Unencapsulated thymoma: a case report.

Thymomas, the most common mediastinal tumors, form capsules. Only a few reports have presented small thymomas without capsule formation, so-called microthymomas. Here, we report a case of an unencapsulated thymoma measuring 18 mm. A 42-year-old female presented with an anterior mediastinal tumor. Computed tomography revealed an 18-mm nodule in the anterior mediastinum. Magnetic resonance imaging revealed a solid tumor that was iso-intense on T1-weighted images and hypo-intense on T2-weighted images. Thoracoscopic partial thymectomy was performed. The histopathological diagnosis was a type B1 thymoma. The tumor was localized within the thymic tissue lacked a fibrous capsule and partially invaded the surrounding fat tissue. To our knowledge, this is the first report of an unencapsulated thymoma, except for microthymomas.

Primary pulmonary epithelioid sarcoma: a case report.

BACKGROUND: Epithelioid sarcoma most frequently occurs in the dermal or subcutaneous area of the distal extremities. To date, there have been three cases of primary pulmonary epithelioid sarcoma reported. We report a case of epithelioid sarcoma that is considered a primary lung tumor. CASE PRESENTATION: A 65-year-old asymptomatic Asian male patient underwent chest radiography during a routine health examination, and an abnormal mass was detected. His past medical history was unremarkable. He smoked 40 cigarettes every day and had slightly obstructive impairment on spirometry. He worked as an employee of a company and had no history of asbestos exposure. He underwent partial resection of the right lung by thoracoscopy. A histological examination of the tumor revealed a cellular nodule of epithelioid and spindle-shaped cells. Some of the tumor cells displayed rhabdoid features and reticular arrangement in a myxomatous stroma. Immunohistochemically, the tumor cells were positive for vimentin, smooth muscle actin (SMA), CD34, and epithelial membrane antigen (EMA); loss of the BAF47/INI1 protein in the tumor cells was also confirmed. A diagnosis of epithelioid sarcoma was established. Careful screening by whole-body positron emission tomography for another primary lesion after surgery did not detect any possible lesion. He had no cutaneous disease. CONCLUSION: To our knowledge, this is the fourth case of a proximal-type epithelioid sarcoma considered as a primary lung tumor.

[Multiple Minute Pulmonary Meningothelial-like Nodules;Report of a Case].

A 57-year-old woman was referred to our hospital for investigation of multiple tiny nodules in the lung fields bilaterally on computed tomography (CT). Video-assisted thoracoscopic lung biopsy was performed to diagnose the pulmonary lesions. Histological analysis showed nodular lesions with interstitial proliferation of uniform, round to oval cells with variable widening of the alveolar septa. Immunohistochemically, the cells were positive for EMA, CD56 and the progesterone receptor, but negative for chromogranin and synaptophysin. The diagnosis was "diffuse pulmonary meningotheliomatosis", with multiple diffuse "minute pulmonary meningothelial-like nodules". Diffuse pulmonary meningotheliomatosis should be kept in mind when we encounter small nodular shadows on a CT scan.

[Pancreatic Pleural Effusion;Report of a Case].

A 50-year-old man was admitted with respiratory failure. Chest X-ray and computed tomography revealed massive left pleural effusion and mediastinal shift. Pleural effusion showed abnormally high amylase levels of 42,600 IU/l and a high protein level of 3.2 g/dl. The serum amylase level was also 42,100 IU/l, and the proportion of pancreatic-type amylase was 88%. We diagnosed the patient with pancreatic effusion. Chest and abdominal enhanced computed tomography and magnetic resonance cholangiopancreatography revealed no pancreaticopleural fistula. He underwent a thoracoscopic examination that revealed brown pleural effusion as well as fibrin clots and thickness of the pleura. Histologically, there was no malignancy and the cause of pleural effusion was considered to be chronic pancreatitis.

[Usefulness of Oxidization-regenerated Cellulose Sheets in Preventing Postoperative Adhesion Confirmed at Second Surgery for Lung Cancer].

The patient was a 42-year-old woman who had been found to have a mixed ground glass opacity in the lung on chest computed tomography, and had underwent right S6 segmentectomy. At surgery, the plain between the upper and lower lobe was covered with a regenerative oxidized cellulose membrane. Two years later, multiple small shadows appeared in the remaining right lower lobe and completion right lower lobectomy was performed by thoracoscopy due to the adhesion to the absence of adhesion. Both of the histological examinations confirmed the diagnosis of minimally invasive adenocarcinoma of the lung. An oxidization regenerated cellulose sheet was effective in preventing postoperative adhesion in pulmonary resection.

[Intrapulmonary hematoma masquerading as metastatic carcinoma of lung cancer].

We herein report a case of intrapulmonary hematoma after lobectomy for lung cancer. A 51-year-old male underwent right upper lobectomy for lung cancer in a thoracoscopic procedure. Three months after the operation, chest computed tomography showed a 16-mm well-circumscribed nodule in the right lower lobe suggesting metastatic carcinoma for lung cancer. We performed the partial resection of the right lower lobe. The histological examination confirmed the diagnosis of an intrapulmonary hematoma. When pulmonary shadow appears after lung operations, intrapulmonary hematoma is one of a choice of differential diagnosis. Magnetic resonance imaging may be useful in establishing the diagnosis when intrapulmonary hematoma is suspicious clinically.

Safe stapling technique for pulmonary vessels with the shortened introducers and curved tips in thoracoscopic surgery.

Endo GIA(™) curved tips with Tri-Stapler(™) is more useful for the approach for pulmonary vessels than conventional straight staplers. Unless adequate space is maintained below the vessels, there is a risk of causing damage to the back of vessels with the curved tip without optional introducers. The recommended method involves passing silk thread through the back of the pulmonary vessels and ligating the thread to the introducer. However, the long introducer often applies tension to pulmonary vessels and can be caught in the tissues surrounding vessels. Therefore, we devised a new method. First, the introducer is shortened to a length of approximately 3 cm and attached to a curved tip. Second, a Penrose drain is passed through the back of the vessels. Last, the introducer is inserted into the drain and the stapler is guided. The vessels can be cut without removing the introducers and Penrose drains from staplers.

[Malignant peripheral nerve sheath tumor causing hemothorax; report of a case].

We herein report a case of malignant peripheral nerve sheath tumor that caused a hemothorax. A 39-year-old male was found to have an abnormal shadow on a chest X-ray. Chest computed tomography showed a 60-mm tumor in the right posterior mediastinum. Fourteen months earlier, he underwent drainage of a hemothorax with a medaistinal tumor but refused to undergo further examinations. We performed a tumor resection combined with the right lower lobectomy and the partial resection of the pericardium because of invasion. The histological examination confirmed the diagnosis of a malignant peripheral nerve sheath tumor. Postoperative radiotherapy was performed. The patient has been well without recurrence for 9 months.

[Pulmonary mucosal associated lymphoid tissue( MALT) lymphoma with 7-year natural history; computed tomography( CT) scan findings and pathological correlations].

A 58-year-old man was found to have an abnormal shadow on chest computed tomography (CT). The size and density of the nodule increased gradually over 7 years. Partial lung resection was performed by a thoracoscopic procedure. The pathological examination and gene analysis revealed that the tumor was primary pulmonary B-cell lymphoma of mucosa associated lymphoid tissue (MALT lymphoma). The CT findings showed that the level of substantial shadow with air bronchograms gradually increased in the center of the mass shadow, while a radial filamentous and ground glass shadow increased in the periphery. The pathological findings showed a cellular lymphocytic infiltrate that had expanded without destroying the existing blood vessels and bronchi in the center area of the tumor, while had expanded in the interstitial area along with vessel bundles in the border area. The CT findings were consistent with the pathological findings.

A thymic cyst in the middle mediastinum: report of a case.

BACKGROUND: Thymic cysts are usually located in the neck or anterior mediastinal compartment. Thymic cysts arising in the middle mediastinum are extremely rare, with only 2 previously reported cases. We herein describe the third case of a thymic cyst in the middle mediastinum. CASE: A 41-year-old female was referred to our department because of an incidental mediastinal mass detected on chest X-ray. Computed tomography showed a well-defined 7 cm mass located in the retroinnominate vein area. Magnetic resonance imaging showed a cystic lesion without any soft tissue density in the circumference. The border of the tumor was clear, without any invasion and continuity with the surrounding tissue. We performed thoracoscopic surgery. After aspiration of the serous contents in an end-pouch, the tumor was removed from the thoracic cavity. A pathological examination showed a fibrotic cyst wall containing the thymic cyst, which diagnosed it as thymic cyst. CONCLUSION: Thymic cysts in the middle mediastinum are extremely rare. A surgical resection provided the histological diagnosis of a thymic cyst in the present case.

[Hyperbaric oxygen therapy for air embolism complicating computed tomography (CT)-guided needle marking of the lung].

Preoperative computed tomography( CT)-guided marking with a short hook wire for small sized lung tumors has become popular along with the spread of thoracoscopic surgery. Systemic arterial air embolism is a very rare but potentially fatal complication. The patient was a 79-year-old man who was found to have a mixed ground glass opacity shadow on chest CT. Almost immediately after marking, he lost consciousness and complete atrio-ventricular (AV) block was found on the electrocardiogram (ECG) monitor. Brain CT showed intravascular air bubbles in the right frontal lobe. Two hours later, his conscious level was recovered completely but remained left hemiplegia. Five hours later, he was transported to another hospital for hyperbaric oxygen therapy. After 3 episodes of the treatment, left hemiplegia recovered with slight sense disorder in the left little finger. When neurologic findings are remained after air embolism, hyperbaric oxygen therapy should be arranged immediately.

[Mediastinal cystic lymphangioma; report of a case].

A cystic lymphangioma is a rare mediastinal benign tumor. A 38-year-old male was referred to our hospital because of an mediastinal mass incidentally detected on chest X-ray. The mass had enlarged rapidly during the course of 1 year. Computed tomography (CT) of the chest showed a 7 cm well defined cystic tumor in the left anterior mediastinum. Magnetic resonance imaging (MRI) demonstrated a mass with heterogeneous high signal intensity on enhanced T2-weighted images. The cystic tumor, localized in the mediastinal adipose tissue, was completely resected by a thoracoscopic procedure. A pathological examination confirmed the diagnosis of a cystic lymphangioma.

Arteriovenous hemangioma in the middle mediastinum: report of a case.

Hemangiomas in the mediastinum are uncommon, and the majority of these tumors are located in the anterior mediastinum. The present report describes an extremely rare case of a hemangioma in the middle mediastinum. A 40-year-old male patient presented with a mass in the left lower lung field on radiographic screening. Chest computed tomography and magnetic resonance imaging revealed a mass measuring 2.5 cm in diameter, which was close to the descending aorta in the left middle mediastinum. The tumor resection was performed by video-assisted thoracic surgery. The thoracoscopic findings revealed a blackish brown mass with a capsule, which had not invaded the descending aorta or cardiac sac. Histologically, the tumor was composed of typical thick-walled vessels and was therefore classified as an arteriovenous hemangioma.

Pleuropulmonary paragonimiasis with intrathoracic mass.

Pleuropulmonary paragonimiasis is a food-borne parasitic disease caused by the lung fluke Paragonimus westermani or other species of Paragonimus, which is endemic in Southeast Asia. It presents mainly pleural effusion or intrapulmonary nodules with respiratory symptoms. However, here we describe an exceedingly rare case of Paragonimus westermani with a mass in the pleural cavity. A 47-year-old man, who had presented with chest pain nine months earlier, was found to have right pleural effusion on detection survey computed tomography. He had a history of asbestos exposure and river fishing as a hobby and was confirmed to have Paragonimus westermani by immunodiagnosis. Because of a high level of hyaluronic acid in pleural effusion, he underwent a thoracoscopic examination. The pleura of the thoracic wall thickened greatly and showed no malignant lesion on biopsy. A white mass measuring 8 cm in diameter showed in the pleural cavity, which partially connected with the diaphragm and pulmonary pleura of the lower lobe. The postoperative pathological examination reported that the intrathoracic mass was a lesion that contained necrotic tissue enveloped with a fibrin capsule, which was thought to be formed by paragonimus.

Minute pulmonary meningothelial-like nodules: clinicopathologic analysis of 121 patients.

Minute pulmonary meningothelial-like nodules (MPMNs) are generally detected incidentally in resected lung specimens. With the development of diagnostic radiology, MPMNs have occasionally been detected on thin-section computed tomography. Their clinicopathologic background remains unclear because there have been no reports of a large series of patients with them. Among 1724 pulmonary resections during a 4 1/2 year period, 271 MPMNs were identified in 121 patients (7.0%) after pathologic examination. Minute pulmonary meningothelial-like nodules were seen more often in females than in males (10.7% versus 4.5%; odds ratio, 2.01; 95% confidence interval, 1.36-2.97; P < .001). Minute pulmonary meningothelial-like nodules were present in all lobes, and the frequency of incidence was not different between lobes. The incidence frequency of MPMNs was not different between age groups. Minute pulmonary meningothelial-like nodules were found more often in patients with malignant pulmonary tumors than in those with benign disease (7.3% versus 2.5%; P = .044). In particular, MPMNs were found more often in patients with lung adenocarcinoma than with other primary pulmonary malignant tumors (9.4% versus 4.5%; odds ratio, 2.33; 95% confidence interval, 1.35-4.02; P < .01). There was no significant difference in clinicopathologic factors between patients with single and multiple MPMNs, except for the size of each nodule.

Clinicopathological analysis of primary lung carcinoma with heterotopic ossification.

Pulmonary heterotopic ossification is an unusual event. The relationship between ossification and lung carcinoma is unclear. The present study analyzed clinicopathological features of primary lung carcinoma with heterotopic ossification. We reviewed 2269 surgically resected primary lung carcinomas and identified 33 with heterotopic ossification, including 15 cases with intratumoral heterotopic ossification (IHO) and 18 cases with extratumoral heterotopic ossification (EHO). All cases with IHO were adenocarcinomas and 10 of 15 (66.6%) cases had confirmed positive mucin staining in the tumor cells. Cases with EHO could be divided into three patterns, and each pattern is potentially associated with the background conditions of lung parenchyma. Immunohistochemistry, BMP-2 production was present in 13 of 15 (86.7%) cases with IHO, although, only 4 of 17 (23.5%) cases with EHO. A prognostic analysis revealed no statistically significant difference to be observed between adenocarcinomas with IHO and without IHO. The present study suggested that IHO associated with adenocarcinomas and BMP-2 production in the tumor cells, whereas EHO was not associated with the biology of the carcinoma.

Recurrent mediastinal liposarcoma twenty years after the initial operation: case report.

We report a case of mediastinal liposarcoma, recurrent after 20 years. A 58-year-old man who presented with dyspnea on exertion was found to have a large mediastinal tumor in chest computed tomography (CT), and he was referred to our hospital. He had undergone an extirpation of a mediastinal liposarcoma about 20 years earlier, and we suspected its recurrence. Because the tumor was very large, it was removed in two stages. Histologically it was diagnosed as a recurrence of the previous well-differentiated liposarcoma. Although liposarcoma is one of the most common soft-tissue sarcomas in adults, a mediastinal liposarcoma is rare. Because the recurrence rate is very high, it is necessary to follow up carefully over a long term.

[Prophylactic effect of magnesium infusion against postoperative atrial fibrillation].

BACKGROUND: Atrial fibrillation (AF) is a common complication of cardiac operation. For the development of postoperative AF, various risk factors have been identified over the years. In a recent study, it was detected that low serum magnesium levels was an independent predictor of AF after coronary artery bypass grafting (CABG). The purpose of this study was to assess the prophylactic effect of intravenous magnesium infusion on postoperative AF. METHODS: A total of 62 consecutive patients who had elective, first time cardiac operation on cardiopulmonary bypass were prospectively categorized to 2 group. In the treatment group, 30 patients received 8.3 mmol of magnesium sulfate in 100 ml of saline solution that was administered over 4 hours, preoperatively, just after admission in the ICU, and at the postoperative day 1, 2, 3, and 4. RESULTS: Postoperative AF occurred in 3/30 (10.0%) patients in the treatment group and in 14/32 (43.8%) patients in the control group (p<0.01). The arrhythmia developed on the 2.9 postoperative day on average. The postoperative length of hospital stay was significantly shortened in the treatment group (15.9 +/- 4.0 days) than that in the control group (20.5 +/- 7.0, p < 0.01). CONCLUSION: Our findings indicate that magnesium sulfate infusion is effective for the prophylaxis of post operative AF.

Lower limits of hematocrit and mixed venous oxygen saturation ensuring sufficient cerebral oxygenation during hemodilution in rabbits.

OBJECTIVES: We have assessed clinically systemic tissue oxygenation by monitoring mixed venous oxygen saturation (SvO2) in addition to hematocrit (Hct) during cardiopulmonary bypass. Based on results of experimental studies together with clinical experience, we previously defined the lower limits of the critical range as an Hct of 12% and an SvO2 of 46%. However, these values do not provide direct information about cerebral oxygenation. This study was performed to identify critical values for these variables that would be able to ensure sufficient jugular venous oxygen saturation (SjO2), which reflects global cerebral oxygenation. METHODS: Normovolemic hemodilution was performed in ten rabbits. Hct, SvO2 and SjO2 were measured every 7 minutes. The safety limit for cerebral oxygenation was defined as an SjO2 of 50% based on studies of Croughwell et al. and Cook et al. The limit point was defined as 7 minutes before the time that the SjO2 decreased below 50% for the first time. RESULTS: Minimal values for Hct and SvO2 to maintain SjO2 at 50% or more during normovolemic normothermic hemodilution, expressed as the 95% confidence interval, were Hct of 7.4% to 10.0% and SvO2 of 41.8% to 51.4%. CONCLUSION: Adopting the higher values of these pairs, safety limits for cerebral oxygenation would be an Hct of 10.0% and an SvO2 of 51.4%. In conclusion, our experiments in rabbits suggest new safety limits during normovolemic normothermic hemodilution of Hct of 12% and SvO2 of 52%, taking both whole-body and cerebral oxygenation into consideration.

Bronchioloalveolar carcinoma of the lung 3 centimeters or less in diameter: a prognostic assessment.

BACKGROUND: Bronchioloalveolar carcinoma (BAC) of the lung is a subtype of adenocarcinoma for which the incidence is actually rising, but the histologic definition of BAC has been recently changed by the revised World Health Organization (WHO) classification in 1999. The clinical features of patients with BAC diagnosed according to the recently revised WHO classification have not yet been clarified. In this retrospective study, we investigated the pattern of recurrence and survival outcome for patients with resected BAC by pathology review, compared with those in patients who had adenocarcinoma other than BAC. METHODS: From 1985 through 2002, 108 patients underwent surgical resection for pulmonary adenocarcinoma 3 cm or less in diameter at the University of Yamanashi, Japan. All of the resected specimens of these 108 patients were pathologically reviewed again to confirm the diagnosis as BAC or adenocarcinoma other than BAC. The tumor was defined as BAC when the adenocarcinoma lesion had a pure bronchioloalveolar growth pattern and no evidence of stromal, vascular, or pleural invasion according to the WHO classification (third edition). RESULTS: Twenty-five patients (23%) had a diagnosis of BAC, and 83 (77%) had a diagnosis of other adenocarcinoma. There was a female predominance among both patients with BAC and those with other adenocarcinoma. Lymph node involvement was seen for 30 lesions (36%) of adenocarcinoma other than BAC, but not for any BAC lesions. The median duration of follow-up after surgery was 5.1 years. There was no recurrence in the postoperative course in patients with BAC for a 5-year disease-free survival rate of 100%, whereas the 5-year disease-free survival rate for other adenocarcinoma was 63.5%. CONCLUSIONS: The patients with resected BAC, which is defined as a noninvasive adenocarcinoma by the revised WHO classification, had an excellent prognosis. However, these results may depend on a strictly accurate pathology diagnosis as BAC. Limited resection might be curative in patients with focal BAC based on evidence of pathologic noninvasive features.