The prognosis of lung cancer patients with idiopathic pulmonary fibrosis (IPF) is reported to be worse than that of those without IPF. Herein, we investigated the prognosis of non-small cell lung cancer (NSCLC) patients with and without IPF who underwent resection, and established a new postoperative therapeutic strategy for NSCLC patients with IPF. Between 2011 and 2020, 437 consecutive patients with pathological stage I NSCLC who underwent complete resection with systematic lymph node dissection were retrospectively analyzed. Of 437 patients, post-propensity score matching analysis showed the five-year recurrence-free probability was significantly lower for patients with IPF than for those without IPF (32.3

Introduction and importance: We report a case of a thymoma that developed in the cyst wall during follow-up of a unilocular thymic cyst. Case presentation: A 70-year-old woman was found to have abnormal findings on a computed tomography (CT) scan of the chest. The chest CT revealed a well-circumscribed, hypodense mass in the left anterior mediastinum. During follow-up 5 years later, a small nodule emerged within the cystic lesion. Surgical resection was performed to establish a definitive diagnosis, which confirmed a type A thymoma, classified as pathologic stage I, arising within a thymic cyst. Clinical discussion: Observation is acceptable in cases of congenital cysts arising in the mediastinum. However, when irregularities or nodules are present in the cyst wall, as in this case, surgical intervention should be considered. Conclusion: This case highlights the occurrence of thymoma within the wall of a unilocular congenital thymic cyst during follow-up. The possibility of such transformation should be considered when planning surveillance, determining its duration, and treating a unilocular thymic cyst.

INTRODUCTION AND IMPORTANCE:Extralobar pulmonary sequestration with torsion is an exceptionally rare condition, especially in adults, and can present with nonspecific symptoms such as abdominal pain, making diagnosis challenging. Timely recognition is critical, as delayed treatment may lead to infarction and serious complications. This report describes the case of a patient with extralobar pulmonary sequestration who presented with abdominal pain. CASE PRESENTATION:An 83-year-old healthy female presented with increasing severe abdominal pain and mild fever that had developed for the past three weeks. Chest and abdominal computed tomography revealed a non-enhancing mass in the right posterior paravertebral area, with mild pleural effusion. Video-assisted thoracoscopic surgery to establish a definitive diagnosis revealed a yellow-whitish ovoid mass with congestion and necrosis, accompanied by bloody pleural effusion. The mass was connected to the mediastinum via a twisted feeding vessel. The final diagnosis was consistent with extralobar pulmonary sequestration with torsion and infarction. The patient's symptoms were relieved immediately after surgery. CLINICAL DISCUSSION:Extralobar pulmonary sequestration with torsion is rare in adults. Abdominal pain is the hallmark symptom of this condition. The lack of contrast enhancement in the lesion with no visible feeding vascular pedicle or pleural effusion is imaging signs of pulmonary sequestration torsion, and surgical resection is the standard treatment. CONCLUSION:This case highlights the importance of considering pulmonary sequestration in the differential diagnosis of unexplained abdominal pain with posterior mediastinal masses, underscoring the value of surgical exploration for diagnosis and treatment.

IntroductionhtaThe prognosis of patients with lung cancer and interstitial lung disease (ILD) is worse than that of patients without ILDs; however, therapeutic options for ILD-associated lung cancer are severely limited. Although ILD is associated with an increased incidence of lung cancer, it is unclear whether the ILD lung environment affects the biological behavior of lung cancer.MethodsWe tested our hypothesis that the lung environment of ILD is associated with the biological behavior and progression of lung cancer using an in vivo murine model of interstitial pneumonia (IP) and lung cancer.ResultsThe bleomycin-induced IP lung environment promoted metastasis to the mediastinal lymph nodes or contralateral lungs in an orthotopic model of lung cancer. The results of our in vivo experiments were supported by clinical data, which indicated that a significantly greater number of carcinomas with vascular invasion and lymphatic permeation, lymph node metastases, and intrapulmonary metastases were found in patients with clinical stage I non-small cell lung cancer and ILD than in those without ILD. In addition, pharmacological treatment of the IP lung environment with pirfenidone (PFD) inhibited tumor progression in the IP lung cancer model.ConclusionWe found that the IP lung environment promotes lung cancer metastasis. The results of this study may pave the way for further clinical studies on the use of PFD alone or in conjunction with conventional chemotherapy in patients with lung cancer and ILD.

INTRODUCTION AND IMPORTANCE:Septic arthritis of the sternoclavicular joint (SASCJ) accounts for <1 % of all joint infections. Owing to the limited literature on the disease, there is no consensus on the general treatment for SASCJ. Here, we report a case of SASCJ complicated by osteomyelitis, mediastinitis, infectious myositis, and cervical and chest wall abscesses that required radical sternoclavicular joint resection and reconstruction using the greater omental flap. In this report, we discuss the treatment strategy for advanced SASCJ cases. CASE PRESENTATION:A 65-year-old man was diagnosed with SASCJ relapse after the failure of antibiotic therapy alone, combined with osteomyelitis, mediastinitis, infectious myositis, and cervical and chest wall abscesses. A radical sternoclavicular joint resection was performed. After negative-pressure wound therapy, serial re-debridement was performed. The greater omental flap was transported into a deep, large residual space. The patient has been relapse-free for 1 year. CLINICAL DISCUSSION:Radical resection of the entire sternoclavicular joint should be the preferred management strategy for patients with sternoclavicular joint infections, especially in cases of osteomyelitis. Although the pectoralis major flap is typically the first choice to cover the defect, we used the omental flap because the locoregional flaps were not large enough to reconstruct the defect. CONCLUSION:The greater omental flap is an advantageous alternative when there is a need to provide coverage for large defects in cases of SASCJ.

PURPOSE:The development of dual energy CT (DECT) has made it possible to provide not only morphological characteristics but also a wide range of quantitative information. The purpose of this study is to differentiate between benign and malignant solitary pulmonary nodules (SPN) by using electron density values obtained from DECT. METHODS:From the image data diagnosed as SPN, DECT images of 54 cases were selected, and the maximum electron density values of SPN were obtained. Electron density values were compared between benign and malignant cases by t-test. Comparisons between histopathological types and histological subtypes were performed by ANOVA. Logistic regression analysis was also applied to estimate the partial regression coefficients on electron density values. RESULTS:Electron density values were 3.56×1020/mm3 for malignant and 3.51×1020/mm3 for benign, with malignancy being significantly higher (p<0.001). ROC analysis showed that the AUC was 0.77. In a comparison between histopathologic types, electron density values were significantly higher for adenocarcinoma and squamous cell carcinoma (p<0.05). There were no significant differences among subtypes. Logistic regression analysis showed a regression coefficient of 1.24 (p<0.01). CONCLUSION:Electron density values obtained from dual energy CT may serve as a useful quantitative parameter for differentiating between benign and malignant SPN. However, attention should be paid to certain histological subtypes, such as invasive mucinous adenocarcinoma, which may exhibit exceptionally low values.

INTRODUCTION AND IMPORTANCE:We report a case of a resected thymoma with preoperative spontaneous regression in a 76-year-old woman. Only 13 cases of spontaneous regression of thymomas have been reported in the English literature, including this one. CASE PRESENTATION:During a regular checkup, chest radiography revealed an abnormal shadow in the right hilum of an asymptomatic 76-year-old woman. Chest computed tomography (CT) revealed a 41 × 32 mm anterior mediastinal tumor. Six months later, she presented with sudden anterior chest pain. Chest CT revealed that the tumor had grown slightly to 43 × 42 mm. Chest CT performed one day preoperatively revealed that the tumor had rapidly shrunk in one month (to 26 × 23 mm) and contained areas of necrosis. Surgical resection was performed to obtain a definitive diagnosis. The postoperative diagnosis was a type AB thymoma, classified as pathological stage I (Masaoka's classification) with intratumoral necrosis. CLINICAL DISCUSSION:The spontaneous regression in the present case might have been related to the necrosis observed in the tumor. We postulate that vascular occlusion due to minute thromboembolism resulted in tumor necrosis. This might have caused inflammation around the tumor, thereby causing the patient's chest pain. CONCLUSION:Thymomas should be included in the differential diagnosis of mediastinal tumors with necrosis that spontaneously regress, and surgical resection is required despite such regression.

Introduction and importance: Pulmonary colloid adenocarcinoma is an extremely rare subtype of lung adenocarcinoma. Owing to its rarity, the detailed clinical features of colloid adenocarcinoma remain largely unknown. This report describes a case of early-stage colloid adenocarcinoma that recurred soon after resection, including its radiological findings. Case presentation: During a routine checkup, a chest roentgenogram revealed an abnormal shadow in the right upper lung field of an asymptomatic 68-year-old man. Computed tomography (CT) showed a well-defined, low-attenuation nodule in the right upper lobe. Right upper lobectomy with mediastinal lymph node dissection was performed. The postoperative histopathological diagnosis indicated pulmonary colloid adenocarcinoma. The pathological stage was classified as T1bN0M0 (stage IA2). Follow-up CT 1 year after the resection revealed an enlarged supraclavicular lymph node and pulmonary nodule in the right lower lobe. Both lesions appeared as well-defined solitary hypoattenuated tumors with minimal enhancement on CT images. Excisional biopsies of both tumors were performed to obtain a definitive diagnosis. Both tumors consisted of abundant mucin in which some tumor cells were floating and were diagnosed as colloid adenocarcinoma recurrences. Clinical discussion: Although colloid adenocarcinoma is generally considered to have indolent clinical behavior, it can recur even in early-stage cases. Conclusion: Colloid adenocarcinoma is a distinct variant of lung adenocarcinoma, characterized by well-circumscribed mucinous lesions with alveolar wall destruction caused by mucin pools and scant tumor cells. The treatment strategy for colloid adenocarcinoma should follow the guidelines for primary lung cancer.

INTRODUCTION AND IMPORTANCE:Bronchial foreign body aspiration is a life-threatening emergency. Largely, the published literature focuses on the removal of foreign bodies by bronchoscopy, while the surgical removal of endobronchial foreign bodies is rarely reported on. Thus, we presented a case of a bronchial foreign body that was successfully removed by a video-assisted thoracoscopic surgical (VATS) bronchotomy, after multiple failed bronchoscopic attempts. CASE PRESENTATION:A 77-year-old male patient presented with a 2-month duration of a persistent cough and low-grade fever after undergoing dental treatment. Bronchoscopy revealed a dental crown surrounded by granulation tissue in the right basal bronchus. The patient was referred to our department for open surgery after undergoing multiple unsuccessful extractions. The bronchial foreign body was removed by a VATS bronchotomy. The postoperative course was uneventful, and the patient was discharged 2 days postoperatively without any complications. CLINICAL DISCUSSION:Most aspirated tracheobronchial foreign bodies can be removed through bronchoscopy; nonetheless, certain aspirated foreign bodies may require surgical intervention. Furthermore, the indications for bronchotomies encompass the failure to remove the foreign body despite repeated attempts, due to immobility, with or without distal bronchial placement. Thoracoscopy is beneficial in providing superior visualization, with an increased likelihood of post-bronchotomy recovery. CONCLUSION:VATS bronchotomy is a safe and effective alternative for the removal of bronchial foreign bodies without sacrificing the functioning of the lung parenchyma.

Introduction and importance We present a case of idiopathic azygos vein aneurysm (AVA) and describe its radiological features. Clinicians should be aware of the imaging findings to avoid the risk of bleeding caused by biopsy. Case presentation An asymptomatic 46-year-old woman was found to have an abnormal shadow on a chest computed tomography (CT) scan during a medical checkup. Plain CT revealed a well-defined, homogeneous mass on the posterior side of the right main bronchus. Contrast-enhanced CT revealed a mass with marked enhancement pointing to a vascular structure. Three-dimensional reconstruction showed that the mass was connected to the azygos arch, and inflow to and outflow from the azygos vein was detected. Subsequently, video-assisted thoracic surgery was performed. Clinical discussion Patients with idiopathic AVA often present with accidental findings of a mediastinal or lung mass on a chest radiographs or CT scans, which can be mistakenly diagnosed as a paratracheal tumor, bronchial cyst, or posterior mediastinal tumor. Needle biopsy should be avoided due to the risk of massive bleeding. During the evaluation of thoracic malignancies, AVAs should be considered in the differential diagnosis, especially in area of the right tracheobronchial angle or right upper or posterior mediastinum. Three-dimensional reconstruction can help surgeons to clarify the disease diagnosis. Conclusion Imaging findings combined with enhanced CT and three-dimensional reconstruction are useful for diagnosing AVAs.

Introduction and importance: Although pleomorphic adenoma is the most common type of parotid gland tumor, its occurrence in the trachea is rare. Here, we describe a successfully resected pleomorphic adenoma of the trachea in a woman with severe respiratory failure that had been preoperatively misdiagnosed as asthma.Case presentation: A 69-year-old woman presented to the emergency department with symptoms of worsening dyspnea and subsequent loss of consciousness. She had a history of progressively worsening wheezing and stridor over the course of 2-years and had been diagnosed with asthma. Arterial blood gas sample analysis indicated type II respiratory failure. A chest computed tomographic scan revealed a tumor in the trachea, which was almost completely obstructing the lower tracheal lumen. The tumor was located just above the carina. To alleviate airway constriction and achieve complete resection, carinal resection with reconstruction was performed. The postoperative diagnosis was pleomorphic adenoma of the trachea.Clinical discussion: Pleomorphic adenoma is a rare tracheal tumor that may present with obstructive airway symptoms that mimic asthma.Conclusion: Tracheal tumors should be considered in patients with chronic respiratory symptoms that do not improve with medication.

Introduction and importance: We presented an extremely rare case of lung abscess following bronchoscopy associated with lung cancer that extended directly into the chest wall. Case presentation: A 49-year-old man with adenocarcinoma underwent bronchoscopy. Eight days after the biopsy, the patient presented with chills and anterior chest wall pain. Chest computed tomography (CT) scan revealed a gas-containing lung abscess, measuring 10 cm in the left upper lobe and subcutaneous emphysema. The coronal view of the CT indicated a continuous passage of air from the lung abscess to the subcutaneous emphysema beneath the pectoralis muscle. Surgical debridement of the subcutaneous abscess was performed, resulting in drainage of a large volume of purulent material. We confirmed that the lung abscess had directly extended to the chest wall, leading to a decision to perform segmentectomy of the upper division of the left lung. Clinical discussion: Lung abscess associated with lung cancer is a rare, life-threatening complication, which may lead to significant delays in the commencement of oncological treatment and potentially worsen long-term outcomes. In the present case, surgical findings confirmed a lung abscess extending directly to the chest wall. Surgical therapy is the treatment of choice for this rare condition, providing rapid focus control. Therefore, prompt initiation of surgical therapy is essential when conservative measures prove ineffective. Conclusion: Lung abscesses may extend into the chest wall during differential diagnosis of infectious diseases of the chest wall. Successful treatment of this rare condition depends on prompt surgical intervention.

Introduction and importance: We present a relatively rare case of intrathoracic chronic expanding hematoma (CEH) after thoracic surgery for lung cancer. CEH is often difficult to distinguish from malignant tumors because of its large size and slow progressive enlargement. In this report, we describe the radiological features of CEH in detail.Case presentation: A 67-year-old man who underwent a left upper lobectomy for lung cancer at 46 years of age presented with hemosputum. Computed tomography revealed a large mass with central low attenuation. Calcification was detected in peripheral lesions of the mass. T2-weighted magnetic resonance imaging (MRI) revealed a mass with mixed low and high signal intensities. Based on the clinical course, the patient was diagnosed with an intrathoracic CEH. A left posterolateral thoracotomy was performed with the patient in the lateral position, and a mass encased in a tough capsule was resected. The postoperative histopathological findings were consistent with CEH.Clinical discussion: CT of intrathoracic CEH shows a lesion with heterogeneous content, a thick wall, and calcifications. However, differentiation from malignant tumors is difficult using CT alone. MRI is a good diagnostic modality for CEH and often shows a mixture of low-and high-intensity areas on T2-weighted images. In addition, the patient's medical history is important because most cases of CEH have a history of trauma or surgery.Conclusion: To diagnose intrathoracic CEH, it is essential to consider the patient's clinical course and MRI findings.

完全内臓逆位に合併した左上葉肺癌に対する胸腔鏡下左上葉切除術の1例を経験したので報告する．症例は74歳男性．検診の胸部X線で左上肺野に異常陰影を指摘された．胸腹部CTでは，左上葉の結節影と胸腹部内臓の完全逆位が認められた．胸腔鏡下に部分切除を行ったところ，術中迅速で腺癌と診断されたため，完全鏡視下に縦隔リンパ節郭清を伴う左上葉切除術を施行した．切除手技は右上葉切除術の手順と全くの鏡像であった．術前に通常の右上葉切除術の手術動画を左右反転させて，完全内臓逆位合併肺癌に対する左上葉切除術の仮想手術動画を作成した．通常手術の鏡像となる手術のイメージを視覚化することで，術前に手術スタッフ間で手術のイメージの共有化を行うことができ，安全かつ円滑に手術を完遂することができた．

Background Spontaneous regression of thymic carcinoma is extremely rare. We report a case of a resected thymic carcinoma with preoperative spontaneous regression in a 67-year-old woman. Case presentation The patient presented with low-grade fever and anterior chest pain. Chest computed tomography (CT) showed a 55 × 43 mm exophytic heterogeneously enhancing mass showing some areas of necrosis. Chest CT done one day preoperatively revealed that the tumor had rapidly shrunk for one month. Surgical resection was performed to obtain a definitive diagnosis and achieve complete resection, yielding a postoperative diagnosis of thymic carcinoma. The patient survived without signs of recurrence for 12 months postoperatively. Conclusions Mediastinal tumors with necrosis demonstrating spontaneous regression should include thymic carcinomas in the differential diagnosis.

Abstract Background Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin and accounts for < 2% of all soft tissue masses. Although SFT has been identified in multiple anatomic locations and can grow anywhere in the body, intrapulmonary SFT are rare. Case presentation In this report, we presented a rare case of intrapulmonary solitary fibrous tumor (SFT) coexisting with lung adenocarcinoma in a 74-year-old man. Chest computed tomography showed a well-defined nodule with punctate calcification and measuring 2.3 × 2.1 cm and two ground-grass nodules with solid component. To obtain a definitive diagnosis and achieve complete resection, surgery was performed. The postoperative diagnosis was intrapulmonary SFT coexisting with lung adenocarcinoma. After surgery, he survived for 6 months without any signs of recurrence. Conclusion Complete resection may be the best treatment for intrapulmonary SFT. Careful follow-up of the postoperative course is important, because differentiating between benignity and malignancy is difficult by histologic findings alone.

We report a rare case of recurrent solitary fibrous tumor (SFT) of the pleura with suspicious malignant transformation. A 78-year-old man had undergone prior surgical resection of the primary and recurrent SFT tumors at 11 and 2 years before the current presentation. Although his primary tumor had a round shape and did not show invasive growth, the current recurrent tumor extended through the neural foramen and had an osteoclastic progression into the thoracic spine. A computed tomography (CT) guided needle biopsy was performed and the pathological diagnosis of the tumor was confirmed as the recurrence of SFT. Immunohistochemically, the MIB-1 proliferation index (Ki-67) of the primary tumor and the current tumor was 1.74 and 30.00%, respectively. These clinical and immunohistochemical findings were strongly suspected the malignant transformation of SFT from benign. He was treated with radiotherapy, and a response was observed.

Background: Several previous researchers have investigated the prognostic value of serum tumor markers, especially carcinoembryonic antigen (CEA).Only a limited number of studies reported the usefulness of serum tumor markers for lung squamous cell carcinoma (SQ).We aimed to examine the significance of serum tumor markers for lung SQ.Methods: Eighty-five lung SQ patients who underwent surgery and followed more than 5-year were included.The ratios of 5-year survivors to all patients in groups with several clinicopathologic factors, including tumor markers, were compared.We also compared the clinicopathologic factors between central type and peripheral type SQ.Results: The majority of patients were male gender and current/ former smokers.Age, pN status, cytokeratin-19 fragment (CYFRA 21-1), squamous cell carcinoma antigen (SCC), and comorbid interstitial pneumonia (IP) were associated with the ratio of 5-year survivors significantly.When patients were compared based on tumor location, high p-stage and CYFRA 21-1 were related to central type SQ.Conclusion: Both SCC and CYFRA 21-1 appeared to be useful prognostic markers for patients with lung SQ.Furthermore, CYFRA 21-1 was related to central type SQ.

Primary thymic mucinous adenocarcinoma is extremely rare; to our knowledge, only 16 cases have been reported to date. A 68-year-old man presented to a previous hospital due to massive pericardial effusion. Cytological examination of the pericardial effusion revealed the presence of adenocarcinoma, and computed tomography showed an anterior mediastinal mass lesion invading the pericardium. Because systemic examination failed to detect other lesions, except for liver metastasis, mediastinal lymph node swelling, and pleural dissemination, a thoracoscopic biopsy of the mediastinal and pleural tumor was performed. The pathological diagnosis was thymic mucinous adenocarcinoma. Although he received chemotherapy, he died due to cancer 6 months after the biopsy.

We report a rare case of pulmonary torsion after nonpulmonary thoracotomy. A 38-year-old woman with schizophrenia committed suicide by a self-infliction of sharp force into the chest and abdomen. During emergent abdominal damage control surgery, a left-sided resuscitative thoracostomy was also performed due to hemorrhagic shock. Although abnormal shadow was detected on postoperative chest roentgenogram and computed tomography, the diagnosis of pulmonary torsion was delayed. Seven days after initial surgery, pulmonary torsion was diagnosed and managed by left upper lobectomy. To our knowledge, this is the first report of pulmonary torsion after resuscitative thoracotomy.