Asthma is a disorder that requires imaging to assess disease severity, complications, and atypical presentations. High-resolution computed tomography (HRCT) has become increasingly valuable in identifying imaging features of asthma and structural mimickers. Asthma typically demonstrates bronchial wall thickening, mosaic attenuation, and air trapping. Chronic eosinophilic pneumonia is characterized by peripheral ground-glass opacities and consolidations. Allergic bronchopulmonary aspergillosis presents with central bronchiectasis, mucus plugging, and high-attenuation mucus. Eosinophilic granulomatosis with polyangiitis reveals nonspecific findings. Excessive central airway collapse is characterized by dynamic tracheal narrowing. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia is marked by multiple small nodules and mosaic attenuation. Recognizing the differences between the aforementioned entities may decrease time to diagnosis and subsequently time to treatment.

We report the case of a 19-year-old man who presented with several months of exertional dyspnea and recent-onset hemostasis. Initial imaging revealed multiple pulmonary nodules. Days later, he was referred to a specialized center with chest pain and signs of pericarditis. Transthoracic echocardiography (TTE) showed pericardial effusion with hematoma, while transesophageal echocardiography (TEE) revealed a vascularized mass in the right atrial wall supplied by the right coronary artery (RCA), with blood leakage into the pericardial space. Due to concern for cardiac perforation, emergency surgery was decided. Intraoperatively, coronary angiography was performed prior to chest closure due to the anatomical complexity of the RCA. Pathology and immunohistochemistry analysis of cardiac, pericardium, and lung specimens confirmed the diagnosis of primary cardiac angiosarcoma. This case represents the aggressive behavior, diagnostic challenges, and therapeutic complexity of cardiac angiosarcoma, and highlights the importance of early diagnosis, accurate imaging, and a multidisciplinary approach.

Rheumatoid arthritis (RA) is an autoimmune disorder primarily targeting joints, with the lungs often being the most affected organ outside the joints. Pulmonary rheumatoid nodules (PRNs) are unusual manifestations of RA in the lungs. We report a case of a 74-year-old Chinese man with a smoking history, diagnosed with RA and treated with leflunomide and prednisone, who showed multiple peripheral or pleural nodules in both lungs on computed tomography (CT) scans. Pathological analysis of the right middle lobe lesion from CT-guided percutaneous core needle biopsy showed lymphocytic and neutrophilic infiltration, eosinophilic necrosis, scattered multinucleated giant cells and no basophilic necrosis or vasculitis. The diagnosis of PRNs was made after thorough examinations and multidisciplinary consultation and tocilizumab was recommended for subsequent therapy. PRNs, a rare extra-articular manifestation of RA, should be distinguished from infections and malignancies. High-resolution chest CT and biopsy can help in the diagnosis.

Granulomatous diseases often present with overlapping clinical and histopathological features, posing a diagnostic challenge, particularly in regions endemic for tuberculosis. We report the case of a 68-year-old diabetic male with a significant smoking history who presented with progressive shortness of breath and cough for almost three weeks' duration and multiple cutaneous nodules, present for six years, that increased in size and number over two months before presentation. Initial evaluation revealed normal chest imaging, negative microbiological tests for tuberculosis, a non-reactive Mantoux test, and elevated serum angiotensin-converting enzyme (ACE) levels, raising suspicion for the presence of granulomatous disease, like cutaneous tuberculosis, sarcoidosis, and other non-tuberculosis mycobacteria. However, further evaluation, including dermatological assessment and histopathological examination of skin lesions, which demonstrated foamy histiocytic infiltration, was performed. Wade-Fite staining revealed numerous acid-fast bacilli with a high bacterial index, confirming the diagnosis of lepromatous leprosy. The patient was initiated on multidrug therapy with rifampicin, dapsone, and clofazimine, with close follow-up. This case highlights the importance of maintaining a broad differential diagnosis in granulomatous diseases and emphasizes the need for tissue diagnosis before initiating empirical therapy, especially in tuberculosis-endemic settings.

Objective: To investigate the clinicopathological features of tuberous sclerosis complex (TSC)-associated multifocal micronodular pneumocyte hyperplasia (MMPH) and the mutation status of TSC1/TSC2 genes. Methods: A retrospective analysis was conducted on 8 MMPH cases diagnosed at Shanghai Pulmonary Hospital Affiliated to Tongji University from September 2020 to August 2024. Clinical information and imaging findings of these cases were collected. Histopathological analysis and next-generation sequencing (NGS) were performed. Results: Among the 8 patients, there were 4 males and 4 females, aged 44 (36, 50) years old. None of them had a definite family history of TSC. Only 1 patient presented with respiratory symptoms at the time of consultation. Four patients had TSC-related cutaneous lesions. Two had shagreen patches, 1 had hypomelanotic macules, and 1 had hypomelanotic macules combined with fibrous plaques on the scalp and angiofibromas. Three patients themselves or their first-degree relatives had a history of epilepsy. Five patients themselves or their first-degree relatives had liver/kidney cysts or a surgical history of renal angiomyolipoma. Computerized tomography scans showed multiple ground-glass nodules in both lungs, with an average diameter of 10.5 (8.5, 11.0) mm. Six cases were diagnosed via surgical resection, and 2 via transbronchial cryobiopsy. Intraoperative frozen sections of the 6 surgically resected cases were all misdiagnosed as early-stage lung adenocarcinoma (including adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive non-mucinous adenocarcinoma), but the diagnosis was corrected to MMPH postoperatively. One of these 6 cases was concurrent with a benign perivascular epithelioid cell tumor (PEComa). Microscopically, MMPH was characterized by multifocal proliferation of type Ⅱ alveolar epithelial cells, which showed bland cellular morphology without atypia or invasive growth. For the case concurrent with PEComa, clear epithelioid cells were observed growing in nests or sheets. Immunohistochemically, the proliferative epithelial cells were positive for TTF-1 and showed low expression of Ki-67. PEComa cells were positive for Melan A and MiTF. NGS showed that TSC1 mutations were detected in 6 cases, TSC2 mutation in 1 case (which also had a concurrent class Ⅲ missense mutation of BRAF G466E), and no mutation in 1 case, with an overall mutation detection ratio is 7/8. No other lung cancer-related driver-gene variations were found in any case. Follow-up data were available for 8 patients. During the follow-up, 1 patient developed scattered thin-walled lucencies in both lungs, but no pathological examination was performed. All patients had a favorable overall survival status, follow-up time was 14.0(9.5,47.0) months. Conclusions: MMPH is a rare, benign TSC-associated pulmonary lesion, often presenting as multiple ground-glass nodules in both lungs. It can be easily misdiagnosed as early-stage lung adenocarcinoma. The diagnosis requires a comprehensive judgment based on clinical data, imaging findings, histopathology, and TSC1/TSC2 gene mutation results.

Persistent chronic cough is a common outpatient symptom, typically caused by gastroesophageal reflux, asthma, or upper airway cough syndrome. Rare causes, including metastatic tumors, may present with nonspecific respiratory symptoms, particularly in patients with a history of malignancy. A 59-year-old man with a prior left frontal grade II solitary fibrous tumor (SFT) resected in 2012 presented with a 2-3-month history of dry cough. Initial empiric therapy for gastroesophageal reflux and post-nasal drip failed. Chest radiograph revealed multiple bilateral pulmonary nodules, and CT chest showed an 8 × 4.5 cm subcarinal mass. Bronchoscopy with transbronchial needle aspiration confirmed metastatic pulmonary SFT. The patient is now being followed by oncology for staging and treatment planning. Persistent cough that does not improve with empiric therapy warrants early imaging, especially in patients with prior malignancy. This case highlights that SFT can metastasize many years after initial treatment, presenting with common symptoms such as cough. Timely reassessment can prevent delays in diagnosis and management.

Indium lung disease remains an ultra-rare interstitial lung disease with no initiative effective in changing the trial. It is related to excessive protein deposition, the development of interstitial inflammation, and subsequent pulmonary fibrosis. This is a "destructive" pulmonary disease. The pathogenesis of indium lung disease remains unclear because the disease progresses continuously, making early diagnosis difficult. This study aimed to identify the histopathological features of pulmonary injury during and after Nano-ITO intratracheal instillation. Male Sprague-Dawley rats were intratracheally instilled (single and multiple) with dispersed Nano-ITO at low (0.6 mg/kg) and high (6 mg/kg) doses and were sacrificed at 1, 4, 8 and 12 weeks after exposure to test inflammation, pulmonary alveolar proteinosis (PAP), and interstitial fibrosis in the lungs. The results demonstrated that even low-dose Nano-ITO exposure made the lungs susceptible to various types of lung injuries that may lead to PAP and disorders of lipid metabolism. The pro-inflammatory action of Nano-ITO-induced progressive interstitial fibrosis may promote this process by aggravating PAP, including the acute aggravation of foamed alveolar macrophages (AM) and lipid metabolism disorders. When inspecting the effects of these inflammatory responses, the current study uncovered the significance of prospective relationships between PAP, lipid metabolism disorders, and pulmonary fibrosis. Nano-ITO induces a large amount of reactive oxygen species production and mitochondrial damage to trigger redox imbalance, ultimately leading to indium lung disease. Nano-ITO causes pulmonary parenchymal lesions, and its pathological features mainly include: foam macrophage accumulation in respiratory bronchioles and alveolar cavities, fibrosis in alveolar septa (collagen deposition in alveolar septa), epithelial-mesenchymal transition (decreased expression of E-cadherin, increases expression of alpha smooth muscle actin and vimentin), intracytoplasmic lipid droplets (Oil Red-O-positive AM), and cholesterol clefts forming small nodules and granuloma. These findings suggest that intratracheal instillation of rats for 12 weeks is sufficient to observe progressive lung lesions caused by Nano-ITO and is an appropriate experimental scheme to evaluate the early stages of indium lung disease.

Immune checkpoint inhibitors (ICIs), a widely adopted therapeutic option for metastatic renal cell carcinoma, are also associated with a range of immune-related adverse events, some of which can be severe and life-threatening. Here, we describe the case of a 70-year-old man with renal cell carcinoma and brain, lung, and bone metastases who developed ICI-associated encephalitis, which was fatal. Initial computed tomography imaging revealed a 9.8 cm mass in the right kidney, multiple pulmonary nodules, and an osteolytic lesion in the left fifth rib. Brain magnetic resonance imaging revealed metastatic lesions in the right parietal lobe and left lateral ventricle. The patient underwent therapy with pembrolizumab and lenvatinib in combination with stereotactic radiotherapy targeting the brain metastases. On day 20 of treatment, the patient developed a generalized seizure, followed by a rapid deterioration in consciousness. He died the following day. Post-mortem examination revealed widespread lymphocytic infiltration of the brain parenchyma, which was consistent with the diagnosis of ICI-associated encephalitis.

Uterine leiomyomas are common benign smooth muscle tumors typically confined to the uterus and hormonally responsive to estrogen and progesterone, typically regressing after menopause. Rarely, they demonstrate metastatic behavior despite benign histology, a condition known as benign metastasizing leiomyoma (BML). BML is exceedingly rare and can mimic malignancy, posing diagnostic challenges. We report a rare case of a 53-year-old woman with a history of hysterectomy for leiomyomas who presented with dyspnea and chest pain. Imaging revealed numerous bilateral pulmonary nodules, later confirmed to be smooth muscle tumors. After being lost to follow-up, she returned 2 years later with new breast and forearm masses. Imaging and biopsy confirmed metastatic smooth muscle tumors consistent with BML. Breast lesions mimicked benign cysts on ultrasound, underscoring the importance of clinical and histological correlation. The patient responded well to treatment with symptom improvement. This case highlights the rare phenomenon of BML metastasizing to multiple extrauterine sites, including the breast and soft tissues, locations infrequently reported. Imaging findings, particularly in the breast, can mimic benign lesions such as simple cysts, underscoring the need for biopsy and correlation with clinical history. BML should be considered in women with a history of uterine fibroids and indolent-appearing metastases without fludeoxyglucose uptake on positron emission tomography, computed tomography, and cystic appearance on ultrasound of breast lesions. Early recognition is crucial to avoid misclassification as malignancy and to guide effective hormonal treatment.

Cryptococcosis predominantly affects immunocompromised individuals, but cases have been reported in immunocompetent hosts. Pulmonary involvement often presents nonspecific features that could resemble lung malignancy. We present a case of a 49-year-old immunocompetent, HIV-negative, non-smoker man with progressive respiratory symptoms and significant weight loss. Imaging revealed multiple pulmonary nodules with mild metabolic activity. Non-invasive diagnostic studies were inconclusive. Histopathological examination of lung tissue demonstrated encapsulated yeasts consistent with Cryptococcus spp., confirmed by fungal culture and MALDI-TOF mass spectrometry. Later, cerebrospinal fluid analysis also showed encapsulated yeasts. The patient was treated successfully with fluconazole, achieving complete clinical and mycological remission.