From the Archives of the AFIP

Rare interstitial lung disease: Pulmonary Langerhans Cell Histiocytosis in a young non smoking Indian female

Adult Pulmonary Langerhans Cell Histiocytosis (PLCH) is a rare interstitial lung disease which occurs almost exclusively in smokers. A marked male predominance was initially reported, but recent studies show both men and women are equally affected due to the increasing smoking habits in women. The natural history is variable with 25% of patients having asymptomatic disease while 10-20% progress rapidly to respiratory insufficiency and death. The diagnosis is not easily recognized by clinicians or pathologists. Awareness of the clinical presentation and classical HRCT findings helps in early diagnosis and management of this disease. We report a rare case of severe PLCH in a young non smoking female with a short history who progressed rapidly to respiratory failure and died.

Cystic lung disease in birt-hogg-dubé syndrome: a case series of three patients

Birt-Hogg-Dubé syndrome is characterized by clinical manifestations such as hamartomas of the skin, renal tumors and lung cysts with spontaneous pneumothoraces. Patients with Birt-Hogg-Dubé syndrome may present with only multiple lung cysts. We report the chest computerized tomography (CT) features of three patients with Birt-Hogg-Dubé syndrome. Each patient had multiple lung cysts of various sizes according to chest CT evaluation, most of which were located in lower lobes and related to pleura. The identification of unique characteristics in the chest CT of patients with Birt-Hogg-Dubé syndrome may provide an efficient mechanism for diagnosis.

Pulmonary lymphangioleiomyomatosis: analysis of disease manifestation by region-based quantification of lung parenchyma

PURPOSE

Lymphangioleiomyomatosis (LAM) is characterized by proliferation of smooth muscle tissue that causes bronchial obstruction and secondary cystic destruction of lung parenchyma. The aim of this study was to evaluate the typical distribution of cystic defects in LAM with quantitative volumetric chest computed tomography (CT).

MATERIALS AND METHODS

CT examinations of 20 patients with confirmed LAM were evaluated with region-based quantification of lung parenchyma. Additionally, 10 consecutive patients were identified who had recently undergone CT imaging of the lung at our institution, in which no pathologies of the lung were found, to serve as a control group. Each lung was divided into three regions (upper, middle and lower thirds) with identical number of slices. In addition, we defined a "peel" and "core" of the lung comprising the 2 cm subpleural space and the remaining inner lung area. Computerized detection of lung volume and relative emphysema was performed with the PULMO 3D software (v3.42, Fraunhofer MEVIS, Bremen, Germany). This software package enables the quantification of emphysematous lung parenchyma by calculating the pixel index, which is defined as the ratio of lung voxels with a density <-950HU to the total number of voxels in the lung.

RESULTS

Cystic changes accounted for 0.1-39.1% of the total lung volume in patients with LAM. Disease manifestation in the central lung was significantly higher than in peripheral areas (peel median: 15.1%, core median: 20.5%; p=0.001). Lower thirds of lung parenchyma showed significantly less cystic changes than upper and middle lung areas combined (lower third: median 13.4, upper and middle thirds: median 19.0, p=0.001).

CONCLUSION

The distribution of cystic lesions in LAM is significantly more pronounced in the central lung compared to peripheral areas. There is a significant predominance of cystic changes in apical and intermediate lung zones compared to the lung bases.

A breath from Houdini - A case of giant bullous emphysema

We describe a case of a young man presenting with exertional dyspnea. His chest radiograph showed hyperlucency in his left lung, and he was subsequently diagnosed to have giant bullous emphysema. An approach to lesions of decreased attenuation on computed tomography of the chest, with a focus on cystic lung diseases is discussed. This is followed by a literature review of the clinical presentation, natural history, radiology and management of giant bullous emphysema. Although this is an uncommon condition, a clinician has to be cognizant of the fact that it may mimic other common respiratory diseases. This review highlights the importance of these caveats as misguided treatment options may lead to devastating consequences.

Persistent pulmonary interstitial emphysema in a case of Langerhans cell histiocytosis

We present the case of a 10-month-old boy with multisystem Langerhans cell histiocytosis showing thin-walled lung cysts along with computed tomography (CT) evidence of persistent pulmonary interstitial emphysema (PPIE), in the absence of pneumothorax or pneumomediastinum. Follow-up CT performed after 6 months demonstrated complete resolution of interstitial emphysema.

Pulmonary Langerhans cell histiocytosis: the many faces of presentation at initial CT scan

Objectives

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial granulomatous disease that usually affects young adults who are smokers. Chest computed tomography (CT) allows a confident diagnosis of PLCH only in typical presentation, when nodules, cavitated nodules and cysts coexist and predominate in the upper and middle lungs.

Methods

This article includes a pictorial essay of typical and atypical presentations of PLCH at initial chest CT. Various appearances of PLCH are illustrated and possible differential diagnosis is discussed.

Results

PLCH can present with some aspecific features that may cause diagnosis of the initial disease to be overlooked or other pulmonary diseases to be suspected. In cases of nodule presentation alone, the main differential diagnosis should include lung metastasis, tuberculosis and other infections, sarcoidosis, silicosis and Wegener’s disease. In cases of cysts alone, the most common diseases to be differentiated are centrilobular emphysema and lymphangiomyomatosis. Clinical symptoms are usually non-specific, although a history of cigarette smoking, coupled with the presence of typical or suggestive findings at imaging, is key to suspecting the disease. Atypical presentations require surgical biopsy for diagnosis.

Conclusions

The radiologist should be familiar with PLCH imaging features to correctly diagnose the disease or need for further investigation.

Teaching Points

• PLCH is a rare interstitial smoking-related disease that usually affects young adults.

• The typical first CT shows a mix of nodules, cavitary nodules and cysts in the upper-middle lungs.

• Atypical appearance, either cysts or nodules alone, mandates that other diagnoses be considered.

• Lung cystic involvement correlates with lung function abnormalities and predicts functional decline.

• Integration of the clinical history and imaging results is key to diagnosis.

[Adult pulmonary Langerhans' cell histiocytosis: approach to the reality of the Spanish population]

BACKGROUND AND OBJECTIVE

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare respiratory disease closely associated with smoking. The aim of the study is to know the reality of PLCH in the Catalonian population.

MATERIAL AND METHODS

We included all patients diagnosed of PLCH in 8 different Catalonian hospitals from April 2011 to December 2012. Epidemiologic, clinical, radiological, functional, diagnostic and therapeutic variables were collected, both at the beginning and at the last visit of the process.

RESULTS

Thirty two patients were included. Overall, patients were middle-aged (38 years), with no gender predominance. Most of them were smokers (71.9%). The main pulmonary function values (forced vital capacity 75.9%, forced expiratory volume in one second 68.9%, diffusing capacity of the lung for carbon monoxide 59.6%) and radiological findings (cysts 89.7%, nodules 60.3%) showed no significant changes during evolution. However, the disease progressed with a worsening lung function in 34.4% of cases. The analysis of the functional outcome (forced vital capacity, forced expiratory volume in one second, and diffusing capacity of the lung for carbon monoxide) did not reveal significant differences according to the persistence or not of smoking (P<0.05).

CONCLUSION

Our patients with PLCH had similar clinical and radiological characteristics to those described in other populations. The results observed regarding the relationship with smoking suggest that there may be other factors beyond smoking, which influence on the evolution of the disease. It therefore seems advisable to design prospective studies to investigate this aspect.

Rare causes of pulmonary hypertension: spectrum of radiological findings and review of the literature

Following a brief introduction covering the clinical signs and symptoms of pulmonary hypertension (PH), its most recent classification into six groups, and the computed tomography (CT) features common to all forms of PH, this paper illustrates the typical patterns that can be found on chest radiography and CT in rare causes of PH. We present and compare with the existing literature our personal series of cases of rare forms of PH, found in the following diseases: veno-occlusive disease, pulmonary capillary haemangiomatosis, non-thrombotic pulmonary embolism (tumour embolism and carcinomatous lymphangitis, talcosis, hydatid disease), pulmonary artery sarcoma, neurofibromatosis, sarcoidosis, and Langerhans cell histiocytosis. Rare forms of PH show low incidence and prevalence, and are, therefore, poorly recognised. Their diagnosis is a challenge for clinicians, pathologists, and radiologists, and any additional knowledge about the CT findings may help the diagnosis in the case of patients affected by PH of unknown origin.

Rapid resolution of pulmonary Langerhans cell histiocytosis

A 38-year-old woman with a long-term history of smoking presented to the lung cancer clinic with weight loss and recurrent lower respiratory tract infections. A diagnosis of Langerhans cell histiocytosis was made by specimen samples taken from video-assisted thoracoscopic surgery. She was advised to stop smoking, which she adhered to. She was followed up in the respiratory clinic with pulmonary function tests every 6 months, which were all normal. Follow-up chest x-ray showed complete resolution of the multifocal interstitial infiltrates, and with smoking cessation, the patient has sustained an excellent quality of life.

Multiple cystic lung disease

A lung cyst is an air-filled lucent structure surrounded by a thin wall. The presence of multiple intrapulmonary cysts is defined as cystic lung disease. Although cystic lung disease is rare, incidental detection has increased significantly in recent years by screening using computed tomography. There are many conditions that can mimic lung cysts and cause cystic lung disease. Clinical, radiographic, and histologic findings are all necessary for a proper diagnosis, and multidisciplinary approaches are frequently required. The aim of this report is to review the causes and characteristics of cystic lung disease to better understand and improve treatment.

Pulmonary Langerhans cell histiocytosis-associated pulmonary hypertension: clinical characteristics and impact of pulmonary arterial hypertension therapies

BACKGROUND

Precapillary pulmonary hypertension (PH) is a complication of pulmonary Langerhans cell histiocytosis (PLCH) associated with increased mortality. However, outcomes and efficacy of pulmonary arterial hypertension (PAH) therapies in patients with PH complicating PLCH(PLCH-PH) remain unknown.

METHODS

Consecutive patients with PLCH with PH confirmed by right-sided heart catheterization were included in the study. Characteristics at baseline and during follow-up as well as survival were analyzed.

RESULTS

Twenty-nine patients were studied. Baseline characteristics of patients with PLCH-PH wereas follows: 83% of patients in World Health Organization (WHO) functional class III to IV, mean 6-min walk distance of 355 ±95 m, mean pulmonary arterial pressure (mPAP) of 45 ±14 mm Hg,cardiac index of 3.2± 0.9 L/min/m 2 , and pulmonary vascular resistance (PVR) of 555 ±253 dyne/s/cm 5. Use of PAH therapy in 12 patients was followed by an improvement in mPAP (56±14 mm Hg and 45±12 mm Hg, P 5 .03) and PVR (701±239 dyne/s/cm 5 and 469±210 dyne/s/cm 5 , P = .01) between baseline and follow-up evaluations. No significant oxygen worsening was observed in the treated group. The 1-, 3-, and 5-year survival estimates of the 29 patients were 96%, 92%, and 73%,respectively. Except a trend toward a better survival rate associated with the use of PAH therapy,WHO functional class was the only variable significantly associated with death.

CONCLUSIONS

In this group of patients, PAH therapies improved hemodynamics without oxygen worsening or pulmonary edema. WHO functional class was the only prognostic factor identified.Prospective clinical trials focusing on this population of patients are warranted

A practical approach to high-resolution CT of diffuse lung disease

Diffuse lung disease presents a variety of high-resolution CT findings reflecting its complex pathology, and provides diagnostic challenge to radiologists. Frequent modification of detailed pathological classification makes it difficult to keep up with the latest understanding. In this review, we describe a practical approach to high-resolution CT diagnosis of diffuse lung disease, emphasizing (1) analysis of "distribution" of the abnormalities, (2) interpretation of "pattern" in relation to distribution, (3) utilization of associated imaging findings and clinical information, and (4) chronicity of the findings. This practical approach will help radiologists establish a way to interpret high-resolution CT, leading to pin-point diagnosis or narrower differential diagnoses of diffuse lung diseases.

Multisystemic Langerhans cell histiocytosis with advanced lung involvement

Langerhans cell histiocytosis is a rare disease of unknown cause, characterized by the proliferation of histiocytic cells (Langerhans cells), that can sometimes be especially difficult to diagnose due to its wide clinical spectrum, ranging from a single lesion to a multisystemic disorder. Appropriate disease staging is fundamental, since treatment depends upon the severity of the disease, and imaging methods play a fundamental role not only in diagnosing and assessing the extent of Langerhans cell histiocytosis, as well as guiding the appropriate treatment for the patient and their monitoring.

Pulmonary Interstitium

The first step in the radiographic evaluation of interstitial lung disease begins with a fundamental knowledge of the anatomy of the pulmonary interstitium and the different patterns of disruption. The anatomy of the pulmonary interstitium as demonstrated on CT of the chest with high resolution cuts is largely essential to establish the various radiological patterns that define interstitial lung disease such as the tree-in-bud, ground-glass opacity, crazy -paving, etc.

Radiological approach to interstitial lung disease: a guide for the nonradiologist

Articles in the past have described the radiological appearances of different interstitial lung diseases (ILDs) in varying levels of detail. However, these articles have generally been written for radiologists with a background in basic chest computed tomography (CT) interpretation. This article summarizes a basic approach for diagnosing ILDs on high-resolution CT (HRCT) for the nonradiologist clinician and discusses the most common HRCT features of common ILDs.

Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.

Rare lung diseases III: pulmonary Langerhans' cell histiocytosis

Pulmonary Langerhans' cell histiocytosis (PLCH) is an unusual cystic lung disease that is also characterized by extrapulmonary manifestations. The current review discusses the presenting features and relevant diagnostic testing and treatment options for PLCH in the context of a clinical case. While the focus of the present article is adult PLCH and its pulmonary manifestations, it is important for clinicians to distinguish the adult and pediatric forms of the disease, as well as to be alert for possible extrapulmonary complications. A major theme of the current series of articles on rare lung diseases has been the translation of insights gained from fundamental research to the clinic. Accordingly, the understanding of dendritic cell biology in this disease has led to important advances in the care of patients with PLCH.

Pulmonary Langerhans cell histiocytosis in adults: high-resolution CT-pathology comparisons and evolutional changes at CT

OBJECTIVE

To compare high-resolution (HR) CT and histopathological findings and to evaluate serial CT findings in pulmonary Langerhans cell histiocytosis (PLCH).

METHODS

We reviewed CT of lung lesions in 27 adults (M:F = 20:7, mean age, 41 ± 12.3 years) with PLCH. After evaluating lung abnormalities including nodules, micronodules, thick-walled, thin-walled, and bizarre-shaped cysts and reticulation, observers compared CT findings obtained at lung biopsy sites with histopathological findings. The final CT was compared with the initial CT to determine disease extent changes.

RESULTS

The most frequently observed patterns of lung abnormalities were micronodules (n = 24, 89%), thick-walled (n = 22, 82%), and thin-walled (n = 22, 82%) cysts. Even thin-walled and bizarre cysts harboured active inflammatory Langerhans cell sheets and eosinophils in their walls. In thin-walled cysts, we noted pericystic inflammatory cell infiltrations along the alveolar walls, as well as pericystic emphysema. Thin-walled or bizarre cysts demonstrated a tendency to coalesce with surrounding cysts via their cystic wall destruction. Fourteen (52%) patients showed improvement and nine (33%) showed progressing disease.

CONCLUSION

More than half of patients with pulmonary PLCH show improvement at follow-up CT. Even thin-walled cysts harbour active inflammatory cells on histopathology and exhibit improvement at follow-up CT.

[Smoking-related interstitial lung diseases: findings at high-resolution CT]

OBJECTIVE

To describe the anatomic and radiologic characteristics common to smoking-related interstitial lung diseases use and to evaluate the association between smoking and these diseases.

MATERIAL AND METHODS

We reviewed the clinical histories of patients with suspected smoking-related interstitial lung diseases from 2001 to 2005 who underwent high-resolution computed tomography and had radiologic findings of desquamative interstitial pneumonia, respiratory bronchiolitis, histiocytosis X, or pulmonary fibrosis. We analyzed the presence of emphysema, ground glass, centrilobar nodules, cysts, honey combing, and overlap among these findings.

RESULTS

Fourteen patients were included. In desquamative interstitial pneumonia, the most common finding was ground glass (100%); in respiratory bronchiolitis, it was centrilobar nodules (100%); cysts were the most common finding in histiocytosis (85.7%) and honey combing was the most common finding in fibrosis (100%). Furthermore, over 75% of the patients had emphysema, which supported the relation with tobacco use. The patients with bronchiolitis also had signs common to the other three diseases (ground glass, honey combing, and cysts).

CONCLUSIONS

There is a relation between smoking and these interstitial diseases, as well as overlapping in their clinical and radiological manifestations.

Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.

Extraosseous langerhans cell histiocytosis in children

Langerhans cell histiocytosis, a rare disease that occurs mainly in children, may produce a broad range of manifestations, from a single osseous lesion to multiple lesions involving more than one organ or system. The clinical course varies widely in relation to the patient's age. Multisystem disease may demonstrate especially aggressive behavior in very young children, with the outcome depending largely on the stage of disease and the degree of related organ dysfunction at the time of diagnosis. Extraosseous manifestations are less commonly seen than osseous ones and may be more difficult to identify. To accurately detect extraosseous Langerhans cell histiocytosis at an early stage, radiologists must recognize the significance of individual clinical and laboratory findings as well as the relevance of imaging features for the differential diagnosis. The pattern and severity of pulmonary, thymic, hepatobiliary, splenic, gastrointestinal, neurologic, mucocutaneous, soft-tissue (head and neck), and salivary involvement in Langerhans cell histiocytosis generally are well depicted with conventional radiography, ultrasonography, computed tomography, and magnetic resonance imaging. However, the imaging features are not pathognomonic, and a biopsy usually is necessary to establish a definitive diagnosis.

Smoking-related Emphysema and Interstitial Lung Diseases

Smoking-related illnesses contribute to a large number of deaths in the industrialized world and their treatment comprises a substantial percentage of total healthcare dollars. The most common and most well-known smoking-related illnesses include chronic obstructive pulmonary disease, bronchogenic carcinoma, and ischemic heart disease. However, the role of cigarette smoking in the pathogenesis of other lung diseases is becoming increasingly apparent. Knowledge of both the histologic and radiographic manifestations of smoking-related lung disease is important to the radiologist as imaging findings can be nonspecific. Finally, correlation of imaging and clinical information may obviate the need for open lung biopsy.

Atypical CT Findings of Isolated Pulmonary Langerhans Cell Histiocytosis in a 4-year-old Boy

A 4-year old boy was admitted to hospital with progressive respiratory failure. A chest roentgenogram revealed hyperinflated lungs and a diffuse reticular pattern. There was no smoking history in the family environment. A thin slice computed tomography of the lungs exhibited extended and diffuse cystic lung disease with no zonal predominance. An open lung biopsy showed pulmonary Langerhans cell histiocytosis. No other organs were involved. Despite treatment initiation the boy succumbed to his pulmonary insufficiency 3 weeks later. Isolated pulmonary Langerhans cell histiocytosis in children may have an unfavorable prognosis and in contrast with adults, it may present on computed tomography with lower lobe predominance and without sparing the lung bases or the anterior parts of middle lobe and lingula.

Smoking-related interstitial lung diseases: radiologic-pathologic correlation

Smoking-related interstitial lung diseases (SRILD) are a heterogeneous group of entities of unknown cause. These diseases include desquamative interstitial pneumonia (DIP), respiratory-bronchiolitis-related interstitial lung disease (RB-ILD), pulmonary Langerhans' cell histiocytosis (LCH) and idiopathic pulmonary fibrosis (IPF). High-resolution CT is highly sensitive in the detection of abnormalities in the lung parenchyma and airways. Ground-glass attenuation can occur in DIP and RB-ILD. Whereas DIP is histologically characterized by intra-alveolar pigmented macrophages, RB-ILD shows alveolar macrophages in a patchy peribronchiolar distribution. LCH shows nodular infiltrates on histopathological examination containing varying amounts of characteristic Langerhans' histiocytes. The HRCT findings are characteristically bilateral, symmetrical and diffuse, involving the upper lobe zones with sparing of the costophrenic angles. The most prominent CT features are nodules (sometimes cavitary) measuring 1 to 10 mm in diameter, cysts and areas of ground-glass attenuation. Pathologically, IPF is characterized by its heterogeneity with areas of normal lung, alveolitis and end-stage fibrosis shown in the same biopsy specimen. High-resolution CT findings consist of honeycombing, traction bronchiectasis and intralobular interstitial thickening with subpleural and lower lung predominance. Since coexisting lesions in the same cases have been observed, a better understanding of the different smoking-related interstitial lung diseases (SRILD) allows a more confident and specific diagnosis.

Pulmonary Cystic Disorder Related to Light Chain Deposition Disease

Light chain deposition disease (LCDD) is a rare disorder that very uncommonly affects the lung. We report three cases of severe cystic pulmonary LCDD leading to lung transplantation. Such a presentation has never been previously reported. The three patients present with a progressive obstructive pulmonary pattern associated with numerous cysts diffusely distributed in both lungs. The disease was histologically characterized by non-amyloid amorphous deposits in the alveolar walls, the small airways and the vessels. It was associated with emphysematous-like changes and small airway dilation. Monotypic kappa light chain fixation was demonstrated on the abnormal deposits and along the basement membranes. Electron microscopy revealed coarsely granular electron-dense deposits in the same localizations. Mild extrapulmonary deposits were found in salivary glands in one patient. No immunoproliferative disorder was identified. We conclude that LCDD may primarily affect the lung, present as a pulmonary cystic disorder, and lead to severe respiratory insufficiency.

Lymphangioleiomyomatosis: Radiologic-Pathologic Correlation

Lymphangioleiomyomatosis (LAM) is an uncommon interstitial lung disease that exclusively affects women, usually during their reproductive years. LAM is characterized pathologically by abnormal proliferation of LAM cells in the lungs and in thoracic and retroperitoneal lymphatics. Thirty-three cases of LAM were reviewed retrospectively for clinical and radiologic findings. Twenty-eight (85%) of 33 women (aged 21-62 years; mean, 37.5 years) were symptomatic. Radiographs (n = 32) demonstrated reticular opacities in 21 (66%) patients, large lung volumes in 17 (53%), pleural effusion in 14 (44%), and pneumothorax in 13 (41%). High-resolution CT (n = 15) and conventional CT (n = 3) showed 2-5-mm bilateral thin-walled cysts in all patients and cysts that were 6-12 mm or larger in patients with severe lung involvement. CT depicted diffuse lung involvement by cysts in nine (50%) patients, relative sparing of lung apices in seven (39%), and relative sparing of lung bases in two (11%). Pleural effusion and pneumothorax were seen at CT in four (22%) and three (17%) patients, respectively. Four cases of tuberous sclerosis complex-associated LAM (TSC-LAM) (women aged 27-50 years; mean, 35.7 years) were similarly reviewed. Three (75%) were symptomatic. Radiographs (n = 4) demonstrated reticular opacities in three (75%) and large lung volumes in two (50%). All high-resolution CT (n = 3) and conventional CT (n = 1) studies showed 2-5-mm bilateral thin-walled cysts and cysts that were 6-12 mm or larger in two patients with severe lung involvement. Pleural effusion and pneumothorax were demonstrated at CT in three (75%) and two (50%) patients, respectively. LAM and TSC-LAM affect symptomatic women who often exhibit reticular opacities and large lung volumes at radiography and bilateral uniform small thin-walled cysts at CT. Large (>12 mm) cysts occur in patients with severe cystic lung involvement. Pneumothorax and pleural effusion are common associated findings.