Pictorial review of the many faces of bronchioloalveolar cell carcinoma

Role of Percutaneous Computed Tomography-guided Lung Biopsy in Non-resolving Consolidation and Identification of Clinical and High-resolution Computed Tomography Characteristics Predicting Outcome

Objective:

Non-resolving consolidation (NRC) with inconclusive sputum, bronchoscopy, and bronchoalveolar lavage results poses a diagnostic dilemma. This retrospective analytical study was conducted to evaluate diagnostic yield and complications of percutaneous computed tomography (CT)-guided lung biopsy (PCLB) in NRC. Assessment of clinical features and high-resolution CT (HRCT) characteristics was also done which may predict outcome.

Materials and Methods:

Data of PCLB performed for lung consolidation from January 2010 to January 2019 were retrospectively evaluated. For the determination of diagnostic yield, a positive result from any one specimen obtained by PCLB (tissue core, aspiration cytology, or microbiology) was sufficient to considered procedure diagnostic if it was concordant with clinical features, imaging findings, response to treatment, and subsequent follow-up. Student’s t-test and Fisher’s exact test were used for statistical analysis.

Results:

Out of total 56 patients, final diagnosis was achieved in 48 (19 malignant and 29 benign). Diagnostic yield was 69.6%. Complications were noted in 10 patients including mild hemoptysis and pneumothorax, which were managed conservatively. No clinical feature was having statistically significant association with final diagnosis. HRCT findings significantly associated with malignant outcome were larger size of consolidation, multiple contiguous lobe involvement, multiple air-filled cysts inside consolidation, and associated ground-glass areas or multiple ground-glass nodules. The absence of air bronchogram was more common in benign cases.

Conclusion:

PCLB is a safe and useful method for obtaining specimen in NRC. Differentiation of benign from malignant outcome is not possible based on clinical findings; however, certain HRCT findings raise suspicion of malignancy.

Genomic analyses based on pulmonary adenocarcinoma in situ reveal early lung cancer signature

BACKGROUND

Non-small cell lung cancer (NSCLC) represents more than about 80% of the lung cancer. The early stages of NSCLC can be treated with complete resection with a good prognosis. However, most cases are detected at late stage of the disease. The average survival rate of the patients with invasive lung cancer is only about 4%. Adenocarcinoma in situ (AIS) is an intermediate subtype of lung adenocarcinoma that exhibits early stage growth patterns but can develop into invasion.

METHODS

In this study, we used RNA-seq data from normal, AIS, and invasive lung cancer tissues to identify a gene module that represents the distinguishing characteristics of AIS as AIS-specific genes. Two differential expression analysis algorithms were employed to identify the AIS-specific genes. Then, the subset of the best performed AIS-specific genes for the early lung cancer prediction were selected by random forest. Finally, the performances of the early lung cancer prediction were assessed using random forest, support vector machine (SVM) and artificial neural networks (ANNs) on four independent early lung cancer datasets including one tumor-educated blood platelets (TEPs) dataset.

RESULTS

Based on the differential expression analysis, 107 AIS-specific genes that consisted of 93 protein-coding genes and 14 long non-coding RNAs (lncRNAs) were identified. The significant functions associated with these genes include angiogenesis and ECM-receptor interaction, which are highly related to cancer development and contribute to the smoking-free lung cancers. Moreover, 12 of the AIS-specific lncRNAs are involved in lung cancer progression by potentially regulating the ECM-receptor interaction pathway. The feature selection by random forest identified 20 of the AIS-specific genes as early stage lung cancer signatures using the dataset obtained from The Cancer Genome Atlas (TCGA) lung adenocarcinoma samples. Of the 20 signatures, two were lncRNAs, BLACAT1 and CTD-2527I21.15 which have been reported to be associated with bladder cancer, colorectal cancer and breast cancer. In blind classification for three independent tissue sample datasets, these signature genes consistently yielded about 98% accuracy for distinguishing early stage lung cancer from normal cases. However, the prediction accuracy for the blood platelets samples was only 64.35% (sensitivity 78.1%, specificity 50.59%, and AUROC 0.747).

CONCLUSIONS

The comparison of AIS with normal and invasive tumor revealed diseases-specific genes and offered new insights into the mechanism underlying AIS progression into an invasive tumor. These genes can also serve as the signatures for early diagnosis of lung cancer with high accuracy. The expression profile of gene signatures identified from tissue cancer samples yielded remarkable early cancer prediction for tissues samples, however, relatively lower accuracy for boold platelets samples.

Invasive mucinous adenocarcinoma with lepidic-predominant pattern coexisted with tuberculosis: a case report

We observed a rare case of invasive mucinous adenocarcinoma (IMA) with a lepidic-predominant pattern accompanied by pulmonary tuberculosis. An 85-year-old man with repeated cough and sputum was admitted to Xinhua Hospital. T-SPOT test result was 212 pg/ml (reference value of negative is < 14 pg/ml), Mycobacterium tuberculosis culture was positive, and tuberculin skin test (PPD) was negative (skin induration < 5 mm). The patient was treated with several courses of antibiotics and anti-tuberculosis treatments. Repeated chest CT scans showed disease progression. Bronchoscopy yielded negative results. PET-CT scans showed negative results. A percutaneous lung biopsy revealed mucin-secreting cells lining the alveolar walls. IMA with a lepidic-predominant pattern was diagnosed after invasiveness was found after experimental treatments. Simultaneous occurrence of pulmonary tuberculosis and lung cancer are common; however, the present case of IMA having a lepidic-predominant pattern and coexisting with active tuberculosis has not been reported yet.

Benign features of infection-related tumor-like lesions of the lung: A retrospective imaging review study

INTRODUCTION

Differentiation of benign and malignant pulmonary tumor-like lesions is challenging but increasingly important. We evaluate the most common imaging features in benign lesions based on the frequency of their appearance and compare with corresponding frequencies in malignant tumors from literature.

METHODS

Retrospective imaging review study in one center between 1 January 2012 and 30 June 2014. We reviewed the data from 2466 pathological examinations of lung specimens collected from the hospital. We excluded malignant or non-tumor-like lesions and identified 133 infection-related lesions for imaging review. The frequency of 11 benign imaging features was evaluated in the selected infection-related tumor-like pulmonary lesions and was compared with corresponding frequency in malignant tumors.

RESULTS

Most of the evaluated lesions were seen to have one to four benign features. The two most common benign features are marginal ground glass or infiltrates (62.4%), followed by pleura-based wedge shape (50.4%). Features with significantly higher frequency in benign infection-related lung lesions than malignancy are calcification or hyperdensity, pleura-based wedge shape, adjacent clustered small nodules, and strongly or poorly enhanced soft tissue part.

CONCLUSIONS

Infection-related lung lesions usually have one to four benign features and the common features with significantly higher frequency than malignant condition are pleura-based wedge shape, calcification or hyperdensity, adjacent clustered small nodules, and strongly or poorly enhanced soft tissue part.

Invasive mucinous adenocarcinoma of the lung presenting as a large, thin-walled cyst: A case report and literature review

Invasive mucinous adenocarcinoma (IMA), formerly referred to as mucinous bronchioloalveolar carcinoma, is a rare variant form of invasive adenocarcinoma and is radiologically characterized by dense pneumonic consolidation, ground-glass opacity and nodules. By contrast, large, thin-walled cysts are rare. We herein report the case of a 75-year-old man with IMA presenting as a large, irregularly shaped cystic lesion. The histological diagnosis was based on specimens obtained during a bronchoscopy. The patient underwent lobectomy followed by anticancer chemotherapy for residual intrapulmonary metastases. Of note, the small metastatic nodules transformed into cystic lesions with thin walls and fused, forming a large, multiloculated cystic lesion. Typical pneumonic consolidation appeared in the pericystic parenchyma later during the clinical course. The available literature on this rare radiological manifestation was also reviewed and discussed. Clinicians should be aware of thin-walled cystic lesions as they may be an unusual radiological finding in IMA.

Case report: Positron emission tomography fails to detect pulmonary adenocarcinoma recurrence after radiofrequency ablation

We describe the case of late recurrence of a focus of invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma) following radiofrequency ablation, despite a negative positron emission tomography/computed tomography scan at 13 months following the ablation. A computed tomography scan performed at 24 months demonstrated unequivocal recurrence of the lesion. Combined positron emission tomography/computed tomography has been described as an adequate modality for the follow-up of thermally ablated pulmonary lesions. However, its utility in the follow-up of well-differentiated pulmonary adenocarcinoma may be limited. Lesion activity may be underestimated by an inherently low metabolic activity. Small lesions may also be susceptible to partial volume effect. Long-term imaging follow-up of well-differentiated pulmonary adenocarcinoma beyond two years after thermal ablation is prudent to avoid missing late recurrence.

Invasive mucinous adenocarcinoma mimicking organizing pneumonia associated with Mycobacterium fortuitum infection

We herein report the case of a 68-year-old man diagnosed with invasive mucinous adenocarcinoma of the lungs. Chest computed tomography showed subpleural ground-glass opacity and small nodules with cavitation. A culture of the bronchoalveolar lavage fluid resulted in the detection of Mycobacterium fortuitum. The patient's lung consolidation rapidly progressed; however, repeated bronchoscopy showed no atypical cells, thus suggesting a diagnosis of organizing pneumonia associated with M. fortuitum infection. However, the surgical biopsy specimen was diagnostic for adenocarcinoma, with no mycobacterial infection. Invasive mucinous adenocarcinoma should not be excluded in the differential diagnosis of patients with clinical features of organizing pneumonia and nontuberculous mycobacterium infection, even if a transbronchial biopsy confirms the absence of malignancy.

Impact of the IASLC/ATS/ERS classification in pN0 pulmonary adenocarcinomas: a study with radiological-pathological comparisons and survival analyses

The aim of this study was: (1) to compare the new pathological findings as detected by the IASLC/ATS/ERS classification with the traditional radiological features in pulmonary pN0 adenocarcinomas, (2) to evaluate their prognostic significance on overall survival (OS). A total of 42 surgically resected pN0 pulmonary adenocarcinomas were analyzed. On CT scans, the following radiological data were recorded: sphericity, predominant margins, cavitation and bronchogram, attenuation and percentage of ground glass opacity (GGO). On pathological examination, tumors were categorized according to the IASLC/ATS/ERS classification; Sica score and grade, pathological stage, tumor major axis, pleural invasion, vascular and lymphatic invasion, peritumoral lymphoid infiltration, and cytological features were also determined. Clinical follow up was available in 37 cases (range 1-117 months). Radiologically, 31 solid and 11 semisolid tumors were found. Morphologically, 2 minimally invasive and 40 invasive adenocarcinomas were diagnosed. In radiological-pathological comparisons, (1) the acinar pattern was higher in tumors with solid attenuation and low GGO (p=0.018); (2) the lepidic pattern was more elevated in tumors with high GGO (p=0.012). In multivariate survival analyses with stage, predominant margins on CT scans (p=0.036) and Sica score (p=0.028) significantly affected OS. This study confirms the validity of the new classification of pulmonary adenocarcinomas in radiological-pathological comparisons and underlines the importance of both radiological and pathological findings in correctly identifying their prognostic features.

Stereotactic body radiation therapy for the treatment of early-stage minimally invasive adenocarcinoma or adenocarcnioma in situ (formerly bronchioloalveolar carcinoma): a patterns of failure analysis

Introduction

Ongoing prospective trials exploring stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) often exclude minimally invasive adenocarcinoma or adenocarcnioma in situ, formerly bronchioloalveolar carcinoma (BAC), due to concerns for accurate target delineation on CT. We performed a patterns of failure analysis to compare outcomes between BAC and other NSCLC subtypes.

Methods

One hundred twenty patients with early stage NSCLC were treated with SBRT from 2004–2009. Pathologic confirmation of NSCLC was obtained in 97 patients. Radiotherapy was delivered according to RTOG guidelines. The log-rank test was used to compare outcomes between BAC and other NSCLC.

Results

Median follow-up was 29 months. The median SBRT dose was 5400 cGy. Thirteen patients had radiographically diagnosed BAC and five patients had biopsy confirmed BAC, of which two had both. The three-year local control was 100% for biopsy-proven or radiographically diagnosed BAC (n = 18) and 86% for all other NSCLC subtypes (n = 102) (p = 0.13). Likewise, no significant difference was detected between BAC and other NSCLC for 3-year regional failure (12% vs. 20%, p = 0.45), progression-free survival (57.6% vs. 53.5%, p = 0.84) or overall survival (35% vs. 47%, p = 0.66). There was a trend towards lower three-year rates of freedom from distant failure in patients with any diagnosis of BAC compared to those without (26% vs. 38%, p = 0.053).

Conclusions

Compared to other NSCLC subtypes, BAC appears to have similar patterns of failure and survival after treatment with SBRT, however there may be an increased risk of distant metastases with BAC. RTOG guideline-based target delineation provides encouraging local control rates for patients with BAC.

Mimics in chest disease: interstitial opacities

Septal, reticular, nodular, reticulonodular, ground-glass, crazy paving, cystic, ground-glass with reticular, cystic with ground-glass, decreased and mosaic attenuation pattern characterise interstitial lung diseases on high-resolution computed tomography (HRCT). Occasionally different entities mimic each other, either because they share identical HRCT findings or because of superimposition of patterns. Idiopathic pulmonary fibrosis (IPF), fibrosis associated with connective tissue disease, asbestosis, end-stage sarcoidosis or chronic hypersensitivity pneumonitis (HP) may present with lower zone, subpleural reticular pattern associated with honeycombing. Lymphangiomyomatosis may be indistinguishable from histiocytosis or extensive emphysema. Both pulmonary oedema and lymphangitic carcinomatosis may be characterised by septal pattern resulting from thickened interlobular septa. Ill-defined centrilobular nodular pattern may be identically present in HP and respiratory bronchiolitis–associated with interstitial lung disease (RBILD). Sarcoidosis may mimic miliary tuberculosis or haematogenous metastases presenting with miliary pattern, while endobronchial spread of tuberculosis may be indistinguishable from panbronchiolitis, both presenting with tree-in-bud pattern. Atypical infection presenting with ground-glass mimics haemorrhage. Ground-glass pattern with minimal reticulation is seen in desquamative interstitial pneumonia (DIP), RBILD and non-specific interstitial pneumonia (NSIP). Obliterative bronchiolitis and panlobular emphysema may present with decreased attenuation pattern, while obliterative bronchiolitis, chronic pulmonary embolism and HP may manifest with mosaic attenuation pattern. Various mimics in interstitial lung diseases exist. Differential diagnosis is narrowed based on integration of predominant HRCT pattern and clinical history.

Teaching Points

• To learn about the different HRCT patterns, which are related to interstitial lung diseases.

• To be familiar with the more “classical” entities presenting with each HRCT pattern.

• To discuss possible overlap of different HRCT patterns and the more common mimics in each case.

• To learn about some clues that help differentiate the various diagnostic mimics on HRCT.

Aspects of bronchioloalveolar carcinoma and of adenocarcinoma with a bronchioloalveolar component: CT findings

Bronchioloalveolar carcinoma has various presentations and a wide spectrum of imaging patterns, as does adenocarcinoma with a bronchioloalveolar component. The objective of this essay was to describe and illustrate the CT findings that are most characteristic of these tumors. Three presentations are described: solitary pulmonary nodule, consolidation, and diffuse pattern. The last two should be included in the differential diagnosis, together with infectious diseases. Knowledge of the various presentations and the use of proper diagnostic procedures are crucial to early diagnosis and to improving survival.

Lung infections: the radiologist's perspective

Imaging plays a key role in lung infections. A CT scan must be carried out when there is a strong clinical suspicion of pneumonia that is accompanied by normal, ambiguous, or nonspecific radiography, a scenario that occurs most commonly in immunocompromised patients. CT allows clinicians to detect associated abnormalities or an underlying condition and it can guide bronchoalveolar lavage or a percutaneous or transbronchial lung biopsy. An organism can vary in how it is expressed depending on the extent to which the patient is immunocompromised. This is seen in tuberculosis in patients with AIDS. The infective agents vary with the type of immune deficiency and some infections can quickly become life-threatening. Clinicians should be aware of the complex radiological spectrum of pulmonary aspergillosis, given that this diagnosis must be considered in specific settings.

How many adenocarcinoma lung cancers come from bronchioloalveolar carcinoma?

BACKGROUND

There is emerging evidence that bronchioloalveolar carcinoma (BAC) is the forerunner of peripheral adenocarcinoma lung cancers (ALC). Since advanced stage ALC is often diagnosed on cytology alone, we hypothesized that the incidence of BAC is underreported and that a large proportion of ALC in our population are part of the BAC-adenocarcinoma sequence.

METHODS

We reviewed the pretreatment computed tomographic (CT) scans of 69 patients with ALC and looked for characteristic features of BAC.

RESULTS

The median patient age was 63, and the majority were of Chinese descent (75.4%). Women comprised 43.5% of the patients (30 patients) and never-smokers comprised 47.8% (33 patients). Only 15 patients (21.7%) had surgical specimens. The presence of BAC components was reported in the pathology of 16 patients (23.2%). CT features classically associated with BAC were found in 35 patients (50.7%). These included air bronchograms or bubble-like lucencies in 24 patients (34.8%), ground-glass opacities in 19 (27.5%), consolidation or pneumonic picture in 11 (15.9%), diffuse small or miliary nodules in 10 (14.5%), and the CT angiogram sign in 4 (5.8%).

CONCLUSIONS

We found provocative radiologic evidence that a large proportion of our ALC cases arise from BAC. The CT findings are consistent with current understanding of the likely pathogenesis of peripheral ALC.

The crazy-paving pattern: a radiological-pathological correlation

The crazy-paving pattern is a linear pattern superimposed on a background of ground-glass opacity, resembling irregularly shaped paving stones. The crazy-paving pattern is initially described as the pathognomonic sign of alveolar proteinosis. Nowadays this pattern is a common finding on high-resolution CT imaging, and can be seen in a number of acute and chronic diseases. The purpose of this paper is to illustrate different diseases that cause this crazy-paving pattern and to correlate the radiological findings from computed tomography with the histopathological findings.

Sclerosing variant of the bronchioloalveolar carcinoma: imaging findings in an atypical case

Bronchioloalveolar carcinoma remains one of the most enigmatic lung cancers, demonstrating varied growth patterns, mixed histological features, and confusing clinical manifestations. This paper reports a case of an unusual form of presentation: a sclerosing type associated with desmoplastic reaction and cicatrization. A 75-year-old woman was admitted with persistent dry cough and progressive dyspnea. Physical examination showed bilateral inspiratory crackles. A chest radiograph and high-resolution computed tomography demonstrated confluent airspace nodules, forming areas of consolidation in both lungs, with signs of architectural distortion. The lung biopsy revealed a nonmucinous sclerosing bronchioloalveolar carcinoma.

Bronchiolar disorders: a clinical-radiological diagnostic algorithm

Bronchiolar disorders are generally difficult to diagnose because most patients present with nonspecific respiratory symptoms of variable duration and severity. A detailed clinical history may point toward a specific diagnosis. Pertinent clinical questions include history of smoking, collagen vascular disease, inhalational injury, medication usage, and organ transplant. It is important also to evaluate possible systemic and pulmonary signs of infection, evidence of air trapping, and high-pitched expiratory wheezing, which may suggest small airways involvement. In this context, pulmonary function tests and plain chest radiographs may demonstrate abnormalities; however, they rarely prove sufficiently specific to obviate bronchoscopic or surgical biopsy. Given these limitations, in our experience, high-resolution CT (HRCT) scanning of the chest often proves to be the most important diagnostic tool to guide diagnosis in these difficult cases, because different subtypes of bronchiolar disorders may present with characteristic image findings. Three distinct HRCT patterns in particular are of value in assisting differential diagnosis. A tree-in-bud pattern of well-defined nodules is seen primarily as a result of infectious processes. Ill-defined centrilobular ground-glass nodules point toward respiratory bronchiolitis when localized in upper lobes in smokers or subacute hypersensitivity pneumonitis when more diffuse. Finally, a pattern of mosaic attenuation, especially when seen on expiratory images, is consistent with air-trapping characteristic of bronchiolitis obliterans or constrictive bronchiolitis. Based on an appreciation of the critical role played by HRCT scanning, this article provides clinicians with a practical algorithmic approach to the diagnosis of bronchiolar disorders.