Cyst-related primary lung malignancies: an important and relatively unknown imaging appearance of (early) lung cancer

Clinical TNM Lung Cancer Staging: A Diagnostic Algorithm with a Pictorial Review

Lung cancer is a prevalent malignant disease with the highest mortality rate among oncological conditions. The assessment of its clinical TNM staging primarily relies on contrast-enhanced computed tomography (CT) of the thorax and proximal abdomen, sometimes with the addition of positron emission tomography/CT scans, mainly for better evaluation of mediastinal lymph node involvement and detection of distant metastases. The purpose of TNM staging is to establish a universal nomenclature for the anatomical extent of lung cancer, facilitating interdisciplinary communication for treatment decisions and research advancements. Recent studies utilizing a large international database and multidisciplinary insights indicate a need to update the TNM classification to enhance the anatomical categorization of lung cancer, ultimately optimizing treatment strategies. The eighth edition of the TNM classification, issued by the International Association for the Study of Lung Cancer (IASLC), transitioned to the ninth edition on 1 January 2025. Key changes include a more detailed classification of the N and M descriptor categories, whereas the T descriptor remains unchanged. Notably, the N2 category will be split into N2a and N2b based on the single-station or multi-station involvement of ipsilateral mediastinal and/or subcarinal lymph nodes, respectively. The M1c category will differentiate between single (M1c1) and multiple (M1c2) organ system involvement for extrathoracic metastases. This review article emphasizes the role of radiologists in implementing the updated TNM classification through CT imaging for correct clinical lung cancer staging and optimal patient management.

Assessments of lung nodules by an artificial intelligence chatbot using longitudinal CT images

Large language models have shown efficacy across multiple medical tasks. However, their value in the assessment of longitudinal follow-up computed tomography (CT) images of patients with lung nodules is unclear. In this study, we evaluate the ability of the latest generative pre-trained transformer (GPT)-4o model to assess changes in malignancy probability, size, and features of lung nodules on longitudinal CT scans from 647 patients (547 from two local centers and 100 from a public dataset). GPT-4o achieves an average accuracy of 0.88 in predicting lung nodule malignancy compared to pathological results and an average intraclass correlation coefficient of 0.91 in measuring nodule size compared with manual measurements by radiologists. Six radiologists' evaluations demonstrate GPT-4o's ability to capture changes in nodule features with a median Likert score of 4.17 (out of 5.00). In summary, GPT-4o could capture dynamic changes in lung nodules across longitudinal follow-up CT images, thus providing high-quality radiological evidence to assist in clinical management.

CT-Guided Core Needle Biopsy of Pulmonary Lesions Associated With Cystic Airspaces: A Case-Control Study

BACKGROUND. Concern may exist that pulmonary lesions associated with cystic airspaces are at risk of increased biopsy complications or lower biopsy accuracy given challenges in targeting tissue abutting or intermingled with the cystic airspaces. OBJECTIVE. The purpose of this study was to evaluate the safety and diagnostic performance of CT-guided core needle biopsy (CNB) of pulmonary lesions associated with cystic airspaces. METHODS. This retrospective study included 90 patients (median age, 69.5 years; 28 women, 62 men) who underwent CT-guided CNB of pulmonary lesions associated with cystic airspaces (based on review of procedural images) from February 2010 to December 2022 and a matched control group (2:1 ratio) of 180 patients (median age, 68.0 years; 56 women, 124 men) who underwent CNB of noncystic noncavitary lesions during the same period. The groups were compared in terms of complications, nondiagnostic biopsies (i.e., nonspecific benignities, atypical cells, or insufficient specimens), and CNB diagnostic performance for detecting malignancy using as reference the final diagnosis from a joint review of all available records. For lesions associated with cystic airspaces that underwent surgical resection after CNB, histologic slides were reviewed to explore the nature of the cystic airspace. RESULTS. The final diagnosis was malignant in 90% (81/90) of lesions associated with cystic airspaces and 92% (165/180) of noncystic noncavitary lesions. Patients with lesions associated with cystic airspaces and patients with noncystic noncavitary lesions showed no significant difference in frequency of complications (overall: 40% [36/90] vs 38% [68/180], p = .79; major: 4% [4/90] vs 6% [10/180], p = .78; minor: 36% [32/90] vs 32% [58/180], p = .59), frequency of nondiagnostic biopsies (12% [11/90] vs 9% [16/180], p = .40), or diagnostic performance (accuracy: 94% [85/90] vs 97% [175/180], p = .50; sensitivity: 94% [76/81] vs 97% [160/165], p = .50; specificity: 100% [9/9] vs 100% [15/15]; p > .99), respectively. All false-negative results for malignancy in both groups occurred in patients with nondiagnostic CNB results. Among lesions associated with cystic airspaces that were resected after CNB (all malignant), the cystic airspaces most commonly represented tumor degeneration (22/31 [71%]). CONCLUSION. CT-guided CNB is safe and accurate for assessing pulmonary lesions associated with cystic airspaces. CLINICAL IMPACT. CNB may help avoid a missed or delayed cancer diagnosis in pulmonary lesions with cystic airspaces.

Incidental pulmonary nodules - current guidelines and management

BACKGROUND

Due to the greater use of high-resolution cross-sectional imaging, the number of incidental pulmonary nodules detected each year is increasing. Although the vast majority of incidental pulmonary nodules are benign, many early lung carcinomas could be diagnosed with consistent follow-up. However, for a variety of reasons, the existing recommendations are often not implemented correctly. Therefore, potential for improvement with respect to competence, communication, structure, and process is described.

METHODS

This article presents the recommendations for incidental pulmonary nodules from the current S3 guideline for lung cancer (July 2023). The internationally established recommendations (BTS guidelines and Fleischner criteria) are compared and further studies on optimized management were included after a systematic literature search in PubMed.

RESULTS AND CONCLUSION

In particular, AI-based software solutions are promising, as they can be used in a support capacity on several levels at once and can lead to simpler and more automated management. However, to be applicable in routine clinical practice, software must fit well into the radiology workflow and be integrated. In addition, "Lung Nodule Management" programs or clinics that follow a high-quality procedure for patients with incidental lung nodules or nodules detected by screening have been established in the USA. Similar structures might also be implemented in Germany in a future screening program in which patients with incidental pulmonary nodules could be included.

KEY POINTS

· Incidental pulmonary nodules are common but are often not adequately managed. · The updated S3 guideline for lung cancer now includes recommendations for incidental pulmonary nodules. · Competence, communication, structure, and process levels offer significant potential for improvement.

CITATION FORMAT

· Glandorf J, Vogel-Claussen J, . Incidental pulmonary nodules - current guidelines and management. Fortschr Röntgenstr 2024; 196: 582 - 590.

Enlarging pulmonary cyst: a rare form of alveolar adenoma

BACKGROUND

Alveolar adenoma is a rare benign tumour, usually presenting as a peripherally located solid mass, sometimes mimicking malignancy.

CASE PRESENTATION

A 37-year-old woman presented with chronic intermittent vague chest discomfort. The chest x-ray showed a simple cyst in the left lower lung field, and serial computed tomography (CT) over the following 2-year period showed rapid growth of the cyst, from 3.5 to 9.0 cm in diameter. The CT scan suggested bronchiolar communication, which was suspected to be the cause of growth, via check-valve mechanism. Thoracoscopic surgery was performed, and we found a thin-walled cyst in the lingular segment. Wedge resection was performed and the pathology was an unexpected alveolar adenoma which had grown on the terminal bronchiole, causing the alveolus to rupture and the cyst to grow. In 48 months of follow-up, there was no evidence of recurrence and the patient's symptoms resolved.

CONCLUSIONS

Rapidly growing pulmonary cysts can lead to complications including rupture with pneumothorax and haemothorax, and surgery is always indicated. Abnormally rapid growth may indicate an underlying pathology such as alveolar adenoma. Surgical resection is the treatment of choice and there have been no reported cases of recurrence. Here we present a rare form of alveolar adenoma, which was a form of rapidly growing pulmonary cyst.

[Progress in Diagnosis and Treatment of Lung Cancer Associated with Cystic Airspaces]

Lung cancer associated with cystic airspaces (LCCA) is a type of lung cancer characterized by the presence of cystic cavities in or around the tumor on imaging. Due to its high potential for misdiagnosis or underdiagnosis, the prognosis of LCCA patients is poor, necessitating further large-scale clinical studies to elucidate its characteristics. Currently, four imaging classification systems exist, and there has been a progressive increase in attention towards LCCA, particularly with regard to the study of its imaging features. The results indicate a correlation between the pathological features and imaging findings of LCCA; however, research on driver gene mutations and molecular subtyping associated with lung cancer remains insufficient. Due to the challenges associated with early diagnosis and the poorer prognosis compared to general types of lung cancer, this paper comprehensively reviews the research progress on LCCA, including its definition, etiology, pathogenesis, imaging features, histological and pathological features, treatment, and prognosis, aiming to serve as a valuable resource for clinical decision-making.
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Pearls and Pitfalls in Lung Cancer Imaging

Imaging plays an essential role in the diagnosis and staging of pulmonary malignancy. Familiarity of less common manifestations of lung cancer including subsolid nodule, consolidation, and cyst associated lung cancer is important to avoid delayed diagnosis and improve patient outcomes. In this article, we review the staging of multifocal lung cancer, PET negative lung cancers (carcinoid and indolent lung adenocarcinoma), and false positive lymph nodes on PET due to infectious and inflammatory etiologies. Knowledge of these potential pitfalls and pearls in lung cancer imaging and correlation with patients' clinical history are essential to prevent misinterpretation.

Cystic Primary Lung Cancer: Evolution of Computed Tomography Imaging Morphology Over Time

PURPOSE

Primary lung cancers associated with cystic airspaces are increasingly being recognized; however, there is a paucity of data on their natural history. We aimed to evaluate the prevalence, pathologic, and imaging characteristics of cystic lung cancer in a regional thoracic surgery center with a focus on the evolution of computed tomography morphology over time.

MATERIALS AND METHODS

Consecutive patients referred for potential surgical management of primary lung cancer between January 2016 and December 2018 were included. Clinical, imaging, and pathologic data were collected at the time of diagnosis and at the time of the oldest computed tomography showing the target lesion. Descriptive analysis was carried out.

RESULTS

A total of 441 cancers in 431 patients (185 males, 246 females), median age 69.6 years (interquartile range: 62.6 to 75.3 y), were assessed. Overall, 41/441 (9.3%) primary lung cancers were cystic at the time of diagnosis. The remaining showed solid (67%), part-solid (22%), and ground-glass (2%) morphologies. Histopathology of the cystic lung cancers at diagnosis included 31/41 (76%) adenocarcinomas, 8/41 (20%) squamous cell carcinomas, 1/41 (2%) adenosquamous carcinoma, and 1/41 (2%) unspecified non-small cell lung carcinoma. Overall, 8/34 (24%) cystic cancers at the time of diagnosis developed from different morphologic subtype precursor lesions, while 8/34 (24%) cystic precursor lesions also transitioned into part-solid or solid cancers at the time of diagnosis.

CONCLUSIONS

This study demonstrates that cystic airspaces within lung cancers are not uncommon, and may be seen transiently as cancers evolve. Increased awareness of the spectrum of cystic lung cancer morphology is important to improve diagnostic accuracy and lung cancer management.

Incidental Lung Nodules on Cross-sectional Imaging: Current Reporting and Management

Pulmonary nodules are the most common incidental finding in the chest, particularly on computed tomographs that include a portion or all of the chest, and may be encountered more frequently with increasing utilization of cross-sectional imaging. Established guidelines address the reporting and management of incidental pulmonary nodules, both solid and subsolid, synthesizing nodule and patient features to distinguish benign nodules from those of potential clinical consequence. Standard nodule assessment is essential for the accurate reporting of nodule size, attenuation, and morphology, all features with varying risk implications and thus management recommendations.

A perplexing airspace: peace of mind now or later

A 36-year-old, nonsmoking woman with a history of asthma presented for a second opinion about a “cavitating” right middle lobe (RML) lesion that was found incidentally 6 months prior, during preoperative evaluation for cholecystectomy. The lesion in question was pleural based, measuring 5.4×4×4.5 cm with thin and thick inner septations along with low-density right hilar and mediastinal adenopathy (figure 1a–c).

A perplexing right middle lobe lesion in a young woman. Peace of mind now or later?https://bit.ly/3veB5wE

[Cystic lung diseases]

Cystic lung diseases present uncommonly and have an undetermined incidence. Cysts result from a broad spectrum of causative mechanisms and diseases leading to variable clinical presentations. The pathogenic mechanisms that can lead to lung cyst formation include infection, neoplastic, systemic, traumatic, genetic and congenital processes. A rigorous, systemic and multidisciplinary approach is advised in the diagnostic workup of these conditions. In this article, we review cystic lung diseases including their presentation and management.

Mucinous adenocarcinoma arising in congenital pulmonary airway malformation: clinicopathological analysis of 37 cases

AIMS

Mucinous adenocarcinoma arising in congenital pulmonary airway malformation (CPAM) is a rare complication, with little being known about its natural course. The aims of this article are to describe a series of mucinous adenocarcinomas arising from CPAMs, and present their clinicopathological features, genetics, and clinical outcome.

METHODS AND RESULTS

Thirty-seven cases were collected within a 34-year period, and the subtype of adenocarcinoma and CPAM, tumour location, stage, growth patterns, molecular data and follow-up were recorded. The cohort comprised CPAM type 1 (n = 33) and CPAM type 2 (n = 4). Morphologically, 34 cases were mucinous adenocarcinomas (21 in situ; 13 invasive), and three were mixed mucinous and non-mucinous adenocarcinoma. Seventeen cases showed purely extracystic (intra-alveolar) adenocarcinoma, 15 were mixed intracystic and extracystic, and five showed purely intracystic proliferation. Genetically, nine of 10 cases tested positive for KRAS mutations, four with exon 2 G12V mutation and five with exon 2 G12D mutation. Residual disease on completion lobectomy was observed in two cases, and three cases recurred 7, 15 and 32 years after the original diagnosis. Two patients died of metastatic invasive mucinous adenocarcinoma.

CONCLUSIONS

Most adenocarcinoma that arise in type 1 CPAMs, are purely mucinous, and are early-stage disease. Intracystic proliferation is associated with lepidic growth, an absence of invasion, and indolent behaviour, whereas extracystic proliferation may be associated with more aggressive behaviour and advanced stage. Most cases are cured by lobectomy, and recurrence/residual disease seems to be associated with limited surgery. Long-term follow-up is needed, as recurrence can occur decades later.

Investigating cystic lung disease: a respiratory detective approach

The cystic lung diseases are rare orphan lung disorders that most physicians will see infrequently in their everyday practice. Diagnostic and treatment options have improved over recent decades, with opportunities for slowing rate of progression and improving outcome for patients. This review provides a summary of the clinical approach to these lung disorders, including how to differentiate between different imaging patterns, clinical features, differential diagnosis and characteristics of the commonest presenting disorders.

Cystic lung diseases are uncommon disorders with a wide differential diagnosis. Treatment has improved over the last decade and respiratory physicians should feel encouraged to investigate such cases thoroughly to reach a final diagnosis.https://bit.ly/2W6Is9D