[Strategy for marginally resectable lung cancer].

Lung cancer accounts for the largest number of new cases of cancer deaths annually. The treatment of locally advanced non-small-cell lung cancer(NSCLC)will continue to be a problem for many years. In particular, the border-zone subset of stage III A(N2)patients, which lies between the generally resectable stage I and II tumors and the unresectable stage III B patients, has been the subject of a wide variety of clinical trials incorporating various combinations of chemotherapy, radiotherapy, and surgery.What is the ideal therapy for stage III A(N2)patients ? is a controversial question, and the role of surgery is not clearly defined because of its heterogeneous nature. Most importantly, treatment decisions for these patients should be dictated by the stage of the patients' disease and the patients' performance status, medical comorbidities, and preferences. At our hospital, therefore, all of these patients' data are discussed at our cancer-board conference, incorporating the options of thoracic surgeons, medical oncologists, and radiation oncologists to determine the optimal prospective treatment strategies for the patients. We focused on a treatment strategy for the patients with the so called marginally resectable' lung cancer in this article.

Ectopic hamartomatous thymoma--a truly rare neoplasm: report of a case.

An ectopic hamartomatous thymoma is an extremely rare benign neoplasm that commonly occurs in the lower neck region. It has distinctive pathological features that include haphazardly arranged spindle cells, epithelial cells, and mature fat tissue. Its histogenesis is still controversial. This report presents a case of a 26-year-old man with ectopic hamartomatous thymoma in the left supraclavicular region, and discusses the current knowledge regarding this type of lesion. Clinicians as well as pathologists should be aware of the existence of this disease so that it can be identified correctly.

A clinicopathological study of resected pulmonary nodules with focal pure ground-glass opacity.

OBJECTIVE: Pulmonary lesions with focal ground-glass opacity (GGO) have been detected increasingly by low-dose helical computed tomography (CT). However, the strategy of treatment for focal pure GGO lesions is still undecided. This study evaluates clinicopathological characteristics of resected pulmonary nodules with focal pure ground-glass opacity. METHODS: Between January 1997 and December 2005, 26 patients (35 lesions) with pure GGO lesions underwent pulmonary resection. The data on patient age, lesion size, pathology, carcinoembryonic antigen (CEA) level and palpability of the tumor in the resected specimen were evaluated. RESULTS: The histological diagnosis was bronchioloalveolar carcinoma (BAC) in 10 patients (12 lesions), atypical adenomatous hyperplasia (AAH) in 15 patients (22 lesions), and focal scar in 1 patient (1 lesion). There were no significant differences in age, sex, tumor size, and CEA level between the patients with BAC, AAH, and focal scar. However, the lesions >10mm in size were all BAC. Palpability of the tumor in the resected specimen was significantly more frequent in BAC cases than in AAH cases (p<0.01). For BAC, lobectomy was performed for four lesions, and limited resection for eight. None of the BACs showed lymphatic or vascular invasion upon pathological examination. At the median follow-up point of 44 months (range: 4-84 months), no recurrences were observed. CONCLUSIONS: BAC and AAH cannot be discriminated by their size. In the resected specimen, BAC lesions are more frequently palpable than AAH lesions. Thoracoscopic surgery is recommended for focal pure GGO after repeated CT even if the GGO lesion is small. Partial resection is a sufficient treatment for pure GGO.

Obstructive subglottic granuloma after removal of a minitracheostomy tube.

We report herein a patient with subglottic granuloma after removal of a minitracheostomy tube (Minitrach II, SIMS Portex Inc., Hythe, Kent, UK). The patient underwent pulmonary resection for lung cancer followed by insertion of the minitracheostomy tube for prevention of sputum retention. The tube was removed 4 days after insertion. Twelve weeks later, the patient developed severe dyspnea and stridor. Bronchoscopy showed an obstructive subglottic granuloma arising from the anterior wall. The granuloma was removed by coring out using a conventional tracheal tube, followed by local injection of methylprednisolone acetate. The patient is now asymptomatic without regrowth of the granulation tissue 12 weeks after the treatment. With complication in mind, attention should be paid to patients suffering dyspnea or stridor after removal of a minitracheostomy tube.

FDG-PET imaging for lymph node staging and pathologic tumor response after neoadjuvant treatment of non-small cell lung cancer.

PURPOSE: A number of studies have demonstrated that 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is effective for staging of lung cancer. However, the efficacy of FDG-PET for staging lung cancer after neoadjuvant treatment is still controversial. This study compared FDG-PET and computed tomography (CT) for lung cancer staging, and evaluated the ability of the two methods to predict the pathologic response of the primary tumor to neoadjuvant treatment. PATIENTS AND METHODS: Twenty-two patients who underwent neoadjuvant treatment followed by surgery were investigated. Eighteen patients received chemoradiotherapy and four patients received chemotherapy only. One hundred and three lymph node stations in the 22 patients were evaluated by FDG-PET and CT. The pathologic responses of the tumors were compared by FDG-uptake and tumor size on CT for the 15 patients who underwent FDG-PET and CT both before and after neoadjuvant treatment. RESULTS: There was no significant difference in the ability of FDG-PET or CT to predict residual viable tumor. Although positive predictive value by FDG-PET (0.29) was lower than that by CT (0.64) (p=0.04) in the mediastinal lymph nodes, there were no statistically significant differences in the other results of lymph nodes by FDG-PET and CT. Both decrease in FDG-uptake and decrease in tumor size by CT after neoadjuvant treatment correlated significantly with pathologic response in the 15 patients (p=0.003 and 0.009, respectively). CONCLUSION: FDG-PET did not appear to offer any advantages over CT for lymph node staging or for predicting the pathologic response after neoadjuvant treatment of non-small cell lung cancer.

Radiofrequency ablation of pulmonary tumors and normal lung tissue in swine and rabbits.

OBJECTIVE: The purpose of the present study was to examine the following during radiofrequency ablation (RFA): (1) the risk of hemorrhage from intrapulmonary large vessels; (2) the risk of incomplete ablation of pulmonary tumors; and (3) the late effect on lung tissue. MATERIALS AND METHODS: A 17-gauge, cool-tip-type radiofrequency electrode was used. The damage to the vessels and bronchi was examined by the injection of a colored silicone rubber, a liquid compound that hardens after injection. To examine the risk of hemorrhage from intrapulmonary large vessels, RFA was conducted at eight sites near the central pulmonary vessels in two swine. To examine the risk of an incomplete ablation for pulmonary tumors, 10 pulmonary nodules were made from a gelatin mixture in another two swine and were treated by RFA. To examine the late effect on lung tissue, RFA was conducted on the peripheral lung in 10 rabbits, and then the ablated regions were examined on days 1, 7, 14, 21, and 28 after RFA. RESULTS: The use of colored silicone rubber enabled us to examine the intrapulmonary vessels and bronchi for opening and leakage. RFA did not damage the large intrapulmonary vessels, even when they were located within the ablated regions. Lung tissue surrounding the gelatin nodules was hardly ablated over its entire circumference. Six of 10 gelatin nodules (60%) showed nonablated areas on the peripheral edges of the nodules. From 21 days after RFA, the ablated rabbit lung formed noninfectious cavities by communicating with the surrounding bronchi. CONCLUSION: It was improbable for hemorrhage to occur even when RFA was conducted near the large intrapulmonary large vessels. Because an incomplete ablation that left tumor cells at the site of ablation could occur during surgery due to the difficulty of ablating the entire tumor circumference, CT scan-guided RFA would be preferable to a surgical approach for making a safe margin. Cavity formation can occur beginning 21 days after RFA, which should be carefully followed up in a clinical setting to identify infection, especially in immunocompromised patients.

Extended resection of lung cancer invading the left subclavian artery by using cardiopulmonary bypass.

We treated a 54-year-old man with large cell carcinoma of the left upper lobe invading the esophagus and the left subclavian artery (SCA) from its origin. The tumor was completely resected by lobectomy under cardiopulmonary bypass. The left SCA was dissected at the aortic arch and reconstructed with a graft. The muscle layer of the esophagus was resected, followed by patching with an intercostal muscle flap. The pathological tumor stage was T4N0M0. The tumor recurred at two months after surgery in the neck lymph nodes and brain. Both sites were treated with radiation therapy and the patient is now alive without recurrence at 26 months after surgery. Lung cancer invading the great vessels and other mediastinal structures can be cured or long survival can be obtained by extended resection and postoperative adjuvant therapy.

Intrapulmonary schwannoma.

A 58-year-old woman was admitted due to an abnormal shadow on chest X-ray, without any symptoms. Chest computed tomography showed a round mass in the anterior segment of the right upper lobe. Segmentectomy was performed and histopathological examination revealed a primary neurogenic tumor of Schwann cell origin. Immunohistochemical staining demonstrated the presence of S-100 protein in the tumor cells. We present a case of intrapulmonary schwannoma and review 62 cases of primary schwannoma of the lung.

Histogram analysis of computed tomography numbers of clinical T1 N0 M0 lung adenocarcinoma, with special reference to lymph node metastasis and tumor invasiveness.

PURPOSE: To predict lymph node metastasis and tumor invasiveness in lung adenocarcinoma from computed tomography findings, we examined computed tomography number histograms of clinical T1 N0 M0 lung adenocarcinomas. PATIENTS AND METHODS: Histograms of pixel computed tomography numbers were made for 100 patients with clinical T1 N0 M0 lung adenocarcinoma. Pathological tumor stages were N0 in 80 patients, N1 in 7, N2 in 9, and T4 due to intrapulmonary metastasis in 4. RESULTS: The histogram showed 3 patterns: 1 peak at a low computed tomography number (n = 18), 1 peak at a high computed tomography number (n = 54), and 2 peaks at both low and high computed tomography numbers (n = 28). Histologically, adenocarcinoma with 1 peak at a low computed tomography number showed a large area of bronchioloalveolar carcinoma-like spread with little area of solid growing tumor or central fibrosis, whereas those with 1 peak at a high computed tomography number showed a large area of solid growing tumor or central fibrosis with little bronchioloalveolar carcinoma-like spread. Adenocarcinomas with 2 peaks had both types of areas. Lymph node or pulmonary metastases were seen in none (0%) of the adenocarcinomas with 1 peak at a low computed tomography number, in 1 (4%) with 2 peaks, and in 20 (37%) with 1 peak at a high computed tomography number. The former 2 types had metastases less frequently than those with 1 peak at a high computed tomography number (P <.01). In the 79 patients with pathological T1 N0 M0, tumor involvement of the intratumoral vessels or pleura was seen in 1 of 18 (6%) adenocarcinomas with 1 peak at a low computed tomography number, which was significantly less frequent than the 18 of 34 (53%) with 1 peak at a high computed tomography number (P <.001) and 10 of 27 (37%) with 2 peaks (P <.05). CONCLUSION: Clinical T1 N0 M0 adenocarcinomas with 1 peak at a low computed tomography number on histogram seldom had lymph node metastasis or tumor involvement of vessels or pleura. Limited surgical resection could be indicated for this type of adenocarcinoma, especially for elderly patients or patients with poor pulmonary function.

Thoracoscopic lobectomy for lung cancer with a largely fused fissure.

BACKGROUND: While isolating the pulmonary arterial branches within the fissure is a crucial step in lobectomy, a largely fused fissure usually hinders its achievement, making lobectomy with video-assisted thoracoscopic surgery (VATS) difficult to achieve. For VATS lobectomy in lung cancer patients with a largely fused fissure, we have conducted an unusual approach for each lobe, and the surgical results were compared between patients with and without a fused fissure. METHODS: Since1999, we have conducted VATS lobectomies in 77 patients. Of these, 10 had largely fused fissures that needed an unusual surgical approach for dividing the pulmonary arterial branches. The other 67 patients had separated fissures that allowed the isolation and division of the arterial branches within it. While the surgical approach used for the patients with largely fused fissures differed in each lobe, most often the lobar bronchus was divided before pulmonary arterial branches within the fissure were divided, with the fused fissure being divided last. RESULTS: There were no significant differences in age, lobectomy site, or tumor stage between the patients with fused fissures and those with separated fissures. The surgical data showed no significant differences between the two groups in operating time, blood loss, duration of chest tube drainage, and hospital stay after surgery. However, the patients with fused fissures required more staples to close the incision than did those with a separated fissure (mean number of staples, 7.7 vs 5.7; p < 0.001). There was no postoperative mortality or morbidity, including prolonged air leakage, in the patients with fused fissures. CONCLUSION: Although the performance of VATS lobectomy for patients with largely fused fissures is more costly, it is feasible and safe. A largely fused fissure is not a limiting factor for the performance of VATS lobectomy.

Is major pulmonary resection by video-assisted thoracic surgery an adequate procedure in clinical stage I lung cancer?

OBJECTIVE: Although several studies have shown that video-assisted thoracic surgery (VATS) for major pulmonary resection is less invasive than open thoracotomy, VATS for lung cancer has been performed in only a limited number of institutions. We aimed to review our experience of VATS for major pulmonary resections, and to determine its safety and adequacy in stage I lung cancer. METHODS: Between August 1999 and March 2003, we performed major pulmonary resection by VATS in 106 patients with lung cancer and preoperatively determined clinical stage I disease. We evaluated the number of procedures converted to open thoracotomy and the reasons for conversion, the intraoperative blood loss, interval between surgery and chest tube removal, length of postoperative hospital stay, postoperative complications, mortality rate, prognoses, and patterns of recurrence. RESULTS: We successfully performed VATS in 95 patients, whereas in another 11 patients (10%) conversion to open thoracotomy was required. The operative procedures were lobectomy in 86 patients, segmentectomy in 8 patients, and bilobectomy in 1 patient. In 95 patients who underwent VATS, postoperative complications developed in 9 patients (9%), and 1 patient (1%) died from pneumonia. In the 86 patients without complications, the mean postoperative hospital stay was 7.6 days (range, 4 to 15 days). In a mean follow-up period of 25 months (range, 6 to 48 months) in patients with non-small cell lung cancer (NSCLC), including the one perioperative death, the 3-year survival rate was 93% in 82 patients with clinical stage I disease, and 97% in 68 patients with pathologic stage I disease. The 3-year disease-free survival rate was 79% in patients with clinical stage I disease, and 89% in patients with pathologic stage I disease. Local recurrence was observed in six patients (6%): recurrence in mediastinal lymph nodes in five patients, and in the bronchial stump in one patient. CONCLUSIONS: Major pulmonary resection by VATS is acceptable in view of its low perioperative mortality and morbidity, and is an adequate procedure for the achievement of local control and good prognosis in patients with clinical stage I NSCLC.

Use of technetium-99m tin colloid for sentinel lymph node identification in non-small cell lung cancer.

BACKGROUND: To test the reliability of sentinel lymph node identification in non-small cell lung cancer, sentinel nodes were localized with a radioactive colloid in patients undergoing surgery. METHODS: Forty-six patients with non-small cell lung cancer undergoing curative resection with mediastinal lymph node dissection were examined. The day before surgery, technetium-99m ((99m)Tc) tin colloid was injected into the peritumoral region. At operation, the radioactivity of the lymph nodes was counted with a handheld gamma counter before (in vivo) and after (ex vivo) dissection. Lymph nodes with an ex vivo radioactive count more than 10 times the background value were identified as sentinel nodes. The correlation between the in vivo and ex vivo results was examined. RESULTS: Lymphoscintigraphy revealed that it took longer than 6 hours for sufficient (99m)Tc tin colloid to reach the sentinel nodes. Sentinel nodes could be identified in 40 patients (87%). Patients whose sentinel nodes could not be identified had a significantly lower ratio of forced expiratory volume in 1 second to forced vital capacity than did those with identifiable sentinel nodes (P =.03). No false-negative sentinel nodes were detected in 14 patients with N1 or N2 disease (0%). In the hilar lymph node stations, the lobar lymph nodes were most frequently identified as sentinel nodes (as often as 85% of the time). Fourteen patients (35%) had sentinel nodes in the mediastinum, the distribution of which depended on the lobe. In vivo and ex vivo counting showed 88% concurrence for the identification of sentinel nodes in mediastinal lymph node stations. CONCLUSION: The identification of sentinel nodes with (99m)Tc tin colloid is a reliable method of establishing the first site of nodal metastasis in non- small cell lung cancer. Sentinel nodes could be hardly identified in patients with a low ratio of forced expiratory volume in 1 second to forced vital capacity because of such conditions as chronic obstructive pulmonary disease. In vivo identification of sentinel nodes in the mediastinum could be useful approach to guide mediastinal lymph node sampling or dissection.

Fluorine 18-tagged fluorodeoxyglucose positron emission tomographic scanning to predict lymph node metastasis, invasiveness, or both, in clinical T1 N0 M0 lung adenocarcinoma.

OBJECTIVE: We sought to predict lymph node metastasis and tumor invasiveness in clinical T1 N0 M0 lung adenocarcinomas, and we measured fluorodeoxyglucose uptake on positron emission tomography. METHODS: Fluorodeoxyglucose positron emission tomography was performed on 44 patients with adenocarcinomas of 1 to 3 cm in size clinically staged as T1 N0 M0 before major lung resection with lymph node dissection. Fluorodeoxyglucose uptake was evaluated by using the contrast ratio between the tumor and contralateral healthy lung tissue. Lymphatic and vascular invasion within tumors, pleural involvement, and grade of histologic differentiation were examined. RESULTS: The pathologic tumor stage was T1 N0 M0 in 36 patients, and a more advanced stage was found in 8 patients. Although all 22 adenocarcinomas with a contrast ratio of less than 0.5 in fluorodeoxyglucose uptake were pathologic T1 N0 M0 tumors, 8 (36%) of 22 with a contrast ratio of 0.5 or greater were of a more advanced stage than T1 N0 M0, with the difference being significant (P =.002). Adenocarcinomas with a contrast ratio of less than 0.5 showed less lymphatic and vascular invasion and less pleural involvement than those with a contrast ratio of 0.5 or greater (P =.006, P =.004, and P =.02, respectively). The grade of histologic differentiation was well differentiated in 19 of 22 adenocarcinomas with a contrast ratio of less than 0.5 (86%), which was a greater frequency than the 4 (18%) of 22 adenocarcinomas with a contrast ratio of 0.5 or greater (P <.001). CONCLUSION: Clinical T1 N0 M0 lung adenocarcinomas with a contrast ratio of less than 0.5 usually did not have lymph node metastasis, had less tumor involvement of vessels or pleura, and were more frequently well differentiated than those with a contrast ratio of 0.5 or greater. Limited lung resection could be indicated, lymph node dissection or mediastinoscopy could be reduced, or both in this type of adenocarcinoma.

The size of metastatic foci and lymph nodes yielding false-negative and false-positive lymph node staging with positron emission tomography in patients with lung cancer.

BACKGROUND: We examined the sizes of lymph nodes and metastatic foci within the lymph nodes that affect false-positive and false-negative lymph node staging by positron emission tomography in lung cancer. METHODS: Preoperative positron emission tomography and computed tomography scans were performed for 564 lymph node stations in 80 patients with peripheral-type lung cancer. The sizes of both the lymph nodes and the metastatic foci within the lymph nodes were measured, and these measurements were compared with those obtained with positron emission tomography scanning. To establish general sizes of metastatic foci within the lymph nodes, 277 metastatic lymph nodes in operative specimens previously resected from another 111 patients with lung cancer were examined as a control. RESULTS: The sensitivity was significantly higher for positron emission tomography than for computed tomographic scanning (P =.026). The sizes of metastatic foci within lymph nodes that showed false-negative (n = 8) and true-positive (n = 28) with positron emission tomography ranged from 0.5 to 9 mm (3 +/- 1 mm) and from 4 to 18 mm (10 +/- 3 mm), respectively (P <.001). None of the metastatic foci smaller than 4 mm could be detected with positron emission tomography scanning. The review of the 277 previously resected metastatic lymph nodes showed that 89 (32%) had metastatic foci smaller than 4 mm. The sizes of true-positive (n = 28) and false-positive (n = 10) lymph nodes ranged from 6 to 15 mm (10 +/- 2 mm) and from 9 to 16 mm (12 +/- 2 mm), respectively (P <.01). None of the false-positive lymph nodes was smaller than 9 mm. CONCLUSIONS: Although positron emission tomography was superior to computed tomography scanning in lymph node staging in lung cancer, positron emission tomography was unable to distinguish metastatic foci smaller than 4 mm, which were not unusual sizes for lymph node metastases in lung cancer. Positive lymph nodes with positron emission tomography smaller than 9 mm are likely to be true-positive rather than false-positive.

Radiological examination for peripheral lung cancers and benign nodules less than 10 mm.

To clarify the differences in radiological findings between primary lung cancers and benign nodules measuring less than 10mm, we examined chest computed tomography (CT) findings. Of 82 patients with solitary pulmonary nodules less than 10mm in diameter who had undergone surgical biopsy, 21 patients with primary lung cancer and 45 patients with benign lesions (9 patients with tuberculosis, 12 with non-specific inflammation, 10 with benign lung tumor, 10 with intrapulmonary lymph nodes and 4 with others) were examined. Seven patients with atypical adenomatous hyperplasia and nine patients with metastatic lung cancer were excluded. Primary lung cancers had an ill-defined tumor margin and spiculation significantly more frequently than benign nodules (P<0.01). Involvement of bronchi or vessels was observed significantly more frequently in primary lung cancers than in benign nodules (P<0.05), while pleural indentation did not show significant differences in frequency. Retrospective chest X-ray or CT films were reviewed for seven patients with primary lung cancers and 12 with benign nodules, with a mean interval of 24+/-17 months. Primary lung cancers enlarged or appeared as new nodules more frequently than benign lung nodules (P<0.05). Among 17 lung cancer patients who underwent mediastinal lymph node dissection, the cancer was at a more advanced stage than T1N0M0 in four (24%). We conclude that ill-defined margins, spiculation, involvement of bronchi or vessels, and tumor enlargement visualized by CT are still important signs of malignancy even for nodules less than 10mm in size. Tumor size, even for lung cancers measuring less than 10mm, is not an indication for limited resection.

In vivo identification of sentinel lymph nodes for clinical stage I non-small cell lung cancer for abbreviation of mediastinal lymph node dissection.

BACKGROUND: We previously reported that an identification of sentinel lymph node (SN) with a techenetium-99m (99mTc) tin colloid by ex vivo counting, i.e. the radio-activity of dissected lymph nodes, was a reliable method of establishing the first site of nodal metastasis in non-small cell lung cancer [J. Thorac. Cardiovasc. Surg. 124(2002)486]. However, for SN navigation surgery, SN should be identified before lymph node dissection (in vivo) but not after that (ex vivo). In order to reduce mediastinal lymph node dissection for clinical stage I non-small cell lung cancer (NSCLC) by SN navigation surgery, the SN identifications for hilar lymph nodes by ex vivo counting, and for mediastinal lymph nodes by in vivo, were evaluated. METHODS: Intra-operative SN identification using 99mTc tin colloid was conducted on 104 patients with clinical stage I NSCLC who had had major lung resections with mediastinal lymph node dissections. The hilar SNs were identified by ex vivo counting (after lung resection) and the mediastinal SNs were identified by in vivo counting (before lymph node dissection). To evaluate the accuracy of mediastinal SN identification by in vivo counting, it was compared with the data by ex vivo counting. RESULTS: SNs were identified in 84 patients (81%). SNs were identified at the hilum by ex vivo counting in 78 patients (93%) and at the mediastinum by in vivo counting in 40 patients (48%). While 15 patients had lymph node metastases, i.e. N1 in six and N2 in nine, the SNs could be found to have metastases during operation in 13 of the 15 patients (87%). The in vivo counting of the mediastinum missed out the mediastinal SNs identified by ex vivo counting in four of the 84 patients (5%). CONCLUSION: If the hilar SNs identified by ex vivo counting and the mediastinal SNs identified by in vivo counting had no metastases, then mediastinal lymph node dissection could be abbreviated for patients with clinical stage I NSCLC.

Evaluation of F-18 fluorodeoxyglucose (FDG) PET scanning for pulmonary nodules less than 3 cm in diameter, with special reference to the CT images.

BACKGROUND: While pulmonary nodules can be substantially divided into solid and ground-glass opacity (GGO) ones on CT image, they have different biological natures which could cause false positive or false negative to diagnose malignancy on positron emission tomography with fluorodeoxyglucose (FDG-PET). To determine the effectiveness of PET for small pulmonary nodules, the nodules were classified into solid and GGO ones, of which results were compared with the data of PET scans. The lower limit size of nodules for PET imaging was also evaluated. METHODS: Prospective FDG-PET scans were undertaken for 136 non-calcified nodules less than 3 cm in diameter. CT density histograms were made for each nodule to classify into solid and GGO ones. RESULTS: Eighty-one nodules were malignant and 55 were benign. All of the 20 nodules less than 1 cm in diameter (n = 8 in malignant, n = 12 in benign), were negative on PET regardless of the histology. In the 116 nodules 1-3 cm in diameter (n = 73 in malignant, n = 43 in benign), there were 15 false negative and 15 false positive nodules, with a sensitivity of 79% and specificity of 65%. CT density histograms showed 101 solid nodules (n = 63 in malignant, n = 38 in benign) and 15 GGO nodules ( n = 10 in malignant, n = 5 in benign). All of the 10 malignant nodules with GGO images were histologically well-differentiated adenocarcinoma and 9 of them (90%) were false negative on PET. Four of the 5 (80%) benign nodules with GGO images were focal pneumonia with well-preserved air spaces, causing false positive on PET. Sensitivity and specificity for nodules with GGO images were 10 and 20%, respectively, which were significantly lower than 90 and 71% for nodules with solid images (P < 0.001). CONCLUSION: Pulmonary nodules which are less than 1cm in size or show GGO images on CT cannot be evaluated accurately by PET.

Differentiating between atypical adenomatous hyperplasia and bronchioloalveolar carcinoma using the computed tomography number histogram.

BACKGROUND: Both atypical adenomatous hyperplasia (AAH) and bronchioloalveolar carcinoma (BAC) appear as ground glass opacity (GGO) lesions by computed tomography (CT) and are sometimes difficult to differentiate. To aid distinction between the two, we examined their CT number histograms. METHODS: Histograms of pixel CT numbers were made for AAH (n = 9) and nonmucinous BAC (n = 8), and the peak and mean CT numbers on the histogram were quantified. RESULTS: Although there was no significant difference in lesion size between AAH and BAC, all AAHs were less than or equal to 1 cm in diameter. All AAHs and BACs manifested one histogram peak. Both the peak and mean CT numbers on the histogram were significantly lower for AAH than for BAC (p < 0.001). However, the degree of overlap between AAH and BAC was less for the peak CT number than for the mean CT number. CONCLUSIONS: The peak CT number on the histogram can help the radiologic differentiation between AAH and BAC. GGO lesions less than or equal to 1 cm in diameter that are diagnosed as AAH from the CT number histogram can be safely followed by CT.

Fluoroscopy-assisted thoracoscopic resection of lung nodules marked with lipiodol.

BACKGROUND: To localize small and deeply situated pulmonary nodules under thoracoscopy with roentgenographic fluoroscopy, we developed a marking procedure that uses both lipiodol and colored collagen. METHODS: Pulmonary nodules were marked with 0.4 mL of lipiodol under computed tomography. The visceral pleura near each nodule was marked with 1 mL of colored collagen, ie, a mixture of atelocollagen and methylene blue. Nodules were marked more than 1 day before thoracoscopy. At thoracoscopy, C-arm-shaped roentgenographic fluoroscopy was used to detect the radiopaque nodules. Eighteen nodules in 16 patients were localized by this procedure. The nodules had an average diameter of 7 mm (range: 4 to 10 mm) and were located an average distance of 19 mm (range: 8 to 30 mm) from the pleural surface under computed tomographic measurement. RESULTS: There were no complications from the marking procedure except for pneumothorax in 1 patient who required chest tube drainage for additional marking. All 18 nodules could be easily localized at thoracoscopy. The colored collagen revealed the pleura near the nodules. The lipiodol showed the nodules on the fluoroscopic monitor, which was used to guide the forceps to grasp the nodules. All of the nodules could be resected completely under thoracoscopy without adding minithoracotomy. The pathologic diagnosis was malignant tumor in 9 patients, atypical adenomatous hyperplasia in 3, and benign lesion in 4. CONCLUSIONS: A marking procedure that uses both lipiodol and colored collagen can localize small and deeply situated pulmonary nodules under fluoroscopy and facilitate safe and successful thoracoscopic resection.

Bilateral internal thoracic artery injury induced by blunt trauma.

A case is reported of a 52-year-old man with bilateral internal thoracic artery (ITA) injury induced by blunt trauma. He was a laborer at a construction site who was hit on the anterior chest by a ceiling block. On arrival at the hospital at one hour after the accident, his general condition was good, and the chest computed tomography (CT) showed a slight hematoma at the mediastinum. However, at 4 hours after the trauma, the blood pressure fell, and the CT showed a large anterior mediastinal hematoma with bilateral hemothorax. A median sternotomy revealed bilateral ITA injury at the level of the 3rd intercostal space and incomplete fractures in the sternum and bilateral rib cartilages. Although hemostasis was achieved by ligation of the injured ITA, bleeding re-occurred from the ITA at the level of the 2nd intercostal space, and this was stopped by a second operation. The patient recovered without any further significant complication. The rarity of blunt trauma-induced ITA injury is discussed, including the mechanism, diagnosis, and treatment.