Interstitial lung disease in primary Sjögren syndrome

BACKGROUND: Primary Sj?gren syndrome (pSS) has been associated with various histologic patterns of interstitial lung disease (ILD). METHODS: We retrospectively identified 18 patients with pSS and suspected ILD who underwent lung biopsies (14 surgical biopsies and 9 bronchoscopic biopsies) at our institution during a 13-year period from 1992 through 2004. Histopathologic findings were analyzed and correlated with radiologic features and outcome. RESULTS: Median age was 62 years (range, 34 to 78 years), and 15 patients (83%) were women. Most patients presented with dyspnea and cough. Chest radiographs demonstrated bilateral infiltrates, and high-resolution CT revealed abnormalities of various types including ground-glass, consolidation, reticular, and nodular opacities. The major histopathologic patterns included nonspecific interstitial pneumonia (NSIP) [five patients], organizing pneumonia (OP) [four patients], usual interstitial pneumonia (UIP) [three patients], lymphocytic interstitial pneumonia (three patients), primary pulmonary lymphoma (two patients), and diffuse interstitial amyloidosis (one patient). In four patients (three with OP and one with amyloidosis), the diagnosis was established on transbronchial biopsy results. Treatment commonly included prednisone with or without another immunosuppressive agent. During the follow-up period (median, 38 months), most patients improved or remained stable except three patients with UIP, one patient with NSIP, and one patient with amyloidosis. Seven patients (39%) died, including three deaths from acute exacerbation of interstitial pneumonia. CONCLUSIONS: A variety of histologic patterns can be seen in patients with pSS-associated ILD. Those with UIP tended to have progression of lung disease. Death from acute exacerbation of interstitial pneumonia may occur in patients with pSS-associated ILD.     

A comparative study of the prognosis for Japanese patients with idiopathic interstitial pneumonia or BOOP based on histopathologic subsets]

We explored the prognosis for 123 patients with either idiopathic interstitial pneumonia (IIP) or bronchiolitis obliterans organizing pneumonia (BOOP). All patients underwent either open lung biopsy or thoracoscopic lung biopsy procedures. The histopathologic diagnosis of IIP included patients with usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), and desquamative interstitial pneumonia with respiratory bronchiolitis-associated interstitial lung disease. The prognosis was poorest for patients with a histologic diagnosis of UIP, and excellent for those who received a diagnosis of BOOP. Although the prognosis is generally considered to be good for patients with NSIP, some NSIP patients in our study died. Histopathologic diagnosis based on surgical lung biopsy is useful in evaluating the prognosis for patients with IIP.     

多发性肌炎/皮肌炎合并肺间质性病变的临床特征

目的 回顾分析病理确诊的多发性肌炎/皮肌炎肺受累患者的临床、影像和病理学特征,以提高临床诊断水平.方法 1980年1月至2006年10月在北京协和医院住院,经病理确诊的多发性肌炎/皮肌炎肺受累患者共26例,其中6例进行尸检,5例行开胸肺活检或经胸腔镜肺活检,15例行经皮肺活检,进行临床、影像和病理学及预后综合分析.结果 26例患者的中位年龄为48岁(19～65岁),男10例,女16例.胸部X线主要表现为磨玻璃样变,双肺斑片状阴影和网格影.病理表现为弥漫性肺泡损伤(DAD)5例;淋巴细胞间质性肺炎2例;非特异性间质性肺炎(NSIP)富细胞型6例,混合型8例;机化性肺炎4例;普通型间质性肺炎(UIP)1例.所有患者均接受了泼尼松+环磷酰胺的治疗.中位随诊时间为15个月(6～108个月),中位生存期为21个月(1～253个月).26例患者中18例病情改善或稳定,8例死亡,其中5例病理表现为DAD,2例为NSIP混合型,1例为UIP.结论 多发性肌炎/皮肌炎肺受累患者的胸部CT及病理表现多样,病理诊断为DAD者预后差.     

The prognostic significance of the histologic pattern of interstitial pneumonia in patients presenting with the clinical entity of cryptogenic fibrosing alveolitis

Lone cryptogenic fibrosing alveolitis (CFA) is a progressive interstitial lung disease, with a median survival of 3 to 6 yr from the onset of dyspnea. CFA can be subdivided into prognostically significant histopathologic patterns, including nonspecific interstitial pneumonia (NSIP). We reviewed 78 patients with a clinicopathologic diagnosis of CFA, biopsied between 1978 and 1989, to evaluate the prevalence and prognostic significance of these histopathologic patterns, in particular NSIP. Biopsy appearances were reclassified by two pulmonary histopathologists as usual interstitial pneumonia (UIP) (47%), NSIP (36%), or desquamative interstitial pneumonia (DIP)/respiratory bronchiolitis-associated interstitial lung disease (RBILD) (17%). The kappa coefficient of agreement between pathologists was 0.49. In 67 cases, follow-up was complete to death or 10 yr after biopsy, with 50 deaths during a median follow-up of 42 mo (UIP, 89%; NSIP, 61%, DIP/RBILD, 0%). Survival was highest in DIP/RBILD and higher in NSIP than UIP, p < 0.0005. When analysis was confined to patients with UIP or NSIP, the mortality of UIP remained higher, p < 0.01, but the 5-yr survival in patients with fibrotic NSIP was only 45%, indicating that this histologic appearance is often associated with a poor outcome. A response to treatment was more frequent in DIP/RBILD than in NSIP (p < 0.01) or UIP (p < 0.0005). This study confirms the prognostic value of subclassifying patients with CFA according to histopathologic pattern. However, in patients with clinically typical CFA, a histologic diagnosis of fibrotic NSIP needs to be interpreted with caution and does not necessarily denote a good outcome.     

Correlations of histologic classification with clinical features and prognosis in interstitial lung disease associated with collagen disease]

We studied 32 patients with interstitial pneumonia associated with collagen disease. All underwent surgical lung biopsy. Twenty-seven were histologically classified as follows: 8 with usual interstitial pneumonia (UIP), 10 with nonspecific interstitial pneumonia (NSIP), 6 with bronchiolitis obliterans organizing pneumonia (BOOP), and 3 with diffuse alveolar damage (DAD). Twenty-five of the patients were treated with corticosteroid but 4 (3 DAD, 1 NSIP) deteriorated rapidly and died within a month after lung biopsy. At the final follow-up, all 8 UIP patients were alive with residual respiratory impairment, whereas 6 NSIP and 4 BOOP patients had almost completely recovered. These findings suggested that histologic classification can be highly valuable to the therapeutic responsiveness and prognosis in cases of interstitial pneumonia associated with collagen disease.     

Diffuse lung cysts in lymphoid interstitial pneumonia: high-resolution CT and pathologic findings

Lymphoid interstitial pneumonia is part of a spectrum of pulmonary lymphoproliferative disorders that range from benign, small, and airway-centered cellular infiltrates (follicular bronchiolitis, nodular lymphoid hyperplasia) to low-grade malignant lymphoma. Most of the cases occur in patients with underlying autoimmune disease or immunodeficiency. The characteristic high-resolution computed tomography findings consist of diffuse ground-glass opacities, ill-defined centrilobular nodules, bronchovascular thickening, interlobular septal thickening, and scattered thin-walled cysts. The cysts may be seen in up to 80% of the patients and are typically few in number and measure less than 3 cm in diameter. This case illustrates extensive cysts as the predominant high-resolution computed tomography finding of idiopathic lymphoid interstitial pneumonia in a 64-year-old man who underwent unilateral lung transplant. Such extensive cystic disease and lung transplantation treatment has not been previously described.     

Lung biopsy in rheumatoid arthritis

Forty open lung biopsies from patients with rheumatoid arthritis and possible "rheumatoid lung disease" were reviewed in an attempt to correlate histology with radiologic, physiologic, and prognostic variables. A wide variety of histopathologic features was seen, and primary and secondary patterns of injury were recognized. Five different groups based on histologic patterns were identified: pulmonary rheumatoid nodules, usual interstitial pneumonia (UIP), bronchiolitis obliterans with patchy organizing pneumonia (BOOP), lymphoid hyperplasia, and cellular interstitial infiltrates. The finding of rheumatoid nodules as the primary pattern imparted a uniformly good prognosis, whereas the pattern of UIP indicated a poor one. Patients with BOOP had a more favorable prognosis than did patients with UIP, as did patients with lymphoid hyperplasia and/or nonspecific cellular interstitial infiltrates. Consistent correlations between pulmonary function testing and roentgenographic and histologic findings were not found. The term "rheumatoid lung disease" is of no use as a histologic diagnosis because it encompasses a broad spectrum of morphologic changes that carry significantly different prognoses.     

Morphologic changes leading to bronchiolitis obliterans in a patient with delayed non-infectious lung disease after allogeneic bone marrow transplantation.

A 37-year-old man developed delayed non-infectious lung disease after undergoing bone marrow transplantation (BMT) for acute myeloid leukaemia. Over a 15-month period, the progression of morphologic changes from cellular interstitial pneumonia to bronchiolitis obliterans organizing pneumonia and cicatricial bronchiolitis obliterans was documented. Pulmonary function tests, high-resolution CT, bronchoalveolar lavage, lung biopsy and extensive microbiological studies were used as diagnostic tools either at onset and during the follow-up. This represents the first reported case in which a model--supported by longitudinal biopsy results--for the evolution of histologic lesions toward bronchiolitis obliterans after BMT is suggested; therapeutic implications are discussed.     

Bronchiolar disorders

Bronchiolar abnormalities are relatively common and occur in a variety of clinical settings. Various histopathologic patterns of bronchiolar injury have been described and have led to confusing nomenclature with redundant and overlapping terms. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Herein, we present a scheme separating (1) those disorders in which the bronchiolar disease is the predominant abnormality (primary bronchiolar disorders) from (2) parenchymal disorders with prominent bronchiolar involvement and (3) bronchiolar involvement in large airway diseases. Primary bronchiolar disorders include constrictive bronchiolitis (obliterative bronchiolitis, bronchiolitis obliterans), acute bronchiolitis, diffuse panbronchiolitis, respiratory bronchiolitis, mineral dust airway disease, follicular bronchiolitis, and a few other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, respiratory bronchiolitis-associated interstitial lung disease, cryptogenic organizing pneumonia (idiopathic bronchiolitis obliterans organizing pneumonia), and pulmonary Langerhans' cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical relevance of a bronchiolar lesion is best determined by identifying the underlying histopathologic pattern and assessing the correlative clinico-physiologic-radiologic context.     

Cellular interstitial pneumonia and follicular bronchiolitis diagnosed by open lung biopsy in a patient with rheumatoid arthritis

A 54-year-old woman under treatment for rheumatoid arthritis was admitted because of aggravation of dyspnea on effort and restrictive pulmonary dysfunction. Although chest X-ray revealed no marked change, the symptoms progressively worsened, necessitating open lung biopsy for diagnosis and treatment. Based on the histopathological findings of the biopsied tissue, the patient was diagnosed as having active rheumatoid lung complicated with cellular interstitial pneumonia and follicular bronchiolitis. The patient responded well to adrenocorticosteroid and immunosuppressor therapy, and is now being followed up as an outpatient. Rheumatoid arthritis can be complicated by diverse lung diseases. Among them one important disease is interstitial pneumonia, which serves as a prognostic factor. When cellular interstitial pneumonia is treated with adrenocorticosteroid therapy, it responds well and its prognosis is good. Therefore, its early detection and appropriate adrenocortical therapy are essential. Patients with rheumatoid arthritis presenting with dyspnea on effort and pulmonary dysfunction should be examined for cellular interstitial pneumonia, follicular bronchiolitis and other lung diseases, even when no marked change is visible on chest X-ray films.     

Idiopathic bronchiolitis obliterans organizing pneumonia. Definition of characteristic clinical profiles in a series of 16 patients

Bronchiolitis obliterans organizing pneumonia (BOOP) is a pathologic finding common to various injuries to the lung of either definite or idiopathic etiology. Since the presentation of patients with idiopathic BOOP varies, we studied 16 patients with BOOP on pulmonary histology to define more distinct and homogeneous clinical and imaging profiles of idiopathic BOOP. We distinguished three groups of patients: group 1 (n = 4), with multiple patchy migratory pulmonary involvement of the pneumonia type. Their clinical course was subacute, with cough, fever, weight loss, mild dyspnea, and increased ESR. Chest x-ray film and CT scan showed multiple alveolar opacities. All patients completely recovered with corticosteroid therapy but relapsed when therapy was stopped too rapidly. Group 2 (n = 5) had solitary pulmonary involvement of the pneumonia type occurring in a similar clinical context. Since carcinoma was suspected, they underwent surgical excision of the pneumonic area and recovered without relapse. Group 3 patients (n = 7) presented with diffuse pulmonary involvement of the interstitial lung disease type. They had more progressive onset of more severe dyspnea, crackles heard over all lung surfaces, and interstitial opacities with or without alveolar opacities on chest imaging. Improvement with corticosteroid therapy was obtained in only three patients. In all three groups, lung function test results showed a restrictive pattern. The obstructive pattern characteristic of pure bronchiolitis obliterans was found in none. BAL showed a mixed pattern (increase of both lymphocytes and polymorphonuclear cells) in the patients of the first two groups. Thus, we distinguished three characteristic clinical and imaging profiles in patients with idiopathic BOOP: multiple patchy pneumonia, solitary pneumonia, and diffuse interstitial lung disease. These profiles are so different that they should be distinguished in clinical studies of idiopathic BOOP.     

Bronchiolitis obliterans organising pneumonia and primary biliary cirrhosis-like lung involvement in a patient with primary biliary cirrhosis

A 55-year-old woman with a 6-year history of primary biliary cirrhosis presented with an acute onset of fever, dyspnoea, crackles over both lower lung fields, and diffuse interstitial and bibasilar patchy pulmonary opacities. After exclusion of an infectious aetiology, an open lung biopsy was performed which revealed two histopathological features: (1) bronchiolitis obliterans organising pneumonia and (2) lympho-histiocytic interstitial pneumonitis and destructive bronchiolitis. Treatment response to corticosteroids and azathioprine followed a bimodal pattern with immediate resolution of her initial presenting symptoms and late resolution of residual gas exchange defects.     

Churg-Strauss syndrome: high resolution CT and pathologic findings

OBJECTIVES: The purpose of this study was to evaluate high-resolution CT findings in 7 patients with Churg-Strauss syndrome and to compare the CT with the histopathologic findings. MATERIALS AND METHODS: High-resolution CT scans of 7 asthmatic patients (4 women, 3 men, age range, 34-62 years, mean 49 years) with Churg-Strauss syndrome were reviewed by 2 observers. Histologic specimens of lung obtained at surgical (n = 3) or transbronchial (n = 3) biopsy or autopsy (n = 1) were reviewed by an expert lung pathologist. The diagnosis of Churg-Strauss was based on clinical, laboratory, and histologic findings. RESULTS: Parenchymal and airway abnormalities included ground-glass opacities (n = 5), areas of air-space consolidation (n = 4), centrilobular nodules (n = 5), nodules 1-3 cm in diameter (n = 3), interlobular septal thickening (n = 4), bronchial wall thickening (n = 4), and areas of atelectasis (n = 1). Surgical biopsy (n = 3) and autopsy (n = 1) specimens demonstrated airspace disease in 3 patients, interlobular septal thickening in 3 patients, and airway abnormalities in 2 patients. Histologically, the airspace disease included eosinophilic pneumonia (n = 2) and small foci of organizing pneumonia (n = 1). The septal thickening was due to edema combined with numerous (n = 2) or few (n = 1) eosinophils. The airway abnormalities (n = 2) included muscle hypertrophy and large airway wall necrosis (n = 1) and eosinophilic infiltration of the airway walls (n = 1). Transbronchial biopsy (n = 3) demonstrated increased eosinophils. CONCLUSION: The main high-resolution CT findings of Churg-Strauss syndrome consist of airspace consolidation or ground-glass opacities, septal lines, and bronchial wall thickening. These reflect the presence of eosinophilic infiltration of the airspaces, interstitium, and airways, and interstitial edema.     

Histopathologic pattern and clinical features of rheumatoid arthritis-associated interstitial lung disease

STUDY OBJECTIVES: To investigate the histopathologic pattern and clinical features of patients with rheumatoid arthritis (RA)-associated interstitial lung disease (ILD) according to the American Thoracic Society (ATS)/European Respiratory Society consensus classification of idiopathic interstitial pneumonia. DESIGN: Retrospective review. SETTING: Two thousand-bed, university-affiliated, tertiary referral center. PATIENTS: Eighteen patients with RA who underwent surgical lung biopsy (SLBx) for suspected ILD. METHOD: SLBx specimens were reviewed and reclassified by three lung pathologists according to the ATS/European Respiratory Society classification. Clinical features and follow-up courses for the usual interstitial pneumonia (UIP) pattern and the nonspecific interstitial pneumonia (NSIP) pattern were compared. RESULTS: The histopathologic patterns were diverse: 10 patients with the UIP pattern, 6 patients with the NSIP pattern, and 2 patients with inflammatory airway disease with the organizing pneumonia pattern. RA preceded ILD in the majority of patients (n = 12). In three patients, ILD preceded RA; in three patients, both conditions were diagnosed simultaneously. The majority (n = 13) of patients had a restrictive defect with or without low diffusion capacity of the lung for carbon monoxide (D(LCO)) on pulmonary function testing; 2 patients had only low (D(LCO)). The UIP and NSIP groups were significantly different in their male/female ratios (8/2 vs 0/6, respectively; p = 0.007) and smoking history (current/former or nonsmokers, 8/2 vs 0/6; p = 0.007). Many of the patients with the UIP pattern had typical high-resolution CT features of UIP. Five patients with the UIP pattern died, whereas no deaths occurred among patients with the NSIP pattern during median follow-up durations of 4.2 years and 3.7 years, respectively. CONCLUSIONS: The histopathologic type of RA-ILD was diverse; in our study population, the UIP pattern seemed to be more prevalent than the NSIP pattern.     

A questionnaire survey of surgical lung biopsy in patients with diffuse lung diseases]

A nationwide questionnaire survey was conducted to investigate the indications, diagnostic yield, complications, outcome, and benefit of surgical lung biopsy for diffuse lung diseases. Surgical lung biopsies were performed in 410 patients at 132 institutes in 1998, 94% of them as video-assisted thoracoscopic surgery (VATS). Interstitial lung diseases of unknown etiology formed the largest diagnostic group, and consisted of 194 patients. The clinical diagnosis prior to lung biopsy was inconsistent with the final diagnosis in 32.8%. Complications were seen in 32 patients, and mortality was 1.2%. Acute exacerbation of the underlying disease was seen in 9 patients, four of whom died. Patients with nonspecific interstitial pneumonia and even usual interstitial pneumonia who were treated following biopsy showed better outcomes than those untreated. The physician in charge judged that 82.2% of the patients received clinical benefits from the biopsy procedure. We concluded that VATS lung biopsies are indicated in more cases to confirm diagnoses and as a reference for treatments in patients with diffuse lung disease.     

Role of surgical lung biopsy in separating chronic hypersensitivity pneumonia from usual interstitial pneumonia/idiopathic pulmonary fibrosis: analysis of 31 biopsies from 15 patients

BACKGROUND: Lung biopsy has been proposed as a criterion for diagnosis of chronic hypersensitivity pneumonia (HP), especially in patients without proven antigen exposure. Histologic findings in some suspected HP patients overlap with usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). We reviewed our experience to determine the specificity of histologic findings in surgical lung biopsies from patients with clinical diagnoses of HP. METHODS: Surgical lung biopsies from patients with chronic HP, idiopathic pulmonary fibrosis, and idiopathic NSIP were reviewed retrospectively without knowledge of the clinical diagnosis. Each specimen was assigned a histologic diagnosis, and selected histologic findings were tabulated. Clinical data were abstracted from medical records. RESULTS: Fifteen patients with clinical diagnoses of chronic HP underwent biopsy of one to three lobes. Ten showed features diagnostic of HP in all specimens. Two had discordant findings that included HP in one specimen and UIP or nonspecific changes in others. Biopsies from two showed only UIP, and one showed NSIP. Diagnostic features were present in all samples from 9 of the 11 patients with more than one biopsy site (81.8%). Three patients died of disease, including both patients from whom biopsies showed only UIP. CONCLUSIONS: Most patients with a clinical diagnosis of chronic HP have supportive histologic findings in surgical lung biopsies. A subset of HP patients has findings indistinguishable from UIP. Sampling from more than one lobe may be helpful in separating HP from idiopathic pulmonary fibrosis.     

Diffuse infiltrative lung disease associated with flecainide. Report of two cases

We present two patients who developed subacute diffuse infiltrative lung disease while receiving flecainide for supraventricular arrhythmia. They had bilateral subpleural lung opacities on computed tomography. Bronchoalveolar lavage revealed increased numbers of lymphocytes and eosinophils, and a low CD4/CD8 ratio. Nonspecific interstitial pneumonia was documented by open lung biopsy in patient 1. The outcome was favorable after flecainide withdrawal and prednisone treatment. Drug-induced pneumonitis should be suspected in patients treated with flecainide presenting with subacute diffuse infiltrative lung disease.     

Advances in the treatment of rheumatic interstitial lung disease

PURPOSE OF REVIEW: Interstitial lung disease frequently complicates the rheumatic diseases. The purpose of this review is to outline recent advances and current concepts regarding the management of these interstitial lung diseases. RECENT FINDINGS: Several histologic lesions cause interstitial lung disease in rheumatic diseases, including nonspecific interstitial pneumonia, usual interstitial pneumonia, organizing pneumonia, lymphocytic interstitial pneumonia, desquamative interstitial pneumonia, and acute interstitial pneumonia. Although the relative frequency of occurrence of these histopathologic lesions is not definitively established, it seems that nonspecific interstitial pneumonia accounts for a large proportion of rheumatic disease-associated interstitial lung diseases. Although usual interstitial pneumonia generally responds poorly to corticosteroid therapy, other forms of interstitial pneumonia are often steroid responsive and have a more favorable long-term prognosis. Pulmonary hypertension is increasingly recognized as a complication of these interstitial lung diseases. Treatment of pulmonary hypertension in these patients provides clinical benefit and may suppress pulmonary inflammation and fibrosis. Lung transplantation is a treatment option for selected patients with severe pulmonary involvement and limited life expectancy. SUMMARY: Interstitial lung disease is common in the rheumatic diseases, may be caused by a variety of lesions that respond differently to treatment, and may lead to the development of pulmonary hypertension. Whether the prognosis of interstitial lung disease associated with rheumatic disease is similar to that associated with the idiopathic interstitial pneumonias is not known. Treatment of these interstitial lung diseases should take into account the specific histologic lesion, the activity of the underlying rheumatic disease, and associated pulmonary hypertension, if present. The diagnosis of a rheumatic disease is no longer an absolute contraindication to lung transplantation.     

Causes and prognosis of diffuse alveolar damage diagnosed on surgical lung biopsy

BACKGROUND: Diffuse alveolar damage (DAD) is a relatively common histopathologic finding at autopsy, particularly in patients dying with ARDS, and can result from a variety of causes. The spectrum of causes and associated prognostic implications for DAD diagnosed by surgical lung biopsy are unclear. METHODS: We identified 58 consecutive patients with DAD diagnosed by surgical lung biopsy over a 7-year period, January 1996 through December 2002. The presenting clinicoradiologic features, causes, and clinical course of these patients were studied. RESULTS: The median age was 61 years, 48% were women, and 60% were immunocompromised. Ninety percent of patients fulfilled the criteria for ARDS at the time of surgical lung biopsy. Chest radiography demonstrated bilateral parenchymal infiltrates, while CT revealed predominantly ground-glass and consolidative opacities. Infections were the most common cause of DAD (22%). Other causes were noninfectious pulmonary complications of hematopoietic stem-cell or solid-organ transplantation (17%), connective tissue diseases (16%), acute exacerbation of idiopathic pulmonary fibrosis (12%), drugs (10%), and radiation therapy (2%). Twelve patients (21%) had acute interstitial pneumonia (ie, no identifiable cause or predisposing condition for DAD). Overall hospital mortality was 53%, with the highest mortality (86%) occurring among patients for whom DAD represented acute exacerbation of idiopathic pulmonary fibrosis. CONCLUSION: Our study showed that infections and acute interstitial pneumonia are the most common causes of DAD diagnosed by surgical lung biopsy. Hospital mortality rate associated with DAD may vary depending on the underlying cause.     

A comparison of bronchiolitis obliterans with organizing pneumonia, usual interstitial pneumonia, and small airways disease

This report is based on 43 cases where a diagnosis of either bronchiolitis obliterans with organizing pneumonia (BOOP), usual interstitial pneumonia (UIP), or small airways disease (SAD) was established by lung biopsy. The severity of histologic abnormalities in the peripheral airways and interstitial spaces were measured on these biopsies using semiquantitative techniques and compared with the clinical data available in 42 of 43 cases, preoperative chest radiographs in 31 of 43, and preoperative pulmonary function tests in 29 of 43. The data show that when a diagnosis of BOOP was made, there was a higher total pathologic score for membraneous bronchiolitis (MB) and respiratory bronchiolitis (RB) than for UIP and SAD (p less than 0.005). This was due to peribronchiolar inflammation and the presence of loose connective tissue in the RB lumen. The pathologic changes in the interstitial space were less severe in SAD than in BOOP or UIP (p less than 0.005). Clubbing was more frequent in UIP (p less than 0.01), and symptoms were of shorter duration in BOOP (p less than 0.05). The radiographic assessment showed that the characteristic finding in BOOP was patchy air-space consolidation, a finding that was not present in UIP or SAD.