We analyzed the association between pathologic lymph node metastasis and clinicopathologic factors in cN0 non-small cell lung cancer (NSCLC). Two-hundred-and-thirteen patients with cN0 NSCLC who underwent lobectomy or pneumonectomy plus systematic mediastinal lymph node dissection (ND2a-2) between July 2015 and April 2020 were evaluated. Tumor location was classified into upper (right upper lobe/left upper segment), middle (middle lobe/lingula segment), S6, and basal (basal segment) based on the locus of origin. The proportions of patients with pN1 and pN2 were 10.8 and 8.1%, respectively, in those with a consolidation tumor ratio (CTR) of 1; they were 7.8 and 2.0%, respectively, in those with 0.5<CTR<1; all patients with 0≤CTR≤0.5 had pN0. The frequencies of pN2 by tumor location were 5.1, 5.0, 13.2 (positive pN2 in the 2a-2 region: 7.9), and 3.6% in the upper, middle, S6, and basal, respectively. Thus, NSCLC in the S6 location has a higher risk of pN2, especially in the 2a-2 region, than lesions of other locations.

A 79-year-old woman underwent resection of a gastrointestinal stromal tumor (GIST) in the rectum. Adjuvant chemotherapy with imatinib was administered for 1.5 years after surgery, and then stopped because of adverse events including nausea and anorexia (Grade 2). Computed tomography showed a 1.4-mm solitary pulmonary nodule in the right middle lobe at 4.5 years after the resection procedure, which gradually increased to 6.4 mm after 7 years. The patient was referred to our institution, as the nodule was suspected to be pulmonary malignancy. A partial resection of the lung was performed and histological examination results led to a diagnosis of pulmonary recurrence of GIST. Since imatinib therapy had adverse effects and was poorly tolerated, the patient was initially observed without any systemic therapy. At 4 months after the lung surgery, new sites of recurrence were found in the 11th rib and left ilium bone. Chemotherapy with imatinib at a reduced dose was administered, which allowed the patient to achieve stable disease. Findings in the present case indicate that even complete resection of a solitary pulmonary metastatic GIST may not achieve complete remission, and imatinib therapy should be considered.

A 68-year-old woman was referred for breast cancer 3 years ago. Preoperative MRI showed an anterior mediastinal cyst, which was suspected to be a thymic cyst. On follow-up, CT showed an enlarged cavity, thickened wall, and increased surrounding lipid density. We suspected infection of the cyst and planned surgery. As the cyst extensively compressed the left brachiocephalic vein, we considered a technique that would allow multidirectional manipulation as appropriate and performed robot-assisted surgery using a subxiphoid and bilateral thoracic approach. The cyst was safely dissected from the left brachiocephalic vein and resected without leakage of its contents. Pathological examination revealed inflammation and fibrosis in the cyst wall, and the diagnosis was thymic cyst. The postoperative course was uneventful, and she was doing well with no recurrence 6 months after the surgery.

Anterior mediastinal cysts are generally followed up without any treatment. In cases of inflammation, surgery is indicated and it is important to avoid mediastinitis and preserve the surrounding vital structures. In this case, a robot-assisted subxiphoid and bilateral thoracic approach contributed to surgical safety for a thymic cyst with suspected infection.

A 68-year-old man underwent a thoracoscopic lobectomy for right middle lobe lung cancer (pTis, Stage 0) at 64 years of age. Three years later, a partly solid nodule on the mediastinal side of the left upper lobe (S3) was detected. Due to progressive enlargement of the nodule (largest diameter: 22 mm, solid component diameter: 6 mm), primary lung cancer was suspected and thoracoscopic left upper segmentectomy was planned.

Preoperative three-dimensional computed tomography (3D-CT) revealed a displaced left upper division bronchus, with independent branching of the left lingular division bronchus. This finding was confirmed on bronchoscopic examination. Further, on 3D-CT, the pulmonary artery (PA) had an abnormal distribution, with A6 arising from the left main PA at the level of A3, with more proximal than normal anatomy. A6 shared a common trunk with A1+2b and A1+2c. The displaced upper division bronchus passed the dorsal side of the left main PA.

Intraoperative findings revealed hyperlobulated areas between the upper and lingular divisions. We carefully examined the anatomical relationship between the bronchus and PA based on preoperative CT, and finally, thoracoscopic left upper segmentectomy was successfully completed. Histological diagnosis of the tumor was adenocarcinoma (pT1mi, pStage IA1).

A 42 year-old-man was transferred to our emergency department with a chief complaint of chest pain. A chest radiograph showed opacity in the left lung field. Contrast-enhanced CT showed massive left hemothorax and dilatation of the left internal mammary artery (IMA) close to the old left costochondral fractures. Rupture of IMA pseudoaneurysm was suspected in this case. Left tube thoracostomy was perfomed. We removed approximately 800 mL of blood. Angiography revealed extravasation of contrast medium from the left IMA. Transcatheter arterial embolization (TAE) was performed. His vitals stabilized after TAE. He was discharged from the hospital 12 days after TAE with no particular problems. Two years later, he showed no signs of recurrence. Rupture of IMA pseudoaneurysm due to blunt trauma is rare. We describe a rare case of IMA pseudoaneurysm, which was probably caused by blunt chest trauma 6 years and 7 months ago. TAE was minimally invasive and useful for the rupture of IMA aneurysm.

Patients with lung metastasis from prostate cancer often show metastasis to other organs, or have multiple metastases; solitary metastasis is rare. PSA is known as a marker of prostate cancer; however, it is difficult to differentiate solitary lung metastasis in PSA-negative cases from primary lung cancer. The patient was a 72-year-old man. He was referred to the Department of Respiratory Medicine of our hospital because PET-CT showed abnormal uptake in a nodule of the right middle lobe of the lung. He underwent radical prostatectomy for prostate cancer 14 years ago, and since then, he has been followed up by examining PSA levels and 5-year diagnostic imaging, but no particular abnormality has been noted. The nodule increased after 1-year CT follow-up, and the patient was referred to our department for the purpose of surgery. Partial resection of the right middle lobe was performed, and intraoperative frozen sectioning revealed the pulmonary tumor to be adenocarcinoma. However, it was difficult to distinguish between primary lung cancer and lung metastasis from prostate cancer, so right middle lobe lobectomy and lymph node dissection were subsequently performed. Immunohistochemical analysis, which was negative for PSA staining but positive for NKX3.1, known as a prostatic tumor suppressor gene and highly specific for poorly differentiated prostate cancer and metastatic lesions, confirmed the pulmonary tumor as lung metastasis from prostate cancer.

Osteosarcoma often arises from the long bones in children and adolescents. Osteosarcoma of the rib is uncommon in the elderly, and primary osteosarcoma of the rib identified by hemothorax is even rarer. An 80-year-old man visited the referring hospital with the chief complaint of dyspnea on exertion. He was transferred to our hospital after chest drainage as a result of right hemothorax and identification of a chest wall tumor. Contrast-enhanced computed tomography of the chest showed a right hemothorax and 7.5-cm-enhanced chest wall tumor. The mass was located primarily in the 7th intercostal space and spread to both the intra- and extrathoracic regions. As gradual progression of anemia was noted, it was judged that there was persistent bleeding from the tumor. Emergency surgery for chest wall tumor resection was performed to control the bleeding. On pathological examination, the tumor was diagnosed as primary rib osteosarcoma. Because of his advanced age, postoperative chemotherapy was not conducted, and radiotherapy was carried out as additional treatment. One year after the procedure, no recurrence was noted. Although primary osteosarcoma of the rib is uncommon, it should be considered as one of the differentiating diagnoses of chest wall tumors.

We report a case of fissureless lobectomy in a lung cancer patient with situs inversus totalis. A 67-year-old woman with situs inversus totalis undergoing maintenance hemodialysis presented to the hospital with an aneurysm at her vascular access point, and she was incidentally identified to have a left upper lobe nodule on computed tomography (CT). After a full-body examination including bronchoscopy, she was diagnosed with a cT1aN0M0, cStage IA1, adenocarcinoma and surgery was performed. Surgery was started using a hybrid video-assisted thoracic surgery approach with small thoracotomy. Intraoperative findings showed that the left lung was divided into three lobes, but because of incomplete lung fissures, fissureless lobectonomy was performed. Although the anatomical location of the pulmonary arteriovenous system and bronchi was a mirror image, we were able to perform fissureless lobectomy of the left upper lobe in the same manner as a normal right upper lobectomy because we understood the anatomy from the preoperative 3-dimensional (3-D) CT. Even in patients with situs inversus totalis, fissureless lobectomy may be feasible with careful preoperative planning, including 3-D CT.

Mediastinal hemangiomas are relatively rare, accounting for 0.5% or less of all mediastinal tumors, and they are difficult to diagnose preoperatively. A 61-year-old female was referred to the Department of Cardiology of our hospital due to electrocardiogram abnormalities noted during a health examination. Coronary CT angiography incidentally revealed a nodule, 1.3 cm long, in the anterior mediastinum. We suspected it to be a thymoma because of the presence of enhancement on CT, and performed thoracoscopic surgery through the left pleural cavity. The tumor was dark-red and elastic-soft, and we resected it with part of the left lobe of the thymus. The tumor was diagnosed as a cavernous hemangioma histopathologically. Cavernous hemangioma should be considered as a differential diagnosis of a mediastinal tumor.

A 44-year-old man was referred to our hospital for the examination of an abnormality noted on a chest radiograph. Computed tomography and magnetic resonance imaging revealed two cystic lesions along the thoracic duct behind the distal aortic arch. We suspected them to be thoracic duct cysts, and performed a left thoracotomy. We accessed the cranial part of the thoracic duct between the left subclavian artery and esophagus, and the caudal part after mobilization of the descending aorta. Moving the descending aorta facilitated exposure of the esophagus from the left chest cavity, and we resected the lesions with thoracic duct. Chylothorax did not appear during the perioperative period. Although resection of a thoracic duct cyst requires appropriate dissection of the thoracic duct, the technique to approach the thoracic duct from the left thoracic cavity has not been established. We report an effective and safe method to resect a thoracic duct cyst from the left thoracic cavity.

We report the case of a 44-year-old man who developed renal infarction possibly secondary to a thrombus in the pulmonary vein stump, following robot-assisted left upper lung lobectomy with systematic lymph node dissection for primary lung cancer. The patient developed fever and abdominal pain 2 days postoperatively, and laboratory investigations showed an elevated white blood cell count and increased serum lactate dehydrogenase, aspartate transaminase, and alanine transaminase levels and a decreased renal function. Contrast-enhanced computed tomography (CECT) confirmed a diagnosis of right renal infarction. The patient had no history of atrial fibrillation, no preoperative coagulation abnormalities, and no echocardiographic abnormalities at symptom onset. Postoperative thrombosis of the left upper pulmonary vein stump was considered to be the most likely etiology. Anticoagulant therapy was initiated promptly, and the renal function improved. Renal infarction should be considered as a differential diagnosis and urgent CECT is warranted in patients with symptoms characteristic of renal infarction or in those with blood abnormalities observed after left upper lobectomy. The involvement of a thrombus in the pulmonary vein stump cannot be ruled out even in the absence of a thrombus on CECT.

Automatic suture devices are generally used intraoperatively for safe closures and tissue cuts. Herein, we report a case of postoperative bleeding following injury to the descending aorta adventitia caused by the protrusion of a staple after wedge resection of the lung. A 63-year-old female with metastatic lung cancer underwent wedge resection of the left lower lobe by thoracoscopic surgery. The drain was removed on the first postoperative day, and the patient was discharged on the second postoperative day. Four days following surgery, she experienced dyspnea and was immediately transported to the hospital. We suspected postoperative bleeding, and an emergency operation was performed. There were massive hematomas in the left intrapleural region. Searching for the active bleeding point, we found an area of coagulation at the descending aorta adventitia. These findings suggested that the protruding staple scratched the aorta during respiration, causing aortic injury. Reports of complications caused by the staples used for automatic suture devices have been published; however, to our knowledge, there has been no report of associated aortic injury. In the case that a staple is in contact with a large vessel during wedge resection of the lung, covering the staple with artificial material or a fat-pad should be considered.

A woman in her twenties was referred to our hospital with a bronchial tumor of approximately 2 cm in diameter, found in the lower lobe of her right lung. Surgery was performed after a bronchoscopic biopsy revealed a typical carcinoid tumor. During the surgery, the tumor location was confirmed by bronchoscopy, and an incision was made at the proximal site of the lower-lobe bronchus. The tumor base was located in the superior segmental bronchus of the lower lobe of the lung, following which the tumor was completely resected by deep wedge broncho-plastic superior segmentectomy. Postoperatively, the middle and basal segmental bronchi remained intact, and the patient did not suffer any complications or recurrence. Therefore, deep wedge broncho-plastic segmentectomy may be a useful option for treating typical bronchial carcinoid tumors, as it preserves the lung function as much as possible while allowing for radical resection.

We report a case of long-term survival even though the patient had skip metastasis after intraoperative removal of an enlarged #3a lymph node from combined large cell neuroendocrine carcinoma. We present the case of a 45-year-old man who underwent video-assisted right upper lobectomy with mediastinal lymph node dissection. Intraoperatively, an enlarged lymph node with anthracosis was found anterior to the superior vena cava and additionally removed. Pathological examination revealed that the patient had combined large cell neuroendocrine cancer which metastasized to the enlarged lymph node. Thus, the staging was determined as pT2a (pl1) N2M0. The patient survived without recurrence for 5 years and 7 months after surgery followed by adjuvant chemotherapy. Some patients may have skip metastasis outside the extent of lymph node dissection, so it is important to observe the thoracic cavity and resect the lymph node.

Dissection and ligation of pulmonary artery branches are the most dangerous procedures during robot-assisted left upper lobectomy. With general port placement centered on the eighth intercostal space, the participation of an assistant is necessary because the retraction arm interferes with other instruments when dissecting the pulmonary artery. By moving the retraction and scope using the port hopping technique, introduced in da Vinci Xi^®, the operator can freely retract the left upper lobe and perform safe dissection.

The port hopping technique is straight-forward, and we think it should be actively performed in robot-assisted left upper lobectomy.