Tuberculous peritonitis after conservative treatment for acute perforated appendicitis: a case report.

BACKGROUND: Interval appendectomy is widely recommended for patients with abscesses due to perforated appendicitis. A concomitant malignancy-related problem was reported after conservative treatment of acute appendicitis with abscess, but perforated appendicitis-associated tuberculous peritonitis was never reported. CASE PRESENTATION: A 67-year-old male patient with a laryngeal cancer history presented to our hospital with an acute appendicitis-associated ileal abscess. He was scheduled for an interval appendectomy after conservative treatment. Fortunately, the symptoms subsided, and the patient was discharged for a later scheduled appendectomy. However, after 3 months, he was readmitted to our hospital with fever and abdominal pain, and emergency surgery was performed, which was suspected to be peritonitis. Intraoperative results revealed numerous white nodules in the abdominal cavity. The condition was diagnosed as tuberculous peritonitis based on macroscopic results, later pathological findings, and positive T-SPOT.TB. The antituberculosis medications were effective, and the patient recovered and was discharged from the hospital 8 days thereafter. CONCLUSION: Patients, particularly those immunocompromised, may develop tuberculous peritonitis after conservative treatment for acute perforated appendicitis.

Conversion hepatectomy for advanced hepatocellular carcinoma after right portal vein transection and lenvatinib therapy.

BACKGROUND: Lenvatinib is a novel tyrosine kinase inhibitor that exhibits an antitumor effect on hepatocellular carcinoma (HCC). An established strategy that involves surgery and usage of lenvatinib for advanced HCC remains elusive. CASE PRESENTATION: A 58-year-old male patient with advanced HCC and untreated hepatitis B was referred to our hospital. The tumor at the right lobe was 10 cm in diameter with right portal vein thrombus. Because of the possible lung metastasis and concern about the remaining hepatic function after extended right hepatectomy, lenvatinib was initiated before surgery. After the confirmation of a sharp decrease of tumor markers during the 3-week lenvatinib therapy, only a right portal vein transection was done leaving the enlargement of the left lobe for improved post-hepatectomy liver function while lenvatinib therapy was continued. The laparotomy revealed that the tumor was invading the right diaphragm. After 7 weeks of lenvatinib administration after right portal vein transection, an extended right hepatectomy with resection of the tumor-invaded diaphragm was successfully done. The lung nodules that were suspected as metastases had disappeared. The patient has been doing well without any sign of recurrence for 1 year. CONCLUSION: The strategy involving the induction of lenvatinib to conversion hepatectomy including the portal vein transection was effective for advanced HCC.

A case of Trousseau's syndrome due to intrahepatic cholangiocarcinoma with an extremely high level of CA19-9.

BACKGROUND: Trousseau's syndrome is a cancer-associated thrombosis. Trousseau's syndrome with cholangiocarcinoma is a rare condition with poor prognosis. CASE PRESENTATION: A 59-year-old female was admitted to our hospital with abdominal pain, headache, and nausea. Abdominal enhanced computed tomography revealed liver tumor, splenic infarction, and bilateral renal infarction. Multiple acute cerebral infarctions were also detected by magnetic resonance imaging. Her preoperative serum levels of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) were > 120,000 U/mL and 589.6 ng/mL, respectively, which were extremely high. Histopathology after right hepatectomy revealed moderately differentiated adenocarcinoma consistent with intrahepatic cholangiocarcinoma. Her serum levels of CA19-9 were trending down to 9029.2 and 2659.8 U/mL at 1 and 3 weeks after surgery, respectively. However, at 7 weeks after surgery, her CA19-9 levels increased in the presence of positive imaging findings in the remnant liver, hilar lymph nodes, and peritoneal cavity. The initiation of combination chemotherapy including gemcitabine and cisplatin had a significant effect. The patient was doing well at 6 months after the surgery. CONCLUSION: This rare case of Trousseau's syndrome due to cholangiocarcinoma suggests that extremely high CA19-9 levels might be a pathogenic factor of this syndrome.

Laparoscopic surgery for two patients with strangulated transomental hernias.

BACKGROUND: Transomental hernias are a rare type of internal hernia. We report two cases of successful cases of laparoscopic repair. One required laparotomy due to concern for intestinal viability. CASE PRESENTATION: The first patient was a 67-year-old man who presented with abdominal pain and vomiting. He had no history of laparotomy or abdominal injury. Computed tomography suggested small bowel obstruction and possible intestinal strangulation. Emergent laparoscopy found approximately 200 cm of small bowel was strangulated around the greater omentum. The strangulation was released laparoscopically, but because of the color of the strangulated bowel, laparotomy was performed to evaluate viability. The involved portion of intestine was not resected. The patient experienced transient postoperative paralytic ileus and was discharged on postoperative day 14. The second patient was a 56-year-old man who presented with abdominal pain. Abdominal computed tomography revealed dilatation of the small intestine and a closed loop suggesting ileus due to intestinal strangulation. An emergency laparoscopy found a transomental hernia, and the strangulation was released laparoscopically. Recovery was uneventful, and the patient was discharged on postoperative day 6. CONCLUSION: Transomental hernia can be successfully treated laparoscopically. In cases where bowel viability is a concern, laparotomy should not be hesitated.

Single incision laparoscopic surgery (SILS) for Meckel's diverticulum.

A 65-year-old male patient presented with a chief complaint of abdominal pain. Abdominal computed tomography (CT) showed slight intestinal dilation and obstruction of the upper right quadrant of the small intestine, while ectopic gastric mucosal scintigraphy revealed abnormal accumulation in agreement with the CT-identified structure. The cause of bowel obstruction was diagnosed as Meckel's diverticulum; the patient was referred for surgery. A small laparotomy was performed with a 35-mm skin incision to the center of the navel. Once a lap disk was attached, a laparoscope was inserted to visualize the abdominal cavity. The small intestine that includes the structure was pulled out from the umbilicus to the outside of the peritoneal cavity and partially resected. On the pathological tissue findings, the patient was diagnosed with Meckel's diverticulum. We report our experience with single-lap laparoscopic surgery for a case of intestinal obstruction caused by Meckel's diverticulum and review pertinent literature.

Novel approach to pleurodesis with 50 % glucose for air leakage after lung resection or pneumothorax.

PURPOSE: Pleurodesis is performed in patients demonstrating air leakage after lung resection and in those with pneumothorax who must avoid surgery. However, there have so far been very few reports of pleurodesis with 50 % glucose. We herein examined the feasibility and effectiveness of this novel pleurodesis technique. METHODS: Thirty-five patients after lung resection and 11 pneumothorax patients without surgery were treated with pleurodesis using 50 % glucose. Approximately, 200 mL of 50 % glucose solution was injected into the pleural space and repeated until the air leakage stopped. Cases in which the air leakage did not stop after three injections were considered to be unsuccessful and subsequently treated with conventional pleurodesis using OK-432. RESULTS: Thirty-nine patients were successfully treated with 50 % glucose, although 7 patients required further treatment with OK-432. The unsuccessful group had some pulmonary comorbidities (P < 0.001), and the pleural effusion volume after pleurodesis was less than that in the successful group (P < 0.001). Although the air leakage did not stop in unsuccessful patients, the amount of air leakage markedly decreased. A temporary elevation of the blood sugar level was observed in 20 patients, but no other side effects had appeared. CONCLUSIONS: Pleurodesis with 50 % glucose is an easy, safe, and effective treatment modality. It is therefore considered to be a useful alternative method for pleurodesis.

Prognostic Significance of Aberrant Methylation of Solute Carrier Gene Family 5A8 in Lung Adenocarcinoma.

BACKGROUND: Solute carrier family 5 member A8 (SLC5A8) is a sodium-coupled transporter for several chemicals. The SLC5A8 gene has been reported to function as a tumor suppressor gene that contributes to carcinogenesis and tumor progression. The expression of SLC5A8 is silenced in colon neoplasia by hypermethylation of CpG-rich islands located in exon 1. In this study, we assessed the significance of aberrant methylation of the SLC5A8 gene as a prognostic factor for lung adenocarcinoma (AD). METHODS: We analyzed the methylation levels of a consecutive series of 143 node-negative stage I and II lung AD samples using pyrosequencing. RESULTS: The methylation level of exon 1 in the SLC5A8 gene was significantly associated with poor prognosis in cases of node-negative stage I and II lung AD. CONCLUSIONS: Gene silencing of SLC5A8 by hypermethylation was associated with poor prognosis in cases of node-negative stage I and II lung AD.

Interstitial Fluid Pressure Correlates Clinicopathological Factors of Lung Cancer.

PURPOSE: Solid tumors show increased interstitial fluid pressure (IFP), which correlates to a number of pathophysiological features of tumors. There have been no reports on the usefulness of measuring IFP in lung cancer. The aim of this study was to examine the relationship between IFP and the clinicopathological characteristics of lung cancer. METHODS: IFP was measured prospectively in 215 patients with 219 lesions showing solid or part-solid appearance. Four patients with double lung cancer were excluded from the analysis, resulting in 211 patients with lung cancer being analyzed for the correlation between IFP and computed tomography (CT) appearance, size, Tumor-node-metastasis (TNM) classification, maximal standardized uptake value (SUVmax), histological type, tumor grade, pleural and vessel invasion, Ki-67 index, and recurrence-free survival (RFS). RESULTS: The mean IFP was 8.5 mmHg; IFP was significantly correlated with the tumor size, SUVmax, TNM, vessel and pleural invasion, and Ki-67 index. Low IFP was associated with a better RFS compared to high IFP. Multivariate analysis did not select IFP as independent prognostic factor. In subgroup analysis of patients with adenocarcinoma, IFP was selected as independent one. CONCLUSIONS: IFP correlates clinicopathological factors of lung cancer. IFP might be used as a prognostic factor for lung cancer.

Multiple lung adenocarcinomas associated with von hippel-lindau disease.

Lung adenocarcinoma has never before been reported to be associated with von Hippel-Lindau (VHL) disease. Here, we report a case of VHL disease in a patient who had metachronous multiple lung adenocarcinomas. The patient is a 64-year-old-woman with VHL disease. She underwent surgical resection of one adenocarcinoma and one atypical adenomatous hyperplasia. A second lung adenocarcinoma developed metachronously. A point mutation in the VHL gene was confirmed in DNA from a blood sample, and loss of heterozygosity at the VHL locus was detected in the lung adenocarcinoma. The VHL dysfunction may have a role in the development of multiple lung adenocarcinomas.

Aberrant methylation and silencing of IRF8 expression in non-small cell lung cancer.

The aim of the present study was to investigate the aberrant methylation and altered expression of the interferon regulatory factor 8 (IRF8) gene in non-small cell lung cancer (NSCLC). Pyrosequencing assays were performed on 191 tumor specimens from NSCLC patients. The changes in IRF8 mRNA expression, prior to and following treatment with a demethylating agent and methylation itself, were examined in 13 lung cancer cell lines by quantitative polymerase chain reaction (qPCR) and pyrosequencing. IRF8 protein expression was examined in 94 of the 191 NSCLC specimens by immunohistochemical analysis. The IRF8 methylation level was significantly higher in the tumor tissues than in matched non-malignant lung tissues (P<0.0001). IRF8 was more frequently methylated in tumor tissues compared with matched non-malignant lung tissues, as defined by a predetermined cut-off value (P<0.0001). The IRF8 methylation level was strongly correlated with the change in mRNA expression in lung cancer cell lines and with the protein expression level in primary tumors. The IRF8 gene was more frequently methylated in patients without an epidermal growth factor receptor (EGFR) mutation than in patients with an EGFR mutation (P=0.015). IRF8 methylation correlated with recurrent prognosis in adenocarcinomas (log-rank test, P=0.048). IRF8 protein expression was frequently silenced in males, smokers, patients with non-adenocarcinoma or with wild-type EGFR, or in an advanced stage. IRF8 is often silenced by its methylation, which is a frequent event in NSCLC and, therefore, methylation of IRF8 may act as a prognostic marker for recurrence. Analysis of IRF8 methylation status may provide novel opportunities for improved prognosis and therapy of resected NSCLC.

Association of a genetic variant of CYP19A1 with multicentric development of lung adenocarcinomas.

BACKGROUND: The detection rate of multiple lung adenocarcinomas, which display multiple ground glass opacity nodules in the peripheral lung, is increasing because of advances in high resolution computed tomography. The genetic backgrounds of multiple nodules and the mechanisms that underlie their multicentric development are unknown. In this study, we examined single nucleotide polymorphisms (SNPs) of the cytochrome P450 19A1 gene to determine if they are associated with multiple adenocarcinomas risk. METHODS: Fifty-one cases of multiple adenocarcinomas with lepidic growth, 62 cases of a single adenocarcinoma with lepidic growth, and 126 control cases were analyzed. Three SNPs were analyzed by using a 5' nuclease assay with TaqMan minor-groove-binder probe. The expression level of CYP19A1 in the noncancerous lung was quantified by real-time reverse transcription polymerase chain reaction (RT-PCR). RESULTS: A minor allele of SNP rs3764221, which is located in the CYP19A1 gene, was significantly associated with multiple adenocarcinomas risk (adjusted odds ratio = 3.06; P = 0.006). Other polymorphisms of CYP19A1 were not significantly associated with the risk of multiple adenocarcinomas. A minor allele of SNP rs3764221 was also associated with a higher level of CYP19A1 messenger RNA expression (P = 0.03). CONCLUSIONS: SNP rs3764221 contributes to the development of multicentric adenocarcinomas in the peripheral lung by causing higher levels of CYP19A1 expression.

Long interspersed nucleotide element 1 hypomethylation is associated with poor prognosis of lung adenocarcinoma.

BACKGROUND: Genome-wide DNA hypomethylation is known to play important roles in genomic instability and carcinogenesis. Methylation in long interspersed nucleotide element 1 (LINE-1) is a good indicator of the global DNA methylation level within a cell. The aim of this study was to evaluate prognostic significance of LINE-1 hypomethylation in lung adenocarcinoma. METHODS: A consecutive series of 211 lung adenocarcinoma patients who underwent curative resections without any preoperative chemotherapy or radiotherapy at Kumamoto University Hospital between April 2010 and December 2012 were included. The LINE-1 methylation levels were quantified in tumor and noncancerous tissue by Pyrosequencing assay. RESULTS: Higher histologic grade and positive findings for vascular invasion were significantly associated with lower methylation levels. The disease-free survival in the hypomethylation group was significantly shorter than that of the non-hypomethylation group. The prognostic difference was more obvious in advanced cases (stage II, III) than in stage I cases. CONCLUSIONS: The LINE-1 methylation level is associated with histologic grade and vascular invasion of lung adenocarcinoma. Additionally, LINE-1 hypomethylation is a useful biomarker to predict early recurrence of lung adenocarcinoma.

[A case of imatinib mesylate-induced pneumonitis based on the detection of epithelioid granulomas by video-assisted thoracoscopic surgery biopsy in a patient with chronic myeloid leukemia].

A 79-year-old man with chronic myeloid leukemia was referred to our department because of dry cough and low-grade fever, 272 days after commencing imatinib mesylate (Gleevec). High resolution computed tomography (HRCT) showed tiny scattered centrilobular nodules and ground-glass opacities throughout both lung fields, suggesting drug-induced pneumonitis. A thoracic video-assisted thoracoscopic surgery (VATS) biopsy specimen from the centrilobular nodules in the right upper lobe demonstrated patchy distribution of epithelioid cell granulomas and intra-alveolar organization. Most of those lesions were predominantly located in the alveolar spaces, which implicated non-transbronchial distribution. Following drug cessation alone, the patient's general condition and radiological abnormalities improved.

A segmentectomy of the right upper lobe has an advantage over a right upper lobectomy regarding the preservation of the functional volume of the right middle lobe: analysis by perfusion single-photon emission computed tomography/computed tomography.

PURPOSE: To evaluate the advantages of a segmentectomy of the right upper lobe (RUL) over a right upper (RU) lobectomy regarding the preservation of the functional volume of the right middle lobe (RML), the postoperative forced expiratory volume in one second (FEV(1)) of the RML was compared between an RU lobectomy and an RUL segmentectomy, by using a coregistered perfusion single-photon emission computed tomography and computed tomography (SPECT/CT). METHODS: The pulmonary function tests and perfusion SPECT/CT were conducted before and after surgery (RU lobectomy: 7; RUL segmentectomy: 13). The FEV(1) of the RML before and after surgery was calculated from the data of the pulmonary function test and SPECT/CT. RESULTS: In the RU lobectomy group, the percentage change of FEV(1) was 71% +/- 12%, which was significantly lower in comparison to 92% +/- 9% in the RUL segmentectomy group (P = 0.001). In the lobectomy group, the preoperative FEV(1) of the RML was 0.17 +/- 0.10 l, which decreased significantly to 0.06 +/- 0.06l after surgery (P = 0.009). In the segmentectomy group, FEV(1) of the RML before and after the surgery were 0.23 +/- 0.10 l and 0.20 +/- 0.111, of which the difference was not significant. CONCLUSION: An RUL segmentectomy has an advantage over an RU lobectomy regarding the preservation of pulmonary function, due to a greater preservation of not only the lung tissue, but also the FEV(1) of the RML.

Repeat FDG-PET for predicting pathological tumor response and prognosis after neoadjuvant treatment in nonsmall cell lung cancer: comparison with computed tomography.

BACKGROUND: The efficacy of fluorodeoxyglucose-positron emission tomography (FDG-PET) for predicting pathological tumor response and prognosis after neoadjuvant chemoradiotherapy followed by surgery in locally advanced nonsmall cell lung cancer (NSCLC) was compared to the predictive value of tumor size as determined by computed tomography (CT). METHODS: Thirty-seven consecutive NSCLC patients who received FDG-PET and CT scans both before and after neoadjuvant chemoradiotherapy were enrolled in this study. The percentage point changes in maximum standard uptake value (SUV) on PET and tumor size on CT after neoadjuvant treatment were defined as the SUV ratio and the size ratio, respectively, and were compared with pathological tumor response and prognosis after surgery. A major pathological response was defined as residual viable tumor cells corresponding to less than one-third the size of the original tumor. RESULTS: Nineteen and 18 patients showed major and minor pathological responses, respectively, after neoadjuvant treatment. The optimal cutoff values for predicting a major pathological response were 0.6 for the SUV ratio and 0.79 for the size ratio. The SUV ratio predicted the pathological tumor response with higher accuracy than the size ratio did (P = 0.04). Neither the SUV ratio nor the size ratio predicted prognosis after surgery. CONCLUSION: For predicting the pathological tumor response after neoadjuvant chemoradiotherapy, the SUV ratio on FDG-PET is superior to the size ratio on CT in patients with NSCLC. However, neither the SUV ratio nor the size ratio could predict prognosis.

Required area of lymph node sampling during segmentectomy for clinical stage IA non-small cell lung cancer.

OBJECTIVE: To investigate the required area of lymph node sampling during segmentectomy, especially for segmental nodes at the nonresected segments, we examined the distribution of sentinel nodes in patients with non-small cell lung cancer who underwent segmentectomy. METHODS: Ninety-four patients with clinical T1 N0 M0 non-small cell lung cancer were treated by using segmentectomy and dissection of lymph nodes with sentinel node identification using (99m)Tc-phytate. Anatomic locations of the segments were classified as either anterior or posterior, and correlations of anatomic location with the distribution of sentinel nodes at the segmental nodes were then examined. RESULTS: Of the 94 patients, segmental nodes at both the resected and nonresected segments could be dissected in 42 patients. Segmental sentinel nodes were found at the resected segments in 27 (64%) of these 42 patients, a frequency that was significantly higher than that (12/42 [29%]) seen at the nonresected segments (P = .001). Seven (47%) of the 15 patients with tumors in the anteriorly located segments had segmental sentinel nodes at the nonresected segments, a frequency that was significantly higher than that (4/24 [17%]) seen in patients with tumors in the posteriorly located segments (P = .04). CONCLUSION: The lymphatic flow from the anteriorly located segment can frequently go directly to the segmental lymph nodes of the posteriorly located segment, probably because the lobar bronchi locate at the posterior side in the thorax. Therefore segmental lymph nodes should be dissected at both the resected and nonresected segments during segmentectomy, especially for tumors in the anteriorly located segment.

A case of primary mediastinal ependymoma.

A 50-year-old female complained of back pain. Computed tomography showed a well-defined spindle-shaped mass 3.4 x 1.0 cm in size in the left paravertebral posterior mediastinum at the Th 3-4 level. The tumor was completely resected via thoracoscopic surgery, which showed no invasion into the surrounding tissue. It consisted of a cyst with a tiny mural solid element. By means of histological and immunohistochemical examinations, we diagnosed the tumor as ependymoma, and the patient remains alive 59 months after resection. As far as we know, 8 reported cases with primary mediastinal ependymoma have been reported. They had the following specific characteristics: (1) All patients were adult females; (2) The tumors were usually located at the paravertebral upper mediastinum; (3) Most of the tumors consisted of cystic and solid elements; (4) The tumors usually made no invasion into the surrounding tissues, though 2 cases had lymph-node metastases.

Is diffusion-weighted magnetic resonance imaging superior to positron emission tomography with fludeoxyglucose F 18 in imaging non-small cell lung cancer?

OBJECTIVE: This retrospective analysis examined whether diffusion-weighted magnetic resonance imaging might be as useful as positron emission tomography with fludeoxyglucose F 18 for (1) discriminating between non-small cell lung cancer and benign pulmonary nodules and (2) predicting aggressiveness of non-small cell lung cancer. METHODS: Diffusion-weighted magnetic resonance imaging and positron emission tomography were performed before surgery in 110 patients with 124 pulmonary nodules smaller than 3 cm, including 96 non-small cell lung cancers and 28 benign nodules. Diffusion of water molecules in magnetic resonance imaging was measured by minimum value of apparent diffusion coefficient. The criterion standard was the result of histologic diagnosis or follow-up examination. Sensitivity and specificity for differentiating between cancers and benign nodules were compared between diffusion-weighted imaging and positron emission tomography. Apparent diffusion coefficient in diffusion-weighted imaging and fludeoxyglucose F 18 uptake in positron emission tomography were examined with respect to pathologic tumor stage; lymphatic, vascular and pleural involvements; and histologic differentiation. RESULTS: There were no significant differences between diffusion-weighted magnetic resonance imaging and positron emission tomography in sensitivity or specificity for non-small cell lung cancer. Whereas positron emission tomography showed significant differences in fludeoxyglucose F 18 uptake between pathologic stages IA versus IB or more advanced stages; between tumors with and without lymphatic, vascular, or pleural involvement; and between well-differentiated and moderately or poorly differentiated adenocarcinomas (P <.01-0.001), no significant differences in apparent diffusion coefficient values in were observed. CONCLUSION: Diffusion-weighted magnetic resonance imaging is equivalent to positron emission tomography in distinguishing non-small cell lung cancer from benign pulmonary nodules but is not as useful for predicting aggressiveness of non-small cell lung cancer.

11C-acetate for positron emission tomography imaging of clinical stage IA lung adenocarcinoma: comparison with 18F-fluorodeoxyglucose for imaging and evaluation of tumor aggressiveness.

BACKGROUND: To determine the usefulness of positron emission tomography (PET) with (11)C-acetate (AC) for imaging lung adenocarcinoma and evaluating its tumor aggressiveness, AC- and (18)F-fluorodeoxyglucose (FDG)-PET were compared. METHODS: One hundred and sixty-nine adenocarcinomas with clinical stage IA and 53 benign nodules were examined by both AC- and FDG-PET before surgery. The sensitivity and specificity for discriminating benign/adenocarcinoma were compared between AC- and FDG-PET. The AC and FDG uptakes were examined to determine the relationship with tumor aggressiveness, i.e., pathological tumor stage, lymphatic, vascular, or pleural involvement, and proliferative activity determined by Ki-67 staining score. RESULTS: While the sensitivity of AC-PET was significantly higher than FDG-PET for bronchioloalveolar carcinoma (BAC) and well-differentiated (W/D) adenocarcinoma (p < 0.001 and 0.006, respectively), there was no significant difference for moderately or poorly differentiated adenocarcinoma. The specificity was not different between them. While FDG uptakes were significantly higher in tumors with pathological advanced stages or those with lymphatic, vascular and/or pleural involvements than in tumors with pathological stage IA or those without these tumor involvements (p = 0.04 to p < 0.001), AC uptake did not show significant differences between the respective sub-groups except according to the tumor stage. While both AC and FDG uptakes showed a significant correlation with Ki-67 staining scores (p = 0.03 and p < 0.001, respectively), the correlation coefficient of former was lower than that of latter (p = 0.07). CONCLUSIONS: While AC-PET can image BAC and W/D adenocarcinoma with a higher sensitivity than FDG-PET, it cannot evaluate tumor aggressiveness of clinical stage IA lung adenocarcinoma as well as FDG-PET.

Positron emission tomography in lung cancer.

Recent advances in positron emission tomography (PET) with 2-deoxy-2-fluoro [F-18]-D: -glucose (FDG) has enabled not only the diagnosis and staging of lung cancer but also the prediction of its malignancy grade. However, FDG-PET has been known to have several pitfalls for imaging of lung cancer. For the effective clinical use of FDG-PET in lung cancer, we reviewed the pitfalls of using FDG-PET in the diagnosis of pulmonary nodules, semiquantitative analysis of FDG-uptake, N-staging, prediction of tumor aggressiveness, prognostic significance, and prediction of pathological response after chemoradiotherapy.