A 77-year-old man with emphysema underwent thoracoscopic left upper lobectomy for primary lung cancer. Three days after the lobectomy, the subcutaneous emphysema expanded rapidly. Chest computed tomography (CT) revealed a 5.5-cm pneumatocele that developed postoperatively in the superior segment of the left lower lung. Surgery was performed on postoperative day 7 because of persistent air leakage, which revealed a pulmonary laceration with air leakage in the anterior basal segment of the left lower lung, and it was repaired. Surgical treatment was not performed for the pneumatocele because there was no leakage from it. Thereafter, the pneumatocele shrank spontaneously. After starting adjuvant chemotherapy, a chest radiograph showed a 9.5-cm lung cyst at the base of the lower left lung field, and bloody sputum was observed in the same period. Consequently, adjuvant chemotherapy was discontinued, and the bloody sputum improved immediately. A year after the lobectomy, chest CT showed that both pneumatoceles had shrunk spontaneously, and there was no lung cancer recurrence. Postoperative pneumatocele is rare, and the treatment strategy has not been determined. This report suggests that conservative treatment may lead to cure.

Partial anomalous pulmonary venous connection is a rare congenital malformation in which a portion of the pulmonary venous system flows into the right atrium, superior vena cava, inferior vena cava, azygos vein, or left brachiocephalic vein rather than the left ventricular system. A 50-year-old man was diagnosed with adenocarcinoma of the left lung following close examination of an abnormal chest shadow discovered during a routine medical checkup. Preoperative chest CT showed PAPVC, but it was an abnormal vessel from a lung lobe that needed to be resected. PAPVC associated with lung cancer does not require special treatment if it returns from the resected lung lobe. However, if it returns from another lung lobe, there is concern about right heart failure, and so caution should be exercised.

In this report, we describe a case of PAPVC associated with a resected lung cancer lobe that was treated with lobectomy, without postoperative complications.

A 30-year-old male presented to our hospital with dyspnea and right chest pain that occurred while he was playing futsal. The patient was diagnosed with right spontaneous hemopneumothorax. A chest tube was placed, and bloody pleural effusion was drained. Emergency surgery was performed, because bloody pleural effusion was persistently drained. The patient developed shock during transportation, and so extracellular fluid was administered immediately. Uniportal video-assisted thoracoscopic surgery (VATS) was performed via the chest tube insertion site into the 6^th intercostal space on the right medial axillary line. A blood vessel-like cord from the parietal pleura at the apex was observed. Further, a hematoma was found in the thoracic cavity and identified as the source of bleeding. Approximately 8 min after the start of the surgery, bleeding from the blood vessel-like cord could be controlled via bipolar cautery hemostasis. After hematoma evacuation, wedge resection of the pulmonary apex including the ruptured bullae was performed. The surgical duration was 63 min, and the volume of blood loss was 41 mL. After the surgery, the patient recovered immediately, and was discharged from our hospital on day 8 of hospitalization, following removal of the chest tube on day 3. Uniportal VATS via the chest tube insertion site can be useful for immediate assessment of the thoracic cavity and facilitate easy hemostasis.

A female in her 50s with right breast cancer was noted to have multiple ground-glass nodules in the bilateral lungs on chest computed tomography (CT), and so was referred to our hospital for biopsy. Bronchoscopic biopsy of the lung nodules failed to provide a diagnosis, so she underwent left S3 segmentectomy for excisional biopsy. The pathological diagnosis was pulmonary nodular lymphoid hyperplasia (PNLH) with no evidence of malignancy. Subsequently, she received right mastectomy and adjuvant chemotherapy for breast cancer. Chest CT at 6 months after the operation for the breast cancer showed regression of the remaining ground-glass nodules. PNLH is a rare condition and its natural history remains unclear, so we are planning to continuously follow-up the patient.

We report a case of localized malignant pleural mesothelioma presenting as a cystic mass. The patient was a 78-year-old man. He was referred to our hospital because of an abnormal chest shadow. CT of the chest revealed a 12-cm cystic tumor shadow bordering the left chest wall and left pleural effusion. Pleural fluid examination showed no malignant findings. Surgery was performed for diagnosis and treatment. The surgery involved an open thoracotomy along the sixth intercostal midaxillary line. The adhesion between the tumor and chest wall and lungs could be detached bluntly, but the adhesion to the pericardium was so strong that it could not be detached, so the tumor was removed, including the pericardium, which adhered to the tumor. The pathological diagnosis was malignant pleural mesothelioma of the sarcomatoid type.

Background. Follicular dendritic cell sarcoma (FDCS) is an uncommon malignant neoplasm arising from follicular dendritic cells (FDC), which exists in the germinal center of lymphoid follicles. Case. A 75-year-old female visited our hospital with the chief complaint of left chest pain. Chest computed tomography revealed a mass lesion of 3.3 cm in the left anterior mediastinum, in contact with the sternum. It was suspected of being a thymoma, and she underwent tumor resection via video-assisted thoracic surgery. Intraoperative findings revealed that the tumor was a distorted, elevated lesion on the back of the sternum to the left costal cartilage. Histopathological examination revealed the proliferation of tumor cells with nuclear atypia in a part of the tissue of hyaline-vascular Castleman disease, immunostaining was positive for CD21 and CD35, and the diagnosis was FDCS. Postoperative radiation therapy of 40 Gy was performed. Now, at 5 years since the operation, she is alive without recurrence. Conclusion. FDCS is a rare disease, and cases of coexistence / transition with Castleman disease have been reported. The associated prognosis is relatively good with surgical resection, although local recurrence and metastasis have been reported. Thus, further follow-up is necessary.

Pneumothorax associated with Birt-Hogg-Dubé (BHD) syndrome is rare in pediatric patients. A 27-year-old woman presented to our hospital with left chest pain and dyspnea and had recently been treated elsewhere for left pneumothorax. We diagnosed her with left pneumothorax. Unusually, she had left pneumothorax of unknown cause at the ages of 12 and 15 years and had received treatment. Chest CT showed multiple small cysts in the lower lobes of both lungs, mainly in the mediastinum, and a 45-mm multilocular cyst in the left lower lobe. We performed thoracoscopic segmentectomy of the basal segment of the left lobe to resect the multilocular cyst. Based on the distinctive imaging findings and family history (father and uncle had pneumothorax), we considered the possibility that this patient had been affected by BHD syndrome since the age of 12 years. After surgery, genetic analysis revealed FLCN mutation, confirming the diagnosis of BHD syndrome. BHD syndrome, determined by detailed review of imaging findings and family history, might be a cause of pediatric pneumothorax.

The patient was a 65-year-old man. He had severe chronic heart failure and interstitial pneumonia. He was referred to our hospital to investigate operability for left refractory pneumothorax. Since general anesthesia was deemed difficult, he underwent non-intubated thoracoscopic surgery with a bulla ligation technique under locoregional anesthesia with sedation. Non-intubated thoracoscopic surgery is a surgical option for high-risk patients.

【Case 1】An 81-year-old male patient presented with a chief complaint of dyspnea. He had a history of COPD, and chest CT revealed an infiltrative shadow in the right lower lobe of the lung and an abscess cavity within the right pleural cavity.

Thoracic drainage was performed, and a tube was inserted into the right lower lobe of the lung. Considering the overall condition, a conservative approach was taken, and open thoracotomy was performed with bronchoscopy for thoracic empyema debridement and pleural decortication. Postoperatively, intensive care management was provided, and improvement in the overall condition was observed.

【Case 2】An 80-year-old male patient, admitted and treated at another hospital for pleurisy, was transferred due to worsening of empyema for further management. Chest CT revealed an abscess cavity within the left pleural cavity and findings of atelectasis in the left lower lobe. Thoracic drainage was performed, and a tube was inserted into the left lower lobe of the lung.

Emergency open thoracotomy for thoracic empyema debridement and lung decortication were conducted with the adjunct use of an extracorporeal membrane oxygenation system. Postoperatively, rapid improvements in the inflammatory response and respiratory symptoms were observed.

【Summary】We encountered two cases requiring surgical intervention due to iatrogenic lung injury caused by thoracic drainage. Surgical approach selection and management strategies tailored to the patients' medical history and pulmonary conditions were deemed necessary to address lung injuries.

A 47-year-old woman had a previous history of right pneumothorax at the ages of 44 and 46. Endometriosis was diagnosed at the onset of pneumothorax when she was 46, and progesterone therapy was initiated. Since then, menstruation had been absent. This time, she developed sudden right chest pain and was diagnosed with right pneumothorax. Chest CT showed bullae and pleural thickness in the right upper lobe, but no abnormal findings involving the diaphragm. As air leakage lasted for 7 days, uniportal video-assisted thoracoscopic surgery was performed. Intraoperative findings revealed multiple perforations around the central tendon of the right diaphragm, through which the liver could be visualized. The area with multiple perforations was repaired by continuous suture using 2-0 polyglactin thread. Small bullae observed in a whitish pleural thickening area of the right upper lobe were resected. She was discharged on postoperative day 2 with an uneventful postoperative course, and hormonal therapy was continued after discharge. She has remained free of recurrence for 3 years since the operation.

A 79-year-old man with type 2 diabetes mellitus was hospitalized for COVID-19, interstitial pneumonia, and bacteremia (Klebsiella pneumoniae). Immediately after discharge from the hospital, he developed lumbar back pain, and close examination at our hospital revealed a middle mediastinal abscess around the descending aorta. He improved after one month of inpatient treatment with intravenous antibiotics. However, the abscess recurred two months later, and so the patient was again hospitalized and treated with intravenous antibiotics. After the second treatment, he received long-term oral antibiotics, but the abscess recurred again five months after discharge. The abscess was deemed refractory, so video-assisted thoracoscopic debridement and drainage of the posterior mediastinal abscess were then performed. Klebsiella pneumoniae was identified in the abscess, the same organism detected at the previous hospital. The patient was treated with antibiotics for 4 weeks postoperatively, and after 2 years, no recurrence has been observed and the patient is considered cured. Mediastinal abscesses can be refractory, as in this case, and surgical drainage should be considered.

Liposarcoma accounts for 16-18% of all malignant soft tissue tumors. Primary liposarcomas arising from the mediastinum are rare, and surgery is the first choice of treatment for these tumors. Herein, we present the case of a 50-year-old man whose routine chest radiograph revealed an abnormal lesion for which he was referred to our hospital. Computed tomography revealed a large tumor in the posterior mediastinum, and the bronchial arteries had enlarged feeding arteries. He was diagnosed with dedifferentiated liposarcoma via magnetic resonance imaging. A cancer board was held involving thoracic surgery, gastrointestinal surgery, cardiovascular surgery, and radiology. A thoracic endovascular aortic repair procedure was planned first to reduce the risk of bleeding during surgery and prevent injury in the case of tumor infiltration in the aorta. This intervention was followed by tumor resection 5 days later. The tumor was resected via bilateral thoracotomy. We resected the tumor with the esophagus because it invaded the tubular organ; however, the lungs were preserved. The pathological diagnosis confirmed dedifferentiated liposarcoma. Reconstruction with a gastric tube was performed on the 27^th postoperative day, and the patient was discharged on the 44^th postoperative day. Here, we report a case in which interdepartmental collaboration by multiple clinical departments was effective.

We encountered a case of hemoptysis due to pulmonary Mycobacterium avium complex that was difficult to control with bronchial artery embolization. A 57-year-old man came to our hospital with a chief complaint of massive hemoptysis. CT of the chest showed a 47-mm cavitary lesion in the upper lobe of the right lung and ground-glass opacities in the lower lobes of both lungs. Emergency bronchial artery embolization was performed to stop the bleeding, but it occurred again 4 hours later, and additional bronchial occlusion was performed to stop the bleeding. The patient underwent right upper lobectomy the next day for the risk of rebleeding, which was successfully performed without complications.

We report a case of severe chest wall muscular hemorrhage caused by acquired hemophilia A. The patient was a 74-year-old man. He was urgently hospitalized with a diagnosis of right secondary pneumothorax caused by emphysematous cyst and began chest drainage. Blood sampling at admission showed that PT was normal, but APTT was prolonged to 61.2 seconds. A large volume of air leakage persisted after the start of treatment, and we performed VATS bullectomy on the 8th day of hospitalization. On post-operative day (POD) 1, after we removed the drainage tube, a hematoma in the muscle layer of the chest wall appeared just below the removal wound. Blood transfusion and chest band compression were performed to control expansion of the hematoma. Blood tests detected decreased blood coagulation factor VIII activity and factor VIII inhibitor, and the patient was diagnosed with acquired hemophilia A. We subsequently started steroid treatment. Two weeks later, normalization of APTT and factor VIII activity was observed, and disappearance of the inhibitor was confirmed three weeks after the start of administration. Although acquired hemophilia A is a relatively rare disease, there are increasing reports of it being diagnosed as a result of post-operative bleeding complications, and there are cases in which the disease progresses to a fatal outcome. Since early diagnosis and therapeutic intervention affect the prognosis, it is a disease that surgeons should have knowledge of.