS

A CECT-based radiomics nomogram was constructed incorporating gender, mean CECT value, and radiomics signature. This nomogram showed favorable predictive efficacy for differentiating SCC from NHL in the palatine tonsil, and might be useful for clinical decision-making.

KEY POINTS

• Differential diagnosis between SCC and NHL in the palatine tonsil is difficult by conventional imaging modalities. • A radiomics nomogram integrated with the radiomics signature, gender, and mean contrast-enhanced CT value facilitates differentiation of SCC from NHL with improved diagnostic efficacy.

MR Imaging of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma is endemic in parts of the world such as southern China and Southeast Asia. It is predominantly an undifferentiated carcinoma with a strong genetic basis and a close association with the Epstein-Barr virus. The ability of MR imaging to depict the boundaries of the primary tumor and its relationship with the complex structures of the skull base makes it the technique of choice for imaging of this disease in the head and neck. This article describes the MR imaging findings pertinent to staging and management and a new role of MR imaging in early cancer detection, in addition to a brief discussion of differential diagnoses.

Extranodal Lymphomas: a pictorial review for CT and MRI classification

Extranodal lymphomas represent an extranodal location of both non-Hodgkin and Hodgkin lymphomas. This study aims to evaluate the role of CT and MRI in the assessment of relationships of extranodal lymphomas with surrounding tissues and in the characterization of the lesion. We selected and reviewed ten recent studies among the most recent ones present in literature exclusively about CT and MRI imaging of extranodal lymphomas. Contrast-enhanced computed tomography (CT) is usually the first-line imaging modality in the evaluation of extranodal lymphomas, according to Lugano classification. However, MRI has a crucial role thanks to the superior soft-tissue contrast resolution, particularly in the anatomical region as head and neck. (www.actabiomedica.it)

Differentiation between nasopharyngeal carcinoma and lymphoma at the primary site using whole-tumor histogram analysis of apparent diffusion coefficient maps

INTRODUCTION

To determine the value of whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating nasopharyngeal carcinoma (NPC) from lymphoma (NPL) at the primary site METHOD AND MATERIALS: One hundred forty-seven patients with nasopharyngeal tumors (89 NPCs and 38 NPLs) who had undergone magnetic resonance imaging (MRI) and diffusion-weighted imaging were retrospectively analyzed. ADC histogram-derived parameters were compared between the NPC and NPL groups by using the Mann-Whitney U test. Receiver operating characteristic (ROC) curves of the histogram parameters were plotted for diagnostic accuracy. Sensitivity and specificity were calculated for each histogram parameter.

RESULTS

In whole-tumor histogram analysis, the mean, median, and 10th and 25th percentiles of ADC were all significantly higher in NPC than NPL (P = 0.045, P = 0.035, P = 0.005, and P = 0.016, respectively). Uniformity was significantly higher in NPC than NPL (P = 0.001). Skewness was significantly lower in NPC than NPL (P = 0.039). For the conventional ROI-based method, ADC_mean values were significantly higher in NPC than in NPL (P = 0.009). The ROC curve analysis showed that uniformity yielded the largest area under the curve (AUC = 0.768) for differentiating NPC from NPL among all ADC metrics, followed by 10th percentiles of ADC (AUC = 0.725); sensitivity and specificity were 76.5% and 71.4%, respectively.

CONCLUSION

Whole-tumor histogram analysis of ADC maps could be helpful for differentiating NPC from NPL.

The utility of MRI histogram and texture analysis for the prediction of histological diagnosis in head and neck malignancies

BACKGROUND

To assess the utility of histogram and texture analysis of magnetic resonance (MR) fat-suppressed T2-weighted imaging (Fs-T2WI) for the prediction of histological diagnosis of head and neck squamous cell carcinoma (SCC) and malignant lymphoma (ML).

METHODS

The cases of 57 patients with SCC (45 well/moderately and 12 poorly differentiated SCC) and 10 patients with ML were retrospectively analyzed. Quantitative parameters with histogram features (relative mean signal, coefficient of variation, kurtosis and skewness) and gray-level co-occurrence matrix (GLCM) features (contrast, correlation, energy and homogeneity) were calculated using Fs-T2WI data with a manual tumor region of interest (ROI).

RESULTS

The following significantly different values were obtained for the total SCC versus ML groups: relative mean signal (3.65 ± 0.86 vs. 2.61 ± 0.49), contrast (72.9 ± 16.2 vs. 49.3 ± 8.7) and homogeneity (2.22 ± 0.25 × 10^- 1 vs. 2.53 ± 0.12 × 10^- 1). In the comparison of the SCC histological grades, the relative mean signal and contrast were significantly lower in the poorly differentiated SCC (2.89 ± 0.63, 56.2 ± 12.9) compared to the well/moderately SCC (3.85 ± 0.81, 77.5 ± 13.9). The homogeneity in poorly differentiated SCC (2.56 ± 0.15 × 10^- 1) was higher than that of the well/moderately SCC (2.1 ± 0.18 × 10^- 1).

CONCLUSIONS

Parameters obtained by histogram and texture analysis of Fs-T2WI may be useful for noninvasive prediction of histological type and grade in head and neck malignancy.

MRI of diffuse large B-cell non-Hodgkin's lymphoma of the head and neck: comparison of Waldeyer's ring and sinonasal lymphoma

To document the magnetic resonance imaging (MRI) features of diffuse large B-cell lymphoma (DLBCL) in Waldeyer's ring (WR) and the sinonasal (SN) region, and to identify any differences between lymphatic and extra-lymphatic DLBCLs, and predictors of disease beyond the neck. Primary, nodal, and multifocal sites on head and neck MRI were compared between 31 WR and 15 SN DLBCL, and between 27 patients with disease confined to the head and neck and 16 patients with disease beyond the neck, using logistic regression. Compared to SN, WR DLBCLs had significantly smaller primary tumour volumes (p = 0.009), less deep invasion (p = 0.001), and more nodal disease (p = 0.016). Tumour site (WR vs. SN) was an independent predictor of deep invasion (p = 0.007). Nodal and multifocal diseases were predictors of disease beyond the neck (p = 0.027 and 0.011, respectively). Lymphatic WR DLBCLs were less locally aggressive but had greater propensity to nodal spread than extra-lymphatic SN DLBCLs. Nodal and multifocal diseases predicted disease beyond the neck.

Preliminary study of diffusion-weighted imaging and magnetic resonance spectroscopy imaging in Kimura disease

In this study, we evaluated the value of diffusion-weighted imaging (DWI) and magnetic resonance (MR) spectroscopy imaging (MRSI) combined with computed tomography (CT) and conventional MR imaging (MRI) in the diagnosis of Kimura disease (KD). The clinical data and CT and MRI findings of 5 patients with KD proven by histopathologic examination were retrospectively reviewed. Diffusion-weighted imaging and MRSI were performed at 1.5 T in 3 patients with KD. Apparent diffusion coefficient (ADC) values and the choline/creatine ratio of the lesions were compared with those of the contralateral normal parotid glands. All imaging results were compared with histopathologic findings. The typical features of KD were subcutaneous lesions, continuously infiltrative parotid lesions with or without intraparotid lymphadenopathies, and reactive cervical lymphadenopathies on CT and conventional MRI. On DWI, the ADC values of all subcutaneous and infiltrative parotid lesions were higher compared to those of normal parotid glands, and the ADC values of reactive lymphadenopathies were lower compared to both. The choline/creatine levels of subcutaneous and infiltrative parotid lesions were slightly higher than those of normal parotid glands. In conclusion, DWI and MRSI offer valuable information that may be characteristic of KD, which can highly suggest the diagnosis of KD when combined with morphological imaging.

Prognostic CT and MR imaging features in patients with untreated extranodal non-Hodgkin lymphoma of the head and neck region

OBJECTIVE

To determine the prognostic CT and MR imaging features of extranodal non-Hodgkin lymphoma in the head and neck region.

METHODS

The clinical data and CT and MR imaging features of 59 patients with histologically confirmed extranodal non-Hodgkin lymphoma in the head and neck region were retrospectively reviewed. Subjects included 27 male and 32 female patients between 13 and 81 years of age, with a mean age of 60.3 years. The clinical outcomes were categorized according to whether relapse or metastasis occurred within 2 years after therapy. The association between the clinical outcome and radiologic factors including tumour size, margin, shape, local tumour invasiveness, regional lymph node involvement, number of involvement sites, and contrast enhancement patterns was determined using univariate and multiple logistic regression analysis.

RESULTS

Radiologic factors including tumour size, margin, shape, and local tumour invasiveness were associated with poor clinical outcomes, as determined by univariate analysis (P < 0.05). Only the lesion margin category (ill-defined) remained an independent risk factor for clinical outcome in multivariate logistic regression analysis, with an OR of 8.14 (P < 0.05).

CONCLUSION

Ill-defined margin of the primary lesion was indicative of unfavourable survival outcome for patients with extranodal non-Hodgkin lymphoma of the head and neck region.

KEY POINTS

• Tumour size, margin, shape and local tumour invasiveness were prognostically relevant. • Tumour margin was an independent risk factor for clinical outcome. • Ill-defined margin of primary lesion was indicative of unfavourable survival outcome.

Primary extranodal non-hodgkin lymphoma of the head and neck in patients with acquired immunodeficiency syndrome: a clinicopathologic study of 24 patients in a single hospital of infectious diseases in Argentina

Introduction Extranodal non-Hodgkin lymphomas (NHLs) are commonly described in patients with acquired immunodeficiency syndrome (AIDS) and are related with an atypical morphology and aggressive clinical course. AIDS-associated lymphomas are characterized by their rapid progression, frequent extranodal manifestations, and poor outcome. Objective The aim of this article is to remake the clinical features of head and neck (HN) NHL in patients with AIDS to facilitate early diagnosis and treatment. Methods We evaluated the epidemiologic, clinical, immunologic, virologic, and histopathologic characteristics of 24 patients with human immunodeficiency virus (HIV)/AIDS with primary HN NHL treated at a single institution between 2002 and 2012. Histopathologic diagnosis was made according to the criteria of the World Health Organization Classification of Tumors of Hematopoietic and Lymphoid Tissues. Additional immunohistochemical stains were applied in all cases. Results Eighteen patients (75%) were men and the median of age was 39 years. The gingiva and the hard palate were the most common sites of the lesions (15 patients, 62.5%). Lactate dehydrogenase levels were elevated in 16 cases (84%). Bone marrow infiltration was detected only in 4 cases (16.6%). The median CD4 T-cell count was 100 cells/µL. According to the histopathologic evaluation, the most common subtype was diffuse large B-cell lymphoma (12 cases, 50%), followed by plasmablastic lymphoma (9 cases, 37.5%) and Burkitt lymphoma (3 cases, 12.5%). Conclusion HN NHL is a severe complication of advanced HIV/AIDS disease. Early diagnosis followed by chemotherapy plus highly active antiretroviral treatment is necessary to improve the prognosis and the survival of these patients.

Central nervous system and head and neck imaging findings of MYC/BCL2 "double hit" B cell lymphoma

MYC/BCL2 double hit lymphoma (DHL) is a rare, recently recognised and highly aggressive subtype of non-Hodgkin lymphoma, with an affinity to involve the central nervous system and the head and neck either at initial presentation or during relapse. We present a case of 43-year-old woman with MYC/BCL2 DHL relapse in the nasopharynx with extensive spread to the neck, skull base, and the central nervous system. To our knowledge, this is the first reported case in the literature describing the MRI and CT scan findings and the profound pattern of disease involvement of this rare neoplasm.

Characteristics and prognostic factors for head and neck non-Hodgkin's lymphoma in Chinese patients

BACKGROUND AND OBJECTIVES

The head and neck region is the second most frequent anatomical site of extranodal lymphomas. These tumours affect many individuals worldwide, justifying epidemiological studies in different countries. This study evaluated the characteristics, treatments and prognostic factors for non-Hodgkin's lymphoma of the head and neck in Chinese patients.

METHOD

The clinical manifestations, clinicopathological characteristics, multidisciplinary treatment and prognostic factors for 102 patients with extranodal non-Hodgkin's lymphoma of the head and neck were analysed retrospectively.

RESULT

The tonsil was the most commonly involved primary site, followed by the nasal cavity. The most common histological subtype was diffuse large B-cell lymphoma, followed by natural killer T-cell lymphoma. Patients receiving a combination of rituximab and chemotherapy did better than those receiving chemotherapy alone. Prognosis was significantly associated with both International Prognostic Index and histological subtype; the former was especially strongly associated with poor survival.

CONCLUSION

In this group of Chinese patients, diffuse large B-cell lymphoma was the most common pathological subtype, but the incidence of T-cell lymphomas was higher than that reported in the USA. Combined rituximab and chemotherapy led to better outcomes than chemotherapy alone. Prognosis depended on both International Prognostic Index and histological subtype.

Magnetic resonance imaging (MRI) and dynamic MRI evaluation of extranodal non-Hodgkin lymphoma in oral and maxillofacial regions

OBJECTIVE

The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI), especially dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), in extranodal non-Hodgkin lymphoma (NHL) of oral and maxillofacial regions.

STUDY DESIGN

Thirteen cases with extranodal NHL were examined using MRI. T1-weighted images (T1WI) and T2-weighted images (T2WI) or short TI inversion recovery (STIR) images were obtained in all cases. Contrast-enhanced images and DCE-MRI were acquired in 10 and 7 cases, respectively. On DCE-MRIs, we analyzed the parameters as follows: contrast index at maximal contrast enhancement (CImax), maximum contrast index (CI) gain/CImax ratio, and washout ratios (WR(300), WR(600), and WR(900)) at 300, 600, and 900 seconds after contrast medium injection.

RESULTS

The signal intensity of all lesions was hypointense to isointense on T1WIs and showed variable contrast enhancement patterns. On T2WIs and STIR images, the signal intensity was isointense to hyperintense in almost all cases. Analysis of DCE-MRI parameters in extranodal NHLs resulted in the identification of 4 types of CI curves according to CImax and WR: (1) CImax greater than 2.0 and WR(900) greater than 40%, (2) CImax greater than 2.0 and WR(900) less than 40%, (3) CImax less than 1.5 and WR(900) greater than 40%, and (4) CImax less than 1.5 and WR(900) greater than 40%.

CONCLUSIONS

The signal intensities on MRI were not specific to extranodal NHL and resembled those of other tumor types. When CImax was less than 1.5 or WR900 was less than 40%, these parameters contributed to diagnosis in extranodal NHLs.

Immunoglobulin G4-related sclerosing disease mimicking invasive tumor in the nasal cavity and paranasal sinuses

IgG4RSD affecting the nasal cavity and paranasal sinuses is extremely rare. A 71-year-old man presented with an invasive mass in the nasal cavity and paranasal sinuses that was confirmed by immunostaining to be IgG4RSD. The occurrence of this disease in the nasal cavity and paranasal sinuses can resemble a malignant tumor on diagnostic imaging.

Differential Diagnosis of Primary Nasopharyngeal Lymphoma and Nasopharyngeal Carcinoma Focusing on CT, MRI, and PET/CT

Objective. No study has done a comparative analysis of radiologic imaging findings between primary nasopharyngeal lymphoma (PNL) and nasopharyngeal carcinoma (NPC). The purpose of this study was to analyze computed tomography (CT) and magnetic resonance (MR) images and to evaluate the maximum standardized uptake value (SUV max) of positron emission tomography (PET)/CT between PNL and NPC, knowing the imaging features that distinguish PNL from NPC.

Study Design. Cross-sectional study.

Setting. University tertiary care facility.

Subjects and Methods. The authors analyzed the features on CT, MR imaging, and PET/CT of 16 patients diagnosed with PNL and 32 patients diagnosed with NPC histopathologically.

Results. Patients with PNL had a larger tumor volume and showed symmetry of tumor shape than did patients with NPC. Patients with PNL also had higher tumor homogeneity than NPC patients on CT, T2-weighted, and postcontrast MR images. All PNL patients showed a high degree of enhancement without invasion to the adjacent deep structure. The involvement of the Waldeyer ring was significantly higher in PNL patients. Cervical and retropharyngeal lymphadenopathy and PET/CT SUV max showed no significant difference between PNL and NPC.

Conclusions. If the images present a bulky, symmetric nasopharyngeal mass with marked homogeneity, a high degree of enhancement, and a higher Waldeyer ring involvement combined with no invasion into the deep structure, PNL should be considered over NPC.

Non-Hodgkin lymphoma with hemorrhagic necrosis of the nasopharynx mimicking an abscess

Radiologic feature of primary nasopharyngeal lymphoma is a predominantly homogenous, nonnecrotic large tumor with no or minimal deep tissue invasion. To the best knowledge, nasopharyngeal lymphoma has not been presented with hemorrhagic necrosis. Thus, we report 2 cases of nasopharyngeal lymphoma with hemorrhagic necrosis mimicking an abscess. The patients had bleeding diathesis such as aplastic anemia or idiopathic portal hypertension.

Nasopharyngeal adenoid cystic carcinoma: magnetic resonance imaging features in ten cases

Nasopharyngeal adenoid cystic carcinoma (NACC) is a rare malignancy with high local invasiveness. To date, there is no consensus on the imaging characteristics of NACC. To address this, we retrospectively reviewed 10 cases of NACC and summarized the magnetic resonance imaging (MRI) features. MR images of 10 patients with histologically validated NACC were reviewed by two experienced radiologists. The location, shape, margin, signal intensity, lesion texture, contrast enhancement patterns, local invasion, and cervical lymphadenopathy of all tumors were evaluated. Clinical and pathologic records were also reviewed. No patients were positive for antibodies against Epstein-Barr virus (EBV). The imaging patterns of primary tumors were classified into two types as determined by location, shape, and margin. Of all patients, 7 had tumors with a type 1 imaging pattern and 3 had tumors with a type 2 imaging pattern. The 4 tubular NACCs were all homogeneous tumors, whereas 3 (60%) of 5 cribriform NACCs and the sole solid NACC were heterogeneous tumors with separations or central necrosis on MR images. Five patients had perineural infiltration and intracranial involvement, and only 2 had cervical lymphadenopathy. Based on these results, we conclude that NACC is a local, aggressive neoplasm that is often negative for EBV infection and associated with a low incidence of cervical lymphadenopathy. Furthermore, MRI features of NACC vary in locations and histological subtypes.

Head and neck MRI of Kimura disease

OBJECTIVES

The purpose of our study was to describe the MR appearance of Kimura disease and to interpret the differences in appearance from malignant parotid gland tumours.

METHODS

MR studies of seven patients with Kimura disease were reviewed. The MR studies included T(1) weighted, T(2) weighted, short tau inversion-recovery, diffusion-weighted (DW) and dynamic contrast-enhanced imaging.

RESULTS

Typical Kimura disease featured subcutaneous lesions, continuously infiltrated parotid lesions from the subcutaneous lesions with or without intraparotid lymphadenopathies, and reactive cervical lymphadenopathies. The subcutaneous lesions showed gradual upward enhancement on dynamic contrast-enhanced MR images. Reactive lymph nodes showed early enhancement on contrast-enhanced MR images and marked high intensity and low apparent diffusion coefficient values on DW images.

CONCLUSION

An indication for making the diagnosis of Kimura disease should be the subcutaneous tissue of the head and neck showing gradual upward enhancement on dynamic contrast-enhanced MRI and a lack of high intensity on DW images, associated with reactive lymph nodes.

Magnetic resonance imaging features of nasopharyngeal carcinoma and nasopharyngeal non-Hodgkin's lymphoma: are there differences?

PURPOSE

To describe differences in the primary tumour and distribution of cervical lymphadenopathy for cases of nasopharyngeal carcinoma (NPC) and nasopharyngeal non-Hodgkin's lymphoma (NPNHL) using magnetic resonance (MR) imaging.

MATERIALS AND METHODS

MR images of patients with NPC (n = 272) and NPNHL (n = 118) were independently reviewed by two experienced radiologists.

RESULTS

NPC had a higher incidence of tumour invasion associated with the levator and tensor muscles of the velum palatine, the longus colli and medial pterygoid muscles, the base of the pterygoid process, the clivus, the base and greater wing of the sphenoid bone, the petrous apex, the foramen lacerum, the foramen ovale, the hypoglossal canal, and intracranial infiltration. In contrast, NPNHL had a higher incidence of tumour invasion associated with the hypopharynx, the palatine and lingual tonsils, as well as the ethmoid and maxillary sinuses. NPNHL also had a higher incidence of extensive and irregular bilateral lymphadenopathy, and lymphadenopathy in the parotid.

CONCLUSIONS

NPC more often involved an unsymmetrical tumour with a propensity to invade both widely and deeply into muscle tissue, the fat space, the neural foramen, and the skull base bone. In contrast, NPNHL tended to be a symmetrical and diffuse tumour with a propensity to spread laterally through the fat space and along the mucosa to the tonsils of the oropharynx and hypopharynx. These differences facilitate a differentiation of these diseases using MR images, and enhance our understanding of the biological behavior of these malignant tumours of the nasopharynx.

Malignant lymphoma of the head and neck

Malignant lymphomas represent approximately 5% of all malignant neoplasms of the head and neck area. They are classically divided into two subgroups, Hodgkin's lymphomas (HLs) and non-Hodgkin's lymphomas (NHLs). We describe the clinical characteristics of head and neck lymphomas and the methods to establish the diagnosis. The World Health Organization classification of lymphoid tissues describes more than 50 different histological types, and we analyse the most common staging system for lymphomas, the Ann Arbor staging system. Finally, the different therapeutic approaches are discussed.

[Radiological diagnosis of the paranasal sinuses]

Although diseases of the paranasal sinuses have a relatively homogeneous clinical presentation, their causes can vary considerably. Radiological imaging only became relevant in paranasal sinus diagnostics following the introduction of cross-sectional imaging. In addition to technical details on imaging procedures and the individual criteria of the different modalities, anatomic details and congenital variations are presented. Particularly in acute inflammatory diseases as well as traumatic lesions, imaging is essential in preoperative planning and postoperative control. The article gives a detailed description of options in radiologic imaging of the paranasal sinuses.

Head and neck non-Hodgkin's lymphoma: a 20-year demographic study of 381 cases

Malignant lymphoma is a lymphoreticular malignancy with considerable geographic variation. The objective of the present study was to provide a preliminary report on patients with head and neck non-Hodgkin's lymphoma (NHL) in a selected Iranian population. In a retrospective review from 1981 through 2001, all cases of NHL occurring in the head and neck region were selected. Histological slides were reviewed and classified according to the Working Formulation. Clinical data including patients' age, sex, initial anatomic site of disease and presenting symptoms were also recorded. Information on 381 cases of NHL was retrieved from the archived medical records; 281 cases were nodal and 100 extranodal. The mean age of the patients with nodal and extranodal disease was 39.3 and 47.7 years, respectively. A significant difference in gender was noted in the nodal group (P<0.001), but not in the extranodal cases. The most common site of involvement in the extranodal subjects was Waldayer's ring. According to histopathologic evaluation, 72% of the specimens were intermediate-, 14% were high-, and 12% were low-grade malignancies. Considering the relative frequency of head and neck lymphoma, establishment of a uniform reporting method seems necessary in order to compare different reports from various populations.

Extraosseous chordoma of the nasopharynx

BACKGROUND AND PURPOSE

Chordoma is a relatively rare tumor of the skull base and sacrum thought to originate from embryonic remnants of the notochord. Chordomas arising from the skull base/clivus are typically locally aggressive with lytic bone destruction. When chordomas occur in an extraosseous location, they may mimic other lesions of the nasopharynx. We present 5 cases of primarily extraosseous chordoma involving the nasopharynx in an effort to improve the preoperative diagnosis of this rare tumor. In addition, we review regional notochordal embryology to explain this variant tumor location.

MATERIALS AND METHODS

We reviewed the clinical and imaging data of 5 pathologically proved cases of extraosseous chordoma of the nasopharynx seen or reviewed at our institution during the last decade. All cases had both CT and MR imaging. The study had institutional review board approval.

RESULTS

The primary clinical complaint in the 5 patients with extraosseous nasopharyngeal chordoma was nasal obstruction. The extraosseous chordomas were centered in the nasopharynx. Bony lytic changes along the anterior surface of the clivus were seen on 5 of 5 CT studies. A midline sinus tract was seen in 3 of 5 patients. MR imaging showed heterogeneous hyperintense T2 signal intensity (5/5).

CONCLUSIONS

Extraosseous nasopharyngeal chordoma is a rare but important lesion to be considered in the differential diagnosis of nasopharyngeal masses. When a midline nasopharyngeal mass is found with an associated clival sinus tract, extraosseous chordoma moves to the top of the differential diagnosis list. Complete removal of the soft-tissue tumor and the clival sinus tract is the treatment of choice in such cases.

Imaging Hodgkin and non-Hodgkin lymphoma in the head and neck

Hodgkin (HL) and non-Hodgkin lymphoma (NHL) involving the head and neck have many overlapping imaging features. Definitive diagnosis depends on histology, but imaging trends may help distinguish lymphoma from other common pathologic entities in the head and neck. CT is useful for staging and assessing bony involvement, whereas MR imaging is performed for soft tissue detail in extranodal disease, especially when there is transpatial disease or intracranial or intraspinal extension. Positron emission tomography has become an important part of staging and surveillance imaging and is particularly useful to distinguish posttreatment fibrosis and residual tumor.

Fluorine-18 Fluorodeoxyglucose PET/CT Patterns of Extranodal Involvement in Patients with Non-Hodgkin Lymphoma and Hodgkin's Disease

Lymphoma may originate in extranodal sites. Extranodal lymphoma may also be secondary to and accompany nodal disease. Fluorine-18 fluorodeoxyglucose (18F-FDG) imaging has an essential role in the staging of lymphoma, in monitoring the response to therapy, and in detection of recurrence. The introduction of 18F-FDG PET/CT hybrid imaging allows for accurate localization of disease and may be specifically beneficial for the detection of unexpected extranodal sites of disease or exclusion of disease in the presence of nonspecific extranodal CT findings. Accurate staging and localization often dictate the appropriate treatment strategy in patients with lymphoma. Therefore, at any stage in the course of the disease, the potential presence of extranodal disease should be considered when interpreting 18F-FDG PET/CT studies in patients with non-Hodgkin lymphoma and Hodgkin's disease.

Lymphomes T/NK du nasopharynx

OBJECTIVE

Discussion of the clinical and paraclinical features of a rare tumor in the nasopharynx, the NK/T-cell lymphoma, with an emphasis on the implications of Epstein Barr Virus (EBV) in its pathogenesis and prognosis.

CASES REPORT

We report the cases of a woman and a man aged 34 and 48, respectively. Clinical presentation was non-specific and diagnosis was established with deep biopsies under general anesthesia. Immunochemistry and in situ hybridization were positive for Epstein Barr virus in tumor cells in both cases. The patients were first treated with chemotherapy (CHOP regimen), then underwent radiotherapy. The first patient achieved complete response at twenty months follow-up. The second patient presented two recurrences which were treated by chemotherapy. He died from acute renal failure during treatment of the second recurrence.

CONCLUSION

Diagnosis of NK/T-cell lymphoma may be delayed in the event of non-specific symptoms. Deep biopsies outside necrotic tissue must be obtained. Search for EBV is important as its presence is a factor of poor prognosis.

Primary lymphoma of the skull base

This case demonstrates the rare finding of a primary malignant lymphoma of the frontobasis and ethmoidal cells in a patient presenting with progressive loss of vision. Computed tomography and MRI demonstrated a homogenously enhancing tumour with extensive bony destructions of the skull base. After transsphenoidal biopsy, histology revealed a highly malignant primary B-cell lymphoma. The patient was further treated with immunochemotherapy. Tissue diagnosis is, therefore, crucial before a definitive therapy is instituted.

The skull base: tumoral lesions

Many lesions occur in the anterior, central and posterior skull base. In order to detect and characterise them, one has to apply the best imaging technique. Today MR is the preferred technique, and the use of CT is more and more restricted to evaluate the presence of calcifications and involvement of thin bony walls, foramina and fissures. However, MR is only superior when the right sequences and imaging planes are used. Many lesions can be characterised by their specific signal intensity on different sequences and by their location. Nevertheless some lesions can only be characterised after biopsy. The purpose of imaging in skull base tumours remains in the first place the evaluation of the exact tumour extent, and this is again best achieved with MR. In this paper the imaging technique and the most frequent skull base tumours are discussed.