Imaging of tumors of the trachea and central bronchi

Lung-RADS Category 3 and 4 Nodules on Lung Cancer Screening in Clinical Practice

Background: Lung-RADS category 3 and 4 nodules account for most cancers among screening-detected lung cancers and are considered actionable nodules with management implications. The cancer frequency among such nodules is estimated in the Lung-RADS recommendations and has been investigated primarily using retrospectively assigned Lung-RADS classifications. Objective: To assess the frequency of cancer among lung nodules assigned Lung-RADS category 3 or 4 at lung cancer screening (LCS) in clinical practice and factors that impact the cancer frequency within each category. Methods: This retrospective study was based on review of clinical radiology reports of 9148 consecutive low-dose CT LCS examinations performed in 4798 patients between June 2014 and January 2021 as part of an established LCS program. Unique nodules assigned Lung-RADS category 3 or 4 (4A, 4B, or 4X) that were clinically categorized as benign or malignant by a multidisciplinary conference, considering histologic analysis and follow-up imaging, were selected for further analysis; benign diagnoses based on stability required at least 12 months of follow-up imaging. Indeterminate nodules were excluded. Cancer frequencies were evaluated. Results: Of the 9148 LCS examinations, 857 (9.4%) were assigned Lung-RADS category 3, and 721 (7.9%) were assigned category 4. The final analysis included 1297 unique nodules in 1139 patients (598 men, 541 women; mean age, 66.0±6.3 years). A total of 1108/1297 (85.4%) nodules were deemed benign, and 189/1297 (14.6%) were deemed malignant. Frequencies of malignancy for category 3, 4A, 4B, and 4X nodules were 3.9%, 15.5%, 36.3%, and 76.8%, respectively. A total of 45/46 (97.8%) endobronchial nodules (all category 4A) were deemed benign based on resolution. Cancer frequency was 13.1%, 24.4%, and 13.5% for solid, part-solid, and ground-glass nodules, respectively. Conclusions: When applying Lung-RADS for LCS clinical practice, the frequency of Lung-RADS category 3 and 4 nodules, as well as cancer frequency in these categories, were higher than prevalence and cancer risk estimated for category 3 and 4 nodules in the Lung-RADS recommendations and reported in earlier studies using retrospective category assignments. Nearly all endobronchial category 4A nodules were benign. Clinical Impact: Future Lung-RADS iterations should consider these findings from real-world practice to improve the system's clinical utility.

Predicting Histology of Tracheobronchial Neoplasms: A CT Based Differentiation Model

BACKGROUND

Tracheobronchial (TB) tumors follow same pathological classification as lung neoplasms; however, some entities are known to favor airways. Distinction of pathological types is necessary for suggesting appropriate management strategy.

PURPOSE

To evaluate utility of multidetector CT (MDCT) in differentiation of primary TB tumors; and assess validity of a scoring system based on imaging biomarkers to differentiate tumor types.

METHODS

MDCT features of 45 patients were analyzed for location, shape, calcification, attenuation, parenchymal changes, bronchoceles, extraluminal extension, lymphadenopathy, metastases. The two largest groups were compared with each other and remaining entities using Chi square tests. Six-point scoring system combining the differentiating features was devised and receiver operating characteristic curve analysis performed.

RESULTS

The most frequent type was neuroendocrine tumors (NET) (51.1%), followed by salivary gland tumors (SGT) (20%); including adenoid cystic carcinoma (ACC) (13.3%) and mucoepidermoid carcinoma (MEC) (6.7%). Comparing NETs with other entities as a whole, and independently with SGTs, significant difference was found among location (p = 0.05 and 0.001 respectively), shape (p < 0.001), calcification (p = 0.038 and 0.041 respectively), attenuation (p = 0.001 and 0.019 respectively), bronchoceles (p = 0.013 and 0.010 respectively). Significant difference was found among ACC and MEC in location (p = 0.01) and morphology (p < 0.001). On receiver operating characteristic (ROC) curve analysis of the score, areas under curve for NET, SGT and ACC were 0.913, 0.872 and 0.962 respectively. Suggested cut-off values were >3.5 for carcinoid (sensitivity 70%, specificity 91%), <2.5 for SGT (sensitivity 78%, specificity 75%), <1.5 for ACC (sensitivity 83%, specificity 92%).

CONCLUSION

Use of a scoring system enables maximum diagnostic accuracy in MDCT differentiation of TB tumors.

Endobronchial Extranodal Marginal Zone B-Cell Lymphoma with Plasmacytic Differentiation

Endobronchial tumors (ET) are unusual and mostly malignant, presenting with non-specific symptoms that often delay appropriate diagnosis and treatment. Lymphomas in the airway represent less than 1% of pulmonary malignancies and require multidisciplinary approach for their management. We present a case of a 48-year-old male former smoker with a one-year history of recurrent respiratory infections and new-onset shortness of breath. Diagnostic tests included a chest computed tomography (CT) reporting the presence of an endobronchial mass and neck and cervical lymph node biopsies with inconclusive results. Bronchoscopy was successfully performed for tumor resection, improving the patient’s respiratory symptoms. Histological analysis described an extranodal marginal zone B-cell lymphoma (ENMZL) with plasmacytic differentiation; a subtype of non-Hodgkin’s lymphoma (NHL) in mucosa-associated lymphoid tissue (MALT), rarely found as an endobronchial growth. ET should be considered in the setting of persistent and worsening respiratory symptoms. ENMZL with plasmacytic differentiation is rarely found as an ET and diagnosis requires bronchoscopic intervention and extensive immunohistochemical analysis.

Extramedullary Plasmacytoma Involving the Trachea: A Case Report and Literature Review

BACKGROUND

Extramedullary plasmacytoma is an uncommon type of plasma cell neoplasm that occurs outside of the bone marrow. Very rarely, extramedullary plasmacytomas can involve the trachea, causing significant respiratory distress.

CASE REPORT

We describe a patient with a history of multiple myeloma who presented with voice hoarseness and dyspnea and was found to have airway obstruction due to an extramedullary plasmacytoma near the larynx. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: It is important to investigate the possibility of upper airway obstruction in cancer patients presenting with hoarseness and dyspnea to prevent incorrect management, which can lead to fatal results. In particular, wheezing and dyspnea in patients with a history of asthma may not always be due to asthma exacerbation. Computed tomography scans and emergency laryngoscopy have been shown to be useful in aiding with correct diagnosis of upper airway obstruction, ensuring appropriate treatment.

Multidimensional evaluation of tracheobronchial disease in adults

The large airways can be affected by a wide spectrum of acquired benign and malignant diseases. These lesions may present as focal or diffuse processes and with narrowing or widening of the airway. Some of these may be asymptomatic for quite some time and may be incidentally detected on imaging, while others may be symptomatic, causing airway compromise. There may be a characteristic radiograph and computed tomography (CT) appearance, suggesting a narrow differential. When the imaging findings are not definitive, tissue may be obtained for pathological analysis. It behooves the radiologist to be familiar with the pathologic findings that correlate with the radiographic or CT appearance of the most frequently seen large airway lesions. In this way, we may improve our diagnostic accuracy. This paper will present the imaging findings of the most prevalent tracheobronchial lesions along with any associated pathology. Teaching Points • The large airways can be affected by many acquired benign and malignant diseases.• Large airway lesions may present as focal or diffuse processes, with narrowing or widening.• There may or may not be characteristic imaging appearance of large airway disease.• If imaging findings are not definitive, tissue may be obtained for pathological analysis.

Diagnostic Value of Multidetector CT and Its Multiplanar Reformation, Volume Rendering and Virtual Bronchoscopy Postprocessing Techniques for Primary Trachea and Main Bronchus Tumors

Purpose

To evaluate the diagnostic value of multidetector CT (MDCT) and its multiplanar reformation (MPR), volume rendering (VR) and virtual bronchoscopy (VB) postprocessing techniques for primary trachea and main bronchus tumors.

Methods

Detection results of 31 primary trachea and main bronchus tumors with MDCT and its MPR, VR and VB postprocessing techniques, were analyzed retrospectively with regard to tumor locations, tumor morphologies, extramural invasions of tumors, longitudinal involvements of tumors, morphologies and extents of luminal stenoses, distances between main bronchus tumors and trachea carinae, and internal features of tumors. The detection results were compared with that of surgery and pathology.

Results

Detection results with MDCT and its MPR, VR and VB were consistent with that of surgery and pathology, included tumor locations (tracheae, n = 19; right main bronchi, n = 6; left main bronchi, n = 6), tumor morphologies (endoluminal nodes with narrow bases, n = 2; endoluminal nodes with wide bases, n = 13; both intraluminal and extraluminal masses, n = 16), extramural invasions of tumors (brokethrough only serous membrane, n = 1; 4.0 mm—56.0 mm, n = 14; no clear border with right atelectasis, n = 1), longitudinal involvements of tumors (3.0 mm, n = 1; 5.0 mm—68.0 mm, n = 29; whole right main bronchus wall and trachea carina, n = 1), morphologies of luminal stenoses (irregular, n = 26; circular, n = 3; eccentric, n = 1; conical, n = 1) and extents (mild, n = 5; moderate, n = 7; severe, n = 19), distances between main bronchus tumors and trachea carinae (16.0 mm, n = 1; invaded trachea carina, n = 1; >20.0 mm, n = 10), and internal features of tumors (fairly homogeneous densities with rather obvious enhancements, n = 26; homogeneous density with obvious enhancement, n = 1; homogeneous density without obvious enhancement, n = 1; not enough homogeneous density with obvious enhancement, n = 1; punctate calcification with obvious enhancement, n = 1; low density without obvious enhancement, n = 1).

Conclusion

MDCT and its MPR, VR and VB images have respective advantages and disadvantages. Their combination could complement to each other to accurately detect locations, natures (benignancy, malignancy or low malignancy), and quantities (extramural invasions, longitudinal involvements, extents of luminal stenoses, distances between main bronchus tumors and trachea carinae) of primary trachea and main bronchus tumors with crucial information for surgical treatment, are highly useful diagnostic methods for primary trachea and main bronchus tumors.

Imaging of the central airways with bronchoscopic correlation: pictorial essay

A wide variety of pathologic processes, both benign and malignant, affect the central airways. These processes may be classified into 4 distinct groups: anatomic variants, lesions that result in focal or diffuse airway narrowing, and those that result in multinodular airway disorder. Key to the accurate assessment of the central airways is meticulous imaging technique, especially the routine acquisition of contiguous high-resolution, 1-mm to 1.5-mm images. These images enable high-definition axial, coronal, and sagittal reconstructions, as well as advanced imaging techniques, including minimum intensity projection images and virtual bronchoscopy. Current indications most commonly include patients presenting with signs and symptoms of possible central airway obstruction, with or without hemoptysis. In addition to diagnosing airway abnormalities, computed tomography (CT) also serves a critical complementary role to current bronchoscopic techniques for both diagnosing and treating airway lesions. Advantages of CT include noninvasive visualization of the extraluminal extent of lesions, as well as visualization of airways distal to central airways obstructions. As discussed and illustrated later, thorough knowledge of current bronchoscopic approaches to central airway disease is essential for optimal correlative CT interpretation.

The Wonderful World of the Windpipe: A Review of Central Airway Anatomy and Pathology

A variety of pathologic processes can involve the central airways. Abnormalities may either diffusely or focally involve the tracheal or mainstem bronchial walls. Diseases that diffusely involve the tracheal wall can be subclassified as sparing the membranous trachea or circumferentially involving the tracheal wall. Focal diseases of the trachea and mainstem bronchi include benign and malignant causes. Additionally, congenital and acquired morphologic abnormalities of the trachea will be reviewed.

Update on multidetector computed tomography imaging of the airways

Recent advances in multidetector computed tomography (MDCT) technology have transformed the imaging evaluation of the trachea and bronchi. Multiplanar 2-dimensional and 3-dimensional volume reconstruction techniques, including external rendering and virtual bronchoscopy, can be generated in mere minutes, thereby complementing conventional axial CT imaging in the depiction of various central airway disease processes including airway stenoses, central airway neoplasms, and congenital airway disorders. Paired inspiratory and dynamic expiratory MDCT imaging, along with newer cine CT imaging methods, have enhanced the assessment of tracheobronchomalacia in both adults and the pediatric population. In addition, MDCT imaging plays an essential complementary role to conventional bronchoscopy, facilitating planning and guidance of bronchoscopic interventions, and providing a noninvasive method for postprocedural surveillance.

MDCT of trachea and main bronchi

Tracheobronchial imaging has undergone a major revolution since the advent of MDCT. The improved spatial and temporal resolution not only allows reformatting images that enhance the comprehension of disease before bronchoscopy or surgery, it has introduced newer techniques such as dynamic expiratory imaging to evaluate for tracheomalacia, which can be a subtle, but a confounding entity for patients and clinician alike. Tracheobronchial diseases can be arbitrarily divided into those that cause focal and diffuse narrowing and widening. Such groupings can help develop a practical approach in evaluating diseases of the central airways.

MDCT of trachea and main bronchi

Tracheobronchial imaging has undergone a major revolution. The improved spatial and temporal resolution has introduced newer techniques such as dynamic expiratory imaging to evaluate for tracheomalacia. This article describes these techniques.