Tumors in the tracheobronchial tree: CT and FDG PET features

18F-FDG PET/CT of Benign Tracheal Schwannoma

ABSTRACT

Schwannoma is a benign tumor originating from Schwann cells. It commonly occurs in the head, neck, and extremities, but rarely occurs in the trachea. Tracheal schwannoma is usually asymptomatic. We reported the 18F-FDG PET/CT findings of a 61-year-old man with bronchoscopically biopsy-proven schwannoma, which presented challenges in differentiation from certain benign tumors and low-grade malignancies in the trachea.

Imaging of Large Airway Disorders

Large airway disorders encompass a large variety of diseases and pathology, with broad categories including anatomic variants, congenital abnormalities, acquired abnormalities, inflammatory/infiltrative causes, infection, and tumors. The most common diseases in each category are discussed with a focus on the salient imaging findings. Pitfalls to beware of are discussed through the article, and concludes with a general method to approaching large airways pathology that should provide the reader with a basic framework and understanding of this complex topic.

[Tracheal Tumours]

Malignant primary tracheal tumours are rare. The most common histological subtypes are squamous cell carcinoma and adenoid cystic carcinoma. These two entities have different prognoses and growth patterns. Tracheobronchoscopy and thoracic sectional imaging are standard diagnostic tools for tumour staging and local evaluation. Complete surgical resection of the affected tracheal segment is the treatment of choice for limited disease without distant metastases. Incomplete gross tumour resection with additional irradiation is an acceptable therapeutic option for adenoid cystic carcinoma. Interventional endoscopy with tumour debulking or tracheal stenting and/or definitive mediastinal radiotherapy are treatment alternatives in either a locally advanced or palliative setting.

Endobronchial solitary fibrous tumors: An enigma for diagnosis

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms constituting less than 2% of all soft tissue tumors. They typically originate in the thoracic cavity, mainly in the pleura, but can also occur in other various sites such as lung parenchyma, pericardium, and bronchus. In this study, a 49-year-old non-smoking female with a history of allergies presented to our pulmonary clinic with a chronic cough. An explorative bronchoscopy revealed an intrabronchial mass in the left superior bronchi, and a 68 Ga-DOTATOC positron emission computed tomography suggested a carcinoid tumor. Subsequent pulmonary segmentectomy unveiled a well-circumscribed polypoid lesion diagnosed as a low-grade bronchus SFT through histopathological and immunohistochemical assessments. The patient was asymptomatic after surgical excision and showed no other lesion during the 6-month follow-up. The endobronchial location of SFT is uncommon, with only a few reported cases in the literature, underscoring the necessity of considering various differential diagnoses, including carcinoid, mucoepidermoid carcinoma, endobronchial pleomorphic adenoma, hamartoma, leiomyoma, and metastasis, depending on location and imaging features. This report underscores the importance of careful histological and immunohistochemical evaluation in understanding and appropriately stratifying the risk associated with polypoid lesions.

Current diagnosis and treatment of salivary gland-type tumors of the lung

Salivary gland-type tumors of the lung are thought to originate from the submucosal exocrine glands of the large airways. Due to their rare occurrence, reports of their study are limited to small-scale or case reports. Therefore, daily clinical practices often require a search for previous reports. In the last 20 years, several genetic rearrangements have been identified, such as MYB::NF1B rearrangements in adenoid cystic carcinoma, CRTC1::MAML2 rearrangements in mucoepidermoid carcinoma, EWSR1::ATF1 rearrangements in hyalinizing clear cell carcinoma and rearrangements of the EWSR1 locus or FUS (TLS) locus in myoepithelioma and myoepithelial carcinoma. These molecular alterations have been useful in diagnosing these tumors, although they have not yet been linked to molecularly targeted therapies. The morphologic, immunophenotypic, and molecular characteristics of these tumors are similar to those of their counterparts of extrapulmonary origin, so clinical and radiologic differential diagnosis is required to distinguish between primary and metastatic disease of other primary sites. However, these molecular alterations can be useful in differentiating them from other primary lung cancer histologic types. The management of these tumors requires broad knowledge of the latest diagnostics, surgery, radiotherapy, bronchoscopic interventions, chemotherapy, immunotherapy as well as therapeutic agents in development, including molecularly targeted agents. This review provides a comprehensive overview of the current diagnosis and treatment of pulmonary salivary gland tumors, with a focus on adenoid cystic carcinoma and mucoepidermoid carcinoma, which are the two most common subtypes.

Pulmonary salivary gland tumor-hyalinizing clear cell carcinoma: a literature review

Primary pulmonary hyalinizing clear cell carcinoma (HCCC) is a very rare lung tumor that accounts for less than 0.09% of all primary lung tumors and has no specific epidemiology. The correct diagnosis requires imaging, laboratory, pathological, immunohistochemical, and molecular examination. The most typical feature of pulmonary HCCC is the clear cell component with clear stroma. In addition, the fusion gene EWSR1::ATF1 due to t(12;22)(q13;q12) is essential for the pathological diagnosis of pulmonary HCCC. The main treatment for pulmonary HCCC is surgery. This review focus on the pathological features, immunohistochemical examination, mutation analysis and treatment of pulmonary HCCC.

Comparison of Lung-RADS Version 1.1 and Lung-RADS Version 2022 in Classifying Airway Nodules Detected at Lung Cancer Screening CT

Purpose To compare the Lung Imaging Reporting and Data System (Lung-RADS) version 1.1 with version 2022 classification of airway nodules detected at lung cancer screening CT examinations. Materials and Methods This retrospective study included all patients who underwent a lung cancer screening CT examination in the authors' health care network between 2015 and 2021 with a reported airway or endobronchial nodule. A fellowship-trained cardiothoracic radiologist reviewed these CT images and characterized the airway nodules by size, location, multiplicity, morphology, dependent portions of airway, internal air, fluid attenuation, distal changes, outcome at follow-up, and final pathologic diagnosis, if malignant. Sensitivity and specificity of Lung-RADS version 1.1 in detecting malignant nodules were compared with those of Lung-RADS version 2022 using the McNemar test. Results A total of 174 patients were included. Of these, 163 (94%) had airway nodules that were deemed benign, while 11 (6%) had malignant nodules. Airway nodules in the trachea and mainstem bronchi were all benign, while lobar and segmental airway nodules had the highest risk for lung cancer (17.2% and 11.1%, respectively). Of the 12 subsegmental airway nodules that were obstructive, three (25%) were malignant and nine (75%) were benign. Nodules with nonobstructive morphologies, dependent portions of airway, internal air, or fluid attenuation were all benign. Only 10 of the 92 (10.9%) patients with positive Lung-RADS by clinical report had cancer. Lung-RADS version 2022 resulted in higher specificity than version 1.1 (82% vs 50%, P < .001), without sacrificing sensitivity (91% for both). Conclusion Compared with the previous version, Lung-RADS version 2022 reduced the number of false-positive screening CT examinations while still identifying malignant airway nodules. Keywords: CT, Lung, Primary Neoplasms, Pulmonary, Lung Cancer Screening, Lung-RADS, Nodule Risk, Airway Nodule, Endobronchial Nodule © RSNA, 2024.

Isolated Endobronchial Metastasis of Breast Cancer Successfully Managed With Multimodal Treatment

Isolated endobronchial metastases of breast cancers, without other visceral metastatic involvement, are exceptional. We report here an observation of isolated endobronchial metastasis discovered 18 months after complete treatment of breast carcinoma. The endobronchial metastasis was revealed by an incoercible cough and hemoptysis. A bronchoscopy revealed a budding tumor process obstructing the right stem bronchus and a biopsy was performed. The anatomopathological and immunohistochemical analysis confirmed the metastatic nature of the endobronchial tumor. The patient received treatment with palbociclib and aromatase inhibitors. Two years after radiotherapy and under hormone treatment, the patient is in complete remission of her breast cancer and endobronchial metastasis. Emerging research suggests that oligometastatic breast cancer carries a superior prognosis. We believe that patients with oligometastatic breast cancer should be treated with curative intent, including ablative therapy to all sites of disease if it can be safely accomplished. This approach may offer an additional chance for prolonged survival.

Tracheal hamartoma masquerading as asthma

We present a rare case of a female non-smoker diagnosed with a large benign tracheal chondrohamartoma, masquerading as severe asthma. The patient was in her late 70s and had a history of asthma. She had presented to hospital with multiple episodes of intractable cough, shortness of breath and wheeze in the year prior to diagnosis. She had been managed for asthma for two decades by different physicians in primary care, based on documented airflow obstruction. Given her repeated admissions, the respiratory team was consulted. In view of the persistent cough despite maximal treatment, she was referred for a thoracic high-resolution CT scan which revealed a large intraluminal tracheal polypoid mass. Flexible bronchoscopy was performed and this confirmed the presence of a large pedunculated mass in the distal trachea. The patient subsequently underwent removal of the mass by means of rigid bronchoscopy, laser and electrocautery followed by argon ablation of residual tissue. She made an excellent recovery with full resolution of her respiratory symptoms and normalisation of her pulmonary function tests.

Clinical and Paraclinical Characteristics of Endobronchial Pulmonary Squamous Cell Carcinoma-A Brief Review

BACKGROUND

Endobronchial squamous cell carcinoma is one of the most common types of tumors located inside the tracheobronchial tree. Patients often present in advanced stages of the disease, which most often leads to a targeted therapeutic attitude of pneumonectomy. Practicing lung parenchyma-preserving surgery led us to undertake this review.

MATERIALS AND METHODS

We used three search platforms-SCIENCE, MEDLINE, and PubMed-in order to identify studies presenting case reports, investigations, and reviews on endobronchial squamous cell carcinoma. We identified the clinical and paraclinical features of endobronchial squamous cell carcinoma. All the selected articles were in English and addressed the clinical criteria of endobronchial squamous cell carcinoma, autofluorescence bronchoscopy in endobronchial squamous cell carcinoma, imaging features of endobronchial squamous cell carcinoma, blood tumor markers specific to lung squamous cell carcinoma, and histopathological features of endobronchial squamous cell carcinoma.

RESULTS

In total, 73 articles were analyzed, from which 48 articles were selected as bibliographic references. We present the criteria used for the identification of endobronchial squamous cell carcinoma in order to highlight its main characteristics and the most reliable technologies that can be used for the detection of this type of cancer.

CONCLUSIONS

The current literature review highlights the clinical and paraclinical characteristics of endobronchial squamous cell carcinoma. It aims to open new paths for research and early detection with respect to the frequent practice of lung parenchymal preservation surgery.

Primary Pulmonary Hyalinizing Clear Cell Carcinoma: Case Series With Review of Literature

Background: Hyalinizing clear cell carcinomas of tracheobronchial origin are very rare salivary gland type tumors accounting for less than 1% of lung tumors with only 13 cases reported to date. Their radiological features, morphological spectrum, and molecular features are not well described. Aim: To perform a clinicopathological analysis of primary pulmonary hyalinizing clear cell carcinomas. Method: A retrospective search of primary pulmonary hyalinizing clear cell carcinomas was conducted from authors' institutions and the clinicopathological features including details of molecular testing were analyzed. Results: Five primary pulmonary hyalinizing clear cell carcinomas were identified. The mean patient age at diagnosis was 48.2 years (range: 33-64 years). Three patients were women. All patients were nonsmokers and 3 were symptomatic; 2 were detected incidentally during health screening. The tumors were located in the main lobar bronchi ranging from 1.3 to 4.9 cm in maximum dimension. Microscopy showed cords and nests of at least, focally clear tumor cells. Mucin cysts lacking goblet cells were seen. All tumors were uniformly positive for p40, p63, AE1/AE3, keratin 7, and epithelial membrane antigen but negative for TTF1, KIT, neuroendocrine markers, and other myoepithelial markers. All cases showed Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Perineural invasion and lymph node metastases were detected in patient 5. Two patients with available follow-up data were recurrence-free until 4 years (patient 1) and 9 months (patient 5) after resection. Conclusion: The present series adds to the scant available literature on primary pulmonary hyalinizing clear cell carcinomas highlighting the characteristic histomorphology, immunoprofiles, and benign outcomes of these rare tumors.

Malignant and Benign Tracheobronchial Neoplasms: Comprehensive Review with Radiologic, Bronchoscopic, and Pathologic Correlation

Tracheobronchial neoplasms are much less common than lung parenchymal neoplasms but can be associated with significant morbidity and mortality. They include a broad differential of both malignant and benign entities, extending far beyond more commonly known pathologic conditions such as squamous cell carcinoma and carcinoid tumor. Airway lesions may be incidental findings at imaging or manifest with symptoms related to airway narrowing or mucosal irritation, invasion of adjacent structures, or distant metastatic disease. While there is considerable overlap in clinical manifestation, imaging features, and bronchoscopic appearances, an awareness of potential distinguishing factors may help narrow the differential diagnosis. The authors review the epidemiology, imaging characteristics, typical anatomic distributions, bronchoscopic appearances, and histopathologic findings of a wide range of neoplastic entities involving the tracheobronchial tree. Malignant neoplasms discussed include squamous cell carcinoma, malignant salivary gland tumors (adenoid cystic carcinoma and mucoepidermoid carcinoma), carcinoid tumor, sarcomas, primary tracheobronchial lymphoma, and inflammatory myofibroblastic tumor. Benign neoplasms discussed include hamartoma, chondroma, lipoma, papilloma, amyloidoma, leiomyoma, neurogenic lesions, and benign salivary gland tumors (pleomorphic adenoma and mucous gland adenoma). Familiarity with the range of potential entities and any distinguishing features should prove valuable to thoracic radiologists, pulmonologists, and cardiothoracic surgeons when encountering the myriad of tracheobronchial neoplasms in clinical practice. Attention is paid to any features that may help render a more specific diagnosis before pathologic confirmation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Management of an Acute Airway Obstruction Due to Tracheal Carcinoma in a Patient With Severe Glottic Stenosis

In this paper, we present the case of acute airway obstruction due to tracheal carcinoma in a patient with glottic stenosis due to previously treated laryngeal carcinoma. Because of severe dyspnea from the obstructive endotracheal mass, tracheotomy under local anesthesia was immediately performed. Intubation with pediatric size (I.D. 4.5 mm) cuffed endotracheal tube was performed by the surgeon through tracheostomy under endoscopic visualization. Blakesley forceps and electrocautery were used for tumor debulking. Postoperatively there were no complications and the patient was discharged after four days. The histopathology report showed a squamous cell carcinoma. The tumor board decided on adjuvant chemoradiotherapy for the treatment of the patient.

Hot Gloved Finger Sign in Endobronchial Metastasis From Hepatocellular Carcinoma on FDG PET/CT

ABSTRACT

Endobronchial metastasis from hepatocellular carcinoma is exceedingly rare. We describe FDG PET/CT findings in a case with isolated endobronchial metastasis from hepatocellular carcinoma 13 years after hepatectomy. The endobronchial metastasis appeared as hypermetabolic branching tubular opacities, producing a hot gloved finger sign on FDG PET/CT. This case indicates that the hot gloved finger sign may be suggestive of extensive endobronchial growing of a malignant condition but not endobronchial mucoid plug.

68Ga-DOTATATE PET/CT Scan as a Valuable Tool for Diagnosis and Staging of the Rare Entity of Tracheal Paragangliomas

ABSTRACT

Primary paraganglioma of the trachea is a rare differential among more common tracheal masses. Definitive diagnosis of tracheal masses is obtained via endoscopic biopsy. Utilization of 68Ga-DOTATATE PET/CT is valuable in the workup of these lesions as paragangliomas would have significantly higher radiotracer uptake compared with the more common squamous cell and adenoid cystic carcinomas. This is particularly important in tracheal paragangliomas, which are typically friable and hypervascular with higher risk of significant bleeding on biopsy. In addition, 68Ga-DOTATATE PET/CT can be used to evaluate for local invasion and metastatic disease as a 1-step imaging modality.

Endobronchial mucoepidermoid carcinoma in a pediatric patient: A case report

Mucoepidermoid carcinoma (MEC) is an uncommon type of salivary gland tumor that can present as an endobronchial neoplasm, most commonly in the adult population. Neuroendocrine carcinoid tumors comprise the majority of bronchial neoplasms in the pediatric population and are nearly indistinguishable from MEC on imaging. We present a rare case of MEC in a 3-year-old presenting with recurrent symptoms of lower airway obstruction and discuss its typical associated symptoms and imaging features.

18FDG PET-Positive Congenital Pulmonary Airway Malformation Mimicking Lung Cancer

ABSTRACT

Adult cases of type 2 congenital pulmonary airway malformation (CPAM) are extremely rare, and no PET/CT findings have been reported for CPAM. We encountered a case of 18FDG PET-positive CPAM mimicking lung cancer in a 45-year-old asymptomatic man. CT revealed a large cavitary mass in the left lower lobe. SUVmax measured by 18FDG PET was 3.5. The patient underwent video-assisted thoracoscopic lobectomy on suspicion of CPAM with/or lung cancer. Histologically, no neoplastic cells were present, and the lesion was consistent with type 2 CPAM. An adenomatoid proliferative pattern and granulomatous lesions may have contributed to a PET/CT false-positive result.

[Surgery of primary tracheal tumors]

OBJECTIVE

To determine the main forms of primary tracheal cancer (PTC), to specify the indications for various surgeries in these patients depending on extent and localization of lesion.

MATERIAL AND METHODS

There were 263 PTC patients. Benign tumors were diagnosed in 68 (25.9%) patients, malignancies - in 195 (74.1%) cases. Tracheal cancer includes 3 basic morphological variants - adenocystic cancer (49.7%), carcinoid (18.7%) and squamous cell carcinoma (19.0%). Other forms of malignancies were much less common. We applied endoscopic intraluminal and open surgeries. In malignant PTC, open surgeries were performed in 165 (84.6%) out of 195 patients. Baseline palliative endoscopic treatment was performed in 30 patients. They underwent airway recanalization (with subsequent tracheal stenting in 19 patients). Endoscopic resection was preferred for benign tumors.

RESULTS

Twenty (12.1%) patients died after open surgery, and 1 (3.3%) patient died after endoscopic procedure. Most lethal outcomes occurred in early years of development of tracheal surgery. The causes of mortality were tracheal anastomotic failure in 12 patients, pneumonia in 6 patients, and arterial bleeding in 2 patients. Severe postoperative period was observed in all 3 patients after tracheal replacement with a silicone prosthesis. Long-term treatment outcomes depended on morphological structure of PTC. Favorable results were observed in patients with neuroendocrine tumor (carcinoid), worse outcomes in adenocystic cancer and unfavorable results in squamous cell carcinoma (p<0.0013). Five-year survival rates were 75%, 65.6%, and 13.3%; 10-year survival rates were 75%, 56.2%, and 13.3%, respectively. These outcomes after combined treatment of primary tracheal cancer were significantly better compared to lung cancer (p<0.05 when compared to global data).

CONCLUSION

Treatment of primary tracheal cancer should be based on classical principles of modern oncology (combined therapy, tumor resection with lymphadenectomy). Open and endoscopic interventions are justified. PTC is characterized by more favorable outcomes compared to lung cancer. It is difficult to analyze long-term results in tracheal cancer depending on various features of tumor process due to small number of observations. Accurate conclusions require multiple-center studies, preferably with international participation, which can convincingly prove certain concept.

Automated procedure assessing the accuracy of HRCT-PET registration applied in functional virtual bronchoscopy

Background

Bronchoscopy serves as direct visualisation of the airway. Virtual bronchoscopy provides similar visual information using a non-invasive imaging procedure(s). Early and accurate image-guided diagnosis requires the possible highest performance, which might be approximated by combining anatomical and functional imaging. This communication describes an advanced functional virtual bronchoscopic (fVB) method based on the registration of PET images to high-resolution diagnostic CT images instead of low-dose CT images of lower resolution obtained from PET/CT scans. PET/CT and diagnostic CT data were collected from 22 oncological patients to develop a computer-aided high-precision fVB. Registration of segmented images was performed using elastix.

Results

For virtual bronchoscopy, we used an in-house developed segmentation method. The quality of low- and high-dose CT image registrations was characterised by expert’s scoring the spatial distance of manually paired corresponding points and by eight voxel intensity-based (dis)similarity parameters. The distribution of (dis)similarity parameter correlating best with anatomic scoring was bootstrapped, and 95% confidence intervals were calculated separately for acceptable and insufficient registrations. We showed that mutual information (MI) of the eight investigated (dis)similarity parameters displayed the closest correlation with the anatomy-based distance metrics used to characterise the quality of image registrations. The 95% confidence intervals of the bootstrapped MI distribution were [0.15, 0.22] and [0.28, 0.37] for insufficient and acceptable registrations, respectively. In case of any new patient, a calculated MI value of registered low- and high-dose CT image pair within the [0.28, 0.37] or the [0.15, 0.22] interval would suggest acceptance or rejection, respectively, serving as an aid for the radiologist.

Conclusion

A computer-aided solution was proposed in order to reduce reliance on radiologist’s contribution for the approval of acceptable image registrations.

Sialadenoma Papilliferum of the Bronchus: An Unrecognized Bronchial Counterpart of the Salivary Gland Tumor With Frequent BRAF V600E Mutations

Sialadenoma papilliferum (SP) is a rare benign tumor of the salivary glands, and only 3 unequivocal cases of SP arising in the bronchus have been reported. We herein describe the histomorphologic and molecular features of 4 bronchial SP cases and discuss the differential diagnosis of this entity and the relationship with its clinicopathologic mimics, in particular, glandular papilloma and mixed squamous cell and glandular papilloma (GP/MP). We encountered 2 male and 2 female patients with bronchial SP (mean: 66.8 y old). All 4 tumors arose in the central bronchus and were characterized by a combination of surface exophytic endobronchial papillary proliferation and a submucosal multicystic component with complex architecture. The neoplastic epithelium consisted predominantly of nonciliated stratified columnar cells with ciliated, squamous, and mucinous cells present focally. While 2 tumors (50%) harbored a BRAF V600E mutation by molecular and immunohistochemical analysis, similar to GP/MP, no KRAS, HRAS, AKT1, or PIK3CA mutations were detected in any of the cases. Two patients were treated with limited resection, while 2 patients underwent lobectomy based on the diagnosis of adenocarcinoma or possible squamous cell carcinoma in situ in the preoperative biopsy. All survived without recurrence or metastasis for 23 to 122 months after treatment. SP can develop in the central bronchus as the bronchial counterpart of the salivary gland tumor and should be considered in the differential diagnosis of endobronchial tumors. In addition, some histologic resemblance and frequent BRAF V600E mutation raise the possibility of SP and GP/MP being on the same disease spectrum.

Brazilian Group of Gastrointestinal Tumours' consensus guidelines for the management of oesophageal cancer

Oesophageal cancer is among the ten most common types of cancer worldwide. More than 80% of the cases and deaths related to the disease occur in developing countries. Local socio-economic, epidemiologic and healthcare particularities led us to create a Brazilian guideline for the management of oesophageal and oesophagogastric junction (OGJ) carcinomas. The Brazilian Group of Gastrointestinal Tumours invited 50 physicians with different backgrounds, including radiology, pathology, endoscopy, nuclear medicine, genetics, oncological surgery, radiotherapy and clinical oncology, to collaborate. This document was prepared based on an extensive review of topics related to heredity, diagnosis, staging, pathology, endoscopy, surgery, radiation, systemic therapy (including checkpoint inhibitors) and follow-up, which was followed by presentation, discussion and voting by the panel members. It provides updated evidence-based recommendations to guide clinical management of oesophageal and OGJ carcinomas in several scenarios and clinical settings.

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.

Focused targeting of inhaled magnetic aerosols in reconstructed in vitro airway models

The pulmonary tract is an attractive route for topical treatments of lung diseases. Yet, our ability to confine the deposition of inhalation aerosols to specific lung regions, or local airways, remains still widely beyond reach. It has been hypothesized that by coupling magnetic particles to inhaled therapeutics the ability to locally target airway sites can be substantially improved. Although the underlying principle has shown promise in seminal in vivo animal experiments as well as in vitro and in silico studies, its practical implementation has come short of delivering efficient localized airway targeting. Here, we demonstrate in an in vitro proof-of-concept an inhalation framework to leverage magnetically-loaded aerosols for airway targeting in the presence of an external magnetic field. By coupling the delivery of a short pulsed bolus of sub-micron (~500 nm diameter) droplet aerosols with a custom ventilation machine that tracks the volume of air inhaled past the bolus, focused targeting can be maximized during a breath hold maneuver. Specifically, we visualize the motion of the pulsed SPION-laden (superparamagnetic iron oxide nanoparticles) aerosol bolus and quantify under microscopy ensuing deposition patterns in reconstructed 3D airway models. Our aerosol inhalation platform allows for the first time to deposit inhaled particles to specific airway sites while minimizing undesired deposition across the remaining airspace, in an effort to significantly augment the targeting efficiency (i.e. deposition ratio between targeted and untargeted regions). Such inhalation strategy may pave the way for improved treatment outcomes, including reducing side effects in chemotherapy.

CT Findings of Central Airway Lesions Causing Airway Stenosis-Visualization and Quantification: A Pictorial Essay

The tracheobronchial tree is a system of airways that allows the passage of air to aerate the lungs and entire body. Several pathological conditions can affect this anatomical region. Multidetector CT (MDCT) helps identify and characterize various large airway diseases. Post-processing tools, such as virtual bronchoscopy and automatic lung analysis, can help enhance the performance of imaging studies. In this pictorial essay review, we provide imaging findings of various bronchial lesions manifested as wall thickening and endoluminal nodules on conventional MDCT and advanced image visualization and analysis.

Endotracheal metastasis of colon cancer on FDG PET/CT

Although tracheal involvement of lung cancer is frequently seen, endotracheal metastasis of colon cancer is a rare entity. Since endotracheal lesion gives no symptom until tracheal lumen nearly occluded, the diagnosis of endotracheal metastasis could be challenging. F-18 fluorodeoxyglucose positron emission tomography/computed tomography may be crucial to detect this unusal distant metastasis of colon cancer. Herein, we report FDG avid endotracheal lesion that was confirmed as metastasis from colon cancer in 56-year-old female patient.

Gradual enhancement pattern of tracheobronchial adenoid cystic carcinoma on multiphasic dynamic computed tomography : a case series

Tracheobronchial adenoid cystic carcinoma is a rare malignancy. To the best of our knowledge, its enhancement pattern on multiphasic contrast-enhanced multidetector computed tomography has not been reported. Herein, we report the computed tomography findings of three consecutive cases of tracheobronchial adenoid cystic carcinoma. All lesions presented a gradual enhancement pattern on multiphasic contrast-enhanced computed tomography. We speculate that the gradual enhancement pattern on multiphasic contrast-enhanced computed tomography could potentially serve as a characteristic imaging feature and may therefore be a clue to diagnose tracheobronchial adenoid cystic carcinoma. J. Med. Invest. 67 : 378-381, August, 2020.

Mediastinal Masses: 18F-FDG-PET/CT Features Based on the International Thymic Malignancy Interest Group Classification

Imaging plays a key role in the management of mediastinal masses. In an effort to standardize the analysis of the mediastinum, the International Thymic Malignancy Interest Group (ITMIG) has proposed a three compartments-based diagnostic classification, intended for clinicians and radiologists. Several articles have documented its usefulness to guide the diagnosis using cross-sectional imaging. Similarly, fluorine-18-radiolabeled fluorodeoxyglucose positron emission tomography combined to computed tomography (¹⁸F-FDG-PET/CT) can be useful in this setting, either as a first-line diagnostic technique, or in addition to cross-sectional imaging. In this article, which is thought as an aid for nuclear medicine physicians and radiologists, we aim to present, based on the ITMIG classification, the main mediastinal pathologies that can be observed with ¹⁸F-FDG-PET/CT, and the additional diagnostic value that can be expected from this technique. For this purpose, we segmented the mediastinum according to the ITMIG classification, and reviewed the available literature for each of the corresponding organs and/or disease. Given the importance of the clinical context for the interpretation of PET imaging, we presented each of the diseases according to: (1) their suggestive clinical context; (2) the suggestive features on nonenhanced CT (which is the standard in PET imaging); and (3) the typical ¹⁸F-FDG characteristics. The purpose of this article is to depict the main features of the most common mediastinal diseases that can be encountered with ¹⁸F-FDG-PET/CT, and to highlight its diagnostic value in this setting, alone or in combination with other imaging modalities.

Follow-Up Recommendations after Curative Resection of Well-Differentiated Neuroendocrine Tumours: Review of Current Evidence and Clinical Practice

The incidence of neuroendocrine neoplasms (NENs) is increasing, especially for patients with early stages and grade 1 tumours. Current evidence also shows increased prevalence, probably reflecting earlier stage diagnosis and improvement of treatment options. Definition of adequate postsurgical follow-up for NENs is a current challenge. There are limited guidelines, and heterogeneity in adherence to those available is notable. Unfortunately, the population of patients at greatest risk of recurrence has not been defined clearly. Some studies support that for patients with pancreatic neuroendocrine tumours (PanNETs), factors such as primary tumour (T), stage, grade (Ki-67), tumour size, and lymph node metastases (N) are of relevance. For bronchial neuroendocrine tumours (LungNETs) and small intestinal neuroendocrine tumours (siNETs), similar factors have been identified. This review summarises the evidence supporting the rationale behind follow-up after curative resection in well-differentiated PanNETs, siNETs, and LungNETS. Published evidence informing relapse rate, disease-free survival, and relapse patterns are discussed, together with an overview of current guidelines informing postsurgical investigations and duration of follow-up.

Lung Masses of Unusual Histologies Mimicking Malignancy: Flurodeoxyglucose Positron Emission Tomography-Computed Tomography Appearance

18F flurodeoxyglucose positron emission tomography-computed tomography (18F FDG PET-CT) is widely used in the evaluation of patients with lung mass suspicious for malignancy. In addition to malignancy, a variety of benign neoplasms and inflammatory lesions can arise in the lungs, many of which show increased FDG concentration, thereby mimicking malignancy. Awareness of the common mimics of lung cancer and a thorough understanding of their key imaging characteristics on CT as well as FDG PET is helpful in narrowing the differential diagnosis, eventually leading to appropriate therapy. In this article, we enlist these mimics and discuss their metabolic and morphologic characteristics and provide a pathophysiological basis for their FDG uptake.

The role of endoscopic ultrasound in the staging of tracheal neoplasm: a brief review

Our case report shows the complexity of dealing with tracheal tumors, highlighting the importance of the method used for staging. In this report, endoscopic ultrasound (EUS) was crucial to identify the involvement of the esophageal muscular propria in a tracheal tumor and change the surgical planning of the case. Staging this kind of tumor represents a challenge for physicians. There is no evidence in the literature on which methods represent the gold standard for T staging.

Tracheobronchial Tumors: Radiologic-Pathologic Correlation of Tumors and Mimics

Tracheobronchial masses encompass a broad spectrum of entities, ranging from benign and malignant neoplasms to infectious and inflammatory processes. This article reviews the cross-sectional findings of tracheal tumors and tumor-like entities, correlates imaging findings with histologic pathology, and discusses pearls and pitfalls in accurately diagnosing and classifying tracheal tumors and mimics.

The utility of 18F-FDG and 68Ga-DOTA-Peptide PET/CT in the evaluation of primary pulmonary carcinoid: A systematic review and meta-analysis

BACKGROUND

Pulmonary carcinoids (PC) are histologically classified into typical carcinoid (TC) and atypical carcinoid (AC). The diagnosis of pulmonary carcinoid and possibly the differentiation between TC and AC could make a significant effect on the treatment planning as well as prognosis. Several studies have explored the utility of Ga-DOTA-Peptide (Ga-labelled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-peptide) and F-flurodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the evaluation of primary pulmonary carcinoids. Therefore, we performed a meta-analysis to evaluate the diagnostic accuracy and prediction efficiency of histological subtypes of these two imaging modalities in primary PC.

METHODS

Relevant studies were identified by searching PubMed, Web of Science, and EMBASE published from 2006 to 2016. Two authors extracted characteristics of patients and their lesions using predefined criteria.

RESULTS

Fourteen studies comprising 352 patients were included in this meta-analysis. The pooled sensitivity of Ga-DOTA-Peptide and F-FDG PET/CT in detecting pulmonary carcinoid were 90.0% (95% CI = 82.0-95.0%; P = .07; I = 49.6%) and 71.0% (95% CI = 66.0-76.0%; P < .001; I = 59.3%), respectively. An SUVmax ratio between Ga-DOTA-Peptide and F-FDG higher than the cutoff value of 4.28 was predictive of TC with 89.3% sensitivity and 100% specificity (AUC, 96.4%; 95% CI, 91.1-100%). The ratio of tumor uptake to atelectatic lung uptake was significantly higher for Ga-DOTA-peptide (2.5-91, mean 30.5 ± 28.1) than for F-FDG (0.3-10.3, mean 2.1 ± 2.3) (P < .001).

CONCLUSIONS

Both Ga-DOTA-peptide and F-FDG are highly sensitive in detecting pulmonary carcinoid, while Ga-DOTA-peptide is more sensitive than F-FDG (90.0% vs 71.0%). The SUVmax ratio was an accurate predictor of the histopathologic variety of the carcinoid tumor, and Ga-DOTA-peptide was better than F-FDG in cases with atelectasis.

Case 260: Endobronchial Posttransplantation Lymphoproliferative Disease

History A 31-year-old woman with a history of bilateral orthotopic lung transplantation performed 10 months earlier for cystic fibrosis presented for a routine follow-up appointment, with her chief symptom being a cough. The cough started approximately 1 month prior to this appointment and was minimally productive of clear to yellow phlegm. In addition to her cough, she reported increased sinus congestion and a sensation of "something in her upper chest." She denied shortness of breath, wheezing, hemoptysis, or cigarette smoking. Review of systems was negative for fever, chills, or night sweats. At physical examination, the patient was afebrile, borderline tachycardic (heart rate, 99 beats per minute), and mildly hypertensive (blood pressure, 138/99 mm Hg). Oxygen saturation was 96% on room air. Laboratory evaluation revealed a white blood cell count of 3.5 × 10⁹/L (normal range, [3.2-9.8] × 10⁹/L). Pulmonary function testing was notable for a newly decreased ratio of forced expiratory volume in 1 second (FEV₁) to forced vital capacity (FVC) of 64% (2.0 and 3.4 L, respectively) (normal FEV₁-to-FVC ratio, 80%), suggesting an obstructive lung process. One month prior to presentation, the patient's sputum cultures grew Pseudomonas and methicillin-resistant Staphylococcus aureus. The patient showed no evidence of active infection at the time of bronchoscopy. Thus, the bacteria were favored to reflect colonization, and antibiotic therapy was not administered at that time. The patient was taking an immunosuppression regimen of mycophenolate mofetil (CellCept; Genentech, San Francisco, Calif) (1 g twice daily), prednisone (10 mg daily), and tacrolimus (Prograf; Astellas Pharma US, Northbrook, Ill) (goal therapeutic range, 12-14 ng/mL). The patient was sent for posteroanterior and lateral chest radiography followed by chest CT ( Figs 1 - 3 ) and fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT ( Fig 4 ).

Ewing's Sarcoma/Peripheral Primitive Neuroectodermal Tumors in Bronchus

Ewing sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET), a member of the Ewing sarcoma family of tumors, is a malignant soft tissue tumor with small undifferentiated neuroectodermal cells. Primary trachea-bronchial ES/pPNET is very rare. The most common pulmonary ES is due to a metastasis. We describe a case of ES/pPNET which originated in the left basal trunk bronchus. The patient was a 30-year-old male, presenting with irritable cough and fever for 10 days. A tumor of 60 mm in diameter was found in the left basal trunk bronchus, extending to the left lower lobe. No distant metastases were detected. Histopathological examination revealed a malignancy of ES/pPNET with a diffuse proliferation of round cells, a Flexner-Wintersteiner rosette formation and positive staining for CD99. The patient was successfully treated with a combination of left lower lobectomy and adjuvant chemotherapy and has remained disease-free for approximately 18 months at follow-up. This case highlights that ES/pPNET should be considered as a differential diagnosis in cases of trachea-bronchial tumors.

Linear Atelectasis around the Hilum on Chest Radiography: A Novel Sign of Early Lung Cancer

BACKGROUND

Linear atelectasis is a focal area of subsegmental atelectasis with a linear shape. Linear atelectasis may occur as a consequence of subsegmental bronchial obstruction.

AIMS

We propose an early roentgen sign of obstructing lung tumors, namely perihilar linear atelectasis, and ascertain whether this phenomenon could be used as a sign to detect radiographically occult primary lung cancer.

MATERIALS AND METHODS

We performed a retrospective review of 45,000 posteroanterior chest radiographs to determine the frequency of appearance and characteristics of perihilar linear atelectasis. The perihilar region of chest radiographs was evaluated for the presence of linear atelectasis. When linear atelectasis was found, the total thickness was measured. Student's t-test was used to evaluate statistical significance, correlating the thickness of atelectasis and the presence of obstructing central primary lung cancer.

RESULTS

Perihilar linear atelectasis was demonstrated in 58 patients. Atelectasis was caused by an obstructing tumor in 21 (36%) cases and a variety of other conditions in 37 (64%) patients. A statistically significant relationship (P < 0.001) was observed between the dimension of perihilar linear atelectasis and primary lung cancer, with 16 of 19 patients with thick (>5.5 mm) perihilar linear atelectasis found to have primary lung cancer.

CONCLUSION

Thick perihilar linear atelectasis is a new diagnostic roentgen sign that suggests subsegmental bronchial obstruction. In this patient subgroup, who are otherwise asymptomatic, a persistent linear atelectasis can be due to primary lung cancer.

Central airway obstruction caused by adenoid cystic carcinoma in pregnancy: a case report and review of the literature

Malignancy complicates one in a thousand pregnancies. The most frequently diagnosed of these are breast, cervical, melanoma, ovarian, and haematological neoplasms. Tumours of respiratory origin are very uncommon during pregnancy. We present a case of tracheal adenoid cystic carcinoma (ACC), a rare type of primary airway tumour, diagnosed in a pregnant woman. To our knowledge, this is the third reported case of tracheal ACC complicating pregnancy. We discuss potential barriers to timely diagnosis of malignancies during pregnancy and consider optimal management strategies, taking into account the potential harm to the mother and foetus in a field with a limited evidence base.

Birt-Hogg-Dubé syndrome: characteristic CT findings differentiating it from other diffuse cystic lung diseases

Birt-Hogg-Dubé (BHD) syndrome is an uncommon, autosomal dominant, multiorgan systemic disorder manifesting as cutaneous fibrofolliculomas, lung cysts with or without spontaneous pneumothorax, and renal tumors. Spontaneous pneumothorax and lung cysts on chest computed tomography (CT) should lead to the inclusion of BHD syndrome in the differential diagnosis, because these findings may develop earlier than other clinical manifestations. Here, we review and describe the characteristic findings of BHD syndrome. The number, shape, size, and distribution of the lung cysts can help to differentiate BHD syndrome from other diffuse cystic lung diseases. Knowledge of the chest CT findings of BHD syndrome may lead to a correct diagnosis and the initiation of an appropriate work-up in order to prevent pneumothorax and for the early detection of renal tumors.

Overview of malignant tracheal tumors

Malignant airway tumors present particular challenges for surgeons, namely: to distinguish symptoms from those of the more frequent benign airway diseases; to separate metastatic disease from the uncommon primary tumors; and to consider curative resection in appropriate candidates. Here, we present a critical review of tracheal malignant obstruction, focusing on the evaluation of a patient with malignant airway tumor, patient selection for resection and the predictors of long-term survival. The new development in primary tracheal tumors is an old story, that of making physicians aware that resection rates in epidemiologic studies remain low, mainly because opportunities for resection are missed.

Imaging of the trachea

Numerous benign and malignant tracheal diseases may affect the trachea primarily and secondarily. While the posterior anterior (PA) and lateral chest radiograph is the conventional study for initial evaluation of the trachea and central airways, findings may not always be apparent on conventional radiographs, and further evaluation with cross sectional imaging is usually necessary. Computed tomography (CT) is the imaging modality of choice for imaging the trachea and bronchi. Familiarity with the imaging appearances of the normal and diseased trachea will enhance diagnostic evaluation.

Endotracheal Leiomyoma Mimicking Malignancy on 18F-FDG PET/CT in a Patient With Papillary Thyroid Carcinoma

Endotracheal leiomyoma is a rare benign lesion, accounting for approximately 1% of tracheal tumors, and generally occurs in the lower respiratory tract. Because its growth causes airway obstruction symptom, surgical treatment is generally suggested after detection. We report a case with leiomyoma of the cervical endotracheal space showing intense FDG uptake on F-FDG PET/CT mimicking malignancy in a 79-year-old woman with papillary thyroid carcinoma.

Diagnostic accuracy of 18F-FDG PET/CT and MR imaging in patients with adenoid cystic carcinoma

Background

The aim of this study was to evaluate the value of 18F–FDG PET/CT (PET/CT) and MRI for local and/or whole-body restaging of adenoid cystic carcinoma of the head and neck (ACC).

Methods

Thirty-six patients with ACC underwent conventional MRI of the head and neck and a whole-body PET/CT and were analysed with regards to detection of a local tumor recurrence, lymph node or distant metastases. A consensus interpretation of all available imaging data was used as reference standard. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were calculated for MRI and PET/CT.

Results

The sensitivity of PET/CT and MRI was 96% (89%), specificity 89% (89%), PPV 96% (96%), NPV 89% (73%) and accuracy 94% (89%) for detection of local tumors. Additionally, PET/CT revealed lymph node metastases in one patient and distant metastases in 9/36 patients. In three patients secondary primaries were found.

Conclusions

Whole-body PET/CT in addition to MRI of the head and neck improves detection of local tumour and metastastic spread in ACC.

Spectrum of CT Findings in Thoracic Extranodal Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) frequently manifests in extranodal structures in the chest, often in the form of secondary involvement but occasionally as primary disease. Because staging and treatment are affected by the presence of extranodal disease at imaging, radiologists' interpretation and management of suspicious findings are critical to patient care. Unfortunately, owing to considerable imaging overlap with other diseases, primary extranodal lymphoma is difficult to diagnose with imaging alone. Radiologists should have a heightened degree of suspicion in patients at risk (including patients with immune compromise, autoimmune diseases, or a history of stem cell or solid organ transplant) or with particular imaging appearances (including the vertebral wraparound sign, nonresolving consolidation, an infiltrative soft-tissue mass, and lesions demonstrating vascular encasement without invasion). For patients with known NHL, positron emission tomography/computed tomography (PET/CT) using fluorine 18 (¹⁸F)-labeled fluorodeoxyglucose (FDG) is now preferred for routine staging in most cases. CT remains heavily used, and identification of subtle extranodal involvement with CT can be improved with use of intravenous contrast material and careful review of multiplanar images. Pericardial effusion, pleural soft tissue (even when mild), mass-like consolidation, perilymphatic nodularity, and new lytic bone lesions are particularly suggestive of secondary involvement in a patient with known NHL. Magnetic resonance imaging is a helpful problem-solving tool when equivocal findings would change staging and treatment. This comprehensive review illustrates the spectrum of CT manifestations of extranodal NHL in the chest, including the pleura, lung, airways, heart, pericardium, esophagus, chest wall, and breast. ^©RSNA, 2017.

18F-FDG PET/CT Imaging of Tracheal Mucoepidermoid Carcinoma

A 54-year-old woman presented with dry cough for 3 months. An FDG PET/CT was performed to evaluate a tracheal nodule, which was revealed by chest CT. The PET/CT images showed increased FDG uptake with SUVmax of 3.3 in the known tracheal lesion. The results of pathological examination from the specimen of bronchoscopy were consistent with tracheal mucoepidermoid carcinoma.