[A case of hemobilia due to the rupture of pancreaticoduodenal artery aneurysm with choledocholithiasis].

A 79-year-old male patient had a huge choledocholithiasis that was difficult to remove and underwent endoscopic retrograde biliary drainage. He complained of hematemesis upon admission to our hospital. Endoscopic retrograde cholangiography showed bleeding from the papilla of Vater and revealed an upper filling defect with a large stone in the common bile duct. Furthermore, computed tomography detected an aneurysm close to the stone. Considering the occurrence of a ruptured pancreaticoduodenal artery aneurysm, we diagnosed this condition as hemobilia. Through angiography, we also detected a saccular aneurysm in the posterior superior pancreaticoduodenal artery (PSPDA);subsequently, selective transcatheter arterial embolization (TAE) was performed. However, bleeding persisted after TAE;therefore, we performed second-time embolization for other PSPDA branches. Consequently, hemostasis was achieved. To date, bleeding has not reoccurred. The pancreaticoduodenal artery constitutes a complex arcade;hence, cases of extremely difficult hemostasis by embolization have been reported. Herein, we have presented a life-saving case of choledocholithiasis treated with TAE for biliary bleeding from a PSPDA aneurysm rupture.

[A Vesected Case of Pancreatic Metastasis from Breast Cancer Which Recurred Six Years after Breast Surgery].

A 43-year-old woman who underwent surgical resection of invasive ductal carcinoma in the left breast at the age of 37 years old presented at our hospital for evaluation of pancreatic tumor. The original tumor was estrogen receptor(ER)progesterone receptor(PgR)and HER2 positive. At that time, she underwent radical mastectomy with no evident nodal disease. Postoperatively, the patient was placed on adjuvant tamoxifen therapy for several years. Six years following the original diagnosis of breast cancer, she was referred to the hospital for routine check-up while asymptomatic. Follow-up examination showed a solitary hypodense mass approximately 0.9 cm in size in the pancreas body on dynamic CT scan. The patient underwent a standard distal pancreatectomy with standard regional lymphadenectomy. Histopathological examination and immunohistochemical features revealed that the tumor was compatible with metastatic pancreatic adenocarcinoma from breast cancer.

Marked accumulation of fluorodeoxyglucose and inflammatory cells expressing glucose transporter-3 in immunoglobulin G4-related autoimmune hepatitis.

Immunoglobulin (Ig)G4-related autoimmune hepatitis (AIH) is a recently proposed subtype that responds well to steroid treatment; however, its pathogenesis remains unclear. We report here a 65-year-old Japanese woman with skin itching and lip swelling. She had liver injury with jaundice, which persisted despite stopping anti-allergic agents. Blood chemistry revealed highly elevated serum IgG and IgG4 (535 mg/dL) levels, and positive anti-nuclear antibody. The diagnosis of AIH was based on liver biopsy. Notably, the IgG4+ /IgG+ cell ratio was 85%. On fluorodeoxyglucose (FDG) positron emission tomography/computed tomography, robust signal intensity was found in the liver, and in enlarged lymph nodes and salivary glands with confirmed IgG4+ cell infiltration. Immunofluorescence analysis of the liver biopsy specimen indicated clear expression of glucose transporter-3 (Glut-3) in IgG4+ inflammatory cells infiltrating into the portal area. This is the first report of simultaneous strong accumulation of FDG and Glut-3 expression in IgG4-related AIH, which might aid in elucidating the pathogenesis of this disease.

ARHGEF15 overexpression worsens the prognosis in patients with pancreatic ductal adenocarcinoma through enhancing the motility and proliferative activity of the cancer cells.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplastic diseases, associated with a remarkably poor prognosis. However, the molecular mechanisms underlying the development of PDAC remain elusive. The aim of this study was to identify genes whose expressions are correlated with a poor prognosis in PDAC patients, and to unravel the mechanisms underlying the involvement of these genes in the development of the cancer. METHODS: Global gene expression profiling was conducted in 39 specimens obtained from Japanese patients with PDAC to identify genes whose expressions were correlated with a shorter overall survival. The effect of gene silencing or overexpression of ARHGEF15 in pancreatic cancer cell lines was examined by introducing siRNAs of ARHGEF15 or the ARHGEF15 expression vector. After assessing the effect of ARHGEF15 deregulation on the Rho-family proteins by pull-down assay, wound healing, transwell and cell viability assays were carried out to investigate the cellular phenotypes caused by the perturbation. RESULTS: The global mRNA expression profiling revealed that overexpression of ARHGEF15, a Rho-specific GEF, was significantly associated with a poor prognosis in patients with PDAC. We also found that the depletion of ARHGEF15 by RNA interference in pancreatic cancer cell lines downregulated the activities of molecules of the Rho signaling pathway, including RhoA, Cdc42 and Rac1. Then, we also showed that ARHGEF15 silencing significantly reduced the motility and viability of the cells, while its overexpression resulted in the development of the opposite phenotype in multiple pancreatic cancer cell lines. CONCLUSION: These data suggest that upregulation of ARHGEF15 contributes to the development of aggressive PDAC by increasing the growth and motility of the pancreatic cancer cells, thereby worsening the prognosis of these patients. Therefore, ARHGEF15 could serve as a novel therapeutic target in patients with PDAC.

[A Case of Pancreatic Head Cancer Showing Pathological Complete Response to Neoadjuvant Chemoradiation Therapy].

The patient was a 64-year-old woman. She was referred to our institute because of a chief complaint of upper abdominal pain. Abdominal computed tomographic scan revealed a 35 mm hypovascular tumor in the pancreatic head and superior mesenteric vein (SMV), as well as thrombosis. We chose neoadjuvant chemoradiation therapy (NACRT) (S-1/RT, 50.4 Gy/28 Fr) and anticoagulants. After the treatment, the primary lesion showed a partial response, and the SMV thrombosis was reduced. We performed pancreaticoduodenectomy. Histopathological examination revealed no cancer cells in the pancreas. Pathological evaluation revealed grade Ⅳ tumor according to the Evans classification. The patient had had no recurrence for 10 months after the pancreaticoduodenectomy.

Evaluation of endoscopic transpapillary brushing cytology for the diagnosis of bile duct cancer based on the histopathologic findings.

BACKGROUND AND AIM: Diagnosis of the bile duct cancer still needs more accuracy. Studies on endoscopic retrograde cholangiopancreatography (ERCP)-guided brushing cytology were carried to evaluate the role of the endoscopic transpapillary brushing cytology for the diagnosis of bile duct cancer. PATIENTS AND METHOD: The study involved 76 consecutive patients who underwent ERCP-guided bile duct cytology for the diagnosis of bile duct cancer from 2008 to August 2012. Three types of cytological specimens were obtained using different sampling methods, i.e., bile aspiration cytology (BAC), brush tip cytology (BTC), and post brushing bile cytology (PBC), to investigate their diagnostic abilities, and comparatively studied with each macroscopic type of the surgically resected specimens. RESULTS: The cancer-positive rate was 67.1 % (BAC alone: 41.9 %), and the use of BTC and PBC in addition to BAC yielded a statistically significant increase of the cancer-positive rate (p = 0.0031). In 34 resected cases, the cancer-positive rate in relation to the macroscopic type was improved by the addition of BTC and PBC to BAC alone for the papillary (87.5 vs. 40.0 %, p = 0.071) and nodular (100 vs. 70.0 %, p = 0.0603) types, but not for the flat type (62.5 vs. 57.1 %; p = 0.7651). CONCLUSION: The diagnostic ability of ERCP-guided brushing cytology could be improved by the addition of PBC. However, the cancer-positive rate was the lowest for the flat type of bile duct cancer.

Evaluation of magnifying endoscopy using narrow band imaging using ex vivo bile duct (with video).

BACKGROUND AND AIM: Detailed endoscopic findings of the bile duct mucosa, even of the non-neoplastic mucosa, have not yet been established. The aim of the present study was to compare a currently used video cholangioscope (CCS) with a magnifying endoscope (ME) that is commonly used for the gastrointestinal tract, for visualization of the bile duct mucosa. METHODS: Ten freshly resected common bile ducts were used in this study. We observed the non-neoplastic bile duct mucosa with CCS and ME, and carried out both conventional white light imaging and narrow band imaging. After histological diagnosis, the 10 specimens were classified into three categories according to the degree of histological inflammation: normal to mild, moderate, and severe. Then, we examined the relationship between the magnifying endoscopic findings and the histopathological findings. RESULTS: In eight of the 10 cases, the visualization obtained with CCS was inferior to that obtained by ME. Five specimens were classified as normal to mild inflammation, and many oval-shaped, depressed areas and a fine, regular network of the microvessels were observed by ME on the mucosal surfaces of these specimens. The remaining specimens were classified as moderate or severe inflammation, and the aforementioned findings could not be clearly visualized. CONCLUSION: CCS does not allow visualization of the bile duct mucosa with high sensitivity. Oval-shaped depressed areas and a fine, regular network of microvessels are characteristic endoscopic features of non-neoplastic bile duct mucosa without inflammation.

Prognostic Factors for Distal Bile Duct Carcinoma After Surgery.

BACKGROUND: Distal bile duct carcinoma continues to be one of the most difficult cancers to manage in terms of staging and radical resection. Pancreaticoduodenectomy (PD) with regional lymph node dissection has become the standard treatment of distal bile duct carcinoma. We evaluated treatment outcomes and histological factors in patients with distal bile duct carcinoma. METHODS: Seventy-four cases of resection of carcinoma of the distal bile ducts treated at our department during the period from January 2002 and December 2016 using PD and regional lymph node dissection as the standard surgical procedure were investigated. Survival rates of factors were analyzed using uni- and multivariate analyses. RESULTS: The median survival time was 47.8 months. On univariate analysis, age of 70 years or older, histologically pap, pPanc2,3, pN1, pEM0, v2,3, ly2,3, ne2,3 and postoperative adjuvant chemotherapy were statistically significant factors. On multivariate analysis, histologically pap was identified as a significant independent prognostic factor. The multivariate analysis identified age of 70 years or older, pEM0, ne2,3 and postoperative adjuvant chemotherapy as showing a significant trend towards independent prognostic relevance. CONCLUSION: The good news about resected distal bile duct carcinoma is that the percentage of those who achieved R0 resection has risen to 89.1%. Our multivariate analysis identified age of 70 years or older, pEM0, ne2,3 and postoperative adjuvant chemotherapy as prognostic factors. In order to improve the outcome of treatment, it is necessary to improve preoperative diagnostic imaging of pancreatic invasion and lymph node metastasis, establish the optimal operation range and clarify whether aortic lymph node dissection is needed to control lymph node metastasis, and establish effective regimens of chemotherapy.

Accuracy of differential diagnosis for pancreatic cancer is improved in the combination of RCAS1 and CEA measurements and cytology in pancreatic juice.

Improvement of diagnostic accuracy for pancreatic cancer in pancreatic disease patients was investigated by examining the combination of three diagnostic methods, i.e., measurements of RCAS1 and CEA levels in pancreatic juice and pancreatic juice cytology. Pancreatic juice was collected from 12 pancreatic cancer (PC) and 26 non-PC patients. RCAS1 and CEA levels were measured by using ELISA. RCAS1 expression on surgically resected tissue was immunohistochemically examined for 2 PC patients. By setting the cutoff level of RCAS1 at 10 U/ml and that of CEA at 18.5 µg/ml, sensitivity of RCAS1 was 42% and that of CEA was 50%. On the other hand, sensitivity and specificity increased from 42% and 85% of RCAS1 alone to 75% and 85% in the examination of RCAS1 + CEA + cytology, and the false-negative rate was also reduced to 25% in this combination. Immunohistochemically, a patient with a high RCAS1 level in pancreatic juice had numerous RCAS1-positive tumor cells in the pancreatic juice. We concluded that RCAS1 and CEA measurements together with cytology in pancreatic juice would be a useful combination method for making a differential diagnosis of PC from non-PC.

Direct cholangioscopy using a double-balloon enteroscope: choledochojejunostomy with intraductal biliary carcinoma.

A 75-year-old man who underwent choledochojejunostomy for gallstones 30 years ago was hospitalized for general malaise. Abdominal computed tomography revealed marked dilation of the intrahepatic bile duct in the right lobe and an image of a hypervascular tumor. Endoscopic retrograde cholangiography using double-balloon enteroscopy (DBE) showed a filling defect that was localized to the right hepatic bile duct. Furthermore, the scope was able to readily pass through the anastomosed site of the choledochojejunostomy and, therefore, we observed the interior of the bile duct using the same scope. We obtained an image showing a whitish, papillary-like tumor, and a biopsy of the tumor rendered the pathology of intraductal papillary mucinous carcinoma. Direct cholangioscopy using DBE is a useful diagnostic tool, particularly in patients with a past history of choledochojejunostomy.

Multi-centric pancreatic cancer without PanIN lesion.

The patient was a 67-year-old man under follow-up after gastric cancer surgery. An abdominal CT scan performed 1 year earlier had shown an approximately 14-mm hypovascular mass in the pancreatic body; however, he did not consent to treatment and was followed up for 1 year. A blood workup showed that the fasting blood glucose level, which had been within normal limits, was elevated to 174 mg/dl (normal, 70-109 mg/dl), and the HbA1c level was 12.0% (normal, 4.3-5.8%). Abdominal CT revealed an approximately 20-mm mass in the pancreatic body and an approximately 12-mm mass in the pancreatic tail, and magnetic resonance imaging cholangiopancreatography (MRCP) showed discontinuity of the main pancreatic duct (MPD). Since these findings led to the suspicion of invasive ductal carcinoma (IDC) of the pancreas developing in the pancreatic body and tail, we performed distal pancreatectomy with splenectomy. Histologically, IDCs were observed in the pancreatic body and tail. However, PanIN was not observed in the MPD between the two carcinomas. They were diagnosed as independent invasive ductal carcinomas of the pancreas.

Pathomorphologic study of undifferentiated carcinoma in seven cases: relationship between tumor and pancreatic duct epithelium.

BACKGROUND/PURPOSE: By the time undifferentiated carcinoma is detected, it has formed a large mass, and it is reportedly difficult to pathologically observe its relationship with the pancreatic duct. In this study, we examined the pancreatic ducts of seven patients of surgical samples, and pathomorphologically investigated the relationship between the adenocarcinomatous and sarcomatous components and the pattern of tumor extension. In addition, we evaluated the usefulness of pancreatic juice cytology by comparison with the findings of the main pancreatic duct (MPD). METHODS: Seven primary undifferentiated carcinomas of the pancreas (from three male and four female patients with a mean age of 59 years) were analyzed. Histopathological evaluation was based on the WHO diagnostic criteria. Pancreatic juice cytology was performed and evaluated in two patients. RESULTS: All the undifferentiated carcinomas contained adenocarcinomatous and sarcomatous components, and two had a distinct glandular structure. However, we could not pathomorphologically confirm the continuity of the adenomatous with the sarcomatous components in any of the patients. Three undifferentiated carcinomas contained osteoclast-like giant cells. Pathological observation of the tumor and MPD was possible in three of the seven undifferentiated carcinomas. PanIN-3 was observed in the MPD of three patients, suggesting extension into the MPD. In one of these three, the tumor presented intraductal growth in the MPD, and preoperative pancreatic juice cytology revealed atypical cells with osteoclast-like giant cells. In the remaining two, the tumor extraductally compressed the MPD upward. CONCLUSIONS: Undifferentiated carcinoma showed two patterns of cancer extension: (1) invasion and expansive growth during the sarcomatous transformation of adenocarcinoma, and (2) intraductal extension. In addition, some undifferentiated carcinomas showed extension in the MPD. Of note, postoperative pancreatic juice cytology may be useful for the diagnosis.

Endoscopic retrieval of migrated plastic stent into bile duct or pancreatic pseudocyst.

Proximally migrated biliary plastic stent and migrated stent in the pancreatic pseudocyst are relatively rare complications. A migrated stent causes poor drainage conditions, which leads to secondary complications such as infection, abscess, perforation and, moreover, becomes a foreign object in the body, and retrieval or re-stenting is therefore necessary. The retrieval of a migrated stent includes surgical, percutaneous and endoscopic approaches, and the most non-invasive method is endoscopic retrieval. However, because very few devices are exclusively designed for retrieval, the current situation is that the available devices are used while taking advantage of various ideas and techniques. From previously reported cases and our experiences of such cases, we herein describe the methods of endoscopic retrieval for stents that have migrated into a bile duct or pancreatic pseudocysts.

Ex vivo magnifying endoscopic observation of bile duct mucosa using narrowband imaging.

BACKGROUND: Detailed endoscopic findings of the bile duct mucosa have not been fully established. This fundamental ex vivo study assesses the relationship between magnified endoscopic findings and pathological findings of the bile duct mucosa. METHODS: Forty-one surgically resected common bile duct mucosae were investigated. Each common bile duct was cut open longitudinally for ex vivo endoscopic observation. A magnifying endoscope commonly used for the gastrointestinal tract was used, using both white light imaging and narrowband imaging. After pathological diagnosis, the association between the magnifying endoscopic findings and histopathology was evaluated. RESULTS: Totally, 39 non-neoplastic mucosae and 13 neoplastic mucosae were evaluated. In 13 non-neoplastic mucosae without inflammation, an oval-shaped depressed area and a fine, regular network of microvessels were observed. These findings were not clearly seen or not seen at all in the non-neoplastic mucosae with inflammation. Although vessels with loop-like structure were observed on all eight papillary tumors of 13 neoplastic mucosae, no characteristic vessels were seen on the other five. CONCLUSIONS: Ishida and colleagues assessed the association between magnifying endoscopic findings and histopathological findings of the bile duct mucosa ex vivo. Oval-shaped, depressed areas and a fine, regular network of microvessels are characteristic features of normal bile duct mucosa, while loop structures may be indicative of a type of tumor vessel.

A case of pancreatic neuroendocrine tumor with multiple cystic components of various sizes.

The patient was a 51-year-old woman who, while undergoing a thorough health checkup, was found to have a tumor (measuring 60 mm in diameter) in the tail of the pancreas by abdominal ultrasonography. Contrast-enhanced computed tomography revealed delayed contrast enhancement; the tumor also contained numerous low-absorption areas showing poor contrast enhancement. On magnetic resonance imaging, the tumor was visualized as having high signal intensity areas inside the tumor on T2-weighted images. Positron emission tomography revealed an abnormal accumulation in the area corresponding to the tumor. Endoscopic ultrasonography (EUS) revealed a relatively hyperechoic solid area, with a number of echo-free areas of various sizes that assumed a honeycomb appearance. EUS-guided fine needle aspiration was carried out targeting the solid area within the tumor, which led to a diagnosis of pancreatic neuroendocrine tumor (PNET). Histopathological examination of the resected specimen revealed that the tumor was composed of numerous cysts of various sizes and solid components. The cysts contained no evidence of necrosis or bleeding. Immunohistochemically, the cystic as well as solid components were CD56 (+), synaptophysin (+) and chromogranin A (+) with MIB1 labeling index of 5%. On the basis of these findings, the final diagnosis was PNET (G2).

Muscle RAS oncogene homolog (MRAS) recurrent mutation in Borrmann type IV gastric cancer.

The prognosis of patients with Borrmann type IV gastric cancer (Type IV) is extremely poor. Thus, there is an urgent need to elucidate the molecular mechanisms underlying the oncogenesis of Type IV and to identify new therapeutic targets. Although previous studies using whole-exome and whole-genome sequencing have elucidated genomic alterations in gastric cancer, none has focused on comprehensive genetic analysis of Type IV. To discover cancer-relevant genes in Type IV, we performed whole-exome sequencing and genome-wide copy number analysis on 13 patients with Type IV. Exome sequencing identified 178 somatic mutations in protein-coding sequences or at splice sites. Among the mutations, we found a mutation in muscle RAS oncogene homolog (MRAS), which is predicted to cause molecular dysfunction. MRAS belongs to the Ras subgroup of small G proteins, which includes the prototypic RAS oncogenes. We analyzed an additional 46 Type IV samples to investigate the frequency of MRAS mutation. There were eight nonsynonymous mutations (mutation frequency, 17%), showing that MRAS is recurrently mutated in Type IV. Copy number analysis identified six focal amplifications and one homozygous deletion, including insulin-like growth factor 1 receptor (IGF1R) amplification. The samples with IGF1R amplification had remarkably higher IGF1R mRNA and protein expression levels compared with the other samples. This is the first report of MRAS recurrent mutation in human tumor samples. Our results suggest that MRAS mutation and IGF1R amplification could drive tumorigenesis of Type IV and could be new therapeutic targets.

Des-γ-carboxyprothrombin (DCP) and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma.

AIM: Des-γ-carboxyprothrombin (DCP) has been used as a tumor marker for hepatocellular carcinoma (HCC). Recently the DCP/NX-DCP ratio, calculated by dividing DCP by NX-DCP, has been reported useful in detecting HCC. The purpose of this study is to clarify the significance of DCP and NX-DCP expression in HCC tissues. METHODS: HCC and non-HCC tissue samples were obtained from 157 patients and were immunohistochemically examined for DCP and NX-DCP expression using anti-DCP antibody and anti-NX-DCP antibody. DCP and NX-DCP expression scores were calculated by multiplying staining intensity grade by percentage of stained area. Serum DCP and NX-DCP levels were determined in 89 patients. We evaluated the relationship between tumor expression, serum level, and pathomorphological findings. RESULTS: Intrahepatic metastasis (im) was significantly more frequent in cases with high DCP expression than in cases with low DCP expression. High NX-DCP expression was associated with significantly lower histological grade, and less frequent im or portal vein invasion (vp) than low NX-DCP expression. Serum DCP was correlated with DCP expression, but serum NX-DCP was not correlated with NX-DCP expression. DCP-positive (≥40 mAU/L), NX-DCP-positive (≥90 mAU/L), and DCP/NX-DCP ratio-positive (≥1.5) cases were associated with significantly larger tumor size and more frequent vp than negative cases. DCP was rarely expressed, but NX-DCP was frequently expressed in non-cancerous liver tissues. Patients with NX-DCP expression-negative tumors showed a lower survival rate than those with NX-DCP expression-positive tumors (p = 0.04), whereas the survival in serum NX-DCP-positive cases was lower than that of serum negative cases (p = 0.02). CONCLUSIONS: DCP and NX-DCP were produced in HCC tissues, but differed in expression level and biological properties. DCP expression, serum DCP or NX-DCP level, and DCP/NX-DCP ratio were closely related to malignant properties of HCC.

Evaluation of endoscopic cytological diagnosis of unresectable pancreatic cancer prior to and after the introduction of endoscopic ultrasound-guided fine-needle aspiration.

With the advances in the multidisciplinary treatment of pancreatic cancer (PC) over the last few years, it is crucial to obtain a histopathological diagnosis prior to treatment. Histopathological diagnosis for unresectable PC is currently performed with endoscopic retrograde cholangiopancreatography (ERCP) in combination with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We retrospectively assessed the results of these two methods and investigated diagnostic performance according to the location of the lesion and the complications. This study was conducted on a series of 263 consecutive cases of unresectable PC diagnosed with endoscopic cytology. Up to 2006, ERCP-guided cytology (group A) was performed as the first choice for the diagnosis of PC. EUS-FNA was introduced in 2007 and became the first choice thereafter (group B), except in cases with obstructive jaundice, in which ERCP-guided cytology during endoscopic biliary stenting (EBS) remains the first choice. There were statistically significant differences in the overall cancer-positive rate between groups A and B (60.4 vs. 75.3%, P=0.01). The cancer-positive rate in the pancreatic body and tail was significantly higher in group B (59.5 vs. 83.3%, P=0.005), whereas there were no significant differences regarding cancer of the pancreatic head. The complication rate was 4.95% in group A and 3.09% in group B (P=0.448). The endoscopic cytology cancer-positive rate in unresectable PC cases was increased as a result of the introduction of EUS-FNA. In conclusion, we recommend performing EUS-FNA in combination with ERCP-guided cytology in cases with a lesion in the pancreatic head that requires EBS.

Evaluation of immunohistochemistry using two different antibodies and procedures for primary lung adenocarcinoma harboring anaplastic lymphoma kinase rearrangement.

Rearrangements of anaplastic lymphoma kinase (ALK) have been recently identified in non-small cell lung carcinomas. Previous studies have revealed characteristic features, including adenocarcinoma histology and mucin production, in ALK-positive lung carcinoma. The present study evaluated immunohistochemistry (IHC) in ALK-positive lung carcinoma using two different antibodies, clone 5A4 and D5F3, and compared the results. On the basis of the aforementioned characteristic features, out of 359 primary lung carcinomas, the ALK status of 14 adenocarcinomas was screened using the intercalated antibody-enhanced polymer (iAEP) method with antibody 5A4, and this was compared with the ALK status obtained using rabbit monoclonal antibody D5F3 and fluorescence in situ hybridization for ALK. Eight cases were demonstrated to be ALK-positive by IHC. Seven cases exhibited ALK rearrangement, which was demonstrated by fluorescence in situ hybridization. The IHC for ALK obtained using D5F3 was comparable with that of the iAEP and exhibited low heterogeneity. This finding suggests that IHC for ALK could be useful in limited tissue samples, such as biopsy specimens or cytology, for the screening of ALK-positive lung carcinoma. In the present study, it was demonstrated that IHC with ALK monoclonal antibody D5F3 was useful for screening lung adenocarcinoma harboring ALK rearrangement.