BACKGROUND: Primary pulmonary myxoid sarcoma (PPMS) is a rare, low-grade malignant tumor, constituting approximately 0.2% of all lung tumors. Despite its rarity, PPMS possesses distinctive histological features and molecular alterations, notably the presence of EWSR1-CREB1 gene fusion. However, its precise tissue origin remains elusive, posing challenges in clinical diagnosis.
UNASSIGNED: A 20-year-old male patient underwent a routine physical examination 6 months prior, revealing a pulmonary mass. Following surgical excision, microscopic evaluation unveiled predominantly short spindle-shaped tumor cells organized in a fascicular, beam-like, or reticular pattern. The stromal matrix exhibited abundant mucin, accompanied by lymphocytic and plasma cell infiltration, with Russell bodies evident in focal areas. Immunophenotypic profiling revealed positive expression of vimentin and epithelial membrane antigen in tumor cells, whereas smooth muscle actin and S-100, among others, were negative. Ki-67 proliferation index was approximately 5%. Subsequent second-generation sequencing identified the characteristic EWSR1-CREB1 gene fusion. The definitive pathological diagnosis established PPMS. The patient underwent no adjuvant chemotherapy or radiotherapy and remained recurrence-free during a 30-month follow-up period.
CONCLUSIONS: We report a rare case of PPMS located within the left lung lobe interlobar fissure, featuring Russell body formation within the tumor stroma, a novel finding in PPMS. Furthermore, the histomorphological characteristics of this case highlight the diagnostic challenge it poses, as it may mimic inflammatory myofibroblastic tumor, extraskeletal myxoid chondrosarcoma, or hemangiopericytoma-like fibrous histiocytoma. Therefore, accurate diagnosis necessitates an integrated approach involving morphological, immunohistochemical, and molecular analyses.

同种异体或自体造血干细胞移植是各种血液系统疾病的主要治疗手段，并显著提高了患者的生存率。但是同种异体造血干细胞移植后机体出现的移植物抗宿主病是降低患者生活质量和长期生存率的关键因素。移植物抗宿主病多表现为多器官受累，其中迟发性非感染性肺部并发症是造血干细胞移植后死亡的重要原因。在这些并发症中，闭塞性细支气管炎综合征是一种由进行性小气道疾病定义的独特临床实体，是最普遍和最具特征的晚期并发症，也是目前唯一被正式认定为肺部移植物抗宿主病的疾病实体。本文报道了1例急性白血病患者异体骨髓移植术后1年半出现移植物抗宿主病——闭塞性细支气管炎，后因重症肺炎致呼吸功能障碍行肺移植术。对患者全肺切除标本进行病理学检查，显微镜下观察见典型的闭塞性细支气管炎，此外见脏层胸膜广泛显著纤维化以及脏层胸膜下肺间质纤维化。本例受体肺病理学检查拓展了对造血干细胞移植后慢性移植物抗宿主病的肺部病理学特征的认识，为进一步临床诊疗提供可靠的病理学依据。.

Blau syndrome (BS), is an autoinflammatory granulomatosis disease characterized by a distinct triad of skin, joint, and eye disorders similar to those of sarcoidosis, but the lung involvement frequently observed in sarcoidosis are rare. Granulomas from patients with BS displayed a distinct morphology indicating an exuberant chronic inflammatory response. Patients with BS may have granulomatous lung lesions, which require early diagnosis. To determine whether therapeutic intervention is needed for lung lesions, examining transbronchial lung cryobiopsy specimens and accumulating cases of BS with lung involvement could be contributed to improving BS management in the future.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is a recently characterized disease associated with somatic mutations in the UBA1 gene, which cause dysregulation of ubiquitin-mediated processes. This case describes a 71-year-old male patient with VEXAS syndrome who presented with refractory lung inflammation with a pattern similar to computed tomography hypersensitivity pneumonitis, a novel finding in VEXAS syndrome. The presented clinical case highlights the protean involvement of the lung in VEXAS syndrome and emphasizes the importance of considering interstitial lung disease in the differential diagnosis.

Mucoepidermoid carcinoma, a salivary gland tumor, rarely occurs in bronchial mucous glands. Brain metastases are rarely seen which makes for a challenging diagnosis and treatment approach. A 40-year-old woman presented with confusion, and ataxia, accompanied by a declining Glasgow Coma Score. Brain computerized tomography revealed two hyperdense, postcontrast-enhanced infra- and supratentorial lesions with perifocal edema. First causing obstructive hydrocephalus. The initial surgery involved external ventricular drainage system placement leading to the patient\'s clinical improvement. After radiological diagnostics, both lesions were resected without complications. Histopathological analysis revealed solid clusters of atypical, polygonal epithelial cells exhibiting mucin production, classified as a poorly differentiated mucoepidermoid carcinoma metastasis which originated from the upper lobe\'s apicoposterior segment and left lung. The correct treatment approach remains elusive due to the infrequent occurrence and challenging diagnosis. While new oncological and radiosurgery options promise improved overall survival rates, radical resection remains the preferred initial option.

Pulmonary arteriovenous malformations (PAVMs) are vascular anomalies resulting in abnormal connections between pulmonary arteries and veins. In 80% of cases, PAVMs are present from birth, but clinical manifestations are rarely seen in childhood. These congenital malformations are typically associated with Hereditary Hemorrhagic Telangiectasia (HHT), a rare disease that affects 1 in 5000/8000 individuals. HHT disease is frequently caused by mutations in genes involved in the TGF-β pathway. However, approximately 15% of patients do not have a genetic diagnosis and, among the genetically diagnosed, more than 33% do not meet the Curaçao criteria. This makes clinical diagnosis even more challenging in the pediatric age group. Here, we introduce an 8-year-old patient bearing a severe phenotype of multiple diffuse PAVMs caused by an unknown mutation which ended in lung transplantation. Phenotypically, the case under study follows a molecular pattern which is HHT-like. Therefore, molecular- biological and cellular-functional analyses have been performed in primary endothelial cells (ECs) isolated from the explanted lung. The findings revealed a loss of functionality in lung endothelial tissue and a stimulation of endothelial-to-mesenchymal transition. Understanding the molecular basis of this transition could potentially offer new therapeutic strategies to delay lung transplantation in severe cases.

Pulmonary nodules are commonly encountered in pulmonary practice. Etiologies could include infectious, inflammatory, and malignant. Placental transmogrification of the lung is an extremely rare etiology of pulmonary nodules. Such condition often presents as unilateral lesions in asymptomatic men. In general, such nodules are generally stable and grow extremely slowly. We highlight an unusual case of placental transmogrification of the lung (PLC) identified in a young female. The patient\'s bilateral nodules were larger than what has been previously cited in the literature and exhibited growth over an 8-year follow-up period.

BACKGROUND: IgG4-related disease (IgG4-RD) is an immune-mediated systemic inflammatory fibrotic disease, which is a relatively rare and novel disease that can involve multiple organs or tissues, with variable clinical manifestations, and for which pulmonary involvement has been reported relatively infrequently.
METHODS: Here we report a case of pulmonary infection that was initially suspected and received anti-inflammatory treatment, but the symptoms did not improve. CT examination indicated progression of the pulmonary lesion, and the nature of the lesion could not be determined by tracheoscopy and bronchoalveolar lavage. The diagnosis of IgG4 related lung disease (IgG4-RLD) was confirmed by percutaneous lung biopsy. A joint literature analysis was conducted to improve clinicians\' understanding of this disease.
RESULTS: The patient\'s history, symptoms, signs and relevant examination results were analyzed. The final diagnosis was IgG4-RLD.
CONCLUSIONS: When the clinical symptoms and imaging manifestations of the patients are consistent with IgG4-RLD, pathological examination can be appropriately performed to clarify the nature of the lesions. More consideration should be given to the possibility of disease diagnosis to avoid misdiagnosis and underdiagnosis, and proper treatment should be given at an early stage.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a deep fungal infection caused by invasion of Aspergillus mycelium into the lung parenchyma resulting in tissue destruction and necrosis, which occurs more often in im-munosuppressed populations. The severity of the disease and the rapid progression of the lung lesions puts pa¬tients at high risk of death and poor prognosis if the correct therapeutic intervention is not given as early as possible.
METHODS: Here we report a case of IPA, which was initially diagnosed as community-acquired pneumonia in a local hospital. The symptoms did not improve after receiving anti-infective treatment. The patient was diagnosed with IPA after completing a chest CT examination and an electronic bronchoscopy, as well as pathogenetic examination of the bronchoalveolar lavage fluid and pathological examination of the left bronchial mass in the respiratory department of our hospital, which was finally diagnosed as IPA. After one week of administration of voriconazole for anti-fungal infection treatment, the patient\'s symptoms improved significantly, and a repeat chest CT suggested that the lung lesions were better than before. In order to raise clinicians\' awareness of this disease, we also conducted a literature analysis.
RESULTS: The final diagnosis of IPA was made by analyzing the patient\'s history, symptoms, signs, and relevant findings.
CONCLUSIONS: When the patient\'s clinical symptoms and imaging manifestations are consistent with IPA, electronic bronchoscopy and pathogenetic and pathological examinations may be appropriately performed to clarify the na-ture of the lesion. More consideration should be given to the possibility of disease diagnosis to avoid misdiagnosis and underdiagnosis. Appropriate treatment should be given at an early stage.

COVID-19 is known to present with acute respiratory distress syndrome pathological manifestations. Studies have shown that patients with COVID-19 can develop diffuse alveolar damage, acute bronchopneumonia, necrotic bronchiolitis, and viral pneumonia. In this study, we investigated 11 cases. Needle necropsies of 11 patients, hospitalized at Tohid and Kowsar hospitals of Kurdistan University of Medical Sciences, with a positive antemortem SARS-CoV-2 (COVID-19) real-time PCR test, were fixated within 3 hours after death in the negative-pressure isolation morgue. The participants included six men (54%) and five women (46%) with a mean age of 73.82±10.58 (52-86) years old. The average hospitalization was 14.27±15.72 days. The results showed interstitial lymphocytic pneumonitis in most of the cases, varied from mild to moderate and up to severe in some cases. In 7 cases, anthracosis was noted, while one case demonstrated anthracosis with fibrosis. The hyaline membrane was reported in two patients. In one case, severe interstitial lymphocytic pneumonia with intra-alveolar exudate with organization, lithiasis, bronchiolitis pattern (BOOP), intra-alveolar hemorrhage, and mild fibrosis were seen. As a result, it is suggested to keep an eye on these pathologies in management of the severe cases of COVID-19 infection.