Evaluation Of Mediastinal Lesions Research Articles

Multimodality imaging of mediastinal masses and mimics.

A wide variety of neoplastic and nonneoplastic conditions occur in the mediastinum. Imaging plays a central role in the evaluation of mediastinal pathologies and their mimics. Localization of a mediastinal lesion to a compartment and characterization of morphology, density/signal intensity, enhancement, and mass effect on neighboring structures can help narrow the differentials. The International Thymic Malignancy Interest Group (ITMIG) established a cross-sectional imaging-derived and anatomy-based classification system for mediastinal compartments, comprising the prevascular (anterior), visceral (middle), and paravertebral (posterior) compartments. Cross-sectional imaging is integral in the evaluation of mediastinal lesions. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to characterize mediastinal lesions detected on radiography. Advantages of CT include its widespread availability, fast acquisition time, relatively low cost, and ability to detect calcium. Advantages of MRI include the lack of radiation exposure, superior soft tissue contrast resolution to detect invasion of the mass across tissue planes, including the chest wall and diaphragm, involvement of neurovascular structures, and the potential for dynamic sequences during free-breathing or cinematic cardiac gating to assess motion of the mass relative to adjacent structures. MRI is superior to CT in the differentiation of cystic from solid lesions and in the detection of fat to differentiate thymic hyperplasia from thymic malignancy.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions.

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions. To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed. Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices. Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

MR Imaging of Mediastinal Masses.

The mediastinum contains vital vascular and nonvascular structures and organs, and a wide variety of abnormalities may arise from this region of the thorax. Although mediastinal masses may be initially detected on chest radiography, cross-sectional imaging plays an important role in the identification and evaluation of mediastinal lesions, enabling the formulation of focused differential diagnoses and ultimately guiding management. Computed tomography (CT) is considered the imaging modality of choice for evaluating most mediastinal masses; however, the role of magnetic resonance (MR) imaging continues to expand, as it is superior to CT in differentiating between cystic and solid masses, identifying cystic and solid components within complex lesions, and distinguishing thymic hyperplasia and normal thymus from thymic epithelial neoplasms and other neoplasms. In addition, it facilitates the staging and restaging of patients with thymic epithelial neoplasms and other tumors that cannot undergo contrast-enhanced CT imaging due to severe contrast allergy and/or impaired renal function. As division of the mediastinum into specific compartments is beneficial for diagnostic and treatment planning purposes and facilitates communication between clinicians in a multidisciplinary setting, a new classification model based on cross-sectional imaging has been developed by the International Thymic Malignancy Interest Group (ITMIG) and accepted as a new standard. In this article, we describe the role of MR imaging in the evaluation of mediastinal masses in conjunction with the new mediastinal compartment classification system introduced by ITMIG.

Transgastric endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) in patients with esophageal narrowing using the ultrasonic bronchovideoscope

Endobronchial ultrasound-guided fine needle aspiration (EBUS-FNA) is emerging as a critical technology in the evaluation of mediastinal lesions and is increasingly regarded as complementary to endoscopic ultrasound (EUS) in this arena. This complementary role may extend into the abdomen in cases where esophageal strictures prevent the passage of the echoendoscope. The objective of the study was to characterize the uses of EBUS-FNA in the evaluation of gastrointestinal lesions in patients with esophageal narrowing. The study design was a single-center case series. The setting was in a tertiary referral center. Four patients underwent EBUS-FNA to evaluate gastrointestinal lesions; esophageal strictures prevented EUS passage in three, the fourth patient did not tolerate transbronchial EBUS but had abdominal lesions within reach of the EBUS scope. EBUS was used to evaluate the liver, adrenal gland, a retroperitoneal mass, and a celiac axis lymph node. EBUS-FNA has greater potential to evaluate abdominal lesions than has been previously recognized. The EBUS scope represents a safe and readily available technology to evaluate patients with esophageal strictures. Interventional endoscopists should be exposed to this modality.

Endobronchial Ultrasound-directed Transbronchial Needle Aspiration in Diagnosis of Mediastinal Lesions: Initial Egyptian Experience

Mediastinal lesions represent a diagnostic challenge and often require invasive approaches. We evaluated the role of radial probe endobronchial ultrasound-directed transbronchial needle aspiration (EBUS-TBNA) in the evaluation of mediastinal lesions. Between March 2005 to February 2006, 30 consecutive patients with enlarged mediastinal lymph nodes from unknown etiologies or suspicious for metastatic bronchogenic carcinoma and mediastinal masses underwent EBUS-TBNA and were clinically followed up. EBUS-TBNA was applied under topical anesthesia, midazolam sedation with a mean dose of 4.6+1.7 mg and prolonged the examination by 14.7 minutes on average. EBUS-directed TBNA was performed in 17 lymph nodes and 13 mediastinal masses, achieving specific diagnosis in 82.3% (14/17) and 84.6% (11/13) of examined lesions, respectively, with an overall yield of 83%. The sensitivity, specificity, and accuracy of EBUS-TBNA in distinguishing benign from malignant mediastinal lesions were 89.4%, 100%, and 93.3%, respectively. EBUS was well tolerated by most of the patients with no TBNA-related complications. In conclusion, EBUS-TBNA of mediastinal lesions is a minimally invasive safe diagnostic technique with high yield, even in the hands of those with initial experience. This initial study is convincing and stimulating for widespread application of EBUS-TBNA in Egyptian bronchoscopy practice.

Endoscopic ultrasound-guided fine-needle aspiration and Trucut biopsy in thoracic lesions: When tissue is the issue

Endoscopic ultrasound-guided fine-needle aspiration (EUS FNA) has a high accuracy in the evaluation of mediastinal lesions. The use of a core biopsy needle for EUS guided biopsy (EUS TCB) may further improve the yield of EUS. The aims of this study are to evaluate the safety of EUS TCB in thoracic lesions and to compare the diagnostic accuracy of TCB with FNA and FNA + TCB. A single-center retrospective study. All patients underwent EUS-FNA and TCB. A cytopathologist was not present during the procedure. EUS FNA, TCB and FNA + TCB diagnostic accuracy were compared. A total of 48 patients were included. The lesions sampled included 41 lymph nodes (six aorto-pulmonary window, 32 subcarinal, two right paratracheal, one paraesophageal ATS station 8), five lung masses, and two esophageal masses. Twenty-nine patients had malignant disease and 19 had benign disorders. The overall diagnostic accuracy of FNA, TCB and FNA + TCB was 79%, 79% and 98% respectively (p = 0.007). TCB changed the diagnosis in nine cases missed by FNA. EUS TCB was better than FNA for benign diseases (89% vs. 63%, p = 0.04). All eight patients with a prior failed biopsy had a correct diagnosis established by EUS. No patient required mediastinoscopy or thoracoscopy after EUS. The combination of TCB and FNA is superior to FNA alone. EUS-guided TCB should be considered in patients with benign disorders of the mediastinum when other modalities fail to yield a diagnosis.

Transesophageal Endoscopic Ultrasound-Guided Fine-Needle Aspiration (EUS-FNA) and Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) Biopsy: a Combined Approach in the Evaluation of Mediastinal Lesions

It would be desirable to develop minimally invasive methods of tissue diagnosis from lymph nodes as well as solid lesions in the mediastinum. The aim of the present study was to test the combined method of transesophageal endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the evaluation of mediastinal lesions. EUS-FNA and EBUS-TBNA were compared in 33 patients, for the staging of lung cancer in patients with an established diagnosis of non-small-cell lung cancer (n = 20) or for diagnosis of a suspicious mediastinal lesion in patients with suspected lung cancer (n = 13). EBUS-TBNA and EUS-FNA were unsuccessful in one patient each. The diagnoses were verified in 28 of the remaining 31 patients either at thoracotomy (n = 9) or during the clinical follow-up (n = 19). A total of 119 lesions were sampled by EUS-FNA (n = 59) and EBUS-TBNA (n = 60). EUS-FNA and EBUS-TBNA demonstrated cancer in 26 and 28 lesions, respectively, and benign cytology in 30 and 28 lesions, respectively. Suspicious cells were found in three and four lesions by EUS-FNA and EBUS-TBNA, respectively. When the 60 EBUS-TBNA samples were compared with the 59 EUS-FNA samples, 11 additional cancer diagnoses and three samples with suspicious cells were obtained by EBUS-TBNA that had not been obtained by EUS-FNA. Conversely, EUS-FNA diagnosed 12 additional cancer diagnoses, one suspicious and one specific benign diagnosis (sarcoidosis) in addition to EBUS-TBNA. With a combined approach (EUS-FNA + EBUS-TBNA) in 28 of the 31 patients in whom a final diagnosis was obtained in the evaluation of mediastinal cancer, 20 patients were found to have mediastinal involvement, whereas no mediastinal metastases were found in eight patients. The accuracy of EUS-FNA and EBUS-TBNA, in combination, for the diagnosis of mediastinal cancer was 100 % (95 % CI, 83 - 100 %). EUS-FNA and EBUS-TBNA appear to be complementary methods. A combined approach with both EUS-FNA and EBUS-TBNA may be able to replace more invasive methods for evaluating lung cancer patients with suspected hilar or mediastinal metastases, as well as for evaluating unclear mediastinal or hilar lesions.

EUS-guided fine-needle aspiration in the mediastinum

The evaluation and management of esophageal and mediastinal disease has changed considerably since the introduction of EUS. EUS provides precise imaging of the histologic layers of the esophageal wall and surrounding mediastinal structures. EUS is now a well-established modality for the staging of a variety of GI and pancreaticobiliary malignancies. Furthermore, it has been reported to play an important role in the evaluation of mediastinal lesions and in the detection of metastasis to lymph nodes.1-9 Traditionally, the mediastinum has been evaluated by radiographic imaging such as CT and by invasive studies like bronchoscopy and mediastinoscopy. Evaluation of the mediastinum using EUS has been reported to be useful for a number of indications. Most notable is the assessment of enlarged lymph nodes that are detected by other imaging modalities such as CT or magnetic resonance imaging. Probably the most important indication for mediastinal imaging is the detection and/or staging of lung cancer. Documentation of lymph node involvement with metastatic disease is crucial in the staging and management of non-small cell lung cancer (NSCLC). The introduction of the curved linear array echoendoscope approximately 8 years ago led to the development of EUS-guided fine-needle aspiration (FNA), which is now becoming recognized as an integral part of endosonography. EUS-guided FNA has been reported to be a safe and effective approach for evaluation of lymph nodes and masses in the posterior mediastinum.10-13 Tissue diagnosis from these lesions has been difficult to obtain by conventional methods such as mediastinoscopy, which is an invasive and tedious procedure, or percutaneous CT-guided puncture, which has a low yield and increased risk, especially in the case of smaller lesions.14 The objectives of this article are twofold: to discuss the clinical utility of EUS and EUS-guided FNA biopsy for evaluating the mediastinum in benign and malignant disease processes including the detection of posterior mediastinal lymph node metastases in patients with NSCLC and to describe the technique for performing safe EUS-guided FNA biopsy in the mediastinum.