Lung Cancers Associated With Cystic Airspaces: Natural History, Pathologic Correlation, and Mutational Analysis. J Thorac Imaging. 2017;32:176-188. [PMID: 28338535 DOI: 10.1097/rti.0000000000000265]

Localized nodular pulmonary amyloidosis mimicking primary lung cancer associated with cystic airspaces: A case report

Localized nodular pulmonary amyloidosis can form pulmonary nodules associated with cystic air spaces, but due to its rarity, it cannot be included in the differential diagnosis without appropriate knowledge. Among the differential diagnoses of nodules with cysts in the lungs is primary lung cancer, however, diagnosis based solely on imaging findings is challenging. A 59-year-old Japanese female was referred to our hospital for an abnormality noted on the chest radiograph of an annual health check. She had no history of smoking or medical issues. Chest computed tomography revealed a 1.2 cm pulmonary nodule with surrounding multilocular cystic air spaces in the superior lingular segment. We suspected it was a nodule of primary lung cancer arising in the pulmonary cyst and performed video-assisted thoracic surgery. As the intraoperative frozen examination after a wedge resection revealed fibrotic tissue without malignancy, we did not do any further resection. The histopathological examination of the permanent section revealed unstructured eosinophilic deposits positive for direct fast scarlet staining, which were consistent with amyloidosis. The surrounding pulmonary cysts contained the check valve made by amyloid deposition. Localized nodular pulmonary amyloidosis can give rise to pulmonary cysts and mimic primary lung cancer associated with cystic air spaces. It should be raised as a potential differential diagnosis for pulmonary nodules with cystic air space formation, particularly in patients without a smoking history.

A nomogram combining CT-based radiomic features with clinical features for the differentiation of benign and malignant cystic pulmonary nodules

BACKGROUND

Currently, the differentiation between benign and malignant cystic pulmonary nodules poses a significant challenge for clinicians. The objective of this retrospective study was to construct a predictive model for determining the likelihood of malignancy in patients with cystic pulmonary nodules.

METHODS

The current study involved 129 patients diagnosed with cystic pulmonary nodules between January 2017 and June 2023 at the Neijiang First People's Hospital. The study gathered the clinical data, preoperative imaging features of chest CT, and postoperative histopathological results for both cohorts. Univariate and multivariate logistic regression analyses were employed to identify independent risk factors, from which a prediction model and nomogram were developed. In addition, The model's performance was assessed through receiver operating characteristic (ROC) curve analysis, calibration curve analysis, and decision curve analysis (DCA).

RESULTS

A cohort of 129 patients presenting with cystic pulmonary nodules, consisting of 92 malignant and 37 benign lesions, was examined. Logistic data analysis identified a cystic airspace with a mural nodule, spiculation, mural morphology, and the number of cystic cavities as significant independent predictors for discriminating between benign and malignant cystic lung nodules. The nomogram prediction model demonstrated a high level of predictive accuracy, as evidenced by an area under the ROC curve (AUC) of 0.874 (95% CI: 0.804-0.944). Furthermore, the calibration curve of the model displayed satisfactory calibration. DCA proved that the prediction model was useful for clinical application.

CONCLUSION

In summary, the risk prediction model for benign and malignant cystic pulmonary nodules has the potential to assist clinicians in the diagnosis of such nodules and enhance clinical decision-making processes.

Small cell lung carcinoma presenting initially with recurrent pneumothoraces: a case report

BACKGROUND

Pneumothorax is a non-physiological collection of air in the pleural space. Pneumothoraces can be broadly divided into Primary, Secondary, and Traumatic. Cancer of the lung is a known cause of secondary pneumothorax in both primary and metastatic lesions, however, pneumothorax as the presentation of lung cancer is exceedingly rare. Non-small cell lung carcinoma (NSCLC) has been reported in the literature to present with a pneumothorax, particularly in adeno/squamous cell carcinomas. It is almost completely unheard of for small cell lung carcinoma (SCLC) to present with a pneumothorax.

CASE PRESENTATION

We present the case of a 62-year-old male patient, presenting twice in two months with spontaneous pneumothorax. The initial management involved admission and chest drain insertion. The patient has a past medical history of COPD and a significant smoking history. On the second admission, he underwent a video-assisted thoracoscopic (VATS) bullectomy and talc pleurodesis. The pathology report of the resected specimen confirmed SCLC with extensive infiltration. No gross evidence of metastatic spread was present on CT. Due to the R1 resection and significant risk of recurrence, the management plan included four cycles of adjuvant chemotherapy with carboplatin and etoposide, and radiotherapy as a consideration upon completion.

CONCLUSIONS

Pneumothorax as the presentation of lung cancer imparts a very poor prognosis, however the reasons for this are largely unknown. Furthermore, the mechanisms underlying spontaneous pneumothorax in lung cancer are also not well understood.

Computed tomography characteristics of cN0 primary non-small cell lung cancer predict occult lymph node metastasis

RATIONALE

Occult lymph node metastasis (OLNM) is frequently found in patients with resectable non-small cell lung cancer (NSCLC), despite using diagnostic methods recommended by guidelines.

OBJECTIVES

To evaluate the risk of OLNM in NSCLC patients using the radiologic characteristics of the primary tumor on computed tomography (CT).

METHODS

We retrospectively reviewed clinicopathologic features of 2042 clinical T1-4N0 NSCLC patients undergoing curative intent pulmonary resection. Unique radiological features (i.e., air-bronchogram throughout the whole tumor, heterogeneous ground-glass opacity (GGO), mainly cystic appearance, endobronchial location), percentage of solid portion, and shape of tumor margin were analyzed via a stepwise approach. We used multivariable logistic regression to assess the relationship between OLNM and tumor characteristics.

RESULTS

Compared with the other unique features, endobronchial tumors were associated with the highest risk of OLNM (OR = 3.9, 95% confidence interval (CI) = 2.29-6.62), and heterogeneous GGO and mainly cystic tumors were associated with a low risk of OLNM. For tumors without unique features, the percentage of the solid portion was measured, and solid tumors were associated with OLNM (OR = 2.49, 95% CI = 1.86-3.35). Among part-solid tumors with solid proportion > 50%, spiculated margin, and peri-tumoral GGO were associated with OLNM.

CONCLUSIONS

The risk of OLNM could be assessed using radiologic characteristics on CT. This could allow us to adequately select optimal candidates for invasive nodal staging procedures (INSPs) and complete systematic lymph node dissection.

CLINICAL RELEVANCE STATEMENT

These data may be helpful for clinicians to select appropriate candidates for INSPs and complete surgical systematic lymph node dissection in NSCLC patients.

KEY POINTS

Lymph node metastasis status plays a key role in both prognostication and treatment planning. Solid tumors, particularly endobronchial tumors, were associated with occult lymph node metastasis (OLNM). The risk of OLNM can be assessed using radiologic characteristics acquired from CT images.

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.

Interpreting Lung Cancer Screening CTs: Practical Approach to Lung Cancer Screening and Application of Lung-RADS

Lung cancer screening via low-dose computed tomography (CT) reduces mortality from lung cancer, and eligibility criteria have recently been expanded to include patients aged 50 to 80 with at least 20 pack-years of smoking history. Lung cancer screening CTs should be interepreted with use of Lung Imaging Reporting and Data System (Lung-RADS), a reporting guideline system that accounts for nodule size, density, and growth. The revised version of Lung-RADS includes several important changes, such as expansion of the definition of juxtapleural nodules, discussion of atypical pulmonary cysts, and stepped management for suspicious nodules. By using Lung-RADS, radiologists and clinicians can adopt a uniform approach to nodules detected during CT lung cancer screening and reduce false positives.

Exploring the molecular and immune-landscape of lung cancer associated with cystic airspaces

To explore the molecular biological characteristics of lung cancer associated with cystic airspaces (LCCA) and its potential roles on prognosis. A total of 165 LCCAs and 201 non-LCCAs were enrolled in this study. Bulk RNA sequencing was implemented in eight LCCAs and nine non-LCCAs to explore the differentially expressed genes. TCGA data were used to analyze LCCA-specific genes that associated with overall survival (OS). The median age was 60 (IQR 53 to 65) years in LCCA cohort. We found LCCA were predominant in men and had less visceral pleura invasion (VPI) or lympho-vascular invasion (LVI). Moreover, LCCA presented with higher histological heterogeneity. Kaplan-Meier analysis showed that patients of age more than 60 and positive VPI had significantly less PFS in LCCA. Cox regression suggested that LCCA, micropapillary subtype proportion and VPI were the independent risk factors for PFS. LCCA had up-regulated pathways associated with EMT, angiogenesis and cell migration. In addition, LCCA displayed higher levels of immunosuppressor infiltration (M2 macrophages, CAFs and MDSCs) and distinct cell death and metabolic patterns. BCR/TCR repertoire analysis revealed less BCR richness, clonality and high-abundance shared clonotypes in LCCA. Finally, Cox regression analysis identified that four cystic-specific genes, KCNK3, NRN1, PARVB and TRHDE-AS1, were associated with OS of lung adenocarcinoma (LUAD). And cystic-specific risk scores (CSRSs) were calculated to construct a nomogram, which performance well. Our study for the first time indicated significantly distinct molecular biological and immune characteristics between LCCA and non-LCCA, which provide complementary prognostic values in early-stage non-small cell lung cancer (NSCLC).

ACR Lung-RADS v2022: Assessment Categories and Management Recommendations

The ACR created the Lung CT Screening Reporting and Data System (Lung-RADS) in 2014 to standardize the reporting and management of screen-detected pulmonary nodules. Lung-RADS was updated to version 1.1 in 2019 and revised size thresholds for nonsolid nodules, added classification criteria for perifissural nodules, and allowed for short-interval follow-up of rapidly enlarging nodules that may be infectious in etiology. Lung-RADS v2022, released in November 2022, provides several updates including guidance on the classification and management of atypical pulmonary cysts, juxtapleural nodules, airway-centered nodules, and potentially infectious findings. This new release also provides clarification for determining nodule growth and introduces stepped management for nodules that are stable or decreasing in size. This article summarizes the current evidence and expert consensus supporting Lung-RADS v2022.

ACR Lung-RADS v2022: Assessment Categories and Management Recommendations

The American College of Radiology created the Lung CT Screening Reporting and Data System (Lung-RADS) in 2014 to standardize the reporting and management of screen-detected pulmonary nodules. Lung-RADS was updated to version 1.1 in 2019 and revised size thresholds for nonsolid nodules, added classification criteria for perifissural nodules, and allowed for short-interval follow-up of rapidly enlarging nodules that may be infectious in etiology. Lung-RADS v2022, released in November 2022, provides several updates including guidance on the classification and management of atypical pulmonary cysts, juxtapleural nodules, airway-centered nodules, and potentially infectious findings. This new release also provides clarification for determining nodule growth and introduces stepped management for nodules that are stable or decreasing in size. This article summarizes the current evidence and expert consensus supporting Lung-RADS v2022.

A case of pulmonary pleomorphic carcinoma associated with cystic airspace

Lung cancer associated with a cystic airspace is frequently misdiagnosed or overlooked. Adenocarcinoma, followed by squamous cell carcinoma, is the most typical histologic type of lung cancer connected to a cystic airspace. Here we present the rare case of lung pleomorphic carcinoma associated with a cystic airspace. We encountered a 74-year-old Japanese man diagnosed by computed tomography (CT) as having a nodule outside a cystic airspace in the lung. Several previous CT images showed that the cystic airspace preceded the nodule. Postsurgery, pathology indicated a diagnosis of pleomorphic carcinoma. Since pulmonary pleomorphic carcinomas pursue an aggressive clinical course, their early detection may contribute to an improved prognosis. Our case demonstrated that pleomorphic carcinoma can arise with cystic airspaces. For early diagnosis of those aggressive lung cancers, chest physicians should carefully examine the walls of cystic airspaces on CT.

Lung adenocarcinoma associated with cystic airspaces: Predictive value of CT features in assessing pathologic invasiveness

OBJECTIVES

Lung adenocarcinoma associated with cystic airspaces (LACA) is a unique entity with limited understanding. Our aim was to evaluate the radiological characteristics of LACA and to study which criteria were predictive of invasiveness.

METHODS

A retrospective monocentric analysis of consecutive patients with pathologically confirmed LACA was performed. The diagnosed adenocarcinomas were classified into preinvasive (atypical adenomatous hyperplasia, adenocarcinoma in situ, or minimally invasive adenocarcinoma) and invasive adenocarcinomas. Eight clinical features and twelve CT features were evaluated. Univariable and multivariable analyses were performed to analyse the correlation between invasiveness, and CT and clinical features. The inter-observer agreement was evaluated using κ statistics and intraclass correlation coefficients. The predictive performance of the model was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 252 patients with 265 lesions (128 men and 124 women; mean age, 58.0 ± 11.1 years) were enrolled. Multivariable logistic regression indicated that multiple cystic airspaces (OR, 5.599; 95 % CI, 1.865-16.802), irregular shape of cystic airspace (OR, 3.236; 95 % CI, 1.073-9.761), entire tumour size (OR, 1.281; 95 % CI, 1.075-1.526), and attenuation (OR, 1.007; 95 % CI, 1.005-1.010) were independent risk factors for invasive LACA. The AUC of the logistic regression model was 0.964 (95 % CI, 0.944-0.985).

CONCLUSION

Multiple cystic airspaces, irregular shape of cystic airspace, entire tumour size, and attenuation were identified as independent risk factors for invasive LACA. The prediction model gives a good predictive performance, providing additional diagnostic information.

Lung cancer screening

Randomised controlled trials, including the National Lung Screening Trial (NLST) and the NELSON trial, have shown reduced mortality with lung cancer screening with low-dose CT compared with chest radiography or no screening. Although research has provided clarity on key issues of lung cancer screening, uncertainty remains about aspects that might be critical to optimise clinical effectiveness and cost-effectiveness. This Review brings together current evidence on lung cancer screening, including an overview of clinical trials, considerations regarding the identification of individuals who benefit from lung cancer screening, management of screen-detected findings, smoking cessation interventions, cost-effectiveness, the role of artificial intelligence and biomarkers, and current challenges, solutions, and opportunities surrounding the implementation of lung cancer screening programmes from an international perspective. Further research into risk models for patient selection, personalised screening intervals, novel biomarkers, integrated cardiovascular disease and chronic obstructive pulmonary disease assessments, smoking cessation interventions, and artificial intelligence for lung nodule detection and risk stratification are key opportunities to increase the efficiency of lung cancer screening and ensure equity of access.

[Lung Imaging Reporting and Data System (Lung-RADS) in Radiology: Strengths, Weaknesses and Improvement]

In 2019, the American College of Radiology announced Lung CT Screening Reporting & Data System (Lung-RADS) 1.1 to reduce lung cancer false positivity compared to that of Lung-RADS 1.0 for effective national lung cancer screening, and in December 2022, announced the new Lung-RADS 1.1, Lung-RADS^® 2022 improvement. The Lung-RADS^® 2022 measures the nodule size to the first decimal place compared to that of the Lung-RADS 1.0, to category 2 until the juxtapleural nodule size is < 10 mm, increases the size criterion of the ground glass nodule to 30 mm in category 2, and changes categories 4B and 4X to extremely suspicious. The category was divided according to the airway nodules location and shape or wall thickness of atypical pulmonary cysts. Herein, to help radiologists understand the Lung-RADS^® 2022, this review will describe its advantages, disadvantages, and future improvements.

High-Resolution Computed Tomography of Cystic Lung Disease

The cystic lung diseases (CLD) are characterized by the presence of multiple, thin-walled, air-filled spaces in the pulmonary parenchyma. Cyst formation may occur with congenital, autoimmune, inflammatory, infectious, or neoplastic processes. Recognition of cyst mimics such as emphysema and bronchiectasis is important to prevent diagnostic confusion and unnecessary evaluation. Chest CT can be diagnostic or may guide the workup based on cyst number, distribution, morphology, and associated lung, and extrapulmonary findings. Diffuse CLD (DCLDs) are often considered those presenting with 10 or more cysts. The more commonly encountered DCLDs include lymphangioleiomyomatosis, pulmonary Langerhans' cell histiocytosis, lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, and amyloidosis/light chain deposition disease.

Case Report: Misdiagnosis of Lung Carcinoma in Patients with Shrunken Lung Cyst After High Altitude Travel

Background

Lung cancer associated with cystic airspace is a rare disease, and the imaging understanding of lung cancer with cystic cavity is still unclear. Little is known in the literature on whether cystic lung cancer is caused by emphysema or ruptured bullae.

Case Reports

We report the case of a 50-year-old female patient after finishing a business trip in November 2021, when another chest CT demonstrated an unexpected reduction in the cyst, with a solid mural nodule on the posterior wall. The airspace of the cyst is only about 13 mm × 12 mm × 6 mm in size. The size of the mural nodule in the posterior wall is about 10 mm × 6 mm × 5 mm. The patient felt anxious due to suspicion of lung cancer. 2.5 months after the last chest CT, she accepted minimally invasive thoracoscopic surgery on the posterior basal segment of the left lower lobe. The postoperative pathology showed benign lesions.

Conclusion

For radiologists, it is important to recognize the process from lung cysts or bullae to LC-CAS, especially the morphological changes of the cyst airspace and the cyst wall, in order to identify the malignant features of lung cysts in time.

Difficulties in the differential diagnosis of large solitary pulmonary cysts

Large solitary cystic lesions are a rare finding, and their differential diagnosis includes cystic airspaces associated with lung cancer, congenital pulmonary airway malformations and pneumatoceles. Here, we report 3 consecutive patients who presented with a large solitary pulmonary cyst on chest computed tomography. All underwent surgical resection, and the histopathological findings were different in all 3 cases. In one patient, a very rare finding of squamous cell carcinoma arising from the cystic lesion in the left lower lobe was confirmed. Therefore, in carefully selected cases, pulmonary cysts should be resected based on the potential risk for recurrent infection and the development of malignancy.

Solitary Pulmonary Nodule Evaluation: Pearls and Pitfalls

Lung nodules are frequently encountered while interpreting chest CTs and are challenging to detect, characterize, and manage given they can represent both benign or malignant etiologies. An understanding of features associated with malignancy and causes of interpretive pitfalls is helpful to avoid misdiagnoses. This review addresses pertinent topics related to the etiologies for missed lung nodules on radiography and CT. Additionally, CT imaging technical pitfalls and challenges in addition to issues in the evaluation of nodule morphology, attenuation, and size will be discussed. Nodule management guidelines will be addressed as well as recent investigations that further our understanding of lung nodules.

A diagnostic dilemma of a pulmonary nodule of a patient who suffered advanced ovarian cancer: A case report and a hypothesis

INTRODUCTION

This report presents a case of lung cancer which can be easily misdiagnosed as distant metastasis. Along with a literature review on the morphological, pathological and prognostic characteristics of lung cancer associated with cystic airspaces (LCCA), it would help to improve our understanding of the dynamic evolution of LCCA, to avoid its delayed diagnosis and treatment. We also propose here a hypothesis on the etiology of LCCA.

CASE PRESENTATION

A patient with advanced ovarian cancer who presented with elevated serum CA125 at time of admission and had undergone TAHBSO at first, and second operation of sigmoid colon resection was performed due to her locoregional recurrence of ovarian cancer. After her second operation, patient showed further increment of serum CA125 and CECT scan indicated an airspace-related pulmonary nodule in the right middle lobe of her lungs. It was suspected that distant metastases of ovarian cancer had reoccurred postoperatively.

CLINICAL DISCUSSION

After comparing the characteristic of metastatic ovarian cancer with LCCA, we diagnosed the pulmonary nodule as primary lung cancer. Surgery eventually confirmed the pulmonary nodule as second primary lung cancer associated with cystic airspaces.

CONCLUSION

The rare occurrence of LCCA should merit special attention from clinicians and radiologists so as to avoid missed or delayed diagnosis. We propose here a hypothesis that LCCA is related to spreading of tumour cells during surgical procedures in lung cancer surgery. Should our hypothesis be substantiated in further studies, this would affect the operation procedures for surgeons in the future.

Pulmonary carcinoma associated with cystic airspaces in two dogs

Malignant pulmonary neoplasia associated with cystic airspaces is a well-recognised disease entity in humans. Two elderly dogs, previously diagnosed with a solitary emphysematous bulla, presented with non-specific clinical signs. At presentation, pulmonary auscultation was unremarkable. In both cases, thoracic CT demonstrated the transformation of the cystic airspace lesions characterised by a progressive increase of the solid component and reduction of the air component. Cytological evaluation and subsequent surgical excision followed by histopathology confirmed pulmonary carcinoma in both cases. These two cases represent the first demonstration of possible malignant transformation of pulmonary cystic airspace in dogs. Veterinarians should consider neoplastic transformation as a differential diagnosis in cases of cystic airspaces, particularly cases with features including thickening or irregularity of the wall, associated soft-tissue nodules or solid and non-solid tissue intermixed within clusters of multiple cystic airspaces. Ongoing monitoring of cystic airspace lesions through diagnostic imaging is recommended.

Serial CT changes in different components of lung cancer associated with cystic airspace in patients treated with neoadjuvant chemotherapy

The aim of this study was to observe changes in different components (solid, cystic airspace, or entire tumor) in lung cancer associated with cystic airspace following treatment with neoadjuvant chemotherapy (NC), using computerized tomography (CT). We analyzed serial (baseline, first-time follow-up, and last-time follow-up) clinical data and CT imaging in six patients treated with NC. The diameters, areas, and volumes of different tumor components (solid, cystic airspace, and entire tumor) were measured. Delta (Δ) was used to represent changes in these parameters between two examinations: Δ1(%) represents the change from baseline to first follow-up after NC, and Δ2(%) represents the change from baseline to last follow-up after NC. We used the intra-group correlation coefficient (ICC) to test for consistency between parameters as measured by two radiologists. The diameter of solid components in all lesions showed a trend of continuous reduction compared with baseline (Δ1 ranged from − 8.3 to − 46.0%, Δ2 from − 30.8 to − 69.2%). For cystic airspace and entire tumors, different lesions showed different trends over the course of treatment. For diameter, area, and volume, Δ1 of changes in the solid component ranged from − 8.3 to − 46.9%, − 19.4 to − 70.8%, and − 19.1 to − 94.7%, respectively; Δ2 ranged from − 30.8 to − 69.2%, − 50.8 to − 92.1%, and − 32.7 to − 99.8% in diameter, area, and volume, respectively. Results were inconsistent between different components of lung cancer associated with cystic airspace that was treated with NC, but the diameter, area, and volume of solid components were continuously reduced during treatment. Furthermore, area and volume measurements showed more-significant variation than diameter measurements.

Solitary multicystic lesion lung cancer: two case reports and review of the literature

Background

Lung cancer associated with cystic airspaces, especially solitary multicystic lesion lung cancer, is a rare disease (a rare imaging performance of non-small cell lung cancer). It is difficult to diagnose owing to the lack of a clear definition; therefore, diagnosis of these neoplastic lesions remains challenging.

Case presentation

We outlined two cases of elderly Chinese men who were admitted to the hospital with a solitary multicystic lesion of the lung and subsequent surgical resection, confirming a diagnosis of adenocarcinoma.

Conclusions

For solitary pulmonary cystic airspaces (especially solitary multicystic lung lesions), it is important to properly recognise their imaging features. Due to the possibility of malignancies, timely surgery is an effective treatment strategy for early diagnosis.

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.

An intrathoracic giant tumour and vanishing lung cyst after tumour resection

A 65-year-old woman was brought to the emergency unit with an approximately 6-month history of persistent fever and cough. Chest computed tomography (CT) demonstrated a 16-cm heterogeneous mass with adjacent large cyst (approximately 4.0 cm). The patient underwent CT-guided biopsy, and benign solitary fibrous tumour (SFT) was immunohistochemically diagnosed. As the symptoms were thought to be due to enlargement of the tumour, surgery was deemed necessary, and the tumour was successfully resected. Based on morphological and immunohistochemical examination of the resected specimen, the final diagnosis was dedifferentiated SFT (DSFT). Follow-up CT verified disappearance of the pulmonary cyst. The cyst was speculated to be caused by a check valve mechanism, which may also suggest a rapid growth of the tumour. At the time of writing, 2 years post-operatively, no tumour recurrence has been identified. This represents the first report of intrathoracic giant DSFT with a cystic lesion returning to normal lung parenchyma.

Prognosis of lung cancer associated with cystic airspaces: A propensity score matching analysis

OBJECTIVE

The association between the morphological characteristics and survival outcome of lung cancer associated with cystic airspaces (LCCAs) is unclear due to rarity of this disease. The current study attempted to compare the survival outcome between LCCAs and non-LCCAs and investigate the correlation between imaging features and prognosis of LCCA.

METHOD

Of 10,835 patients diagnosed with non-small cell lung carcinoma (NSCLC) between January 2015 and December 2016, 123 patients with LCCA were included. The non-LCCA group comprised 3136 patients with primary solitary adenocarcinoma or squamous cell lung cancer. Propensity score matching (PSM) was performed for age, sex, tumor size, tumor stage, and lymph node involvement in a 1:1 ratio between the LCCAs and non-LCCAs, and the correlation between radiological features and recurrence-free survival (RFS) was analyzed.

RESULT

The computed tomography (CT) lesion size was found to be higher in all LCCA subtypes, particularly in Type III (a cystic airspace with a mural nodule) and Type IV (mixed) LCCAs (3.09 and 3.65 cm, respectively), than in non-LCCAs (2 cm) after PSM. Three-year RFS in the LCCA group was higher than in the non-LCCA group (Type I- IV LCCAs: 100%, 84%, 77% and 83%, respectively vs. non-LCCAs: 77%). However, statistically significant difference was only found in comparison between LCCA Type I (thin-walled) and non-LCCA groups (P = 0.026). Type III lung cancer exhibited the worst survival among all four LCCA subtypes.

CONCLUSIONS

The CT lesion size and pathologic tumor size varied significantly across LCCAs. Type I LCCAs exhibited better survival than non-LCCAs, whereas Type III LCCAs exhibited the worst survival rate among the four LCCA subtypes.

Tumor size in patients with severe pulmonary emphysema might be underestimated on preoperative CT

OBJECTIVES

To evaluate the effect of emphysema on tumor diameter measured on preoperative computed tomography (CT) images versus pathological specimens.

MATERIALS AND METHODS

We investigated patients who underwent primary lung cancer surgery: 55 patients (57 tumors) with severe emphysema and 57 patients (57 tumors) without emphysema. The tumor diameters measured in the postoperative pathological specimens were compared with those measured on the axial CT images and on multiplanar reconstruction (MPR) CT images by two independent radiologists; a subgroup analysis according to tumor size was also performed. A paired or unpaired t test was performed, depending on the tested subjects.

RESULTS

In the emphysema group, the mean axial CT diameter was significantly smaller than the mean pathological diameter (p = 0.025/0.001 for reader 1/2), whereas in the non-emphysema group, the mean axial CT diameter was not significantly different from the pathological one for both readers. The difference between CT axial diameter and pathological diameter (= CT diameter - pathological diameter) was significantly smaller (i.e., had a stronger tendency toward underestimation on radiological measurements) in the emphysema group compared with the non-emphysema group (p = 0.014/0.008 for reader 1/2), and the difference was significantly smaller in tumors sized > 30 mm than tumors sized ≤ 20 mm in both groups.

CONCLUSIONS

Tumor size is significantly smaller on preoperative CT in patients with severe emphysema compared to patients without emphysema, especially in the case of large tumors. MPR measurement using the widest of three dimensions should be used to select T-stage for patients with severe emphysema.

KEY POINTS

• The presence of emphysema affects the accuracy of tumor size measurements on CT. • Compared to patients without emphysema, the tumor size in severe emphysema patients tends to be measured smaller in preoperative CT than the pathological specimen. • This trend is more evident when large tumors are measured on axial CT images alone.

Clinical Value and Pathologic Basis of Cystic Airspace Within Subsolid Nodules Confirmed as Lung Adenocarcinomas by Surgery

PURPOSE

To investigate the clinical value and pathologic basis of cystic airspace within lung adenocarcinomas manifesting as subsolid nodules.

PATIENTS AND METHODS

A retrospective study was conducted on a total of 541 surgically confirmed lung adenocarcinomas manifesting as subsolid nodules in computed tomography images, including 87 cases with cystic airspace and 454 cases without cystic airspace. The pathologic characteristics of the cases with and without cystic airspace were compared. The investigation of the pathologic structure of cystic airspace was attempted on the postoperative paraffin sections.

RESULTS

There was a significant difference in the containing of cystic airspace between preinvasive and invasive adenocarcinomas (10.5 vs 26.6%; P < .001). Multivariate analysis indicated that cystic airspace is an independent predictor of invasive adenocarcinomas (odds ratio, 3.220; 95% confidence interval, 1.822-5.687). Nodules containing multiple cystic airspaces are more likely to be invasive adenocarcinomas than nodules with a single cystic airspace (47.1 vs 72.2%; P < .05). On paraffin sections, the walls of the cystic airspace seemed to be mainly composed of atypical hyperplasia and/or tumor cells on the surface and the remaining smooth muscle cells and stroma below, which is similar to the structure of bronchi.

CONCLUSIONS

Cystic airspace may be a reliable predictor of invasive adenocarcinomas, the classification method based on the number of cystic airspaces might be suitable for the computed tomography-based typing of cystic airspace within subsolid nodules. Cystic airspace may derive from the destroyed and enlarged bronchi owing to the growth or infiltration of atypical hyperplasia and/or tumor cells.

Molecular profiling in lung cancer associated with cystic airspaces

'Lung cancer associated with cystic airspaces' is a rare radiological entity that is more frequently encountered on imaging studies and is gaining more attention since the widespread use of CT for lung cancer screening. Numerous aspects of this entity remain unraveled, including molecular profiling. The goal of this observational retrospective single-center case series is to investigate the molecular profile of lung cancers presenting with this specific morphology in a Caucasian population. Between January 2014 and May 2017, 13 patients were presented at the Multidisciplinary Thoracic Oncology Tumor Board with imaging findings consistent with 'lung cancer associated with cystic airspaces'. Electronic medical files were reviewed for patient characteristics, stage, histopathological findings and - in particular - molecular profiling. Histopathological diagnosis showed adenocarcinoma in 11 patients in our series. Mutational analysis in 10 showed different molecular alterations: an EGFR exon 18 mutation, ROS1 rearrangement and BRAF mutation in one patient each. Two patients showed KRAS mutations. With 5 out of 10 patients with an adenocarcinoma presenting with cystic airspace morphology showing a molecular alteration, this may indicate that in this subgroup, molecular profiling is mandatory, regardless of smoking history.

Lung-RADS Version 1.1: Challenges and a Look Ahead, From the AJR Special Series on Radiology Reporting and Data Systems

In 2014, the American College of Radiology (ACR) created Lung-RADS 1.0. The system was updated to Lung-RADS 1.1 in 2019, and further updates are anticipated as additional data become available. Lung-RADS provides a common lexicon and standardized nodule follow-up management paradigm for use when reporting lung cancer screening (LCS) low-dose CT (LDCT) chest examinations and serves as a quality assurance and outcome monitoring tool. The use of Lung-RADS is intended to improve LCS performance and lead to better patient outcomes. To date, the ACR's Lung Cancer Screening Registry is the only LCS registry approved by the Centers for Medicare & Medicaid Services and requires the use of Lung-RADS categories for reimbursement. Numerous challenges have emerged regarding the use of Lung-RADS in clinical practice, including the timing of return to LCS after planned follow-up diagnostic evaluation; potential substitution of interval diagnostic CT for future LDCT; role of volumetric analysis in assessing nodule size; assessment of nodule growth; assessment of cavitary, subpleural, and category 4X nodules; and variability in reporting of the S modifier. This article highlights the major updates between versions 1.0 and 1.1 of Lung-RADS, describes the system's ongoing challenges, and summarizes current evidence and recommendations.

Clinicopathologic and Longitudinal Imaging Features of Lung Cancer Associated With Cystic Airspaces: A Systematic Review and Meta-Analysis

BACKGROUND. Lung cancer (LC) associated with cystic airspaces is an uncommon presentation that is underrecognized on imaging. Additionally, understanding of its underlying pathology and risk factors is limited, which can contribute to delays in diagnosis. OBJECTIVE. The purpose of this analysis was to systematically review, analyze, and synthesize the medical literature to determine the imaging features of LC associated with cystic airspaces. EVIDENCE ACQUISITION. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included published research reporting the clinical, pathologic, and imaging features of LC associated with cystic airspaces. We then performed a pooled analysis of continuous and categoric data with respect to patient clinical characteristics, tumor pathologic features, underlying driver mutation, CT features, and evolution of these features over time. EVIDENCE SYNTHESIS. The analysis included eight original observational studies with a combined total of 341 patients with LC associated with cystic airspaces (weighted mean age, 61.8 years; range, 30-87 years; 135 women and 206 men). Most patients were current or previous smokers (127/192 [66.1%]). The most common histologic finding was adenocarcinoma (289/328 [88.1%]) followed by squamous cell carcinoma (30/328 [9.1%]). The most common driver mutations were EGFR (46/122 [37.7%]) and KRAS (21/122 [17.2%]). The cysts in LC associated with cystic airspaces commonly had nonuniform (104/114 [91.2%]) and thick (83/222 [37.4%]) walls, irregular margins (53/142 [37.3%]), and were unilocular (173/272 [63.6%]). Most cysts had a nodular component (210/328 [64.0%]). Over time, most cysts showed development or enlargement of the nodular component (61/89 [68.5%]), approximately half showed wall thickening (43/89 [48.3%]), and a minority evolved into completely solid lesions (11/89 [12.4%]). The size of the cystic component increased in 36 of 89 patients (40.4%), decreased in 28 (31.5%), and remained stable in 24 (27.0%). CONCLUSION. LC associated with cystic airspaces occurs most commonly as adeno-carcinoma and is seen in both smokers and nonsmokers. The cysts associated with LC show wall thickening and mural nodularity, which may evolve over time. LC associated with cystic airspaces can be indolent, and long-term surveillance with imaging should be considered if cysts are not resected. CLINICAL IMPACT. Familiarity with the imaging features and temporal evolution of LC associated with cystic airspaces can minimize delays in LC diagnosis. Future management guidelines should include protocols for follow-up and management of cystic lung lesions identified during diagnostic and LC screening CT.

Diagnostic Accuracy of CT-Guided Core Needle Biopsy for Thin-Walled Cavitary Pulmonary Lesions

OBJECTIVE. The purpose of this article is to evaluate the accuracy of and complications with CT-guided percutaneous core needle biopsy (CNB) of thin-walled cavitary pulmonary lesions. MATERIALS AND METHODS. This retrospective study involved 32 CNBs in 30 patients who had thin-walled cavitary pulmonary lesions (wall thickness < 5 mm) and underwent CT-guided CNB. After the 30 patient records were evaluated for the diagnostic accuracy, sensitivity, and specificity of CT-guided CNB, the results were compared with the final diagnosis after surgery or clinical follow-up. Each patient was reviewed for complications including pneumothorax, thoracotomy tube insertion, hemorrhage, and hemoptysis. RESULTS. The final diagnosis indicated 19 malignant and 11 benign lesions. Two lesions with indeterminate biopsy results (anthracofibrosis and focal interstitial thickening) were excluded. The sensitivity, specificity, and diagnostic accuracy of thin-walled cavities were 89.5%, 100%, and 93.3%, respectively. There were no statistical differences in the accuracy, sensitivity, or specificity according to wall thickness, cavity size, or lesion depth. Chest CT immediately after biopsy revealed mild pneumothorax in seven patients and moderate to severe pneumothorax requiring placement of a thoracotomy tube in one patient. CT after biopsy indicated mild parenchymal hemorrhage in 15 patients and hemoptysis in one patient. CONCLUSION. CT-guided CNB is a useful and accurate diagnostic technique for biopsy of a pulmonary thin-walled cavity.

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.

Evolution of cystic airspaces lung lesions on immune checkpoint inhibition in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) can be associated with pulmonary cystic airspaces (pCAs). pCAs are radiologically classified into four types based on whether the nodule or mass extrudes the wall of the pCAs. In most cases, response evaluation of these lesions by Response Evaluation Criteria in Solid Tumors (RECIST) V.1.1 is challenging. Based on the observation of a case of morphological evolution of pCAs associated with NSCLC in a patient receiving immune checkpoint inhibitor (ICI), we reviewed retrospectively imaging scans of 92 consecutive advanced patients with NSCLC treated at our institution. Overall, three cases of pCAs associated with NSCLC obtained a remarkable change following ICI. Of note, these changes were not always seen in the context of a clear radiological objective response. The morphological changes observed may reflect a novel pattern of response to immunotherapy agents that clinicians should be aware of. This pattern of response, not reported before, warrants further investigation and, if confirmed, we believe that it should be considered in future version of immune RECIST.

Lung cancer from a focal bulla into thin-walled adenocarcinoma with ground glass opacity — an observation for more than 10 years: A case report

BACKGROUND

Thin-walled lung cancer manifests as a cystic lesion, mostly adenocarcinoma. It is often misdiagnosed as a benign lesion in clinical practice, thus delaying the diagnosis and surgical treatment. Its natural course is rarely recorded and observed; thus, the pathogenesis and diagnosis need to be clarified and improved.

CASE SUMMARY

A 66-year-old man developed a mass in the upper lobe of the right lung and a small, thin-walled cavity in the lower lobe of the right lung in 2007. The right upper lobe mass was confirmed to be adenocarcinoma after surgery. The cavity diameter increased from 11 mm to 31 mm over 10 years, and a ground glass opacity lesion appeared around the bulla on computed tomography. A second operation confirmed that the lesion was lepidic predominant adenocarcinoma. Here we report a rare case of lung cancer developing from a focal bulla to a thin-walled adenocarcinoma for more than 10 years and confirm that the check-valve mechanism explains the pathogenesis.

CONCLUSION

Solitary thin-walled lung adenocarcinoma is a rare tumor in terms of its clinical manifestations, pathogenesis, and disease progression. The check-valve mechanism can explain the cause of thin-walled lung cancer. Close follow-up and accurate imaging are necessary.

Clinicopathological characteristics of solitary cavitary lung cancer: a case-control study

Background

With the emerging radiological techniques and the increasing incidence of adenocarcinoma, the composition and structure of cavitary lung cancer have been significantly changed. The aim of the study was to demonstrate clinicopathological characteristics of solitary cavitary lung cancer which was ≤3 cm.

Methods

A case-control study was designed through retrospective data analysis of clinicopathological data of 946 cases with solitary lung cancer smaller than 3 cm. Univariable and multivariable analysis were used to identify the risk factors of cavitation.

Results

Cavitary lung cancer occurred more frequently in patients who were elderly (P=0.044), male (P=0.004), who had a smoking history (P=0.018), higher carcinoembryonic antigen (CEA) level (P<0.001), peripheral lesions (P=0.017), solid nodules (P<0.001), spiculation (P=0.003), vascular convergence (P<0.001), air bronchogram (P=0.004), larger tumor size (P<0.001), advanced T stage (P<0.001), lymph node metastasis (P=0.028) and advanced pTNM stage (P=0.004). In addition, cavitary lung cancer was more common in papillary predominant tumors (P=0.017), while noncavitary lung cancer occurred more frequently in AIS/MIA (P=0.002) and lepidic predominant tumors (P<0.001). It was confirmed that cavitation was significantly associated with elderly (P=0.013), male (P=0.003), larger maximum tumor diameter (P<0.001), solid nodules (P<0.001), larger pT size (P=0.016) and advanced pN stage (P=0.036) in multivariable analysis. ROC curves showed that the AUV was greater in maximum tumor diameter than in pT size predicting cavitation (0.71 vs. 0.66). A cut off value of 20.9 mm showed a discriminatory power of cavitation with a sensitivity of 68.7% and a specificity of 71.2%.

Conclusions

Comparing with noncavitary lung cancer, cavitary lung cancer smaller than 3 cm may have worse prognostic clinical, radiological and pathological characteristics. Especially, cavitary lung cancer present as more solid nodules on CT images and present with more invasive on pathological findings.

Stepwise Disease Progression Model of Subsolid Lung Adenocarcinoma with Cystic Airspaces

OBJECTIVES

Subsolid lung adenocarcinoma with cystic airspaces (LACA) is a unique manifestation of lung cancer. This study was conducted to establish a radiologic disease progression model of LACA and to explore its association with the clinical course and clinicopathologic features of LACA.

MATERIALS AND METHODS

Sixty patients with LACA who underwent surgery at our center between 2004 and 2017 were retrospectively reviewed. The morphological changes of LACA over time on 98 serial computed tomography scans from 27 of 60 patients were tracked to establish a radiologic disease progression model. Associations between this model and the clinicopathologic characteristics of LACA were investigated.

RESULTS

The following stepwise progression model of LACA was developed: in phase I, cystic airspaces (CAs) appear in the middle of non-solid nodules; in phase II, the CAs grow; in phase III, a solid component appears on the border of the CAs; and in phase IV, the solid component gradually surrounds the CAs and becomes thicker, and the CAs shrink. In total, 10 (17%), 33 (55%), and 17 (28%) LACA patients were classified as belonging to phases II, III, and IV at the time of surgery, respectively. More advanced phases were associated with higher pathologic T and N staging, lymphovascular invasion, visceral pleural invasion, spread through air spaces, and solid/micropapillary subtype. In the multivariate analysis, our model demonstrated a good discrimination capability for cancer recurrence risk.

CONCLUSIONS

The stepwise disease progression model of LACA based on radiologic findings developed in this study represented its natural clinical course and clinicopathologic features well.

Pulmonary high-grade fetal adenocarcinoma associated with cystic airspace: A case report

Lung cancers associated with cystic airspaces have a life‐threatening risk of a missed or delayed diagnosis. Here, we report a case of pulmonary high‐grade fetal adenocarcinoma, a rare lung carcinoma associated with cystic airspaces, as confirmed by computed tomography (CT) scan. A 73‐year‐old asymptomatic male with a 52‐pack a year smoking habit was referred to our hospital. Lung CT showed a thin‐walled cystic space with exophytic and endophytic solid nodules along the cyst wall. After surgery, histological analysis of a resected lung specimen revealed a pure high‐grade fetal adenocarcinoma probably associated with emphysematous bullae in pulmonary emphysema, suggesting smoking contributed to this pure form, as well as the emphysema. In conclusion, when treating elderly men with a smoking history, physicians need to carefully examine the walls of cystic airspaces on CT for fetal adenocarcinoma.

Key points

Significant findings of the study•

Pulmonary high‐grade fetal adenocarcinoma may be associated with emphysematous bullae manifesting as cystic air spaces as shown by computed tomography.

What this study adds•

When scanning by computed tomography, physicians should carefully examine the pulmonary cystic airspace walls in elderly men with a smoking history.

Can pseudocavitation in lung tumors predict the diagnosis of adenocarcinoma with lepidic growth?

OBJECTIVE

To determine the prevalence of pseudocavitation in lung tumors and whether its presence makes it possible to predict the diagnosis of adenocarcinoma with lepidic growth.

MATERIAL AND METHODS

We retrospectively reviewed chest CT studies for 212 consecutive lung tumors included in a CT perfusion database and for 351 consecutive adenocarcinomas diagnosed between July 2007 and September 2017. Two radiologists blinded to the pathology report determined whether air cysts were present in the tumors, excluding lesions with necrosis and those surrounded by bullae or emphysema. We analyzed whether the presence of pseudocavitation was associated with the histologic type, size, or EGFR positivity of the tumor as well as with the age or sex of the patient. We also evaluated the relationship with the histologic subtype of the tumor in patients who underwent surgery. We used the chi-square test for categorical variables and logistic regression for continuous variables.

RESULTS

Pseudocavitation was present in 15% of the tumors and was significantly more common in adenocarcinomas (24.1%), p=0.003, although it was also observed in 9.8% of the epidermoid carcinomas and in 3% of the microcytic carcinomas. For the diagnosis of adenocarcinoma, the presence of pseudocavitation yielded 92.4% specificity, 24% sensitivity, 73.3% PPV, 58.4% NPV, and 37.6% accuracy. In the resected adenocarcinomas, 65% of the tumors with pseudocavitation had lepidic growth; the prevalence of pseudocavitation was 40.6% in tumors with lepidic growth, 31.5% in those with acinar growth, and 33% in those with papillary growth. Pseudocavitation was significantly more common in women (29%); no differences were found with respect to age, size, or EGFR positivity.

CONCLUSIONS

Pseudocavitation is more common in adenocarcinomas with lepidic growth and in women.

Lung cancers associated with cystic airspaces: CT features and pathologic correlation

OBJECTIVE

Lung cancer associated with cystic airspaces (LCCA) is a rare entity. The diagnosis and treatment is often delayed due to lack of comprehension of this disease. We aimed to elucidate LCCA's clinicopathological characteristics and investigate imaging features correlated with pathological invasiveness.

METHOD

The preoperative computed tomographic (CT) scans of 10,835 patients diagnosed with NSCLC between January 2015 and December 2016 were reviewed by two thoracic radiologists for association with a cystic airspace. A clinicopathological and radiological feature analysis was done.

RESULT

A total number of 123 LCCA patients were identified and four morphologic patterns were recognized: I, thin-walled type (n = 23, 18.7%); II, thick-walled type (n = 34, 27.6%); III, a cystic airspace with a mural nodule (CWN) type (n = 43, 35.0%); and IV, mixed type (n = 23, 18.7%). A solid component in the cyst wall predicted histological invasiveness in all four types of LCCA. The proportion of moderately/poorly (M/P)-differentiated subtype in type III (85.0%) was higher than in other three patterns (which were 50.0%, 50.0%, and 69.6%, respectively). Multivariate analysis revealed that type III pattern (odds ratio [OR], 6.5; 95% confidence interval [CI], 1.1-36.4; P = 0.035), part-solid/solid component in wall (part-solid: OR, 27.2; 95% CI, 5.6-3131.6; P < 0.001; solid: OR 614.6; 95% CI, 36.4-10,368.6; P < 0.001), and irregular inner surface of cyst (OR 7.0; 95% CI 1.9-26.2; P = 0.004) were independent risk factors for the M/P-differentiated subtype. EGFR mutations were the predominant genetic alterations in each type of LCCAs, but no significant difference was found among them.

CONCLUSIONS

In LCCA, morphological patterns and wall components were two important predictors for determining pathological invasiveness.

CT Characteristics and Pathologic Basis of Solitary Cystic Lung Cancer

There are increasing reports of a type of lung cancer that manifests as solitary cystic airspaces. The purpose of this case series was to identify the CT features and possible mechanisms of solitary cystic lung cancer, on the basis of CT observations and pathologic characteristics. The clinical, imaging, and pathologic data of 106 patients with solitary cystic lung cancer were collected and analyzed between January 2011 and December 2017. CT images were reviewed independently by three radiologists who were blinded to pathologic findings. Demographic data and clinical and smoking status were extracted from the medical records. The mean age was 58.8 years 6 10.6 (standard deviation) (range, 30–82 years). CT features in the 106 patients included nonuniform cystic walls in 96 (90.6%) patients, cyst septations in 62 (58.5%) patients, nodular walls in 58 (54.7%) patients, ground-glass opacity around the cyst in 53 patients (50.0%), and irregular margins in 42 (39.6%) patients. At histologic examination, the majority of cases (81 [87.1%] of 93) were adenocarcinoma.

Diagnostic and clinical features of lung cancer associated with cystic airspaces

"Lung cancer associated with cystic airspaces" is an uncommon manifestation, in which lung cancer presents on imaging studies with a cystic area with associated consolidation and/or ground glass. With the widespread use of computed tomography (CT), both in clinical practice and for lung cancer screening, these tumors are being more frequently recognized. An association of this entity with smoking has been established with the majority of cases reported being in former and current smokers. The true pathogenesis of the cystic airspace is not yet fully understood. Different causes of this cystic airspace have been described, including a check-valve mechanism obstructing the small airways, lepidic growth of adenocarcinoma on emphysematous lung parenchyma, cyst formation of tumor and tumor growth along the wall of a pre-existing bulla. Adenocarcinoma is the commonest histological type, followed by squamous cell carcinoma. Two classification systems have been described, based on morphological features of the lesion, taking into account both the cystic airspace as well as the morphology of the surrounding consolidation or ground glass. The cystic component may mislead radiologists to a benign etiology and the many different faces on imaging can make early diagnosis challenging. Special attention should be made to focal or diffuse wall thickening and consolidation or ground glass abutting or interspersed with cystic airspaces. Despite their atypical morphology, staging and management currently are still similar to that of other lung cancer types. Although the rarity of this entity will hamper larger studies, numerous aspects regarding this particular lung cancer type still need to be unraveled. This manuscript reviews the CT-imaging findings and gives an overview of available data in the English literature on pathogenesis, histopathology and clinical findings. Differential diagnosis and pitfalls are discussed as well as future directions regarding staging and management.

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

It is well known that lung cancer can manifest itself in imaging as solid and subsolid nodules or masses. However, in this era of increased computed tomography use another morphological computed tomography appearance of lung cancer is increasingly being recognised, presenting as a malignancy in relation to cystic airspaces. Despite the fact that it seems to be a relatively common finding in daily practice, literature on this entity is scarce and presumably the overall awareness is limited. This can lead to misinterpretation and delay in diagnosis and, therefore, increased awareness is urgently needed. This review aims to illustrate the imaging appearances of cyst-related primary lung malignancies, demonstrate its mimickers and potential pitfalls, and discuss the clinical implications based on the available literature and our own experience in four different hospitals.