Objective: To present the pulmonary histopathological alterations found in the autopsies of patients with acute respiratory failure (ARF) and determine whether underlying diseases and certain associated risk factors increase the incidence of these histopathological patterns. Methods: Final autopsy reports were reviewed, and 3030 autopsies of patients > 1 year of age with an underlying disease and associated risk factors were selected. All had developed diffuse infiltrates and died of ARF-related pulmonary alterations. Results: The principal pulmonary histopathological alterations resulting in immediate death were diffuse alveolar damage (DAD), pulmonary edema, lymphocytic interstitial pneumonia (LIP) and alveolar hemorrhage. The principal underlying diseases were AIDS, bronchopneumonia, sepsis, liver cirrhosis, pulmonary thromboembolism, acute myocardial infarction (AMI), cerebrovascular accident, tuberculosis, cancer, chronic kidney failure and leukemia. The principal associated risk factors were as follows: age ≥ 50 years; arterial hypertension; congestive heart failure; chronic obstructive pulmonary disease; and diabetes mellitus. These risk factors and AIDS correlated with a high risk of developing LIP; these same risk factors, if concomitant with sepsis or liver cirrhosis, correlated with a risk of developing DAD; thromboembolism and these risk factors correlated with a risk of developing alveolar hemorrhage; these risk factors and AMI correlated with a risk of developing pulmonary edema. Conclusion: Pulmonary findings in patients who died of ARF presented four histopathological patterns: DAD, pulmonary edema, LIP and alveolar hemorrhage. Underlying diseases and certain associated risk factors correlated positively with specific histopathological findings on autopsy.

Keywords: Respiratory insufficiency; Autopsy; Lung diseases, interstitial; Pulmonary edema; Hemorrhage.

Sclerosing mediastinitis is a rare disorder characterized by an extensive fibrotic reaction involving the mediastinum. Due to the compression or invasion of mediastinal structures, the disorder mimics neoplasia. We present three cases of superior vena cava syndrome in which sclerosing mediastinitis was confirmed. The pathophysiological process is related to enlarged mediastinal lymph nodes, fibroblast proliferation and collagen deposition. The main causes of sclerosing mediastinitis are histoplasmosis and tuberculosis, both of which are prevalent in Brazil. It is difficult to make an accurate histopathological diagnosis using minimally invasive methods, and there is no effective treatment for this condition. In order to make a definitive diagnosis and resolve the aerodigestive tract obstruction, exploratory surgery is indicated.

Keywords: Mediastinitis/physiopathology; Mediastinum; Pulmonary fibrosis; Mediastinal neoplasms; Diagnosis, differential; Case reports [Publication type].

Pulmonary artery sarcomas are rare, difficult-to-diagnose tumors that frequently mimic chronic pulmonary thromboembolism. We report the cases of two female patients with clinical signs of dyspnea and lung masses associated with pulmonary artery filling defects on chest CT angiography. We performed 18F-fluorodeoxyglucose positron emission tomography, which revealed increased radiotracer uptake in those lesions. Pulmonary artery sarcoma was subsequently confirmed by anatomopathological examination. We emphasize the importance of this type of tomography as a noninvasive method for the diagnosis of these tumors.

Keywords: Positron-emission tomography; Pulmonary artery; Pulmonary embolism; Leiomyosarcoma; Histiocytoma, malignant fibrous.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has played a key role in the diagnosis of mediastinal, paratracheal, and peribronchial lesions, as well as in lymph node staging for lung cancer. Despite its minimally invasive character, EBUS-TBNA has demonstrated a diagnostic yield comparable with that of established surgical methods. It has therefore gained credibility and has become a routine procedure at various referral centers. A successful EBUS-TBNA procedure requires careful planning, which includes a thorough review of the radiological imaging and special care during specimen collection and preparation, as well as technical expertise, experience with the procedure itself, and knowledge of the potential complications inherent to the procedure. The most common indications for EBUS-TBNA include lymph node staging for lung cancer and the diagnostic investigation of mediastinal/hilar masses and lymph node enlargement. Recently, tumor biomarkers in malignant samples collected during the EBUS-TBNA procedure have begun to be identified, and this molecular analysis has proven to be absolutely feasible. The EBUS-TBNA procedure has yet to be included on the Brazilian Medical Association list of medical procedures approved for reimbursement. The EBUS-TBNA procedure has shown to be a safe and accurate tool for lung cancer staging/restaging, as well as for the diagnosis of mediastinal, paratracheal, and peribronchial lesions/lymph node enlargement.

Objective: To compare histopathological findings and the degree of apoptosis among rat lungs preserved with low-potassium dextran (LPD) solution, histidine-tryptophan-ketoglutarate (HTK) solution, or normal saline (NS) at two ischemia periods (6 h and 12 h) using an experimental rat model of ex vivo lung perfusion. Methods: Sixty Wistar rats were anesthetized, randomized, and submitted to antegrade perfusion via pulmonary artery with one of the preservation solutions. Following en bloc extraction, the heart-lung blocks were preserved for 6 h or 12 h at 4°C and then reperfused with homologous blood for 60 min in an ex vivo lung perfusion system. At the end of the reperfusion, fragments of the middle lobe were extracted and processed for histopathological examination. The parameters evaluated were congestion, alveolar edema, alveolar hemorrhage, inflammatory infiltrate, and interstitial infiltrate. The degree of apoptosis was assessed using the TdT-mediated dUTP nick end labeling method. Results: The histopathological examination showed that all of the lungs preserved with NS presented alveolar edema after 12 h of ischemia. There were no statistically significant differences among the groups in terms of the degree of apoptosis. Conclusions: In this study, the histopathological and apoptosis findings were similar with the use of either LPD or HTK solutions, whereas the occurrence of edema was significantly more common with the use of NS.

Keywords: : Organ preservation; Organ preservation solutions; Lung transplantation; Reperfusion injury; Apoptosis.

Objective: To compare two models of pulmonary hypertension (monocrotaline and monocrotaline+pneumonectomy) regarding hemodynamic severity, structure of pulmonary arteries, inflammatory markers (IL-1 and PDGF), and 45-day survival. Methods: We used 80 Sprague-Dawley rats in two study protocols: structural analysis; and survival analysis. The rats were divided into four groups: control; monocrotaline (M), pneumonectomy (P), and monocrotaline+pneumonectomy (M+P). In the structural analysis protocol, 40 rats (10/group) were catheterized for the determination of hemodynamic variables, followed by euthanasia for the removal of heart and lung tissue. The right ventricle (RV) was dissected from the interventricular septum (IS), and the ratio between RV weight and the weight of the left ventricle (LV) plus IS (RV/LV+IS) was taken as the index of RV hypertrophy. In lung tissues, we performed histological analyses, as well as using ELISA to determine IL-1 and PDGF levels. In the survival protocol, 40 animals (10/group) were followed for 45 days. Results: The M and M+P rats developed pulmonary hypertension, whereas the control and P rats did not. The RV/LV+IS ratio was significantly higher in M+P rats than in M rats, as well as being significantly higher in M and M+P rats than in control and P rats. There were no significant differences between the M and M+P rats regarding the area of the medial layer of the pulmonary arteries; IL-1 and PDGF levels; or survival. Conclusions: On the basis of our results, we cannot conclude that the monocrotaline+pneumonectomy model is superior to the monocrotaline model.

Keywords: Monocrotaline; Hypertension, pulmonary; Pneumonectomy; Interleukin-1; Receptor, platelet-derived growth factor beta.

Since they were first established, ex vivo models of lung reconditioning have been evaluated extensively. When rejected donor lungs are used, the great variability among the cases can hinder the progress of such studies. In order to avoid this problem, we developed a technique that consists of separating the lung block into right and left blocks and subsequently reconnecting those two blocks. This technique allows us to have one study lung and one control lung.

Keywords: Lung transplantation; Transplantation conditioning; Organ preservation; Organ preservation solutions.