[Morphology of hypersensitivity pneumonitis]. / Morfologiya giperchuvstvitel'nogo pnevmonita.

Hypersensitivity pneumonitis (HP) is one of the most common interstitial lung diseases, the manifestations of which are diverse, and the diagnosis is complex and requires a multidisciplinary approach. HP is an immunologically determined disease in response to inhaled antigens. The main feature of the disease is terminal bronchiole's involvement accompanied by interstitial inflammation and/or fibrosis together with the presence of non-necrotizing granulomas in the interalveolar septa and bronchioles. The article presents the histological features of non-fibrous and fibrotic variants of the disease. Well-defined diagnostic criteria were formulated on the basis of published international recommendations and the authors' own experience.

[Comparative pathomorphological characteristics of idiopathic pulmonary fibrosis and fibrotic hypersensitivity pneumonitis]. / Sravnitel'naya patomorfologicheskaya kharakteristika idiopaticheskogo legochnogo fibroza i fibroznogo giperchuvstvitel'nogo pnevmonita.

The paper presents an X-ray morphological differential diagnosis of idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (FHP). It describes the etiology, pathogenesis, radiological signs, and pathoanatomy of IPF and FHP. For differential diagnosis, radiological and morphological signs were studied in 105 patients with IPF and in 111 patients with FHP. The mean ages of patients with IPF or FHP were 65.0±8.9 and 48.9±12.3 years, respectively. The history of IPF to the moment of its diagnosis ranged from 1 to 18 months, while that of FHP was 35 to 79 days. The authors describe the additional morphological signs of FHP: delicate collagen fibrosis; smooth muscle metaplasia in the interalveolar septa and fibrotic areas; fibroblastic foci mainly in the walls of bronchioles; plasma cell infiltration of interalveolar septa with a touch of neutrophils and eosinophils. A table has been compiled for differential diagnosis according to the morphological signs of IPF and FHP.

Pathological Features in 100 Deceased Patients With COVID-19 in Correlation With Clinical and Laboratory Data.

Background: Autopsies on COVID-19 deceased patients have many limitations due to necessary epidemiologic and preventative measures. The ongoing pandemic has caused a significant strain on healthcare systems and is being extensively studied around the world. Clinical data does not always corelate with post-mortem findings. The goal of our study was to find pathognomonic factors associated with COVID-19 mortality in 100 post-mortem full body autopsies. Materials and Methods: Following necessary safety protocol, we performed 100 autopsies on patients who were diagnosed with COVID-19 related death. The macroscopic and microscopic pathologies were evaluated along with clinical and laboratory findings. Results: Extensive coagulopathic changes are seen throughout the bodies of diseased patients. Diffuse alveolar damage is pathognomonic of COVID-19 viral pneumonia, and is the leading cause of lethal outcome in younger patients. Extrapulmonary pathology is predominantly seen in the liver and spleen. Intravascular thrombosis is often widespread and signs of septic shock are often present. Conclusion: The described pathological manifestations of COVID-19 in deceased patients are an insight into the main mechanisms of SARS-CoV-2 associated lethal outcome. The disease bears no obvious bias in severity, but seems to be more severe in some patients, hinting at genetic or epigenetic factors at play.

Telocytes in the Myocardium of Children with Congenital Heart Disease Tetralogy of Fallot.

Telocytes, a new type of interstitial stem cells with long thin processes that form a three-dimensional network around cardiomyocytes, vessels, and nerve fibers were described in the myocardium of children with tetralogy of Fallot. Two types of morphologically different telocytes, spindle-shaped and rounded, were identified. Contacts of telocytes with stem cells and interstitial macrophages were found. Telocytes were more common in the immature myocardium, where the assembly of myofibrils in cardiomyocytes was not completed and small Ki-67+ cardiomyocyte progenitor cells were present. Telocytes expressed immunohistochemical markers CD117, vimentin, CD34, and CD44. Localization and ultrastructural characteristics of telocytes suggested their participation in stem cell differentiation, coordination of neoangiogenesis, and paracrine regulation of all components of the interstitium.

[Histological differential diagnosis of granulomatous lung diseases (Part II)]. / Gistologicheskaia differentsial'naia diagnostika granulematoznykh boleznei legkikh (chast' II).

Granulomatous diseases are a heterogeneous group of the diseases of different etiology, which are manifested by a variety of clinical syndromes and variants of tissue changes, by non-uniform sensitivity to therapy and by the predominance of the common dominant histologic sign - the presence of granulomas that determine the clinical and morphological essence of each disease. Granuloma is a chronic inflammatory response, which involves macrophages and other inflammatory cells. After antigen exposure, the activation of T lymphocytes, macrophages, epithelioid cells, and multinucleated giant cells results in granuloma formation. Granuloma also contains the extracellular matrix produced by fibroblasts, which can demarcate and isolate the antigen. Granulomatous diseases are classified by their etiology as infectious and non-infectious. However, recent investigations demonstrate that pathogenic microorganisms can cause granulomas in the diseases previously considered non-infectious. In some cases, it is very difficult to classify a granulomatous process as infectious and non-infectious. The aim of this paper is to draw the attention of readers to the diversity of granulomatous diseases, to describe the key points of pathological and anatomical manifestations of various infectious diseases, and to determine an approach to the differential diagnosis of granulomatoses.

[Histological differential diagnosis of granulomatous lung diseases (part I)]. / Gistologicheskaia differentsial'naia diagnostika granulematoznykh boleznei legkikh (chast' I).

Granulomatous diseases are a heterogeneous group of the diseases of different etiology, which are manifested by a variety of clinical syndromes and variants of tissue changes, by non-uniform sensitivity to therapy, and by the predominance of the common dominant histologic sign - the presence of granulomas that determine the clinical and morphological essence of each disease. Granuloma is a chronic inflammatory response, which involves macrophages and other inflammatory cells. After exposure to an antigen, T-lymphocytes, macrophages, epithelioid cells, and multinucleated giant cells are activated, resulting in the formation of granulomas. Granuloma also includes the extracellular matrix produced by fibroblasts, which can demarcate and isolate the antigen. According to etiology, granulomatous diseases are classified as infectious and non-infectious. However, recent investigations demonstrate that pathogenic microorganisms can cause granulomas in diseases previously considered non-infectious. In some cases, it is very difficult to classify a granulomatous process as infectious and non-infectious. The aim of this paper is to draw the attention of readers to the diversity of granulomatous diseases, to describe the key points of pathological and anatomical manifestations of various non-infectious diseases, as well as to determine an approach to the differential diagnosis of granulomatoses.

[Kaposi's sarcoma in the grafted lung]. / Sarkoma Kaposhi v transplantirovannykh legkikh.

The paper provides a clinical note. A 45-year-old patient suffered from severe primary emphysema and underwent bilateral lung transplantation. A year after surgery, exercise dyspnea again appeared in the patient. Lung computed tomography revealed multiple rounded soft tissue masses; thoracoscopic biopsy and further histological examination proved the development of Kaposi's sarcoma in the patient. The tumor disappeared completely following corrected immunosuppressive therapy. After 22 months of transplantation, the patient died from gastrointestinal bleeding. This case is of interest due to that Kaposi's sarcoma develops extremely rarely in the allogeneic lung after its transplantation.

[Pathomorphological features of pulmonary Langerhans cell histiocytosis].

The paper provides the clinical and X-ray characteristics of pulmonary Langerhans cell histiocytosis (PLCH). It describes pulmonary pathohistological changes in this disease, characterizes the cellular composition of granuloma, and gives methods that can verify the diagnosis of PLCH. A case of PLCH with severe respiratory failure, for which bilateral lung transplantation and histological examination of removed lungs have been made, is described.

Resident stem cells in the myocardium of patients with obstructive hypertrophic cardiomyopathy.

Interventricular septum myocardium was studied in 40 patients with obstructive hypertrophic cardiomyopathy. Immunohistochemical assay revealed c-kit-positive resident cardiac stem cells in 82.5% patients. The content of the connective tissue and myofibrillar disarray zones and the degree of cardiomyocyte hypertrophy and myolysis were determined. In 30% cases, cardiomyocytes containing atrial natriuretic peptide were detected in the interventricular septum myocardium. The data were compared with clinical and functional parameters of patients. It was found that cardiac stem cells are present in patients, whose myocardium was characterized by increased density of the connective tissue, hypertrophy of mature cardiomyocytes, medium degree of myolysis in them, and accumulation of natriuretic peptide, a cardiac failure marker, in cardiomyocytes.

[Pneumocystic pneumonia].

The article is devoted to short description of epidemiology, clinical and radiologic demonstration of pneumocystic pneumonia. The features of pathologicoanatomic changes at pneumocystic pneumonia are described. Own observation about combination of classic and scarce histological changes at this disease is in the article.

Resident cardiomyocyte precursor stem cells in the myocardium of infants of the first two years of life with tetralogy of Fallot.

We studied the content of resident myocardial stem cells, cardiomyocyte precursors, in myocardial biopsy specimens from the right ventricular outflow tract of patients of the first two years of life with tetralogy of Fallot. Myocardial resident stem cells were detected by the method of confocal immunohistochemistry using antibodies to c-kit and sarcomeric α-actin. The diameter of right ventricular cardiomyocytes was measured; the presence of myolysis zones was semiquantitatively evaluated. Electron microscopic analysis of right ventricular cardiomyocytes was performed. The data on the content of resident myocardial stem cells were compared with clinical and functional parameters of the patients and morphological peculiarities of the myocardium. C-kit-positive resident myocardial stem cells were detected in the right ventricle of 17.4% patients with tetralogy of Fallot. The content of resident myocardial stem cells in these patients varied from 4 to 45 (median 11) per 1 mln cardiomyocytes; this parameter was higher in patients with high content of small cardiomyocytes (diameter <10 µ) and cardiomyocytes with incomplete myofibril assembly in the right ventricular myocardium.

[Calcification and ossification of lungs].

The different types of lung calcification and ossification including idiopathic and developing after various diseases are in the article. We have described rare lung pathology - pulmonary alveolar microlithiasis. We have drawn attention to the possible mechanisms of lung calcification and ossification development.

[Pathological anatomy in A/H1N1 influenza].

Forty autopsy cases died from A/H1N1 influenza in Moscow, the Moscow Region, and Chita were analyzed. Major changes were found to develop in the trachea and lung. The lung showed the pattern of exudative and proliferative stages of diffuse alveolar lesion. In addition, the signs of viremia-associated infectious-toxic shock, as suggested by pronounced changes in the brain, kidneys, liver, spleen, adrenals, and lymph nodes were revealed. Bacterial bronchopneumonia was detected only in 20% of cases.

[Pathomorphology of the lung in severe influenza A/H1N1].

Thirty-five autopsy cases of influenza A/HIN1 in Moscow were analyzed. Primary pathological changes were found in the trachea and lung. The lung showed a pattern of the exudative and proliferative stages of diffuse alveolar damage. In addition, there were signs of infectious-toxic shock associated with viremia, as suggested by pronounced changes in the brain, kidneys, liver, spleen, adrenals, and lymph nodes. Bacterial bronchopneumonia was detected in only 20% of cases.

[Morphofunctional characteristics of pulmonary and bronchial arteries in bronchial asthma, chronic obstructive lung disease, idiopathic fibrosing alveolitis].

Morphological and morphometric studies have shown that secondary pulmonary hypertension is characterized by more pronounced pathological changes in the pulmonary arterial branches in severe chronic obstructive lung disease (COLD) than in idiopathic fibrosing alveolitis. Secondary pulmonary hypertension does develop in atopic bronchial asthma. Moreover, there are more significant pathological changes in the pulmonary arteries than in the bronchial ones. In severe COLD, the development of emphysema affects that of pulmonary arterial hypertension.

[Morphological characteristics of stenosis of the major duodenal papilla].

The study demonstrates a broad spectrum of pathological processes (of inflammatory, tumorous, and tumor-like genesis) of the major duodenal papilla, which result in its stenosis. It should be stressed that only a comprehensive clinical and morphological approach to diagnosing diseases of the major duodenal papilla and accordingly to choosing an adequate treatment may be a success. The morphological studies are currently prominent.

[The first successful bilateral lung transplantation in Russia].

Lung transplantation is one of the most difficult fields of contemporary transplantology. The operation was performed on a 53-year-old female who had been suffering from terminal stage COPD. The period of cold ischemia for the right and left lung was 1 hour 30 minutes and 2 hours 25 minutes respectively. The total operation time was 4 hours and 40 minutes. There were no surgical complications. There were no signs of transplant rejection 6 weeks after the operation. The considerable decrease in dispnea and increase in quality of life were registered during the follow-up. FEV1 was increased by 80% and 6 minute walk test distance was increased by 200 meters.

[Ovarian endometriosis: characteristics of the blood circulatory bed].

Glandular cystic ovarian endometriosis (OE) is characterized by a more intensive blood supply than cystic OE. This type of OE is characterized by a high proliferative glandular epithelial activity detected by an immunohistochemical study using antibodies to PCNA and CA-125. Moreover, a positive correlation is found between the serum concentration of CA-125 and the expression of this antigen in the epitheliocytes of an endometrioid cyst in both glandular-cystic and cystic OE. Thus, the findings permit the determination of the morphofunctional activity of a type of OE and its aptness to the progression of the disease and to the development of recurrences.

[Aminotransferases in early development of salmonid fish].

The activities of alanine and aspartate aminotransferases were assessed in the embryos and juveniles of the rainbow trout Parasalmo mukiss L. and chum salmon Oncorchyncus keta W. Changes in subcellular localization of these enzymes and their activities were found at different pH optima in each subcellular fraction of the rainbow trout during ontogenesis.

[Morphofunctional characteristics of microvessels in serous tumors of the ovaries].

High vascularization is noted in serous papillary ovarian tumors of a low malignancy grade, particularly in malignant serous ovarian tumors with low vascularization in benign neoplasms. Pronounced morphological changes in the vascular wall are found mainly in malignant tumors and tumors of a low malignancy grade where primitive blood vessels of a sinusoid type with a thin muscle wall prevail. Types of vascularization in the tumors studied are variable and this correlates with results of color doppler mapping.