Kichizo Kaga

Although the routine use of immunohistochemistry has improved the accuracy of histopathologic diagnosis in clinical practice, new methods for discovering novel diagnostic markers are still needed. We sought new diagnostic markers for malignant pleural mesothelioma (MPM) using a reverse translational approach with limited archival tissues from a very rare case. Total RNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues of a synchronous collision tumor consisting of MPM and pulmonary adenocarcinoma (PAC) was employed for gene expression profiling (GEP) analysis. Among the 54 genes selected by GEP analysis, we finally identified the following two candidate MPM marker genes: PHGDH and TRIM29. Immunohistochemical analysis of 48 MM and 20 PAC cases showed that both PHGDH and TRIM29 had sensitivity and specificity almost equivalent to those of calretinin (sensitivity 50% and 46% vs. 63%, and specificity 95% and 100% vs. 100%, respectively). Importantly, of the 23 epithelioid MMs, all 3 calretinin-negative cases were positive for TRIM29. These two markers may be diagnostically useful for immunohistochemical distinction between MPMs and PACs. This successful reverse translational approach based on FFPE samples from one very rare case encourages the further use of such samples for the development of novel diagnostic markers.

This study aimed to determine the usefulness and limitations of videoassisted thoracoscopic (VATS) lobectomy using one-window and puncture method (1WPM). This study involved 14 patients who underwent lobectomy using the 1WPM at our institute from 2008 to 2017. The study patients comprised of 3 men and 11 women with a median age of 10.5 years (range, 0-72 years). There were eight cases in children younger than 18 years old and the youngest patient was 9 days old. The diagnoses were congenital pulmonary cystic disease (n = 7), primary lung cancer (n = 4), metastatic lung tumor (n = 1), and others (n = 2). The 1WPM was successful in 9 of 14 patients (64.3%) and, in 5 cases (35.7%), needed conversion to either two-window method (TWM) using additional port (n = 3) or open thoracotomy (n = 2). The causes for conversion were need for additional bronchoplasty or lymph node dissection (n = 3), failure of one-lung ventilation (n = 1), and presence of a small thoracic cavity that made the procedure extremely difficult (n = 1). In the group that was successfully treated with 1WPM, the median values were as follows: operation time, 193 min (range, 112-480 min); blood loss, 0 ml (range, 0-90 ml); drainage duration, 1 day (range, 1-4 days); and postoperative hospital stay, 7 days (range, 4-13 days). Lobectomy by 1WPM can be safely performed and has good postoperative course and this procedure can be applicable and effective in small infants.

Since a displaced bronchus related to the left upper lobe is an uncommon anatomical anomaly, it has a risk of being accidentally resected during left upper lobe resection unless they are identified preoperatively. A case of video-assisted thoracic surgery (VATS) segmentectomy that was safely performed under preoperative identification of a displaced subsegmental bronchus and anomalous pulmonary vessels is presented. A 48-year-old woman visited our hospital because of an abnormal shadow on a radiograph on a health check. The chest computed tomography (CT) showed a multicystic mass with a diameter of 35 mm on dorsal interlobar parenchyma between the S1+2 and S6 segments in the left lung. The three-dimensional (3D) CT with multiplanar reconstruction showed that B1+2b+c passed to the dorsal side of the left main pulmonary artery (PA), which was considered a displaced bronchus. The branch of A6 arose from the left main PA at the level of the branches of A3 and A1+2, more proximal than the normal anatomy, and passed to the dorsal side of a displaced B1+2b+c. The branch of V1+2 passed between B6 and the bronchus to the basal segment and joined V6 at the dorsal side of the pulmonary hilum. Intraoperative findings of the anatomy of the bronchi and pulmonary vessels were exactly the same as the preoperative 3D CT findings, so segmentectomy of S1+2b+c and S6 by VATS was performed safely. Then there were accessory fissures between S1+2 and S3 and between S6 and the basal segment. The pathological diagnosis was a left lung abscess. A preoperative 3D CT may be helpful for identifying anatomical anomalies. An anatomical anomaly should be suspected if accessory fissure is found during surgery.

Pulmonary arteriovenous malformations (PAVMs) can be associated with life-threatening complications such as paradoxical embolization, cerebral abscess, and hemothorax. Therefore, all adults with PAVMs should be offered treatment. Percutaneous transcatheter embolization is the first-line treatment, but 5–25% of cases require further treatment due to persistence after embolization. Recently, the role of minimally invasive thoracic surgery as a definitive treatment has been evaluated. We describe a case of a small peripheral PAVM causing hemothorax, which was safely treated with video-assisted thoracoscopic surgery (VATS). In our case, the PAVM appeared to protrude into the pleural cavity on chest computed tomography (CT), perhaps explaining why it led to a hemothorax. A 64-year-old man with a history of a brain abscess, for which he underwent surgery 6 months previously, developed a left-sided hemothorax. He had experienced recurrent epistaxis and received anticoagulation therapy for chronic atrial fibrillation. Chest CT after drainage revealed a solitary 15-mm nodule in the periphery of the left lower lobe, and identification of a feeding artery and draining vein on three-dimensional CT suggested that the node was a PAVM. The PAVM was adjacent to the diaphragm and multi-detector CT (MDCT) and three-dimensional CT (3DCT) showed that the nodule slightly displaced the diaphragm and protruded into the pleural cavity. After discussion in a multidisciplinary conference, it was decided that surgical treatment would be preferable to catheter embolization. The patient underwent VATS with three ports, the largest of which was 15 mm. The PAVM protruded from the peripheral lung like a polyp, and wedge resection was performed after simple adhesiolysis. There were no complications, and the patient is asymptomatic after 1-year of follow-up. As in the present case, PAVMs protruding into the pleural cavity can cause hemothorax, and surgical wedge resection of the involved lung as a definitive treatment is feasible and possibly safer than catheter embolization, particularly if the PAVM is localized close to the visceral pleura. Protrusion into the pleural cavity (polypoid appearance) was detected using MDCT and 3DCT preoperatively.

Although asbestos acts as a potent carcinogen in pleural mesothelial and pulmonary epithelial cells, it still remains unclear whether asbestos causes specific and characteristic gene alterations in these different kinds of target cells, because direct comparison in an identical patient is not feasible. We experienced a rare synchronous collision tumor composed of malignant pleural mesothelioma (MPM) and primary pulmonary adenocarcinoma (PAC) in a 77-year-old man with a history of long-term smoking and asbestos exposure, and compared the DNA copy number alteration (CNA) and somatic mutation in these two independent tumors. Formalin-fixed paraffin-embedded (FFPE) tissues of MPM and PAC lesions from the surgically resected specimen were used. Each of these MPM and PAC lesions exhibited a typical histology and immunophenotype. CNA analysis using SNP array was performed using the Illumina Human Omni Express-12_FFPE (Illumina, San Diego, CA, USA) with DNA extracts from each lesion. Somatic mutation analysis using next-generation sequencing was performed using the TruSeq Amplicon Cancer Panel (Illumina). The CNA analysis demonstrated a marked difference in the frequency of gain and loss between MPM and PAC. In PAC, copy number (CN) gain was detected more frequently and widely than CN loss, whereas in MPM there was no such obvious difference. PAC did not harbor CNAs that have been identified in asbestos-associated lung cancer, but did harbor some of the CNAs associated with smoking. MPM exhibited CN loss at 9p21.2-3, which is the most common genetic alteration in mesothelioma. In this particular case, asbestos exposure may not have played a primary role in PAC carcinogenesis, but cigarette smoking may have contributed more to the occurrence of CN gains in PAC. This comparative genetic analysis of two different lesions with same amount of asbestos exposure and cigarette smoke exposure has provided information on differences in the cancer genome related to carcinogenesis.

We previously reported that arterial infarction of vital organs after lobectomy might occur only after left upper lobectomy and be caused by thrombosis in the left superior pulmonary vein stump. We hypothesized that changes in blood flow, such as blood stasis and disturbed stagnant flow, in the left superior pulmonary vein stump cause thrombosis, and this was evaluated by intraoperative ultrasonography. From July 2013 to April 2014, 24 patients underwent lobectomy in the Steel Memorial Muroran Hospital. During the procedure, an ultrasound probe was placed at the pulmonary vein stump and the velocity in the stump was recorded with pulse Doppler mode. The peak velocity and the presence of spontaneous echo contrast in the stump were evaluated. After the operation, the patients underwent contrast-enhanced CT within 3 months. The operative procedures were seven left upper lobectomies, four left lower lobectomies, seven right upper lobectomies, and six right lower lobectomies. Blood flow was significantly slower in the left superior pulmonary vein stump than in the right pulmonary vein stumps. However, that was not significantly slower than that in the left inferior pulmonary vein stump. Spontaneous echo contrast in the pulmonary vein stump was seen in three patients who underwent left upper lobectomy. Of the three patients with spontaneous echo contrast, two patients developed thrombosis in the left superior vein stump within 3 months after the operation. There was no patient who developed arterial infarction. In patients who underwent left upper lobectomy, intraoperative ultrasonography to evaluate blood flow and the presence of spontaneous echo contrast in the left superior pulmonary vein stump may be useful to predict thrombosis that may cause arterial infarction.

The O-arm is an intraoperative imaging device that can provide computed tomography images. Surgery for small lung tumors was performed based on intraoperative computed tomography images obtained using the O-arm. This study evaluated the usefulness of the O-arm in thoracic surgery. From July 2013 to November 2013, 10 patients with small lung nodules or ground glass nodules underwent video-assisted thoracoscopic surgery using the O-arm. A needle was placed on the visceral pleura near the nodules. After the lung was re-expanded, intraoperative computed tomography was performed using the O-arm. Then, the positional relationship between the needle marking and the tumor was recognized based on the intraoperative computed tomography images, and lung resection was performed. In 9 patients, the tumor could be seen on intraoperative computed tomography images using the O-arm. In 1 patient with a ground glass nodule, the lesion could not be seen, but its location could be inferred by comparison between preoperative and intraoperative computed tomography images. In only 1 patient with a ground glass nodule, a pathological complete resection was not performed. There were no complications related to the use of the O-arm. The O-arm may be an additional tool to facilitate intraoperative localization and surgical resection of non-palpable lung lesions.

Thrombosis in the left upper pulmonary vein stump after left upper lobectomy is a very rare but important complication because it occurs in the systemic circulation system. We previously made the first ever report on the frequency and risk factors of thrombosis in the pulmonary vein stump after lobectomy. In this study, we conducted an investigation in a different hospital to determine whether this was a common complication. From 2008 to 2012, 151 patients who underwent lobectomy and following enhanced CT within 2 years after the operation were studied. Postoperative contrast-enhanced CT imaging was retrospectively checked. We found thrombosis in the pulmonary vein stump in 5 of the 151 patients (3.3%). All 5 patients underwent left upper lobectomy (17.9% of the patients who underwent left upper lobectomy). These 5 patients did not have infarction of any vital organ. The thrombus was disappeared several months later on contrast-enhanced CT in 3 patients and followed in 2 patients. On univariate analysis, there was a significant difference only in the operative procedure (p < 0.001). Thrombosis in the pulmonary vein stump occurred with high frequency in patients who underwent left upper lobectomy. Because the frequency of thrombosis in this study was the same as in our previous report, this might be a common complication.