MRI findings of mediastinal neurogenic tumors

Unlocking the Potential of Chest MRI: Strategies for Establishing a Successful Practice

Chest MRI is a valuable tool for assessing chest structures, particularly when CT produces inconclusive results. MRI provides exceptional soft-tissue resolution and enables the determination of lesion location, size, and invasion into neighboring structures. Its applications span various clinical scenarios, including the differentiation of non-tumorous and tumorous conditions in the mediastinum or pleura, planning of surgical interventions and treatments for such tumors, evaluation of post-treatment recurrence, staging of lung cancer, and diagnosis of progressive massive fibrosis. Despite the technical hurdles posed by cardiac and respiratory motion, advancements in sequence and scan techniques have enabled high-quality chest MRI examinations to be conducted across diverse clinical settings. This pictorial essay aims to offer comprehensive resources and strategies for radiologists to integrate chest MRI into clinical practice and to overcome its present challenges.

Supraclavicular-median sternotomy approach for a large neurilemmoma invading the thoracic outlet: a case report and review of the literature

BACKGROUND

Large mediastinum tumors invading the thoracic outlet have consistently been a challenge in thoracic surgery. Due to the large size of the tumor and its proximity to many important tissues, appropriate surgical approaches are crucial for a successful surgery.

CASE PRESENTATIONS

Here, we present a case of a large neurilemmoma that invaded the thoracic outlet that was resected by a supraclavicular-median sternotomy approach. The case was a 58-year-old woman with a large mass in the right chest cavity that had invaded the thoracic outlet. The preoperative biopsy showed a blood clot with a few fibrous connective tissues covered by a single layer of flat epithelium. There was insufficient evidence to diagnose the mass as a tumor, and imaging examinations suggested a diagnosis of solitary pleural fibroma. For good exposure of the cranial and caudal aspects of the large mass, we devised a median sternotomy combined with a supraclavicular approach and safely achieved complete resection. The patient recovered well and experienced no severe complications or functional restrictions of the upper extremity. The postoperative pathology diagnosis was a neurilemmoma.

CONCLUSIONS

The supraclavicular-median sternotomy approach could be an optional approach for the complete resection of large mediastinal tumors invading the thoracic outlet.

MRI Findings and Differential Diagnosis of Anterior Mediastinal Solid Tumors

The anterior mediastinum is the most common location of mediastinal tumors, and thymic epithelial tumors are the most common mediastinal tumors. It is important to differentiate thymic epithelial tumors from malignant lymphomas and malignant germ cell tumors because of the different treatment strategies. Dynamic contrast-enhanced MRI and diffusion-weighted imaging can provide additional information on the differential diagnosis. Chemical shift imaging can detect tiny fat tissues in the lesion and is useful in differentiating thymic hyperplasia from other solid tumors such as thymomas. MRI findings reflect histopathological features of mediastinal tumors, and a comprehensive evaluation of MRI sequences is important for estimation of the histopathological features of the tumor. In this manuscript, we describe the MRI findings of anterior mediastinal solid tumors and the role of MRI in the differential diagnosis.

Diagnostic approach for mediastinal masses with radiopathological correlation

PURPOSE

Mediastinal masses have various histopathological and radiological findings. Although lymphoma is the most common type of tumor, thymic epithelial and neurogenic tumors are common in adults and children, respectively, but several other types are difficult to distinguish. No previous review has simply and clearly shown how to differentiate mediastinal masses.

METHOD

We conducted a review of the latest mediastinal classifications and mass differentiation methods, with a focus on neoplastic lesions. Both older and recent studies were searched, and imaging and histopathological findings of mediastinal masses were reviewed. Original simple-to-use differentiation flowcharts are presented.

RESULTS

Assessing localizations and internal characteristics is very important for mediastinal mass differentiation. The mass location and affected organ/tissue should be accurately assessed first, followed by more qualitative diagnosis, and optimization of the treatment strategy. In 2014, the International Thymic Malignancy Interest Group presented a new mediastinal clinical classification. In this classification, mediastinal masses are categorized into three groups according to location: prevascular (anterior)-, visceral (middle)-, and paravertebral (posterior)-compartment masses. Then, the internal characteristics and functional images are evaluated.

CONCLUSIONS

Differentiation of mediastinal masses is very difficult. However, if typical imaging findings and clinical characteristics are combined, reasonable differentiation is possible. In each patient, proper differential diagnosis may contribute to better treatment selection.

Posterior mediastinal extralobar pulmonary sequestration misdiagnosed as a neurogenic tumor: A case report

BACKGROUND

Pulmonary sequestration-both intralobar and extralobar-is a rare congenital developmental malformation. Extralobar pulmonary sequestrations (EPS) have their own pleura but are separated from the bronchus and usually occur in the left lung. They are mainly found mainly between the lower lobe and the mediastinum. EPS is rarely found within the mediastinum itself, even rarer so in the posterior mediastinum.

CASE SUMMARY

We report the case of a 27-year-old man who was misdiagnosed with a neurogenic tumor based on preoperative contrast-enhanced computed tomography (CT) and magnetic resonance imaging findings. Contrast-enhanced chest CT revealed a posterior mediastinal mass measuring 1.2 cm × 1.4 cm × 3.3 cm, which consisted of some cystic areas and showed slight enhancement. The mass was in the 11^th paravertebral region and attached to the 11^th thoracic vertebra behind the descending aorta in the posterior mediastinum. An arteriole originating from the intercostal artery and a vein originating directly from the hemiazygos vein were found in the pedicle of the mass. The mass was resected in a uniport video-assisted thoracoscopic surgery. During the operation, the pyramid-shaped mass appeared well-encapsulated. Postoperative histopathology established a diagnosis of EPS. One month later, a follow-up CT of the thorax showed good recovery.

CONCLUSION

Although EPS rarely occurs in the posterior mediastinum, its diagnosis should be considered when posterior mediastinal tumors are suspected.

Comparative Role of MDCT and FDG-PET/CT in the Diagnostic Evaluation of Mediastinal Mass Lesions: An Institutional Experience

Background Mediastinal mass lesions span a wide histopathological and radiological spectrum. Partition of the mediastinum into specific compartments aids in differential diagnosis of mass lesions, assistance in biopsies, and other surgical procedures. Multidetector row computed tomography (MDCT) is a promising three-dimensional imaging tool allowing substantial anatomical volumes to be routinely covered with isotropic submillimeter spatial resolution to precisely localize lesions and biopsy needles for both benign and malignant disease lesions of the mediastinum.

Objective The aim of this study was to categorize mass lesions according to the mediastinal compartments to study their MDCT characteristics and to provide a comparative role of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the diagnostic evaluation of mediastinal mass lesions.

Materials and Methods Patients with clinical or radiological suspicion of mediastinal lesions on the basis of an abnormal chest radiograph were referred to the department of radiodiagnosis at a tertiary care center between April 2015 and December 2019 for MDCT evaluation. A total of 80 cases were correlated with the histopathological diagnosis excluding aneurysms. Size, CT density (Hounsfield unit [HU] mean), and maximum standardized uptake value (SUVmax) of mediastinal and chest wall lesions were determined on FDG-PET/CT.

Results This study included a total of 102 cases, 72 males and 29 females. Mediastinal mass lesions were most common in the age group 46 to 60 years. Anterior mediastinum (n = 43, 42.2%) is the most commonly involved compartment followed by posterior mediastinum (n = 37, 35.9%) and middle mediastinum (n = 22, 21.8%). Transcompartmental involvement is more commonly seen involving the anterior and middle mediastinum. The SUVmax, HU mean, and size were higher in malignant cases (p = 0.001, p = 0.003, and p = 0.004, respectively). The current study found a cutoff value of 4.61 for SUVmax to discriminate benign lesions from malignant ones with a sensitivity and specificity of 73.7 and 75.9%, respectively (area under the curve: 0.841, 95% confidence interval: 0.793–0.965, p = 0.0001). The values of SUVmax and HU mean were higher in solid benign lesions than those of cystic benign lesions (p = 0.007 and p = 0.003, respectively).

Conclusion In the current study, MDCT has high diagnostic accuracy of ∼94% overall as compared with histopathology, and 97 and 92% for benign and malignant lesions, respectively, in the evaluation of mediastinal mass lesions. FDG-PET/CT may be complementary to conventional imaging methods for the evaluation of mediastinal and chest wall mass lesions. However, confirmatory tissue sampling is required to confirm PET positive findings for the definite diagnosis.

Retrospective analysis of the clinical presentation and imaging of eight primary benign mediastinal schwannomas

OBJECTIVE

Mediastinal schwannomas are sometimes confused with other neoplasms during initial radiological studies, especially when there is a history of cancer in another area. In these cases, a more accurate analysis using computed tomography (CT) or even magnetic resonance (MRI) is required. Our study aimed to perform a retrospective analysis of the clinical and imaging features for a series of patients with mediastinal schwannomas that were confirmed by histology and immunohistochemistry.

RESULTS

We found eight patients, five men and three women, with an average age of 51 years for this study. The main signs and symptoms at diagnosis were chest pain, dyspnea, cough, and dysphagia. CT showed that the tumor was located in the posterior compartment of the chest in 7/8 cases. Tumors > 10 cm were more heterogeneous and showed cystic changes. All patients underwent posterolateral thoracotomy, and radiological follow-up showed no evidence of recurrence. Histological analysis was considered the gold standard to confirm diagnosis, along with at least one neurogenic IHC marker. In conclusion, mediastinal schwannomas are benign encapsulated tumors. According to CT, schwannomas > 10 cm show cystic degeneration more frequently. Posterolateral thoracotomy allows complete resection and is considered the surgical approach of choice.

ACR Appropriateness Criteria® Imaging of Mediastinal Masses

Mediastinal masses can present with symptoms, signs, and syndromes or incidentally. Selecting the appropriate diagnostic imaging study for mediastinal mass evaluation requires awareness of the strengths and weaknesses of the various imaging modalities with regard to tissue characterization, soft tissue contrast, and surveillance. This publication expounds on the differences between chest radiography, CT, PET/CT, ultrasound, and MRI in terms of their ability to decipher and surveil mediastinal masses. Making the optimal imaging choice can yield diagnostic specificity, avert unnecessary biopsy and surgery, guide the interventionist when necessary, and serve as a means of surveillance for probably benign, but indeterminate mediastinal masses. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Clinical Practice Guidance for Non-Vascular Thoracic MRI

Historically thoracic MRI has been limited by the lower proton density of lung parenchyma, cardiac and respiratory motion artifacts and long acquisition times. Recent technological advancements in MR hardware systems and improvement in MR pulse sequences have helped overcome these limitations and expand clinical opportunities for non-vascular thoracic MRI. Non-vascular thoracic MRI has been established as a problem-solving imaging modality for characterization of thymic, mediastinal, pleural chest wall and superior sulcus tumors and for detection of endometriosis. It is increasingly recognized as a powerful imaging tool for detection and characterization of lung nodules and for assessment of lung cancer staging. The lack of ionizing radiation makes thoracic MRI an invaluable imaging modality for young patients, pregnancy and for frequent serial follow-up imaging. Lack of familiarity and exposure to non-vascular thoracic MRI and lack of consistency in existing MRI protocols have called for clinical practice guidance. The purpose of this guide, which was developed by the Canadian Society of Thoracic Radiology and endorsed by the Canadian Association of Radiologists, is to familiarize radiologists, other interested clinicians and MR technologists with common and less common clinical indications for non-vascular thoracic MRI, discuss the fundamental imaging findings and focus on basic and more advanced MRI sequences tailored to specific clinical questions.

Lingual schwannoma in an adolescent boy: A case report

Oral cavity schwannoma is still considered a rare entity in the head and neck region. Schwannoma is a benign encapsulated nerve sheath tumour that originate from Schwann cells with an approximate incidence of 1% in the oral cavity. The tongue is the most common location among oral cavity tumours. We report a rare case of tongue schwannoma in 12-year-old boy who presented to our centre complaining of swelling of the tongue, which had increased in size and interfered with his speech in 2018; he had been previously asymptomatic since birth. A diagnosis was established based on the following imaging studies: computed tomography (CT) and magnetic resonance imaging (MRI). He underwent simple transoral excision of the ventral tongue mass under general anaesthesia with no complications, and the final pathological result confirmed the diagnosis of schwannoma.

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Oral cavity schwannoma is a rare tumour in the head and neck region.

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CT and MRI help in the diagnosis.

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Transoral excision is the most common procedure.

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Pathological examination confirms the diagnosis.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Imaging findings of lesions in the middle and posterior mediastinum

Lesions in the middle and posterior mediastinum are relatively rare, but there are some useful radiological clues that can be used to diagnose them precisely. It is useful to determine the affected mediastinal compartment and the locations of the main thoracic nerves on medical images for diagnosing such mediastinal lesions. Neurogenic tumors can occur in the middle mediastinum, although they generally arise as posterior mediastinal tumors. Based on the above considerations, we review various characteristic imaging findings of middle and posterior mediastinal lesions, and their differential diagnoses.

Anterior mediastinal lesions: CT and MRI features and differential diagnosis

Anterior mediastinum is the most common location of mediastinal tumors, which include various solid and cystic lesions. The lesion location and CT and MRI features are important in the differential diagnosis. Recently, CT-based mediastinal compartment classification systems were proposed and suggested to be useful for accurate evaluation of mediastinal lesions. CT and MRI reflect the pathological findings of mediastinal lesions, and knowledge of the pathological features is important for the differential diagnosis. In this article, we review the CT and MRI features of anterior mediastinal lesions and describe important points in the differential diagnosis.

A giant ganglioneuroma accompanied with scoliosis

Ganglioneuroma is a rare benign neoplasm. Patients with ganglioneuroma show no symptoms. We describe a rare case of giant ganglioneuroma with scoliosis in a 35-year-old woman, who presented to our hospital for haemoptysis. We combined with neurosurgeons to remove the tumour successfully. After 16 months of follow-up, there is no evidence of tumour recurrence.

Pediatric Mediastinal Masses:: Role of MR Imaging as a Problem-Solving Tool

Computed tomography (CT) is the imaging modality of choice for evaluating mediastinal masses detected by radiography or clinical presentation. However, CT results can often be indeterminate. Thoracic magnetic resonance (MR) imaging is a noninvasive way to characterize mediastinal lesions, site of origin, and involvement of adjacent structures by providing higher soft tissue contrast than CT, with superior tissue characterization and higher diagnostic specificity. Thoracic MR imaging of mediastinal masses can increase diagnostic certainty, reduce the number of surgical interventions, and improve clinical decision making. In this review article, current imaging techniques and clinical applications of MR imaging as a problem-solving tool for assessing mediastinal masses in pediatric patients are discussed.

Diagnostic accuracy of multidetector computed tomography scan in mediastinal masses assuming histopathological findings as gold standard

Purpose

Aim of the study was to: 1) present MDCT characteristics of different mediastinal mass lesions, 2) estimate proportion of benign and malignant mediastinal mass lesions based on MDCT findings, and 3) find out the diagnostic accuracy with sensitivity, specificity, positive predictive value, and negative predictive value of MDCT in mediastinal mass lesions assuming histopathology as gold standard.

Material and methods

This study was an analysis of 60 patients who underwent MDCT scan for characterisation of mediastinal mass lesion, and subsequently imaging findings were verified with pathological diagnosis.

Results

Out of 60 patients 65% were malignant and 35% were benign. Metastatic carcinoma was the leading diagnosis. Sensitivity of MDCT in this study came out to be 94%, specificity is 90%, with a positive predictive value of 94% and negative predictive value of 90% with diagnostic accuracy of 93%.

Conclusions

Mediastinal mass lesion can be accurately diagnosed with MDCT which is a non-invasive and easily available modality requiring clinical data for accurate diagnosis and management. Co-relation of MDCT findings with other imaging findings is complex and requires adequate clinical data for optimum diagnostic confidence.

Synchronous Ganglioneuroma and Schwannoma Mistaken for Carotid Body Tumor

Ganglioneuromas are a very rare benign neural tumor, commonly derived from the ganglia of the sympathetic system, and are composed of mature Schwann cells, ganglion cells, and nerve fibres. They may arise anywhere from the base of the skull to the pelvis along the paravertebral sympathetic plexus. We report a rare case of synchronous ganglioneuroma and schwannoma, mistaken for carotid body tumor. The coexistence of these two entities in head and neck region is very rare.

Castleman Disease of the Thorax: Clinical, Radiologic, and Pathologic Correlation: From the Radiologic Pathology Archives

Castleman disease is a complex lymphoproliferative disease pathologically divided into two subtypes, the hyaline vascular variant (HVV) and the plasma cell variant (PCV). The HVV is the most common, is thought to represent a benign neoplasm of lymph node stromal cells, and is treated with surgical resection. It is most commonly found in the mediastinum, where it classically appears as a unicentric, avidly enhancing mass at computed tomography (CT) and magnetic resonance imaging. This appearance can mimic other avidly enhancing mediastinal masses, and location, clinical history, laboratory data, and nuclear medicine single photon emission CT (SPECT) and positron emission tomography (PET) studies can help narrow the differential diagnosis. Multicentric Castleman disease (MCD), which in the majority of cases is composed of the PCV, is an aggressive lymphoproliferative disorder associated with human herpesvirus infection, interleukin 6 dysregulation, and other systemic disorders. While it can be difficult to differentiate MCD from lymphoma, the presence of avidly enhancing lymph nodes can suggest the diagnosis. The purpose of this article is to review the clinical, immunologic, and pathologic findings associated with both unicentric Castleman disease and MCD and discuss how the imaging findings correlate with the pathophysiology of the disease.

Assessment of paraspinal neurogenic tumors with diffusion-weighted MR imaging

PURPOSE

To assess paraspinal neurogenic tumors with diffusion-weighted MR imaging.

METHODS

Retrospective analysis was done upon 34 patients with paraspinal neurogenic tumors that underwent diffusion-weighted MR imaging. The ADC values of the mediastinal neurogenic tumors were calculated and correlated with biopsy results.

RESULTS

The ADC of benign paraspinal neurogenic tumors (1.5 ± 0.28 × 10^-3 mm²/s) was significantly higher (P = 0.001) than that of malignant peripheral nerve sheath tumors (0.995 ± 0.198 × 10^-3 mm²/s). Selection of 1.15 × 10^-3 mm²/s as a cut-off point for differentiating malignant from benign neurogenic tumors revealed an area under the curve of 0.885, an accuracy of 91.1%, a sensitivity of 90.9%, and specificity of 91.3%. There was significant difference (P = 0.04) in the ADC of schwannomas (1.55 ± 0.29 × 10^-3 mm²/s) from neurofibromas (1.33 ± 0.08 × 10^-3 mm²/s). The cut-off ADC value of 1.44 × 10^-3 mm²/s was used to differentiate schwannomas and neurofibromas with an area under the curve of 0.86, an accuracy of 82.6%, a sensitivity of 100%, and a specificity of 76.5%.

CONCLUSION

Diffusion-weighted MR imaging is imaging parameter that can be used for differentiation of benign from malignant paraspinal neurogenic tumors.

Angiofibrolipoma of Posterior Mediastinum with Transforaminal Extension

Angiofibrolipoma is a histological variant of lipoma, which commonly occurs in subcutaneous tissues. In the present report we illustrate the case of an angiofibrolipoma of the posterior upper mediastinum in a 75-year-old man presented with progressive chest pain. Xray chest showed a homogeneous opacity vertically oriented along the right lateral aspect of thoracic vertebrae with an obtuse angle to the mediastinum. The upper extremity of the mass extended above the superior clavicle, suggestive of a posterior mediastinal lesion. Thoracic magnetic resonance imaging revealed a posterior mediastinal mass, in keeping with a nonaggressive lesion, with particular endocanalar extension and heterogeneous signal and enhancement patterns that was highly suggestive of a mixed mesenchymal tumor. The tumor was incompletely removed by right postero-lateral thoracotomy with final diagnosis of angiofibrolipoma. To the author's knowledge, such a case of angiofibrolipoma located in the posterior mediastinum has not been previously reported in the literature.

Diffusion weighted imaging in differentiating malignant and benign neuroblastic tumors

PURPOSE

Our aim was to assess diffusion weighted imaging (DWI) of neuroblastic tumors and whether apparent diffusion coefficient (ADC) value may have a role in discrimination among neuroblastoma, ganglioneuroblastoma and ganglioneuroma.

MATERIAL AND METHODS

The DWIs (b = 0-800 s/mm(2)) of 24 children (13 girls, 11 boys) who were diagnosed neuroblastic tumors on histopathological examination (neuroblastoma = 15, ganglioneuroblastoma = 5, ganglioneuroma = 4) were evaluated retrospectively. The ADC maps were performed by drawing freehand ROI on PACS (Sectra Workstation IDS7, Linköping, Sweden).

RESULTS

We observed a significant decrease in ADC value of neuroblastomas 0.869 ± 0.179 × 10(-3) mm(2)/s compared to ganglioneuroblastomas 0.97 ± 0.203 × 10(-3) mm(2)/s and ganglioneuromas 1.147 ± 0.299 × 10(-3) mm(2)/s (p = 0.026). There was no significant difference in between ganglioneuroblastoma and ganglioneuroma (p = 0.16). In detecting neuroblastomas; the sensitivity, specificity, negative and positive predictive values of ADC were 74, 67, 78.6, 66 % respectively with a cut-off value of 0.93 × 10(-3) mm(2)/s.

CONCLUSION

Our study stands out as the most comprehensive study with larger sample size on this topic. Moreover, we are able to suggest a cut-off value which can discriminate neuroblastoma from ganglioneuroblastoma and ganglioneuroma. We believe that ADC will evolve to an objective, quantitative measurement in discrimination among malignant and benign neuroblastic tumors.

Posterior mediastinal ectopic meningioma: a case report

Primary ectopic meningiomas occurring in the mediastinal region are extremely rare. So far, only five cases of primary mediastinal meningioma have been reported in the literatures. The imaging characteristics and the clinicopathological significance of mediastinal psammomatous meningioma have not been detailed. Here, we report the case of a 42-year-old male with primary posterior mediastinal psammomatous meningioma. The clinical features, imaging, and pathological findings are carefully analyzed, and the relevant literatures were reviewed.

Neuroendocrine tumors: beyond the abdomen

Several classification systems for neuroendocrine tumors (NETs) exist, which use variable terminology and criteria for grading and staging. This variability in terminology can cause confusion and difficulty in recognizing which tumors are, in fact, members of this heterogeneous group of malignancies. The largest group of NETs, the gastroenteropancreatic NETs, has been well described and characterized; however, there are less-recognized extra-abdominal NETs that can arise from nearly any organ in the body. In this article, the clinical features and imaging appearances of the extra-abdominal NETs will be reviewed, compared, and contrasted. This diverse group consists of paragangliomas, Merkel cell carcinomas, esthesioneuroblastomas, NETs of the lung, and medullary thyroid carcinomas. Recognition of these tumors as part of the larger group of NETs is important for understanding how best to approach imaging for their diagnosis, staging, and potential treatment. Familiarity with the computed tomographic and magnetic resonance imaging appearances and the role of radionuclide imaging of these heterogeneous groups aids in the correct diagnosis and in treatment planning.

Soft tissue sarcoma misdiagnosed as benign peripheral neurogenic tumor

BACKGROUND

Because of the distinctive clinical and MR findings associated with benign peripheral neurogenic tumors (BPNTs), they are commonly diagnosed without histological confirmation. As such, they are one of the most frequently misdiagnosed entities among the soft tissue sarcomas (STSs) that undergo initial unplanned excision. In this study, we investigate the characteristics of STSs misdiagnosed as BPNTs.

METHODS

We present a series of nine STS patients with an initial preoperative diagnosis of BPNT (BPNT-STS), and compare their clinical and MR findings to those of the 18 genuine BPNT patients, matched for site, depth, and size of tumors as well as related nerves.

RESULTS

Among the nine BPNT-STS cases, the most common histological diagnosis was synovial sarcoma (n = 4). Six patients (67 %) had deep-seated tumors; four patients (44 %) had tumors 5 cm or greater in size. BPNT-STS patients were more likely to experience pain (78 % vs. 22 %) and shorter symptom duration (9 vs. 55 months) compared to BPNT patients. A target sign on MR imaging was observed only in BPNT patients (0 % vs. 50 %), whereas peritumoral edema was found only in BPNT-STS patients (33 % vs. 0 %).

CONCLUSIONS

If a tumor suggestive of a BPNT is painful, with a relatively short symptom duration, and presents with peritumoral edema without a definite target sign on MR images, the possibility of an STS must be considered.

Hypervascular mediastinal masses: action points for radiologists

Hypervascular mediastinal masses are a distinct group of rare diseases that include a subset of benign and malignant entities. Characteristic features and known association with syndromes and genetic mutations assist in achieving a diagnosis. Imaging allows an understanding of the vascularity of the lesion and should alert the radiologist and clinician to potential hemorrhagic complications and avoid percutaneous CT guided biopsies. In such cases, pre-procedure embolization and surgical biopsy maybe considered for better control of post procedure hemorrhage. The purpose of this article is to describe and illustrate the clinical features and radiologic spectrum of hypervascular mediastinal masses, and discuss the associated clinical and genetic syndromes. We will present an imaging algorithm to determine further evaluation and subsequently guide treatment.

A diagnostic approach to the mediastinal masses

Background

Multiple different types of mediastinal masses may be encountered on imaging techniques in symptomatic or asymptomatic patients. The location and composition of these lesions are critical to narrowing the differential diagnosis.

Methods

Radiological compartmentalisation of the mediastinum helps in focusing the diagnosis of masses on the basis of their site. Some diseases, however, do not occur exclusively in any specific compartment and can spread from one compartment to another.

Results

Tissular components of the mass, the degree of vascularisation and the relationships with mediastinal structures assessed by computed tomography (CT) or magnetic resonance imaging (MRI) are a leading edge of the radiological diagnosis. Special applications at MRI have been developed over the recent years in order to identify accurately tissular components of the mediastinal masses. The likelihood of malignancy of the mediastinal masses is influenced by the symptomatology and the age of the patient. This article reviews the most commonly encountered mediastinal masses considering clinical history and manifestations, anatomical position and certain details seen on different imaging modalities that allow correct diagnosis in many cases.

Conclusion

Familiarity with the radiological features of mediastinal masses facilitates accurate diagnosis, differentiation from other mediastinic processes and, thus, optimal patient treatment.

Teaching Points

• CT and MRI are important for the diagnosis of mediastinal masses.

• The location and tissue characteristics on imaging studies are critical to narrow down the differential diagnosis of mediastinal masses.

• Symptomatology and patient age affect the likelihood of malignancy.