Background: Epipericardial fat necrosis (EFN) is a rare benign disorder where the epipericardial fat pad develops necrotic change without any clear cause. The etiology is unknown.

Case: A 65-year-old male presented with chest pain. Chest computed tomography showed a 6-cm mass in the anterior mediastinum. He showed strong signs of inflammation based on a blood test. Chest magnetic resonance imaging revealed that the mass was well-capsulated, containing fat tissue with edematous change and accompanied with inflammatory changes in the surrounding structures. In a previous CT performed 5 years ago, there was no abnormality in the anterior mediastinum. He underwent surgery to confirm the diagnosis as malignancy could not be excluded. The mass was strongly adhesive to the right lung and pericardium, which were partially resected together. Conversion from a thoracoscopic to open approach was necessary because of these strong adhesions. There were no complications. The patient was discharged on the 10^th day after surgery. Chest pain and serum inflammatory signs resolved postoperatively. Microscopically, the mass consisted of fat tissue with necrotic change. In combination with the clinical course, the mass was diagnosed as epipericardial fat necrosis.

Conclusion: We report the case of a rare disease, epipericardial fat necrosis, involving a patient presenting with chest pain.

Case 1: The patient was a male patient aged 70 years old who had been observed for benign pleural effusion associated with asbestos exposure for 3 years. After a sudden increase in pleural effusion was observed, chest drainage was started in the internal medicine department; however, pleural effusion persisted. Surgery was performed due to antibiotic resistance. We performed pruritus as well as small thoracotomy. High-pressure lavage with pulse lavage irrigation involving 10 L of saline was performed at the end of the operation. The drain was removed on the 11th postoperative day and the patient was discharged on the 16th postoperative day.

Case 2: The patient was a male patient aged 74 years old who had a history of surgery for right-sided breast cancer. Two years previously, he developed right-sided cancer pleurisy and was treated with chemotherapy. Surgery was subsequently performed as the patient developed empyema. Thoracoscopic surgery was performed to remove as much of the pleural cavity as possible, and high-pressure irrigation using pulse lavage irrigation with 8 L of saline was performed at the end of the operation. The drain was removed on the second postoperative day and the patient was discharged on the seventh postoperative day. Both cases had chronic pleural effusion and the dead space did not resolve completely; however, it was possible to successfully treat the patients by performing pruritus to treat the empyema followed by high-pressure lavage with a pulse lavage system. If a dead space remains, reheating of the empyema may be a concern; however, as in the present cases, empyema can be cured by achieving a state that is as sterile as possible at the time of surgery using high-pressure cleaning with pruritus and a pulse cleaning device. We report two cases of successful pulse lavage system application for acute empyema and discuss the relevant literature.

Schwannoma is a benign tumor that often occurs in the posterior mediastinum and arises from the sympathetic or intercostal nerve. The majority of cases are not symptomatic, and an operation is performed without a pathological diagnosis. Case: A 69-year-old woman complaining of a chronic cough underwent computed tomography (CT) for the inspection of a gastric submucosal tumor (SMT). Incidentally, it showed a cyctic tumor on the dorsal side of the left main bronchus, surrounded by the descending aorta and esophagus. We conducted endoscopic ultrasound fine needle aspiration (EUS-FNA) and diagnosed it as a schwannoma pathologically. The nodule affected the bronchial wall, and so was a suspected cause of coughing. We removed the tumor by thoracoscopic surgery, and it was revealed that it originated from the vagus nerve. It is difficult to diagnose a middle mediastinal tumor preoperatively because it could be close to critical organs and vessels. Although needle biopsy involves a risk of bleeding, we could make a preoperative diagnosis. We encountered the rare case of a symptomatic middle mediastinum schwannoma that originated from the vagus nerve.

A 33-year-old man who had undergone a bullectomy for spontaneous pneumothorax two years before was referred to our hospital because of an abnormal chest radiograph shadow. Chest CT revealed a right chest wall tumor located at the site of the previous operative wound. The tumor was resected en bloc together with part of the 4^th and 5^th ribs and intercostal muscle. The defect of the chest wall was reconstructed using artificial material. The tumor was diagnosed pathologically as a desmoid tumor that showed the proliferation of spindle-shaped cells and invaded the ribs and intercostal muscle. The tumor was completely resected with a sufficient margin. No evidence of recurrence has been noted for 12 years since the operation. Primary chest wall desmoid tumors are rare, but should be considered for differential diagnosis if a tumor develops at the site of a previous operative wound.

The diagnosis of tracheal carcinoma is likely delayed due to the lack of early symptoms, and complete tumor resection rates remain low. We report a tracheal carcinoma patient who underwent neoadjuvant chemoradiotherapy followed by tracheal resection and reconstruction. A 47-year-old man with hemosputum was diagnosed with primary tracheal squamous cell carcinoma. The tumor was 6 cm long (nine cartilaginous rings), and esophageal invasion and metastasis to the right para-tracheal lymph node were suspected. He received chemotherapy consisting of Cisplatin-Vinorelbine with concurrent radiotherapy (50-Gy in 25 fractions). Although staging after the induction therapy revealed partial regression of the tumor and lymph node, re-biopsy of transtracheal mucosa indicated residual malignant cells. To achieve local control, we performed tracheal resection and reconstruction with an omentoplasty at anastomosis. He was discharged without any problems with anastomosis and has remained free from recurrence for 13 months. There is a risk associated with chemoradiotherapy followed by tracheal resection and reconstruction, but it can be safe and effective with careful case selection and surgery.

An 81-year-old woman had hemoptysis in 2009. Chest computed tomography (CT) showed a huge mass with partial calcification in the left chest. Mycobacterium tuberculosis was identified in her sputum culture. She was treated with chemotherapy for 6 months. Sputum culture changed to negative, and the symptoms improved. In 2012, chronic expanding hematoma (CEH) was diagnosed by CT with enlargement of the mass; however, she had no symptoms and desired observation. In 2014, she was admitted with complaints of hemosputum and dyspnea. She underwent left pleuropneumonectomy (EPP) for CEH due to its growth and worsening of the clinical symptoms. The postoperative course was satisfactory and she is now in good health without recurrence of CEH. It is very important to minimize the direct approach to the capsule of hematoma to reduce the risk of hemorrhage and recurrence. EPP may be an appropriate surgical procedure for CEH like in this case when improvement of the compressed lung cannot be expected.

A 64-year-old man visited our hospital with a chief complaint of bloody sputum. Chest computed tomography (CT) revealed a solid nodule in S6 of the left lower lobe. FDG-PET showed an accumulation (SUVmax: 1.7) around the nodule shadow. Although bronchoscopy was performed, we could not make a definitive histological or bacteriological diagnosis. Follow-up examination revealed that CYFRA21-1 levels were continuing to rise (max: 12.0 ng/mL) with a gradually swelling nodule on chest CT. Based on a suspected diagnosis of lung cancer, segmentectomy (S6) was performed, and the subsequent diagnosis based on the nodule was pulmonary actinomycosis. The CYFRA21-1 level decreased to normal after resection of the lesion, followed by antibiotic therapy. This suggests that the CYFRA21-1 level might reflect the disease activity of pulmonary actinomycosis. Pulmonary actinomycosis is clinically difficult to distinguish from lung cancer. Surgical resection may thus be useful both diagnostically and therapeutically.

A man in his 50s was admitted to our department due to a pulmonary nodule and mediastinal mass noted on CT. The patient had undergone left nephrectomy and kidney transplantation for chronic renal failure and was diagnosed with renal cell carcinoma based on an examination of the isolated kidney 13 years ago. During follow-up, computed tomography showed a solitary nodular shadow in the upper left lung along with a mass that gradually increased in size in the right mediastinum, so the case was referred to our department. Thoracoscopic resection of the mediastinal tumor was performed with a right-hand approach. Clear cell carcinoma and mediastinal lymph node metastasis of renal cell carcinoma were diagnosed. Two-stage thoracoscopic left upper segment resection was performed for the left upper lung nodule, and the patient was diagnosed with metastatic renal cancer. One year after surgery, no recurrence was noted. Hematogenous metastasis is the most frequent form of metastasis in renal cell carcinoma, but the prognosis is still unknown in cases of resection of lung and contralateral isolated mediastinal lymph node metastases. It may be possible to improve the prognosis by completely resecting isolated lesions with different metastatic routes.

Sclerosing pneumocytoma is a rare tumor, accounting for approximately 1% of all lung tumors. It is difficult to preoperatively diagnose because the histological features of sclerosing pneumocytoma vary. A 48-year-old woman with familial adenomatous polyposis was referred to our hospital for an abnormal shadow. Chest computed tomography showed a solitary nodule with intrabronchial extension occupying the superior segment of the left lower lobe. Bronchoscopy showed a tumor that extended into the superior segmental bronchus, and it was suspected to be lung adenocarcinoma by transbronchial biopsy. She underwent left lower lobectomy and lymph node dissection under thoracoscopy. Histochemical and immunohistochemical investigations confirmed the resected tumor to be sclerosing pneumocytoma. We report a surgical case of sclerosing pneumocytoma with intrabronchial extension, which was suspected to be lung adenocarcinoma.

A 69-year-old man presented to our hospital with a chest nodule that was incidentally detected on computed tomography. The patient was pathologically diagnosed with lung cancer by transbronchial lung biopsy. The patient had a history of esophageal cancer treatment by chemoradiation therapy using proton-beam irradiation followed by salvage esophagectomy. Since the radiation field covered not only the mediastinum but also the left hilar pulmonary vessels and bronchus, and the patient showed malnourishment (BMI=15.6 kg/m2) and diabetes mellitus, the high risk of a bronchopleural fistula was considered in addition to the complication of severe fibrosis. Therefore, left upper division segmentectomy was selected as the operative method. The procedure was completed successfully with appropriate care, such as taping the left pulmonary artery trunk before resection of vessels, and covering the bronchial stump with a pedicled latissimus dorsi muscle flap. The postoperative course was excellent, and no relapse of lung cancer was detected for a year after surgery.

A 46-year-old Japanese woman, who had stayed in South America for a long time, presented with an abnormal shadow on a medical checkup. Chest computed tomography (CT) showed a nodule of 20 mm in diameter in the right lower lung. CT-guided lung biopsy revealed a non-malignant nodule. Moreover, infections, such as nontuberculous mycobacteriosis and mycosis, were not observed. The patient was expecting to receive medical treatment upon returning to Japan. Thus, she visited her previous hospital and underwent endobronchial ultrasonic-guided transbronchial needle aspiration for the pulmonary nodule. Results revealed an inflammatory granuloma with coagulation necrosis. Because the diagnosis of a malignant tumor had not been ruled out, she was admitted to our hospital for surgical resection. For diagnosis and treatment, lung wedge resection was performed under video-assisted thoracic surgery. Pathological findings revealed that the lesion was a non-neoplastic mass: an epithelioid cell granuloma with coagulation necrosis. The mycobacterium smear was negative. However, the Grocott smear revealed several round or oval mycotic bodies, such as yeast, in the lesion. After surgery, based on serum examination, the patient tested positive for anti-histoplasma antibody, and she was finally diagnosed with pulmonary histoplasmosis. Because the patient had a normal immune response and did not present with symptoms, she did not receive adjuvant antifungal drug therapy in accordance with the Infectious Diseases Society of America guideline. The postoperative course was uneventful. At 20 months after surgery, there had been no relapse. Our case report reveals that pulmonary histoplasmosis is difficult to differentiate from lung cancer.

The patient was a 73-year-old woman with general malaise. Laboratory examination revealed elevated immunoglobulin and interleukin-6 levels.

Computed tomography (CT) of the chest revealed multiple lymphadenopathy of the right supraclavicular and mediastinal regions. We suspected multicentric Castleman's disease and initiated treatment with corticosteroid therapy, but the steroid therapy was ineffective. The patient subsequently underwent resection of the largest of the upper mediastinal lymph nodes via video-assisted thoracoscopic surgery for diagnosis and disease activity control. Postoperatively, her symptoms and signs resolved. Histopathological findings showed vascularity and follicular dendritic cell prominence of the germinal centers. The expanded mantle zones consisted of concentric rings of lymphocytes with an "onion skin" appearance. These findings were characteristic of the features of the hyaline-vascular type. Other histopathological findings included polytypic plasmacytosis in the interfollicular space, being more typical of the plasma-cell type.

Therefore, the patient was diagnosed with mixed-type multicentric Castleman's disease. Symptomatic treatment with medications is the standard therapy for multicentric Castleman's disease. If medications are ineffective, resection of the most enlarged lymph nodes should be considered as part of the treatment protocol.

Paragangliomas typically arise from the paraganglionic system, and are rarely observed in the middle mediastinum. Here, we report the case of a patient with a paraganglioma located in the middle mediastinum. A 46-year-old woman was found to have an abnormal mass on chest computed tomography (CT). The mass displayed a contrast effect in the middle mediastinum. From the findings on chest CT and magnetic resonance imaging (MRI), we suspected the mass to be a paraganglioma and performed iodine-123-labeled meta-iodobenzylguanidine (123I-MIBG) scintigraphy, which revealed high accumulation in the mass. Therefore, the middle mediastinal tumor was resected by median sternotomy. The tumor was surrounded by the superior vena cava, ascending aorta, and right pulmonary artery. The tumor also had many blood vessels flowing from the aortic arch and coronary arteries, and these vessels were ligated at the time of tumor resection. The histological diagnosis of the lesion was paraganglioma. The patient has been doing well and was free from recurrence 18 months after surgery. Although a paraganglioma in the middle mediastinum is rare, it can be readily diagnosed by accurate preoperative examination.

We report the case of a very rare right mediastinal basal pulmonary artery (A7). A 61-year-old man was diagnosed with primary lung cancer in the right lower lobe (adenocarcinoma, cT2bN0M0 Stage IIA). Preoperative 3D-CT revealed a right aberrant A7 branching off directly from the right main pulmonary artery and passing down over the posterior surface of the pericardium, medially apart from the bronchus intermedius, into the right lower lobe. The patient underwent video-assisted right lower lobectomy with systematic lymphadenectomy. We identified and divided the aberrant pulmonary artery safely; that is, our knowledge of its existence in advance by 3D-CT probably prevented accidental bleeding during the surgery.

Here, we report a rare case of hibernoma (brown fat tumor) arising from the right chest wall. A 49-year-old asymptomatic woman was pointed out as showing a mass lesion in the right thoracic wall in a routine follow-up study after surgical and endocrine therapy for right breast cancer. Since this pleural-based, non-invasive mass had grown rapidly over a period of three months, differential diagnosis to rule out malignant neoplasias was required. We performed thoracoscopic marginal resection for diagnosis and treatment. Histopathologically, the tumor consisted of an intermixture of multivacuolated cells with granular eosinophilic cytoplasm and mature adipocytes with large single vacuoles.

A 66-year-old woman with hemosputum was pointed out as having a cavitation in the left upper lobe on chest CT. Since Aspergillus was isolated from bronchial lavage, antifungal drugs were administered for one year, with no improvement of the cavitation. Then, transbronchial lung biopsy was performed again and the histology suggested pulmonary MALT (mucosa-associated lymphoid tissue) lymphoma. Surgery was performed for definitive diagnosis, and the final diagnosis confirmed pulmonary MALT lymphoma. Although pulmonary MALT lymphoma radiologically presents with various forms of shadow, there are rare reports of MALT lymphoma presenting with cavitation. Additionally, when a patient's condition does not improve with antifungal drugs against pulmonary aspergillosis in cases such as the present patient, we should consider the possibility of coexisting malignant tumors.

Pulmonary artery reconstruction has become acceptable in radical pulmonary resection for locally advanced lung cancer to preserve the pulmonary parenchyma, and should be performed to spare large lingular branches arising from the distal to superior segmental branches of the left lower lobe during left lower lobectomy. A 69-year-old woman who underwent left S⁶ segmentectomy for pulmonary metastasis of rectal cancer 4 years previously with stump recurrence (2.2 × 1.4 cm) of the left lower lobe adjacent to the left pulmonary artery was admitted for surgery. Chest computed tomography revealed an interlobar lingular artery type with both superior and inferior lingular arteries arising from the left interlobar pulmonary artery. Posterolateral left thoracotomy was performed. The lung strongly adhered to the chest wall throughout the thoracic cavity and aorta. Therefore, adhesiolysis was performed first. The inferior pulmonary vein and left lower bronchus were stapled before dissection of the pulmonary artery. The left pulmonary artery could not be separated from the tumor because the adhesions were strong and extensive. The pulmonary artery was isolated and clamped after an intravenous injection of heparin sodium. The adhered pulmonary artery was resected en bloc with the left lower lobe. The wall flap was flipped and tailored to the defect and then sutured with nonabsorbable monofilament material. We present a patient who successfully underwent pulmonary artery reconstruction using a common basal artery wall flap to preserve lingular branches during completion left lower lobectomy.

We herein report a rare case of completion pneumonectomy involving a patient who developed relapse in the ipsilateral residual lung after surgery for pulmonary aspergillosis and whose recurrent lesion caused contralateral pneumonia as the infection source. A 64-year-old man who had undergone left upper lobectomy+left S6 segmentectomy for pulmonary aspergillosis 9 years previously visited our hospital because of cough, sputum production, appetite loss, and body weight loss. Chest computed tomography revealed right-sided pneumonia and a left pulmonary abscess. He was admitted to the hospital and treated with antibiotics and an antifungal agent. His right pneumonia improved, but the left pulmonary abscess did not; therefore, we performed left completion pneumonectomy. His postoperative clinical course was uneventful, and he was discharged from our hospital on postoperative day 30. Histopathological examination revealed that the lesion had been caused by Aspergillus infection. He remained well with no evidence of recurrence for 8 years postoperatively.