Kikuchi-Fujimoto disease is characterized by fever and lymphadenopathy, usually localized in the cervical region. This disease principally affects young females. It can be confused with lymphoma, adenocarcinoma metastasis and tuberculosis. We report two cases of Kikuchi‑Fujimoto disease. In the first case, a 28-year-old female had been treated for tuberculosis one year prior and presented with a clinical and histological profile consistent with Kikuchi-Fujimoto disease. The second patient, a 58-year-old female, initially received treatment for Wegener's granulomatosis and, subsequently, for tuberculosis. Histopathological examination followed by immunohistochemical analysis confirmed the diagnosis of Kikuchi-Fujimoto disease in both cases. After the definitive diagnosis had been made, both patients were treated symptomatically, and both presented clinical improvement within one month. Subsequently, the latter patient developed systemic lupus erythematosus.

Keywords: Fever; Lymph nodes; Rare diseases; Tuberculosis, lymph node; Histiocytic necrotizing lymphadenitis; Lupus erythematosus, systemic.

Connective tissue disease-associated interstitial lung disease (CTD-ILD) represents a group of systemic autoimmune disorders characterized by immune-mediated organ dysfunction. Systemic sclerosis, rheumatoid arthritis, idiopathic inflammatory myositis, and Sjögren's syndrome are the most common CTDs that present with pulmonary involvement, as well as with interstitial pneumonia with autoimmune features. The frequency of CTD-ILD varies according to the type of CTD, but the overall incidence is 15%, causing an important impact on morbidity and mortality. The decision of which CTD patient should be investigated for ILD is unclear for many CTDs. Besides that, the clinical spectrum can range from asymptomatic findings on imaging to respiratory failure and death. A significant proportion of patients will present with a more severe and progressive disease, and, for those, immunosuppression with corticosteroids and cytotoxic medications are the mainstay of pharmacological treatment. In this review, we summarized the approach to diagnosis and treatment of CTD-ILD, highlighting recent advances in therapeutics for the various forms of CTD.

Keywords: Lung diseases, interstitial; Collagen diseases; Scleroderma, systemic; Arthritis, rheumatoid; Myositis; Therapeutics.

Air cysts abnormally emerging from the trachea and/or larger bronchi is an extremely rare disease. Only a few isolated cases of paratracheal air cysts associated with chronic lung diseases have been described in the literature. The aim of this communication is to describe two cases of this rare, clinical entity in members of the same family. The father of the patients died from this disease at 43 years of age and his two daughters are currently under treatment. The clinical findings are similar to those of chronic pulmonary suppuration syndrome. The diagnosis was established by bronchovideoscopy, axial CT with 3D reconstitution and virtual bronchoscopy. The patients are under observation and palliative treatment is being administered.

Keywords: Lung diseases. Cysts. Trachea. Bronchi. Bronchoscopy. Computed tomography.

Castleman's disease is a rare lymphoproliferative disorder, with focal or systemic lymph node involvement, which rarely affects the lung parenchyma. We report the case of an asymptomatic immunocompetent male patient who had the rarest histological variant of the disease, a nodular parenchymal presentation. The patient underwent lobectomy, and the postoperative evolution was favorable. In the last 10 years, there have been only five reports of Castleman's disease presenting as a solitary pulmonary nodule. This case underscores the fact that Castleman's disease, albeit rare, should be included in the differential diagnosis of pulmonary nodules.

Keywords: Giant lymph node hyperplasia; Lymphoproliferative disorders; Solitary pulmonary nodule.

Respiratory bronchiolitis-associated interstitial lung disease is one of many within the spectrum of smoking-related diffuse infiltrative lung diseases. The clinical and functional characteristics are typically subtle. Herein, we describe two cases of diagnosed through open-lung biopsy, and characterized by insidious evolution of dyspnea, digital clubbing, cystic lesions on computed tomography scans, and hipoxemia upon exertion. We emphasize that, when smokers are evaluated, it is imprtant to consider a diagnosis of respiratory bronchiolitis-associated interstitial lung disease in the context of interstitial cystitis, as well as in that of lymphangioleiomyomatosis, eosinophilic granuloma and idiophatic pulmonary fibrosis.

Keywords: Smoking. Interstitial lung diseases. Bronchiolitis.

Many interstitial lung diseases (ILDs) share mechanisms that result in a progressive fibrosing phenotype. In Brazil, the most common progressive fibrosing interstitial lung diseases (PF-ILDs) are chronic hypersensitivity pneumonitis, idiopathic pulmonary fibrosis, unclassified ILD, and connective tissue diseases. PF-ILD is seen in approximately 30% of patients with ILD. Because PF-ILD is characterized by disease progression after initiation of appropriate treatment, a diagnosis of the disease resulting in fibrosis is critical. Different criteria have been proposed to define progressive disease, including worsening respiratory symptoms, lung function decline, and radiological evidence of disease progression. Although the time elapsed between diagnosis and progression varies, progression can occur at any time after diagnosis. Several factors indicate an increased risk of progression and death. In the last few years, antifibrotic drugs used in patients with idiopathic pulmonary fibrosis have been tested in patients with PF-ILD. The effects of nintedanib and placebo have been compared in patients with PF-ILD, a mean difference of 107.0 mL/year being observed, favoring nintedanib. The U.S. Food and Drug Administration and the Brazilian Health Regulatory Agency have approved the use of nintedanib in such patients on the basis of this finding. Pirfenidone has been evaluated in patients with unclassified ILD and in patients with other ILDs, the results being similar to those for nintedanib. More studies are needed in order to identify markers of increased risk of progression in patients with ILD and determine the likelihood of response to treatment with standard or new drugs.

Keywords: Alveolitis, extrinsic allergic; Idiopathic pulmonary fibrosis; Lung diseases, interstitial; Connective tissue diseases.

The authors present a case of a patient with Behçet's disease who complained about sudden dyspnea while performing light physical exercises, about non-productive cough, weakness, and frontal headache; he also presented significant weight loss in the last month while being treated for an alleged tuberculosis. After going through an episode of massive hemophthisis, his clinical history and physical examination were reevaluated and his new diagnosis was concluded to be Behçet's disease. Thus, the authors started treatment by giving immunosuppressive drugs and corticosteroids and, as a consequence, regression of the aneurysm was noted. In this article the authors discuss the clinical, radiological, histopathologic and therapeutic features of this syndrome.

Keywords: Behçet's disease. Pulmonary arterial aneurysms.

Tracheal tumors are rare and can be difficult to diagnose due to their capacity to mimic other obstructive lung diseases, such as asthma and COPD. We report the case of a female patient with a tracheal tumor. She had previously been treated for asthma and COPD, with little response to the treatment. The onset of infectious complications prompted further investigation. Chest CT images suggested the presence of a tumor, which was confirmed by fiberoptic bronchoscopy. The tumor was endoscopically resected. However, the patient evolved to death due to pneumonia and septic shock.

Keywords: Lipoma; Lung diseases, obstructive; Tracheal neoplasms.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension. Surgical biopsy was usually required for diagnostic confirmation. However, the morbidity, mortality and limited benefit of this procedure have generated discussion regarding noninvasive diagnostic techniques. We present the case of a female patient with progressive dyspnea, hypoxemia and pulmonary hypertension, the last diagnosed via catheterization. Computed tomography revealed septal thickening and diffuse micronodules. Bronchoalveolar lavage revealed occult alveolar hemorrhage. Treatment with an endothelin antagonist was started, resulting in symptomatic and functional improvement. Occult alveolar hemorrhage differentiates PVOD from idiopathic pulmonary hypertension. We believe that this finding, in combination with characteristic tomographic findings, is sufficient to establish a diagnosis of PVOD.

Keywords: Hypertension, pulmonary; Pulmonary veno-occlusive disease; Bronchoalveolar lavage; Receptors, endothelin/antagonists & inhibitors.

Recent studies have suggested an association between pulmonary arterial hypertension (PAH) and thyroid diseases (hypothyroidism and hyperthyroidism). This combination has a good prognosis, because the increase in the pulmonary artery pressure is usually slight and reverses after the treatment of the thyroid disease. Although the exact mechanism involved in the pathogenesis of this combination has not yet been established, it has been hypothesized that thyroid hormones and autoimmunity have a direct influence. Due to the high prevalence of thyroid disease in patients with PAH, thyroid function tests should be considered in the investigation of every patient with PAH. In this review, we describe the prevalence of PAH in patients with thyroid diseases and the prevalence of thyroid disease in patients with PAH, as well as addressing the principal effects that thyroid diseases have on the respiratory system. In addition, we report the treatment effects in patients with these diseases.

Keywords: Hypertension, pulmonary; Graves disease; Hyperthyroidism; Hypothyroidism; Thyroid hormones; Echocardiography.

Castleman's disease is a rare disorder of the lymphoid tissue. We report the case of a female patient with bilateral otosclerosis, no respiratory symptoms, and pleural effusion discovered as an incidental finding on a chest X-ray. Computed tomography of the chest revealed a mediastinal mass. The biopsy findings demonstrated that it was a plasmacytic variant of Castleman's disease. The patient underwent mediastinal mass resection. This resulted in near-total resolution of the effusion, which remained as a small loculation within the left pleural space.

Keywords: Giant lymph node hyperplasia; Pleural effusion; Case reports.

Gastroesophageal reflux disease often presents as heartburn and acid reflux, the so-called "typical" symptoms. However, a subgroup of patients presents a collection of signs and symptoms that are not directly related to esophageal damage. These are known collectively as the extraesophageal manifestations of gastroesophageal reflux disease. Principal among such manifestations are bronchospasm, chronic cough and laryngitis, which are classified as atypical symptoms. These manifestations comprise a heterogeneous group. However, some generalizations can be made regarding all of the subgroups. First, although the correlation between gastroesophageal reflux disease and the extraesophageal manifestations has been well established, a cause-and-effect relationship has yet to be definitively elucidated. In addition, the main proposed pathogenic mechanisms of extraesophageal reflux are direct injury of the extraesophageal tissue (caused by contact with gastric acid) and the esophagobronchial reflex, which is mediated by the vagus nerve. Furthermore, gastroesophageal reflux disease might not be considered in the differential diagnosis of patients presenting only the atypical symptoms. In this article, we review the extraesophageal manifestations of gastroesophageal reflux disease, discussing its epidemiology, pathogenesis, diagnosis and treatment. We focus on the most extensively studied and well-established presentations.

Keywords: Gastroesophageal reflux/complications; Asthma; Laryngitis; Cough; Fundoplication; Respiration disorders/etiology

A 50-year-old woman with chagasic esophageal achalasia and megacolon presented with nonproductive cough, chest pain and dyspnea. A chest X-ray showed bilateral opacity suggestive of lobar pneumonia. Open lung biopsy revealed lipoid pneumonia resulting from aspiration of mineral oil from a mineral oil-based laxative that the patient had been taking regularly for the last three years. The authors discuss concomitance of chagasic megacolon and esophageal achalasia with lipoid pneumonia and make recommendations regarding the use of mineral oil-based products by these patients.

Keywords: Pneumonia, aspirtion/etiology. Pneumonia, lipid/etiology. Esophageal achalasia/pathology. Chagas disease/complications.

Chronic obstructive pulmonary disease is progressive and is characterized by abnormal inflammation of the lungs in response to inhalation of noxious particles or toxic gases, especially cigarette smoke. Although this infirmity primarily affects the lungs, diverse extrapulmonary manifestations have been described. The likely mechanisms involved in the local and systemic inflammation seen in this disease include an increase in the number of inflammatory cells (resulting in abnormal production of inflammatory cytokines) and an imbalance between the formation of reactive oxygen species and antioxidant capacity (leading to oxidative stress). Weakened physical condition secondary to airflow limitation can also lead to the development of altered muscle function. Chronic obstructive pulmonary disease presents diverse systemic effects including nutritional depletion and musculoskeletal dysfunction (causing a reduction in exercise tolerance), as well as other effects related to the comorbidities generally observed in these patients. These manifestations have been correlated with survival and overall health status in chronic obstructive pulmonary disease patients. In view of these facts, the aim of this review was to discuss findings in the literature related to the systemic manifestations of chronic obstructive pulmonary disease, emphasizing the role played by systemic inflammation and evaluating various therapeutic strategies.

Keywords: Pulmonary disease, chronic obstructive/complications; Nutritional status; Exercise tolerance;

Background: Mycobacterium kansasii is a nontuberculous mycobacterium that can colonize the lungs and cause pulmonary infection. Objective: To report authors' study of 6 patients with pulmonary disease caused by M. kansasii infection in a series of 6 patients diagnosed over 5 years. Method: Between June 1995 and June 2000, 1,349 patients diagnosed with tuberculosis were admitted to the Ipiranga Ari Nogueira da Silva Sanitarium. M. kansasii was identified in the sputum cultures of six (0.44%) of these patients. Results: Patient ages ranged from 25 to 77 years, 5 of the 6 were male, and all presented symptomatic chronic lung disease. All patients tested negative for HIV. Chest radiographs confirmed a history of lung disease; all presented thin walled cavities and adjacent pleural thickening was seen in 2. All patients were initially treated with isoniazid-rifampin-pyrazinamide. In 2 patients, intolerance to pyrazinamide necessitated the substitution of pyrazinamide with ethambutol. Based on the culture results, pyrazinamide was also replaced by ethambutol in 2 other patients. All patients were treated for 9 months or longer, and only one patient suffered recurrence of the disease. After being considered cured of the M. kansasii infection, 1 patient died of respiratory insufficiency due to silicosis. Conclusions: Mycobacteriosis due to M. kansasii was found only rarely and may be attributable to the characteristics of our patients. Therapy with isoniazid, rifampin and pyrazinamide with eventual replacement of the latter by ethambutol was shown to be effective.

Keywords: Mycobacterium kansaii. Lung diseases. Respiratory insufficiency.

Oxygen free radicals are molecules that present unpaired electrons in their outer orbit and can transform other molecules such as proteins, carbohydrates, lipids and deoxyribonucleic acid. Oxygen free radicals are produced in various clinical conditions in which hypoxic microenvironments are generated and reoxygenation follows. Such situations include clinical shock, septicemia, systemic inflammatory response, fulminant hepatitis, organ transplant and respiratory failure. In this review, we discuss the main concepts related to oxygen free radicals: the principal types and their formation, as well as the way in which they affect cellular structures and cause significant tissue damage. We present also the main antioxidants that guard against oxidative stress, including glutathione, glutathione peroxidase, superoxide dismutase, catalase, and N-acetylcysteine. The influence of oxygen free radicals on the principal pulmonary diseases are also discussed, with special emphasis given to oxygen free radicals in cigarette smoke, chronic obstructive pulmonary disease, asthma, sleep apnea syndrome and acute respiratory distress syndrome.

Keywords: Key words: Oxygen free radicals. Antioxidant substances. Oxidative stress. Lung diseases.