The significance of necrotic mediastinal lymph nodes on CT in patients with newly diagnosed Hodgkin disease

CT-guided percutaneous transthoracic needle biopsy for anterior mediastinal lymphoma: the role of PET/CT

BACKGROUND

Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is not recommended as the diagnostic modality of choice for anterior mediastinal lymphoma, despite its advantages of minimal invasiveness and easy accessibility.

PURPOSE

To identify the modifiable risk factors for non-diagnostic results from CT-guided PTNB for anterior mediastinal lymphoma.

MATERIAL AND METHODS

This retrospective study identified CT-guided PTNB for anterior mediastinal lesions diagnosed as lymphoma between May 2007 and December 2021. The diagnostic sensitivity and complications were investigated. The appropriateness of PTNB targeting was evaluated using positron emission tomography (PET)/CT and images from intra-procedural CT-guided PTNB. Targeting was considered inappropriate when the supposed trajectory of the cutting needle was within a region of abnormally low metabolism. The risk factors for non-diagnostic results were determined using logistic regression analysis.

RESULTS

A total of 67 PTNBs in 60 patients were included. The diagnostic sensitivity for lymphoma was 76.1% (51/67), with an immediate complication rate of 4.5% (3/67). According to the PET/CT images, PTNB targeting was inappropriate in 10/14 (71.4%) of the non-diagnostic PTNBs but appropriate in all diagnostic PTNBs (P <0.001). Inappropriate targeting was the only significant risk factor for non-diagnostic results (odds ratio = 203.69; 95% confidence interval = 8.17-999.99; P = 0.001). The number of specimen acquisitions was not associated with non-diagnostic results (P = 0.40).

CONCLUSIONS

Only inappropriate targeting of the non-viable portion according to PET/CT was an independent risk factor for non-diagnostic results. Acquiring PET/CT scans before biopsy and targeting the viable portion on PET/CT may help improve the diagnostic sensitivity of PTNB.

Typical and Atypical Imaging Features of Malignant Lymphoma in the Abdomen and Mimicking Diseases

Malignant lymphoma typically presents with homogeneous enhancement of enlarged lymph nodes without internal necrotic or cystic changes on multiphasic CT, which can be suspected without invasive diagnostic methods. However, some subtypes of malignant lymphoma show atypical imaging features, which makes diagnosis challenging for radiologists. Moreover, there are several lymphoma-mimicking diseases in current clinical practice, including leukemia, viral infections in immunocompromised patients, and primary or metastatic cancer. The ability of diagnostic processes to distinguish malignant lymphoma from mimicking diseases is necessary to establish effective management strategies for initial radiological examinations. Therefore, this study aimed to discuss the typical and atypical imaging features of malignant lymphoma as well as mimicking diseases and discuss important diagnostic clues that can help narrow down the differential diagnosis.

[Lesions of the prevascular mediastinum]

CLINICAL/METHODOLOGICAL ISSUE

Mediastinal masses are a group of heterogenous lesions which may be a coincidental finding or present with symptoms. More than half of mediastinal lesions are located in the prevascular mediastinum. As these tumors are not often encountered in clinical routine, making a diagnosis with a high degree of confidence may seem challenging.

STANDARD RADIOLOGICAL METHODS

The latest computed tomography (CT)-based classification of the mediastinal compartments by the International Thymic Malignancy Interest Group (ITMIG) moves away from earlier radiograph-based classification systems and helps to reliably classify tumors based on location, although in some cases the lesion can occupy more than one compartment.

PERFORMANCE

Radiology plays an important role in the evaluation of anterior mediastinal lesions. Although in some cases imaging features alone allow a diagnosis to be made; in other cases knowledge of important radiological features and their analysis in the context of patient factors like age and duration of symptoms can help to narrow down the differential diagnosis, avoid unnecessary workup, and guide further steps.

PRACTICAL RECOMMENDATIONS

Computed tomography (CT) is central for the characterization of mediastinal masses in clinical routine. In some situations, like in the case of thymic cysts or thymic hyperplasia, magnetic resonance imaging (MRI) can be used as a noninvasive problem-solving tool.

MRI-Based Stepwise Approach to Anterior Mediastinal Cystic Lesions for Diagnosis and Further Management

As the majority of incidentally detected lesions in the anterior mediastinum is small nodules with soft tissue appearance, the differential diagnosis has typically included thymic neoplasm and prevascular lymph node, with benign cyst. Overestimation or misinterpretation of these lesions can lead to unnecessary surgery for ultimately benign conditions. nonsurgical anterior mediastinal lesions. The pitfalls of MRI evaluation for anterior mediastinal cystic lesions are as follows: first, we acknowledge the limitation of T2-weighted images for evaluating benign cystic lesions. Due to variable contents within benign cystic lesions, such as hemorrhage, T2 signal intensity may be variable. Second, owing to extensive necrosis and cystic changes, the T2 shine-through effect may be seen on diffusion-weighted images (DWI), and small solid portions might be missed on enhanced images. Therefore, both enhancement and DWI with apparent diffusion coefficient values should be considered. An algorithm will be suggested for the diagnostic evaluation of anterior mediastinal cystic lesions, and finally, a management strategy based on MRI features will be suggested.

Necrosis on pre-radiotherapy 18F-FDG PET/CT is a predictor for complete metabolic response in patients with non-small cell lung cancer

To investigate necrosis on pre-radiotherapy (RT) 18F-FDG PET/CT (PETNECROSİS) as a predictor of complete metabolic response (CMR) in patients with non-small cell lung cancer (NSCLC).We evaluated patients with inoperable stage I-III NSCLC who underwent pre- and post-radiotherapy 18F-FDG PET/CT. The relationship between CMR and PETNECROSIS, SUVmax, gross tumor volume calculated with 18F-FDG PET/CT (GTVPET-CT), tumor size, histology, metabolic tumor volume (MTV), and RT dose was assessed using logistic regression analysis. To evaluate necrosis on 18F FDG PET/CT, we drew a region of interest (ROI) in the area showing visually very low/or no fluorodeoxyglucose (FDG) uptake on PET images. If the SUVmax was lower than the blood pool SUVmax and showed significantly lower attenuation (10-30 Hounsfield units [HU]) from the surrounding tissue on non-intravenous contrast-enhanced low-dose correlative CT, we defined it as necrotic (PETNECROSİS).Fifty-three patients were included in this study. The mean age was 68.1 ± 9.8 years. Twenty-one patients had adenocarcinoma, and 32 had squamous cell carcinoma. All parameters were independent of histologic status. Multivariate logistic regression analysis showed that SUVmax ≤11.6 vs >11.6, (P = .003; OR, 7.670, 95CI%: 2.013-29.231) and PETNECROSİS absence/presence were independent predictors for CMR (P = .028, OR: 6.704, 95CI% 1.214-30.394).The necrosis on 18F FDG PET/CT and SUVmax > 11.6 could be an imaging marker for the complete metabolic response after definitive chemoradiotherapy or definitive RT alone in patients with NSCLC.

Patterns and Predictors of Failure in Recurrent or Refractory Large B-Cell Lymphomas following Chimeric Antigen Receptor (CAR) T-Cell Therapy

PURPOSE

Chimeric antigen receptor T-cell (CAR T) therapy is capable of eliciting durable responses in patients with relapsed/refractory (R/R) lymphomas. However, the majority of treated patients relapse. Patterns of failure following CAR T have not been previously characterized and may provide insights into the mechanisms of resistance guiding future treatment strategies.

METHODS AND MATERIALS

Retrospective analysis of R/R large B-cell lymphoma patients treated with anti-CD19 CAR T at an NCI-designated Comprehensive Cancer Center from 2015 to 2019. Pre- and post-treatment PET/CTs were analyzed to assess the progression of existing (local failures) versus new, non-overlapping lesions (de novo failures) and to identify lesions at high-risk for progression.

RESULTS

A total of 469 pretreatment lesions in 63 patients were identified. At a median follow-up of 12•6 months, 36 (57%) patients recurred. The majority (n=31, 86%) had a component of local failure with 13 (36%) patients exhibiting strictly local failures. Even at progression, 84% of recurrent patients continued to have a subset of pretreatment lesions maintain PET/CT resolution. Lesions at high-risk for local failure included those with a diameter ≥5cm (OR 2•34, 95%CI 1•55-3•55; p<0•001), an SUV_max≥10 (OR 2•08, 95%CI 1•38-3•12; p<0•001), or that were extranodal (OR 1.49, 95% CI 1.10-2.04; p=0.01). In the 69 patients eligible for survival analysis, those with any lesion ≥5cm (n=46, 67%) experienced inferior PFS (HR 2•41, 95%CI 1•15-5•04; p=0•02) and OS (HR 3•36, 95%CI 1•17-9•96; p=0•02).

CONCLUSION

The majority of patients who recur following CAR T experience a component of local progression. Furthermore, lesions with high-risk features, particularly large size, were associated with inferior treatment efficacy and patient survival. Taken together, these observations suggest that lesion-specific resistance may contribute to CAR T treatment failure. Locally-directed therapies to high-risk lesions, such as radiotherapy, may be a viable strategy to prevent CAR T failures in select patients.

Integrative Radiogenomics Approach for Risk Assessment of Post-Operative Metastasis in Pathological T1 Renal Cell Carcinoma: A Pilot Retrospective Cohort Study

Despite the increasing incidence of pathological stage T1 renal cell carcinoma (pT1 RCC), postoperative distant metastases develop in many surgically treated patients, causing death in certain cases. Therefore, this study aimed to create a radiomics model using imaging features from multiphase computed tomography (CT) to more accurately predict the postoperative metastasis of pT1 RCC and further investigate the possible link between radiomics parameters and gene expression profiles generated by whole transcriptome sequencing (WTS). Four radiomic features, including the minimum value of a histogram feature from inner regions of interest (ROIs) (INNER_Min_hist), the histogram of the energy feature from outer ROIs (OUTER_Energy_Hist), the maximum probability of gray-level co-occurrence matrix (GLCM) feature from inner ROIs (INNER_MaxProb_GLCM), and the ratio of voxels under 80 Hounsfield units (Hus) in the nephrographic phase of postcontrast CT (Under80HURatio), were detected to predict the postsurgical metastasis of patients with pathological stage T1 RCC, and the clinical outcomes of patients could be successfully stratified based on their radiomic risk scores. Furthermore, we identified heterogenous-trait-associated gene signatures correlated with these four radiomic features, which captured clinically relevant molecular pathways, tumor immune microenvironment, and potential treatment strategies. Our results of accurate surrogates using radiogenomics could lead to additional benefit from adjuvant therapy or postsurgical metastases in pT1 RCC.

Relationship between semiquantitative 18F-fluorodeoxyglucose positron emission tomography metrics and necrosis in classical Hodgkin lymphoma

Semiquantitative ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG PET) parameters have been proposed as prognostic markers in classical Hodgkin lymphoma (cHL). In non-Hodgkin lymphoma necrosis as assessed by ¹⁸F-FDG PET or computed tomography (CT) (necrosis^visual) correlates with an adverse prognosis. We investigated whether semiquantitative ¹⁸F-FDG PET metrics correlate with necrosis^visual, determined the incidence of necrosis^visual and explored the prognostic impact of these factors in cHL. From 87 cHL cases treated with ABVD, (escalated) BEACOPP or CHOP chemotherapy between 2010 and 2017, 71 had both a NEDPAS/EARL accredited ¹⁸F-FDG PET and a contrast enhanced CT scan. Semiquantitative ¹⁸F-FDG PET parameters were determined using Hermes Hybrid 3D software. Necrosis^visual, defined by photopenic tumor areas on ¹⁸F-FDG PET and attenuation values between 10 and 30 Hounsfield units (HUs) on CT, was assessed blinded to outcome. Univariate Cox regression survival analyses of progression free survival (PFS) were performed. Necrosis^visual was observed in 18.3% of cHL patients. Bulky disease (tumor mass >10 cm in any direction) (P = 0.002) and TLG (P = 0.041) but no other semiquantitative parameters were significantly associated with necrosis^visual. In exploratory univariate survival analysis for PFS the covariates IPS, bulky disease, MTV and TLG were prognostic, while necrosis^visual was not.

CT findings predict survival of patients with peripheral T cell lymphoma: a preliminary study

Background Peripheral T-cell lymphoma (PTCL) is an uncommon disease with poor clinical outcomes. Radiological reports on the survival of patients with PTCL are scarce. The purpose of this study is to investigate the prognostic value of CT findings to predict clinical outcomes in fifty-one patients with histologically proven PTCL. Patients and methods The clinical data and CT images of all patients were retrospectively reviewed. CT features including number of involvement sites, lesion size, shape, margin, density, peritumoral invasion, intratumoral necrosis, lymph node involvement, and degree of contrast enhancement were evaluated. Univariate and multiple logistic regression analysis were used to determine the association between the clinical outcome and radiologic factors. Results Multiple site involvement, an ill-defined margin with peritumoral invasion, inhomogeneous density, and intratumoral necrosis were found to be associated with poor outcomes in univariate analysis (P < 0.05). An ill-defined margin with peritumoral invasion, was identified as an independent risk sign by further multivariate logistic regression analysis (P < 0.05). The area under the ROC curve of this CT feature was 0.745 (P < 0.05). Conclusions An ill-defined margin with peritumoral invasion was a valuable prognostic factor to predict the worse clinical outcomes in patients with PTCL.

Anterior mediastinal Hodgkin lymphoma presenting as an extremely hypervascular tumor on computed tomography: A case report

RATIONALE

In the thorax, Hodgkin lymphoma (HL) most frequently involves the anterior mediastinal and paratracheal regions and tends to spread to contiguous nodal groups. Enlarged lymph nodes typically have homogeneous soft tissue attenuation similar to that of muscle tissue on computed tomography (CT).

PATIENT CONCERNS

A contrast-enhanced CT examination of a 19-year-old man with right-sided chest pain showed an intense, heterogeneously enhancing mass with organization of serpentine and dilated blood vessels in the right anterior mediastinum that had invaded the upper lobe of the right lung.

DIAGNOSES

Following a wedge resection, histopathological examination showed Reed-Sternberg cells that were positive for CD-15 and CD-30, which is typical of HL.

INTERVENTIONS

The patient was started treatment with 6 cycles of doxorubicin, bleomycin, vincristine, and dacarbazine (ABVD) regimen.

OUTCOMES

After chemotherapy, the patient had shown a partial response to the treatment.

LESSONS

This presentation of HL as an extremely hypervascular anterior mediastinal mass on CT imaging has not been previously reported in the literature. This case suggests that HL should be included in the differential diagnosis of a hypervascular anterior mediastinal mass, especially if the patient is a young adult.

CT imaging of primary pancreatic lymphoma: experience from three referral centres for pancreatic diseases

Purpose

To describe CT characteristics of primary pancreatic lymphoma (PPL), a rare disease with features in common with adenocarcinoma.

Materials and methods

Fourteen patients were enrolled. CT: unenhanced scan, contrast-enhanced pancreatic and venous phases. Image analysis: tumour location; peri-pancreatic vessel encasement; necrosis; enlarged lymph nodes; fat stranding; enlarged bile duct and pancreatic duct; neoplasm longest dimension, volume and density.

Results

Histopathological diagnoses: follicular non-Hodgkin lymphoma (5/14), diffuse large B-cell lymphoma (6/14) and high-grade B-cell lymphoma not otherwise specified (3/14). Six of 14 PPLs were located in the pancreatic head and 7/14 in the body-tail; 1/14 involved the whole gland. In 5/14 cases the superior mesenteric artery and vein were encased; splenic vein and artery encasement was depicted in 2 PPLs. Necrosis was present in 2/14. Enlarged retroperitoneal lymph nodes were found in 11 cases and fat stranding in all patients. The bile duct was dilated in six cases and the pancreatic duct in five. Mean neoplasm longest diameter and volume were 8.05 cm and 210.8 cm³. Mean tumour attenuation values were 39.1 HU at baseline, 60.6 HU in the pancreatic phase and 71.4 HU in the venous phase.

Conclusions

PPL presents as a large mass lesion with delayed homogeneous enhancement; peri-pancreatic fat stranding and vessel encasement are present, without vascular infiltration. Pancreatic duct dilatation is rare.

Key points

• Primary pancreatic lymphoma (PPL) is a rare haematological disease

• PPL presents imaging features in common with pancreatic carcinoma but also some distinctive findings

• The majority of PPLs are large lesions with delayed homogeneous enhancement

• Peri-pancreatic fat stranding and vessel encasement are common in PPL

• Vascular infiltration and pancreatic duct dilatation are rare in PPL

Benign features of infection-related tumor-like lesions of the lung: A retrospective imaging review study

INTRODUCTION

Differentiation of benign and malignant pulmonary tumor-like lesions is challenging but increasingly important. We evaluate the most common imaging features in benign lesions based on the frequency of their appearance and compare with corresponding frequencies in malignant tumors from literature.

METHODS

Retrospective imaging review study in one center between 1 January 2012 and 30 June 2014. We reviewed the data from 2466 pathological examinations of lung specimens collected from the hospital. We excluded malignant or non-tumor-like lesions and identified 133 infection-related lesions for imaging review. The frequency of 11 benign imaging features was evaluated in the selected infection-related tumor-like pulmonary lesions and was compared with corresponding frequency in malignant tumors.

RESULTS

Most of the evaluated lesions were seen to have one to four benign features. The two most common benign features are marginal ground glass or infiltrates (62.4%), followed by pleura-based wedge shape (50.4%). Features with significantly higher frequency in benign infection-related lung lesions than malignancy are calcification or hyperdensity, pleura-based wedge shape, adjacent clustered small nodules, and strongly or poorly enhanced soft tissue part.

CONCLUSIONS

Infection-related lung lesions usually have one to four benign features and the common features with significantly higher frequency than malignant condition are pleura-based wedge shape, calcification or hyperdensity, adjacent clustered small nodules, and strongly or poorly enhanced soft tissue part.

Tumor necrosis could reflect advanced disease status in patients with diffuse large B cell lymphoma treated with R-CHOP therapy

Tumor necrosis (TN) can lower responsiveness to chemotherapy and confer basic resistance to anti-cancer therapy. We investigated the association of TN with poor clinical features and outcome in diffuse large B cell lymphoma (DLBCL). We examined the presence or absence of TN in 476 DLBCL patients of who received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy. Eighty-nine (18.7 %) patients had TN at diagnosis. Patients with TN had a progression-free survival (PFS) and overall survival (OS) of 39.3 and 46.7 %, whereas patients without TN had a PFS and OS of 73.4 and 82.6 %. Adverse clinical factors of poor Eastern Cooperative Oncology Group performance status ≥ grade 2 (p = 0.005), elevated lactate dehydrogenase ratio >1 (p < 0.001), advanced Ann Arbor stage (p = 0.002), and bulky disease (p = 0.026) were more prevalent in the TN group than the non-TN group. Cox regression model analysis revealed TN as an independent prognostic factor for PFS and OS in DLBCL (PFS, hazard ratio [HR] = 1.967, 95 % confidence interval [CI] = 1.399-2.765, p < 0.001; OS, HR = 2.445, 95 % CI = 1.689-3.640, p < 0.001). The results indicate that TN could reflect adverse clinical features and worse prognosis in DLBCL patients receiving R-CHOP therapy.

Prognostic value of tumor necrosis at CT in diffuse large B-cell lymphoma

OBJECTIVE

To determine the prognostic value of tumor necrosis at computed tomography (CT) in newly diagnosed diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS

This retrospective study included 51 patients with newly diagnosed DLBCL who had undergone both unenhanced and intravenous contrast-enhanced CT before R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin and prednisolone) chemo-immunotherapy. Presence of tumor necrosis was visually and quantitatively assessed at CT. Associations between tumor necrosis status at CT and the National Comprehensive Cancer Network (NCCN) International Prognostic Index (IPI) factors were assessed. Cox regression analysis was used to determine the prognostic impact of NCCN-IPI scores and tumor necrosis status at CT.

RESULTS

There were no correlations between tumor necrosis status at CT and the NCCN-IPI factors categorized age (ρ=-0.042, P=0.765), categorized lactate dehydrogenase (LDH) ratio (ρ=0.201, P=0.156), extranodal disease in major organs (φ=-0.245, P=0.083), Ann Arbor stage III/IV disease (φ=-0.208, P=0.141), and Eastern Cooperative Oncology Group (ECOG) performance status (φ=0.015, P=0.914). In the multivariate Cox proportional hazards model, only tumor necrosis status at CT was an independent predictive factor of progression-free survival (P=0.003) and overall survival (P=0.004).

CONCLUSION

The findings of this study indicate the prognostic potential of tumor necrosis at CT in newly diagnosed DLBCL.

Role of Structural Imaging in Lymphoma

The lymphomas, Hodgkin lymphoma and non-Hodgkin lymphoma, are among the most common types of cancer in the United States. Imaging plays an important role in the evaluation of patients with lymphoma, because it aids in treatment planning and in the determination of prognosis. Structural imaging entails the assessment of morphologic features of normal tissues and organs of the body and of malignant lesions within these structures, and plays a major role in the noninvasive assessment of lymphoma. This article reviews cross-sectional structural imaging modalities with an emphasis on computed tomography and magnetic resonance imaging, with some mention of ultrasonography.

Cross-sectional evaluation of thoracic lymphoma

Thoracic lymphomas most frequently involve mediastinal lymph nodes in the anterior mediastinum and paratracheal areas. The lymphomas may also involve lung, thymus, pleura, pericardium, chest wall, and the breast and their radiologic manifestations are diverse. Lymphomas (mostly BALT lymphoma and large B-cell lymphoma) may arise primarily from the lung with various imaging features including single or multiple nodule(s) and area(s) of consolidation. CT is currently the most important imaging modality for the evaluation of thoracic lymphoma but FDG PET also plays a crucial role in the clinical management of these cases.

Cross-sectional evaluation of thoracic lymphoma

In patients who have lymphoma, the presence and distribution of thoracic involvement is important in both tumor staging and treatment. Thoracic involvement in Hodgkin lymphoma (HL) is more common than in non-Hodgkin lymphoma (NHL). In HL, mediastinal lymphadenopathy with contiguous spread is a hallmark, and lung parenchymal involvement at the initial presentation is almost always associated with mediastinal lymphadenopathy. NHL is more heterogeneous and generally presents at a more advanced stage than HL. Most often, mediastinal involvement occurs as a disseminated or recurrent form of extrathoracic lymphoma. Bulky mediastinal disease with compression of adjacent structures can occur, particularly with high-grade subtypes of NHL and isolated lung disease without mediastinal lymphadenopathy can occur in contrast to HL.

Tuberculosis versus non-Hodgkin’s lymphomas involving small bowel mesentery: Evaluation with contrast-enhanced computed tomography

AIM: To evaluate the specific computed tomography (CT) imaging criteria for differentiating tuberculosis involving the small bowel mesenteric lymph nodes from lymphomas.

METHODS: We retrospectively reviewed the anatomic distribution, CT enhancement patterns of lymphoma in 18 patients with mesenteric tuberculosis and 22 with untreated non-Hodgkin’s lymphomas (NHL) involving small bowel mesentery (SBM). Of the 18 patients with tuberculosis, 9 had purely mesenteric tuberculous lymphadenopathy (TL), and 9 had mesenteric TL accompanied with tuberculous mesenteritis (TLM).

RESULTS: CT showed that tuberculosis and NHL mainly affected lymph nodes in the body and root of SBM. Homogeneously enhanced lymph nodes in the body and root of SBM were found more often in the NHL (P < 0.05). Homogeneously mixed peripheral enhanced lymph nodes in the body of SBM were found more often in mesenteric TL and TLM (P < 0.05). Peripheral enhanced lymph nodes in the root of SBM were found more often in mesenteric TL and TLM (P < 0.01). “Sandwich sign” in the root of SBM was observed more often in NHL (P < 0.05).

CONCLUSION: Anatomic lymph node distribution, sandwich sign and specific enhancement patterns of lymphadenopathy in SBM on CT images can be used in differentiating between tuberculosis and untreated NHL involving SBM.

Tuberculous abscess in hepatoduodenal ligament: Evaluation with contrast-enhanced computed tomography

Two patients with tuberculous abscess in the hepatoduodenal ligament were studied. Both patients underwent contrast-enhanced computed tomography (CT) scan. The abscess showed a low density with an irregular thick wall in the hepatoduodenal ligament on CT images, the margin was poorly defined. Contrast-enhanced CT images showed the contrast-enhanced thick wall, homogeneous and peripheral-enhanced lymph nodes. Although features of the tuberculous abscess in the hepatoduodenal ligament could be conspicuously shown with contrast-enhanced CT, further experience is needed to evaluate the potential value of CT in detecting early tuberculous abscess in relation to other entities in the hepatoduodenal ligament.

MRI of neck nodes in non-Hodgkin's lymphoma of the head and neck

The aim of this study is to describe the imaging features of neck nodes in non-Hodgkin's lymphoma (NHL). The MR scans of 61 patients undergoing staging of a primary extranodal NHL of the head and neck were reviewed retrospectively. Those MR images with nodal disease were assessed for (a) the pattern of nodal disease, (b) presence of nodal necrosis and (c) presence of extracapsular neoplastic spread (ENS) and nodal matting. The features of the nodal disease were analysed in relationship to the sites of the primary NHL (palatine tonsil (PT) n=23, nasal cavity (NC) n=24, nasopharynx (NP) n=6, other extralymphatic sites (OES) n=8), and histology (natural killer/T-cell (NK/T) n=26, diffuse large cell (DLC) n=24, other subtypes (OS) n=11). Nodal disease was present in 26 patients (43%) and occurred in NHL of the PT n=16 (70%), NP n=3 (50%), NC n=5 (21%) and OES n=2 (25%) and in DLC n=15 (63%), NK/T n=6 (23%) and OS n=5 (45%). Nodal disease was significantly more frequent in DLC than NK/T lymphomas (p=0.0053). Nodal disease spread in a contiguous fashion in 25 (96%) patients with nodes. Necrosis was present in 7 of 26 (27%) being present in DLC of the PT in 5, NK/T of the NP in one and NK/T of the NC in one. ENS and matting were present in 19 (73%) and 13 (50%) patients with nodes, respectively. ENS was found in DLC, NK/T, OS, NC, NP, PT, OES (11, 4, 4,1, 2, 14, 2, respectively) and matting was found in DLC, NK/T, OS, NC, NP, PT, OES (9, 3, 1, 0, 2, 10, 1, respectively). Nodal NHL spreads in a contiguous fashion and is most commonly associated with DLC lymphoma of the NP and PT in Waldeyer's ring. Extracapsular nodal spread is frequent and found in most histological subtypes especially those arising from Waldeyer's ring. Necrosis is more common than previously believed.

Cystic Tumors in the Anterior Mediastinum

Anterior mediastinal neoplasms comprise a diverse group of tumors and occasionally manifest as a cystic lesion. We retrospectively reviewed computed tomography (CT) scans in 46 patients with pathologically proved cystic anterior mediastinal tumors. We categorize them into a pure cystic mass and a cystic tumor with a solid portion. In this pictorial essay, the radiologic appearances of cystic anterior mediastinal tumors are described with CT and illustrated with their gross and histopathological findings on resected specimen.

Computerised tomography in the staging of Hodgkin's disease and non-Hodgkin's lymphoma

The last 25 years have seen major changes in the imaging investigation and subsequent management of patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL); accurate staging is vital for prognostication and treatment in both, and particularly in HD. The choice of imaging modality for staging depends on its accuracy, impact on clinical decision-making, and availability. Modern CT scanners fulfil most of the desired criteria. The advent of CT scanning, along with the development of ever more effective chemotherapeutic regimens, has resulted in the virtual demise of bipedal lymphangiography (LAG) as a staging tool in patients with lymphoma. It has rendered superfluous a battery of other tests that were in routine use. This contribution reviews the evidence for the use of CT in preference to LAG. CT accurately depicts nodal enlargement above and below the diaphragm, has variable sensitivity for intra-abdominal visceral involvement and is generally outstanding in depicting the extent of disease, especially extranodal extension. Despite the advances in CT technology, there are still areas where CT performs less well (e.g. disease in normal-sized lymph nodes, splenic and bone marrow infiltration). The influence of technical factors, such as the use of intravenous contrast medium, is discussed. In some instances, CT is not the imaging modality of choice and the place of newer techniques such as MRI and endoscopic ultrasound will be reviewed.

Middle mediastinal lesions: imaging findings and pathologic correlation

Lesions primarily involving the middle mediastinum are uncommon and include lymph node diseases, cystic lesions, neurogenic tumors, mesenchymal tumors, tumors of mediastinal organ, amd other benign processes. In this article, we illustrate imaging findings of a variety of middle mediastinal lesions with pathologic correlation.

Primary mediastinal tumors: part II. Tumors of the middle and posterior mediastinum

Lymphoma, mediastinal cysts, and neurogenic neoplasms are the most common primary middle and posterior mediastinal tumors. Lymphoma may involve the anterior, middle and/or posterior mediastinum, frequently as lymphadenopathy or as a discrete mass. Foregut cysts are common congenital mediastinal cysts and frequently arise in the middle mediastinum. Pericardial cysts are rare. Schwannoma and neurofibroma are benign peripheral nerve neoplasms, represent the most common mediastinal neurogenic tumors, and rarely degenerate into malignant tumors of nerve sheath origin. Sympathetic ganglia tumors include benign ganglioneuroma and malignant ganglioneuroblastoma and neuroblastoma. Lateral thoracic meningocele is a rare cause of a posterior mediastinal mass.