A comparative study of robot-assisted thoracoscopic surgery and conventional approaches for short-term outcomes of anatomical segmentectomy

OBJECTIVES

Since anatomical segmentectomy requires meticulous dissection of the segmental pulmonary vessels and bronchus, robot-assisted thoracoscopic surgery (RATS) has been widely adopted in recent years. We investigated the usefulness of RATS segmentectomy by comparing perioperative outcomes with conventional approaches including open thoracotomy or video-assisted thoracoscopic surgery (VATS). We compared perioperative outcomes of segmentectomy between RATS and conventional approaches including open thoracotomy or video-assisted thoracoscopic surgery (VATS).

METHODS

This single-institutional retrospective study comprised 231 patients with primary lung cancer who underwent segmentectomy by RATS or conventional approaches between January 2011 and December 2022. Surgical outcomes and postoperative complications were analyzed among patients whose background factors were adjusted by propensity score matching (PSM).

RESULTS

Before PSM, there were significant differences in age, smoking status, and types of segmentectomy. After PSM, 126 patients (63 patients in each group) were included in this analysis. The RATS group had significantly shorter operative time (154 vs 210 min; p < 0.01), fewer bleeding amounts (10 vs 40 mL; p < 0.01), and shorter duration of chest drainage (2 vs 2 days; p = 0.04) than the conventional-approach group. There was no significant difference in the incidence of all complications; however, the incidence of postoperative pneumonia was significantly lower than in the conventional-approach group (p = 0.02).

CONCLUSIONS

RATS segmentectomy is proposed to be useful. It was suggested that RATS segmentectomy may be useful with better perioperative results than the conventional approach. Further studies on oncological long-term outcomes and cost-benefit comparisons are needed.

Typical carcinoid in right middle lobe of pulmonary hypoplasia

BACKGROUND

Pulmonary typical carcinoid occurring in hypoplasia of the right middle lobe is very rare.

CASE PRESENTATION

A routine examination's chest X-ray revealed an abnormal shadow in the right middle lung field of an 82-year-old Japanese woman. A chest computed tomography scan showed a solid 2.5 × 2.0-cm nodule in the very small right middle lobe. A trans-bronchial lung biopsy of the mass in the right middle lobe was performed; it revealed atypical cells with round nuclei growing in multiple foci, and immunostaining was positive for chromogranin A, synaptophysin and CD56, suggesting pulmonary carcinoid. The preoperative clinical diagnosis of primary lung cancer, cT1cN0M0 stage IA3 was considered. A right middle lobectomy and mediastinal lymph node dissection were performed by video-assisted thoracic surgery. Intraoperatively, the middle lobe of the right lung was very small, with 1- to 2-mm-dia. pulmonary arteries and veins that were considered hypoplastic. The final histopathological diagnosis was typical carcinoid, pT2aN0M0 stage IB based on the presence of pleural invasion.

CONCLUSIONS

Including the present patient, only nine cases of lung cancer occurring within pulmonary hypoplasia have been reported, most of which were typical carcinoid.

Dynamic transition of molecular subtypes in relapsed small cell lung cancer treated with multimodal therapy: A case report

Several transcription factors in small cell lung cancer (SCLC), including achaete-scute homolog 1 (ASCL1) and neurogenic differentiation factor 1 (NEUROD1), contribute to rapid tumor growth and early metastatic dissemination. Recent studies suggested that these molecular subtypes represent neuroendocrine differentiation in dynamic SCLC evolution. In the present case, a 62-year-old man was diagnosed with limited disease SCLC originating from the right upper lobe. Biopsy specimens were positive for ASCL1 but negative for NEUROD1. Six months after concurrent chemoradiotherapy and prophylactic cranial irradiation, the primary tumor had regrown and salvage surgery was performed. The pathological diagnosis was recurred SCLC, and postoperative histopathology was positive for both ASCL1 and NEUROD1. The patient was subsequently followed up; however, he had multiple bone metastases 9 months after surgery. It was speculated that the shift to NEUROD1-high expression in tumor cells surviving concurrent chemoradiation therapy may be related to the poor outcome after combined modality treatment.

Combination treatment with antibiotics and surgical lung resection for Mycobacterium abscessus pulmonary infection in a breast cancer patient

A 51-year-old woman was admitted to our hospital because of pneumonia after chemotherapy with doxorubicin and cyclophosphamide for left breast cancer. The patient was diagnosed with Mycobacterium abscessus pulmonary infection by the detection of M. abscessus complex (MABC) in sputum cultures. However, MABC is intrinsically resistant to most of the antibacterial agents, and MABC pulmonary disease outcomes with modern antibiotic treatment are currently the worst among all mycobacterial species. We herein report the successful treatment of M. abscessus pulmonary infection by a combination treatment with antibiotics and surgical lung resection.

Comparison between robot-assisted thoracoscopic surgery and video-assisted thoracoscopic surgery for mediastinal and hilar lymph node dissection in lung cancer surgery

OBJECTIVES

Lymph node dissection (LND) with robot-assisted thoracoscopic surgery (RATS) in lung cancer surgery has not been fully evaluated. The aim of this study was to compare LND surgical results between video-assisted thoracoscopic surgery (VATS) and RATS.

METHODS

We retrospectively compared perioperative parameters, including the incidence of LND-associated complications (chylothorax, recurrent and/or phrenic nerve paralysis and bronchopleural fistula), lymph node (LN) counts and postoperative locoregional recurrence, among 390 patients with primary lung cancer who underwent lobectomy and mediastinal LND by RATS (n = 104) or VATS (n = 286) at our institution.

RESULTS

The median total dissected LN numbers significantly differed between the RATS and the VATS groups (RATS: 18, VATS: 15; P < 0.001). They also significantly differed in right upper zone and hilar (#2R + #4R + #10L) (RATS: 12, VATS: 10; P = 0.002), left lower paratracheal and hilar (#4L + #10L) (RATS: 4, VATS: 3; P = 0.019), aortopulmonary zone (#5 + #6) (RATS: 3, VATS: 2; P = 0.001) and interlobar and lobar (#11 + #12) LNs (RATS: 7, VATS: 6; P = 0.041). The groups did not significantly differ in overall nodal upstaging (P = 0.64), total blood loss (P = 0.69) or incidence of LND-associated complications (P = 0.77).

CONCLUSIONS

In this comparison, it was suggested that more LNs could be dissected using RATS than VATS, especially in bilateral superior mediastinum and hilar regions. Accumulation of more cases and longer observation periods are needed to verify whether RATS can provide the acceptable quality of LND and local control of lung cancer.

A rare case of combined thymoma and a multilocular thymic cyst discovered due to chest pain

Background

A thymoma with chest pain and multilocular thymic cysts (MTCs) is very rare.

Case presentation

A 49-year-old man presented to another hospital complaining of an anterior chest pain. Chest computed tomography (CT) showed an anterior mediastinal tumor 60 × 30 × 55 mm in size. The boundary with the pericardium or left brachiocephalic vein seemed to be partially unclear while enhanced by the contrast medium, and so the tumor could have invaded them. No definitive diagnosis of myasthenia gravis was made although the serum anti-acetylcholine receptor antibody count was high. We performed an extended thymectomy with combined partial resection of left brachiocephalic vein, left upper lobe, and left phrenic nerve. He was discharged with no chest pain and no complications post-surgery. The tumor was pathologically type B2 thymoma with hemorrhage necrosis and MTCs, and we diagnosed Masaoka stage II because of no histological infiltration to the organs.

Conclusions

We speculated that hemorrhagic necrosis due to infarction in tumor caused the inflammation to spread to the surrounding organs, which was related to the chest pain and the development of MTCs.

Transformation from adenocarcinoma to squamous cell carcinoma associated with long-term administration of EGFR-TKIs

Although patients with non-small cell lung cancer exhibiting EGFR mutations generally respond to tyrosine kinase inhibitors (TKIs), the majority of patients acquire resistance ~1 year after treatment. EGFR T790M mutations, MET or HER2 amplifications and phenotypic transformations contribute to the mechanism of EGFR-TKI resistance. The transformation of small cell lung cancer frequently occurs, although few convert to squamous cell carcinoma associated with the administration of EGFR-TKIs. The current study reports a case of EGFR-mutated adenocarcinoma of the lung that transitioned to squamous cell carcinoma in association with long-term EGFR-TKIs administration.

Upregulation of glucose and amino acid transporters in micropapillary carcinoma

Micropapillary carcinoma (MPC), a relatively rare histologic carcinoma observed in various organs, is associated with vascular invasion, nodal metastasis, and poor prognosis. MPC is different from papillary carcinoma as it has no fibrovascular core and is thus considered essentially hypovascular. MPCs are known to upregulate glucose transporter 1 (GLUT1) via the activation of a transcription factor, hypoxia-inducible factor (HIF)-1. Here we evaluated the expression of nutrient transporters in MPCs to gain a better understanding of the system used by MPCs to compensate for their intrinsic poor vascularity. We immunohistochemically evaluated 29 MPCs including breast (n=14), lung (n=8), gastrointestinal tract (n=5), and urinary tract cancers (n=2), and compared them with non-micropapillary control cancers (n=32) regarding the expression of amino acid (ASCT1, ASCT2, LAT1, and SNAT1) and glucose (GLUT1, GLUT2) transporters. Each section was scored by the staining intensity (0-3) multiplied by the occupying area (0-10), with a possible range 0-30. The average scores of the MPC and control groups were compared by Student's or Welch's t-test according to the homoscedasticity. The MPC group showed significantly higher scores for ASCT1 (p=0.007), ASCT2 (p=0.001), GLUT1 (p<0.001), and GLUT2 (p<0.001), whereas no significant scores were noted for LAT1 and SNAT1. In conclusion, MPC could be associated with the upregulation of several nutrient transporters, which may contribute to the malignant potential by supporting the survival of cancer cells.

Pure high-grade fetal adenocarcinoma of the lung: a case report

Background

Pure high-grade fetal adenocarcinoma of the lung (H-FLAC) is a very rare tumor.

Case presentation

An annual check-up revealed an abnormal shadow in the left middle lung field of a 63-year-old Japanese man. Chest computed tomography (CT) showed a 3.6 × 2.8 cm pulmonary lesion with clear boundary in the left upper lobe. A transbronchial lung biopsy revealed non-small cell carcinoma. A left upper lobectomy and mediastinal lymph node dissection were performed. Histologically, the tumor consisted of solid proliferation of atypical cell with clear cytoplasm. Another histological component and morulae were not contained. Immunohistochemically, the tumor was focally positive for alpha-fetoprotein (AFP) and beta-catenin in the cell membrane. Accordingly, we made the diagnosis of pure H-FLAC, pT2aN2M0, stage IIIA. Two courses of adjuvant chemotherapy (cisplatin and vinorelbine) were administered but then the treatment was discontinued due to the patient’s adverse reaction. At 25 months after the surgery, the patient had relapsed.

Conclusions

We report a very rare case of pure H-FLAC. This histology has been considered to predict an extremely poor prognosis; therefore, the elucidation of genetic abnormalities and effective treatment is awaited.

Clinical Significance of Subcellular Localization of Maspin in Patients with Pathological Stage IA Lung Adenocarcinoma

BACKGROUND/AIM

Maspin is a tumor-suppressor protein and its prognostic value in lung adenocarcinoma has been reported. However, little is known about the clinical impact of subcellular localization of maspin in early-stage lung adenocarcinoma. We aimed to evaluate the clinical significance of subcellular localization of maspin in patients with pathological stage (p-stage) IA lung adenocarcinoma categorized by the new eighth edition TNM classification.

PATIENTS AND METHODS

We immunohistochemically analyzed 181 tissue samples from p-stage IA1 (n=37), IA2 (n=92) and IA3 (n=52) lung adenocarcinomas using antibody for maspin.

RESULTS

The 181 cases fell into five predominant subtypes: lepidic (n=32), acinar (n=97), papillary (n=30), solid (n=20) and micropapillary (n=2). The frequencies of maspin staining were: cytoplasmic-only in 24.9%; pancellular (nuclear and cytoplasmic) in 8.8%; nuclear-only in 0.6%; no staining in 65.7%. Cytoplasmic-only staining significantly correlated with high pathological T-classification (p=0.039), lymphatic invasion (p=0.002) and poorer tumor differentiation (p=0.002). The patients were followed-up for 12-151 months (median=74 months), and the cytoplasmic-only staining significantly correlated with shorter disease-free survival (DFS) (p=0.034) and disease-specific survival (DSS) (p=0.036) by log-rank tests. In Cox's multivariate analysis, lymphatic invasion had the most significant effect on shorter DFS and DSS.

CONCLUSION

The expression of maspin in the cytoplasm alone could be useful for predicting unfavorable prognoses in patients with p-stage IA lung adenocarcinoma.

Prognostic Factors for Post Recurrence Survival in Resected Pathological Stage I Non-small Cell Lung Cancer

Background

Recurrence of lung cancer after surgical resection is a major obstacle in the cure and long-term survival of patients and has become the most common cause of death. However, prognostic factors and efficacy of therapy after recurrence remain controversial. We evaluated the prognostic factors of post recurrence survival (PRS) in patients of resected stage I non-small cell lung cancer (NSCLC).

Methods

Of the 551 patients who underwent surgery for stage I NSCLC between 2005 and 2013, we reviewed 89 (16.2%) patients who had recurrence. We examined PRS using the Kaplan-Meier method and multivariate Cox regression analyses.

Results

The median follow-up period after recurrence was 21.0 months. The median recurrence free interval (RFI) was 16.8 months. The 1-year PRS and 3-year PRS were 65.6% and 44.7%, respectively. Multivariate analysis revealed that size of primary lesion > 25 mm (P = 0.048), RFI ≤ 17 months (P = 0.048) and no treatment for recurrence (P < 0.001) were independent poor-prognosis factors of PRS. We further examined PRS in 66 patients who underwent any post recurrence therapy. For the patients who underwent treatment after recurrence, bone metastasis (P = 0.025) and treatment without epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) (P = 0.049) were independent poor prognostic factors.

Conclusion

PRS may be associated with characteristics of a recurrent lesion, including the biology of the recurrent tumor, RFI, recurrent site, the treatment for recurrence, rather than characteristics of primary lesion. Although further validation is needed, this information is important for the design of clinical trials for post-recurrence therapy.

Podoplanin expression in cancer-associated fibroblasts predicts unfavourable prognosis in patients with pathological stage IA lung adenocarcinoma

AIMS

Podoplanin expression in cancer-associated fibroblasts (CAFs) has been proposed as an unfavourable indicator in squamous cell carcinoma of the lung, but little is known about its clinical significance in early-stage lung adenocarcinoma. We evaluated the prognostic impact of podoplanin expression in patients with pathological stage (p-stage) IA lung adenocarcinoma as categorised by the 8th edition of the tumour-node-metastasis classification for lung cancer.

METHODS AND RESULTS

Immunohistochemical analyses using anti-podoplanin antibody were performed on resected specimens from 158 patients with p-stage IA lung adenocarcinoma. When more than 10% of cancer cells or CAFs showed immunoreactivity with podoplanin, the specimens were classified as podoplanin-positive. Podoplanin-positive status in cancer cells (n = 8) was not correlated with clinicopathological factors or with patient prognosis. Podoplanin-positive status in CAFs (n = 41) was correlated significantly with poorer tumour differentiation (P < 0.001), the presence of lymphatic invasion (P < 0.001) and high-grade (solid and/or micropapillary) components constituting ≥1% of the entire tumour (P < 0.001). The log-rank test showed that podoplanin-positive status in CAFs was associated significantly with shorter disease-free survival (DFS) (P < 0.001) and disease-specific survival (P = 0.015). In Cox's multivariate analysis, podoplanin-positive status in CAFs had the most significant effect on shorter DFS [hazard ratio (HR) = 4.411, P = 0.004], followed by the presence of high-grade components (HR = 3.581, P = 0.013).

CONCLUSIONS

Podoplanin expression in CAFs could be an independent predictor of increased risk of recurrence in patients with p-stage IA lung adenocarcinoma.

Subcellular Localization of Maspin Correlates with Histone Deacetylase 1 Expression in Human Breast Cancer

BACKGROUND/AIM

Maspin is known to be a tumor suppressor protein. Its nuclear localization and endogenous inhibition of histone deacetylase 1 (HDAC1) are considered crucial for its tumor suppressor activity. However, it remains unclear whether subcellular localization of maspin correlates with HDAC1 expression level in human breast cancer.

PATIENTS AND METHODS

Immunohistochemical analyses were performed on 164 resected specimens of invasive breast carcinoma using antibodies for maspin and HDAC1. Subcellular localization of maspin protein and HDAC1 mRNA expression level in two human breast cancer cell lines (MCF7, MDA-MB-231) and mammary epithelial cell line (MCF10) were analyzed by immunofluorescence and quantitative polymerase chain reaction, respectively.

RESULTS

The frequency of cytoplasmic-only, pancellular (combined nuclear and cytoplasm) and no staining of maspin were 31%, 14.0% and 55%, respectively. The cytoplasmic-only subgroup showed significantly higher histological grade (p=0.004), negative progesterone receptor status (p=0.003) and shorter disease-free survival compared to the pancellular subgroup (p=0.043). High HDAC1 expression was observed in 60% of cases and was significantly correlated with cytoplasmic-only staining compared to pancellular (p<0.001) or no staining (p=0.004). Immunofluorescence analysis revealed that maspin protein was localized mainly in the cytoplasm in MCF7 and MDA-MB-231 cells, while in both the nucleus and cytoplasm in MCF10A cells. HDAC1 mRNA levels were significantly up-regulated in MCF7 and MDA-MB-231 cells compared to MCF10A cells (p<0.001).

CONCLUSION

High HDAC1 expression may contribute to the aggressiveness of human breast cancer with cytoplasmic-only expression of maspin.

Initial Results of Robotic Surgery for Primary Lung Cancer: Feasibility, Safety and Learning Curve

BACKGROUND

At the end of 2016, robot-assisted thoracoscopic surgery (RATS) was still not covered by Japanese national health insurance. Therefore, few institutions in Japan perform RATS and even fewer have reported procedures as they occurred earlier. So, we decided to focus on the initial results of RATS for primary lung cancer.

METHODS

We retrospectively reviewed 44 patients who underwent RATS for primary lung cancer from January 2011 to August 2016. After mastering the initial procedure, we introduced a completely portal robotic pulmonary resection procedure using a carbon dioxide insufflation system. Cases were divided into 2 groups: the early period (20 cases) and the later period (24 cases).

RESULTS

There was no case of conversion to video-assisted thoracoscopic surgery or thoracotomy. In the 44 cases of primary lung cancer, median operating time was 239.5 min, console time was 179 min, blood loss was 10 mL, drainage period was 2 days, morbidity of Grade 2 or more (Clavien-Dindo classification) was 18.2%, morbidity of Grade 3 or more was only 4.6%, and there was no 30-day mortality. Median operating and console times were significantly shorter in the later period (215 min and 159.5 min, respectively) than in the initial period (300.5 min and 228 min, respectively). Median blood loss was significantly lower in the later period (5 mL) than in the initial period (50 mL). Five-year overall and disease-free survival rates were 100% and 88.9%, respectively.

CONCLUSION

RATS for primary lung cancer is feasible and safe, has a faster learning curve, and provides satisfactory. Studies with longer follow-ups and larger numbers of cases are necessary.

[Two Surgical Cases of Müllerian Cyst Arising From the Posterior Mediastinum]

We experienced 2 cases of Müllerian cyst. Case 1 was a 48-year-old woman with a paravertebral cystic tumor. The tumor grew from 23 to 31 mm in diameter for the 3 years. She underwent video-assisted thoracic surgery(VATS) for the excision of the tumor. Case 2 was a 40-year-old woman with a paravertebral cystic tumor, who underwent VATS. The Histological finding showed that the tumors of both cases were the cysts lined by non-stratified cuboidal to columnar epithelium and epithelial cells were positive in the nucleus with estrogen receptor immunohistochemically. The resected cysts were finally diagnosed as Müllerian cyst. Twenty four published cases of Müllerian cyst were reported before, including symptomatic and growing cases. There were some reports of malignant transformation in cases of pelvic origin.

Podoplanin Expression in Cancer-associated Fibroblasts Predicts Poor Prognosis in Patients with Squamous Cell Carcinoma of the Lung

BACKGROUND/AIM

Podoplanin is a candidate cancer stem cell marker in squamous cell carcinoma (SCC). Several studies have reported the prognostic value of podoplanin expression in tumor cells in lung SCC but few have focused on its expression in cancer-associated fibroblasts (CAFs). The aim of this study was to analyze the prognostic significance of podoplanin expression, with special reference to the expression pattern in both tumor cells and CAFs.

PATIENTS AND METHODS

Immunohistochemical analyses using anti-podoplanin antibody were performed on 126 resected specimens of lung SCC. When more than 10% of tumor cells or CAFs showed immunoreactivity with podoplanin levels as strong as those of the positive controls, the specimens were classified as a podoplanin-positive.

RESULTS

Podoplanin-positive status in tumor cells (n=54) was correlated with a lower incidence of lymphatic invasion (p=0.031) but there were no significant differences in disease-free survival (DFS) and disease-specific survival (DSS) by the log-rank test. Podoplanin-positive status in CAFs (n=41) was correlated with more advanced stage (p=0.008), higher frequency of pleural invasion (p=0.002) and both shorter DFS (p=0.006) and DSS (p=0.006). In Cox's multivariate analysis, podoplanin-positive status in CAFs was an independent negative prognostic factor for DFS (p=0.027) and DSS (p=0.027).

CONCLUSION

Podoplanin expression in CAFs might be an independent unfavorable prognostic indicator in patients with lung SCC, irrespective of the expression status of tumor cells.

Desmoid tumor requiring differentiation from port-site relapse after surgery for lung cancer

Thoracoscopic left lower lobectomy with lymph node dissection for lung cancer was performed in a 76-year-old man. The diagnosis was pT2aN2M0 adenocarcinoma. Sixteen months after surgery, CT revealed a pleural tumor measuring 38 mm at the surgical port wound. CT-guided biopsy revealed fibroma. However, the tumor size increased 4 months after biopsy, and surgery was performed. An intraoperative diagnosis revealed benign fibroma. Thoracoscopic tumorectomy was conducted. The pathological diagnosis was desmoid tumor. As the margins of the resected specimen were positive, radiotherapy was performed. During the 16-month follow-up period, there has been no relapse. Pleural desmoid tumors must be differentiated from port-site relapse.

Case of thoracoscopic right upper lobectomy for lung cancer with tracheal bronchus and a pulmonary vein variation

A 58-year-old woman visited our hospital with the chief complaint of an abnormal chest shadow. Chest CT showed an 18-mm ground-glass opacity in the right upper lobe, which became enlarged over time, and lung cancer was suspected. At the same time, a tracheal bronchus originating directly from the trachea was observed. She underwent thoracoscopic right upper lobectomy and mediastinal lymph node dissection. During surgery, in addition to the tracheal bronchus, a pulmonary vein variation was seen running dorsal to the pulmonary artery. Her postoperative course was uneventful. Tracheal bronchus is a rare anomaly, with an incidence of 0.1%-5%. Since tracheal bronchus is often accompanied by pulmonary vessel variations and may be associated with repeated previous infections, care should be taken when performing thoracoscopic lung resection.

Mediastinal malignant lymphoma difficult to diagnose: a patient report

We report a 58-year-old man who suffered from shortness of breath on exertion with wheezing. A chest enhanced computed tomography (CT) scan showed an irregular tumor in the middle mediastinum involving the right main pulmonary artery, vena cava superior and right main bronchus. Transbronchial lung biopsy and endobronchial ultrasound-guided transbronchial needle aspiration yielded no evidence for a pathological diagnosis of malignancy. We employed mediastinoscopy, which led to a diagnosis of lymphoid reactive change. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scan revealed a high FDG uptake in the tumor lesion. Because the CT scan and FDG-PET findings led to a marked suspicion of malignancy, we decided to attempt biopsy by a video-assisted thoracoscopic surgery (VATS) approach. Flow cytometry showed a monoclonal pattern, and the final diagnosis was mediastinal follicular lymphoma both pathologically and immunohistologically. The patient achieved a complete remission by following chemotherapy. Low-grade malignancy type of lymphoma such as follicular lymphoma that generally contains small-cell components often presents a diagnostic challenge and the VATS approach was effective for the diagnosis of such type of mediastinal lymphoma.

Sister Mary Joseph's nodule that originated from lung adenocarcinoma

Umbilical metastasis of cancer, known as Sister Mary Joseph's nodule (SMJN), is a rare phenomenon. It is usually due to intraabdominal malignancies and is quite rare from lung cancer. Here we describe a case of SMJN that originated from advanced lung adenocarcinoma. SMJN should be noted as an important sign of some hidden malignancy including lung cancer.

Thoracoscopic resections of bronchogenic cysts arising in the posterior mediastinum: a report on 3 patients

We report 3 cases of patients with bronchogenic cyst arising in the posterior mediastinum. The patients were a 19-year-old male, a 36-year-old female and a 33-year-old female, whose cysts were detected as abnormal shadows in the chest. In 2 of them, neurogenic tumors were suspected preoperatively. We performed thoracoscopic resection for the 3 tumors. Bronchogenic cysts may occur ectopically, and the posterior mediastinum must be sufficiently recognized as a rare but possible ectopic site.

[A case of repetitive monomorphic ventricular tachycardia]

We present a case treated with aprindine and metoprolol combined with a DDD type pacemaker for repetitive monomorphic ventricular tachycardia. A 50-year-old man was admitted because of palpitation and near syncope attack. Electrocardiogram showed repetitive monomorphic ventricular tachycardias (RBBB LAD type) and R-R interval of about 440 msec and I degree A-V block in sinus rhythm. Electrophysiologic study disclosed that overdrive pacing in HRA suppressed ventricular tachycardias. Left ventriculography revealed a dilated left ventricular and decreased contractility. Antiarrhythmic agents such as quinidine sulfate, procainamide, disopyramide, mexiletine, lidocaine and propranolol were not effective. But, the combination of propranolol and aprindine decreased the rate of the ventricular tachycardia. With aprindine 60 mg/day and metoprolol 60 mg/day combined with the atrioventricular sequential pacing at 85/min, ventricular tachycardia completely disappeared.

[Significance of right precordial ST elevation in experimental right ventricular infarction]

We produced experimental isolated right ventricular infarction (RVI) with closed chest method, and examined ECG changes of right precordial leads and changes of cardiac output (C. O) in 19 dogs. As a result, ECG showed ST depressions in leads, II, III, aVF and V2-V6 and ST elevations in a VR lead in all 15 cases of the proximal occlusion of right coronary artery (RCA). In 10 of 15 dogs ST elevations in some right precordial leads occurred, and the sensitivity of ST elevation in single right precordial lead was 60% (V5R), 53% (V4R) and 47% (V3R and V1), respectively for the detection of RVI. When left circumflex artery (LCX) was occluded, ST elevation in V4R lead after RCA occlusion was blocked. Therefore, it is thought that the sensitivity of ST elevation in right precordial lead may be lower than expectation in identifying RVI. Concerning anterior chest leads, none of 15 dogs with RVI showed ST elevations in leads V2-V6 in this study. If ST elevations in right precordial leads did not appear, variation of C.O was small and C.O reduced in proportion to the extension of ST elevations in right precordial leads.