Tissue Sampling Methods Research Articles

EUS-guided single-incision needle-knife biopsy: description and results of a new method for tissue sampling of subepithelial GI tumors (with video)

The diagnostic efficacy of current tissue sampling techniques for upper GI subepithelial tumors (SETs) appears to be limited. Better tissue acquisition techniques are needed to improve the diagnostic yield in this setting. Our purpose was to determine the safety and diagnostic yield of EUS-guided needle-knife incision and forceps biopsy (SINK biopsy) of upper GI SETs. Retrospective database review. Academic tertiary-care referral center. This study involved 14 consecutive patients referred for EUS evaluation of upper GI SETs with previous unsuccessful attempts at tissue diagnosis by conventional forceps biopsy. EUS-guided needle-knife incision and forceps biopsy. The safety and diagnostic yield of this method, compared with EUS-guided fine-needle aspiration (EUS-FNA), when possible. SINK biopsy provided tissue samples that were sufficient for definite histologic diagnosis in 13 of 14 cases (diagnostic yield 92.8%). There were 8 gastric GI stromal tumors. In 7 of 8, the size of SINK specimens allowed immunohistochemical analysis, and the evaluation of malignant potential was carried out by means of mitotic index determination in 5 cases (71.42%). SINK biopsies determined the pathological diagnosis of all (4 of 4) nonmesenchymal lesions. Eight patients underwent both EUS-FNA and SINK, with final histologic diagnosis determined in 6 of 8 cases (75%) by SINK versus 1 of 8 cases (12.5%) by EUS-FNA (Fisher exact test, P = .023). There were no procedure-related complications. A single-center, retrospective analysis with small sample size. SINK biopsy appears to be an easy, safe, and effective technique for determining the definitive pathological diagnosis, evaluation of the malignant potential, and planning management of SETs. It could be a reliable alternative to conventional FNA, providing larger samples that improve the histologic yield.

Direct visualization of indeterminate pancreaticobiliary strictures with probe-based confocal laser endomicroscopy: a multicenter experience

Because of the low sensitivity of current ERCP-guided tissue sampling methods, management of patients with indeterminate pancreaticobiliary strictures is a challenge. Probe-based confocal laser endomicroscopy (pCLE) enables real-time microscopic visualization of strictures during an ongoing ERCP. To document the utility, performance, and accuracy of real-time pCLE diagnosis compared with histopathology. Prospective observational study within the framework of a multicenter registry. Five academic centers. This study involved 102 patients with indeterminate pancreaticobiliary strictures. Clinical information, ERCP findings, tissue sampling results, and pCLE videos were collected prospectively. Investigators were asked to provide a presumptive diagnosis based on pCLE during the procedure before pathology results were available. All patients received at least 30 days of follow-up until definitive diagnosis of malignancy was established or 1-year follow-up if index tissue sampling was benign. Diagnostic accuracy, sensitivity, specificity of ERCP-guided pCLE compared with ERCP with tissue acquisition. There were no pCLE-related adverse events in the study. We were able to evaluate 89 patients, of whom 40 were proven to have cancer. The sensitivity, specificity, positive-predictive value, and negative-predictive value of pCLE for detecting cancerous strictures were 98%, 67%, 71%, and 97%, respectively, compared with 45%, 100%, 100%, and 69% for index pathology. This resulted in an overall accuracy of 81% for pCLE compared with 75% for index pathology. Accuracy for combination of ERCP and pCLE was significantly higher compared with ERCP with tissue acquisition (90% vs 73%; P = .001). Investigators had access to all relevant clinical information, which may have biased the predictive characteristics of pCLE. Probe-based CLE provides reliable microscopic examination and has excellent sensitivity and negative predictive value. The significantly higher accuracy of ERCP and pCLE compared with ERCP with tissue acquisition may support supplementing ERCP with pCLE.

Mo1429 Intraductal Aspiration: A Promising New Tissue Sampling Technique for Diagnosis of Suspected Malignant Pancreatobiliary Strictures

Cytologic and tissue acquisition in suspected malignant pancreatobiliary strictures are frequently non-conclusive. Brushing is the standard sampling method at endoscopic retrograde cholangiopancretography (ERCP), but lacks sensitivity for cancer detection (18% to 60%). We assessed a novel tissue-sampling method for cancer detection at ERCP in a pilot study.

Pancreatic Rest Resection Using Band Ligation Snare Polypectomy

BackgroundAlthough pancreatic rests have characteristic endoscopic features, confirming a histological diagnosis may be desirable to exclude other significant pathology.AimsThe aim of this study was to assess the efficacy and safety of endoscopic band ligation snare polypectomy (EBLSP) for removal of suspected pancreatic rests and to compare the diagnostic yield to other endoscopic tissue sampling methods.MethodsAn electronic endoscopic report database was searched for patients referred for evaluation of incidentally found gastric antral subepithelial lesions. Tissue sampling technique, pathology, and complications were recorded.ResultsRemoval of suspected pancreatic rests with EBLSP was successful in all 21 cases without complications. Nineteen of 21 (90%) who underwent EBLSP had a histological diagnosis of heterotopic pancreas compared with 5 of 14 (36%) who underwent tissue sampling with biopsy and/or snare (P = 0.001). The endoscopic characteristics of the histology proven pancreatic rests were an antral subepithelial mass with central umbilication measuring 6–10 mm in diameter and located 2–6 cm from the pylorus in the 3–7 o’clock position.ConclusionsEndoscopic band ligation snare polypectomy resection of gastric antral lesions suspected to be pancreatic rests had a diagnostic yield superior to standard biopsy forceps and snare polypectomy techniques. However, because all pathologically confirmed pancreatic rests had typical endoscopic appearances of pancreatic rests, it may not be necessary to obtain histologic diagnosis for every suspected gastric antral heterotopic pancreas.

Effects of different methods of non-lethal tissue sampling on butterflies

1. We investigated the effects of two methods of non-lethal tissue sampling on post-release flight behaviour (short-term response) and survival (long-term response) of two butterflies, Pieris rapae and Coenonympha tullia, within the same natural habitat. We applied three treatments: control (no tissue removal), wing clipping, and leg removal. Our study is the first to directly compare the effects of these common sampling methods. 2. We monitored the flight behaviour of the butterflies by following individuals immediately after their release. In 99 behaviour trials of P. rapae and 101 of C. tullia we found no significant differences in proportion of time spent flying or displacement per unit time among treatment groups in either species. 3. We used standard mark–recapture techniques continuously throughout the flight season to compare the survival of individuals. We marked a total of 687 P. rapae and 490 C. tullia butterflies. We found no significant differences in survival among treatments in either species. 4. We detected differences between the sexes in survival in P. rapae and flight behaviour in C. tullia. In addition to indicating differences in ecology between the sexes, these results also suggest that our analyses were sufficiently powerful to detect a significant effect of tissue removal had such an effect existed. 5. Our work is an important addition to the accumulating evidence that these methods of non-lethal tissue sampling are generally not detrimental. These sampling techniques closely mimic conditions in the wild, as wing wear and leg losses occur naturally.

964 A NOVEL BIOMARKER FOR HEPATOCELLULAR CARCINOMA IN HEPATITIS C VIRUS DEPENDENT CIRRHOSIS

retrograde cholangiopancretography (ERCP), but lacks sensitivity for cancer detection (18%-60%). We assessed a novel tissue-sampling method for cancer detection at ERCP in a pilot study. Aims and methods: 35 consecutive patients with suspected malignant pancreatobiliary strictures were prospectively studied through tissue sampling at ERCP. All patients signed an informed consent. For each patient we performed standard brushing of the stricture. After that, we modified a second catheter by removing the brush, and moved the tip back and forth within the stricture at least 10 times, aspirating fluid through a specimen trap connected to a suction line. We called this novel manipulation of the stricture IntraDuctal Aspiration (IDA). Intraductally aspirated fluids were evaluated by two experienced cytopathologists. A definitive diagnosis was obtained at the end of the follow-up. Our aims were to compare feasibility, sample adequacy, accuracy, sensitivity and specificity, positive and negative predictive value (PPV, NPV), and safety of IDA versus standard brushing. Results: Twenty-two male/13 female, mean age 61±20, underwent ERCP for suspected malignant pancreatobiliary stricture. Thirtytwo had biliary stricture and three had pancreatic stricure. Both techniques were successfully applied to each stricture. Our cytopathologists judged IDA sample adequacy significantly superior to brushing (p < 0.001). Diagnostic accuracy was 97% and 88% for IDA and brushing, respectively. The sensitivity and specificity for cancer detection were 92% (95%CI 60–100%) and 100% (95%CI 80– 100%) for IDA, and 67% (95%CI 12–98%) and 100% (95%CI 42–100%) for brushing. PPV and NPV were 100% (95%CI 68–100%) and 95% (95%CI 74–100%) for IDA, and 100% (95%CI 20–100%) and 83% (95%CI 36–99%) for brushing. There were no adverse events. Conclusions: We found this novel tissue sampling technique (IDA) to be feasible and safe. IDA sample adequacy for cytodiagnosis was superior to standard brushing, with a higher rate of accuracy, sensitivity and NPV. These preliminary data appear to suggest that IDA may represent a new gold-standard for cytodiagnosis at ERCP. Further studies of larger numbers of patients will be necessary to confirm these findings.

One-step acquisition of functional biomolecules from tissues.

Direct determination of functional biomolecular chemistry of clinically relevant tissues in vivo is a challenging task. Current approaches, based on tissue retrieval by biopsy and subsequent solubilization, are limited in terms of accurate representation of tissue constituents, reproducibility, and retention of functionality of solubilized tissue biomolecules. Using a pool of known surfactants, we designed and screened a large combinatorial library of surfactant formulations, which led to the discovery of rare synergistic formulations that greatly enhance tissue solubilization as well as preserve bioactivity of solubilized molecules, in particular proteins. By combining these formulations with a short ultrasound application, we developed a tissue sampling method--STAMP (Surfactant-based Tissue Acquisition for Molecular Profiling)--for rapid one-step determination of functional tissue chemistry in vivo. We specifically demonstrate STAMP-assisted profiling of a multitude of proteins, lipids, and genomic DNA in skin and mucosal tissues. Applications of this sampling methodology to rapid molecular diagnostics of cutaneous allergies and infectious diseases are also presented.

New Direct and Frontal Tissue Acquisition Tools for Gene Expression Analysis in Personalized Medicine

As high-throughput genotyping studies are increasingly being complemented with global gene expression/ transcriptomics analyses, tissue sampling and biopsy methods are becoming a prominent bottleneck in personalized medicine. Surprisingly, this topic has seldom been studied in detail. Quantitative molecular biology and high quality tissue sampling methods need to be developed in parallel, in order to understand disease pathophysiology, determine optimal individualized care, and identify molecular targets for novel therapies. This also calls for a critical reexamination of the subject of tissue acquisition and biopsy instruments in pharmacogenomics and personalized medicine. A perfect biopsy should be patient and operator friendly, of high quality, in adequate volume amenable to multiplexed molecular analyses, and affordable. Surgery, although still the gold standard, is seldom chosen because of the costs, risks and constraints of general anesthesia. Tru-cut microbiopsies are largely inappropriate as the samples are too small. Vacuum-assisted large core devices are expensive and principally restricted to the breast tissue. These traditional sampling approaches tend to take more ad random tissue resulting in substantial contamination with blood, and adjacent normal and non-target tissues. Contamination means low sample quality when it comes to quantitative analysis of gene products. Test results most probably become unreliable. The tissue acquisition problem, i.e., “not enough high quality tissue in sufficient quantity”, is addressed by the newer Direct and Frontal (D) harvesting tools which this paper aims to discuss. Recent literature provides evidence that these harvesting tools give tissue samples between 150 and 300 mg of highly specified parts of the diseased area in a way very similar to open surgery. In addition, they open new avenues for future bio-banking, pharmacogenomics and personalized medicine. We suggest that further comparative research and clinical applications of the different tissue sampling and biopsy methods for quantitative molecular biology are timely and essential in the field of personalized medicine. Keywords: Genetic variability and drug dosage, multiple model drug dosage, optimal stochastic adaptive control, population pharmacokinetic modeling, therapeutic drug monitoring

583 Safety and accuracy of MR-guided vacuum biopsy of breast lesions visible by breast MRI alone

The use of breast magnetic resonance imaging (MRI) in the diagnosis, staging, and management of breast cancer is rapidly increasing. MRI has the ability to detect malignancy that is occult to physical exam, ultrasound, and mammography. These qualities necessitate methods for MRI-guided tissue sampling. This article reviews all previously published and currently accepted methods for MRI-guided tissue sampling. The data to support these techniques are provided where appropriate. A detailed technique for vacuum-assisted breast biopsy is included. We will also review the data on other MRI-guided breast interventions such as transcutaneous tissue ablation.

Comparison of Microarray Analysis of Fine Needle Aspirates and Tissue Specimen in Thyroid Nodule Diagnosis

Microarray technology provides a new opportunity to improve the diagnostic accuracy of fine needle aspiration (FNA) in evaluating thyroid nodules. Here, we evaluate whether ex vivo FNA and tissue samples can be used interchangeably in microarray and whether the method of acquisition affects the precision of the gene list that is generated. To assess whether FNA samples provide adequate material for reliable gene expression analysis, paired tissue and FNA samples were collected from 13 thyroid nodules; 7 malignant, 6 benign. RNA was extracted from each specimen, converted to complimentary DNA and hybridized to AffymetrixU-133 GeneChips. Cluster analysis was then performed using 61 genes predetermined to differentiate benign from malignant nodules. Clustering patterns were evaluated using 2-group K-means and hierarchical analysis. Twelve concordant pairs were used to generate differentially expressed genes between the sampling methods. Twenty-five of 26 samples clustered concordantly with the pathologic diagnosis. The sensitivity, specificity, and accuracy were 100%, 100%, and 100% for FNA and 85.7%, 100%, and 92.3% for tissue, respectively. Two-group K-means revealed an adjacent grouping for 12 of 13 pairs. Hierarchical analysis clustered 8 of 13 pairs together. Sixty-seven genes were differentially expressed between FNA and the tissue sampling methods. These genes predominantly represented stromal components and were upregulated in the tissue compared with FNA samples. We conclude that FNA is a reliable alternative to tissue samples in predicting malignancy with microarray.

KRAS Mutation : Comparison of Testing Methods and Tissue Sampling Techniques in Colon Cancer

Treatment of colon carcinoma with the anti-epidermal growth factor receptor antibody Cetuximab is reported to be ineffective in KRAS-mutant tumors. Mutation testing techniques have therefore become an urgent concern. We have compared three methods for detecting KRAS mutations in 59 cases of colon carcinoma: 1) high resolution melting, 2) the amplification refractory mutation system using a bifunctional self-probing primer (ARMS/Scorpion, ARMS/S), and 3) direct sequencing. We also evaluated the effects of the methods of sectioning and coring of paraffin blocks to obtain tumor DNA on assay sensitivity and specificity. The most sensitive and specific combination of block sampling and mutational analysis was ARMS/S performed on DNA derived from 1-mm paraffin cores. This combination of tissue sampling and testing method detected KRAS mutations in 46% of colon tumors. Four samples were positive by ARMS/S, but initially negative by direct sequencing. Cloned DNA samples were retested by direct sequencing, and in all four cases KRAS mutations were identified in the DNA. In six cases, high resolution melting abnormalities could not be confirmed as specific mutations either by ARMS/S or direct sequencing. We conclude that coring of the paraffin blocks and testing by ARMS/S is a sensitive, specific, and efficient method for KRAS testing.

Diagnosis of pancreatic tumors by endoscopic ultrasonography

Pancreatic tumors are highly diverse, as they can be solid or cystic, and benign or malignant. Since their imaging features overlap considerably, it is often difficult to characterize these tumors. In addition, small pancreatic tumors, especially those less than 2 cm in diameter, are difficult to detect and diagnose. For characterizing pancreatic tumors and detecting small pancreatic tumors, endoscopic ultrasonography (EUS) is the most sensitive of the imaging procedures currently available. This technique also provides good results in terms of the preoperative staging of pancreatic tumors. EUS-guided fine needle aspiration (EUS-FNA) has also proved to be a safe and useful method for tissue sampling of pancreatic tumors. Despite these advantages, however, it is still difficult to differentiate between benign and malignant, solid or cystic pancreatic tumors, malignant neoplasms, and chronic pancreatitis using EUS, even when EUS-FNA is performed. Recently, contrast-enhanced EUS with Doppler mode (CE-EUS) employing ultrasound contrast agents, which indicate vascularization in pancreatic lesions, has been found to be useful in the differential diagnosis of pancreatic tumors, especially small pancreatic tumors. However, Doppler ultrasonography with contrast-enhancement has several limitations, including blooming artifacts, poor spatial resolution, and low sensitivity to slow flow. Consequently, an echoendoscope was developed recently that has a broad-band transducer and an imaging mode that was designed specifically for contrast-enhanced harmonic EUS (CEH-EUS) with a second-generation ultrasound contrast agent. The CEH-EUS technique is expected to improve the differential diagnosis of pancreatic disease in the future. This review describes the EUS appearances of common solid and cystic pancreatic masses, the diagnostic accuracy of EUS-FNA, and the relative efficacies and advantages of CE-EUS and CEH-EUS along with their relative advantages and their complementary roles in clinical practice.

Comparison of different tissue sampling methods for protein extraction from formalin-fixed and paraffin-embedded tissue specimens

Aims Protein extracts from formalin-fixed and paraffin-embedded (FFPE) tissue for proteomic analysis has recently gained attention. In this study, we explored the possibility to standardize tissue sampling from paraffin blocks and compared the protein extracts with those obtained from fresh frozen material. Materials and methods Fresh frozen and FFPE material was obtained from five patients with pancreatic ductal adenocarcinoma either by cutting sections with a microtome or by stamping a cylinder with tissue micro-array technology. All samples were weighed, forwarded to protein extraction and analyzed by polyacrylamide gel electrophoresis and Western blotting. Immunohistochemistry allocated proteins in tissue sections. Results Sampling of tissue was highly reproducible, as assessed by sample weight. While protein concentrations were significantly higher in fresh frozen material compared to FFPE material, equal amounts of protein were extracted from FFPE using either paraffin sections or core cylinders in SDS–PAGE, all three procedures showed comparable protein patterns. In Western blotting, annexin I had the same molecular weight independent of the sample source and sampling procedure. Conclusions The sampling of FFPE specimens for protein extraction and analysis can be standardized, uncovering equal amounts of tissue and protein. In addition, the proteins extracted from FFPE tissue seem to be the same compared with those extracted from fresh frozen tissue.

Tissue Sampling and Genomic DNA Purification from the Western Clawed Frog Xenopus tropicalis: Figure 1.

INTRODUCTIONThe extraction of genomic DNA from Western clawed frog (Xenopus tropicalis) tissue samples is an essential step for genotyping known mutations, identifying live animals carrying nonfluorescent transgenes, and reverse genetic screening techniques. We describe here a method for sampling tail tissue from X. tropicalis tadpoles at stage 48 and later. This method of tissue sampling allows a significant amount of genomic DNA to be obtained from tadpoles without killing them. In both Xenopus laevis and X. tropicalis, the tip of the tail is able to regenerate following surgery and its removal does not have a significant effect on the survival of the tadpole when performed carefully. Genomic DNA purification can be carried out in “deep-well” 96-well plates, making it amenable to high-throughput applications. Typically, the DNA yield is sufficient for more than 100 standard 50-μL polymerase chain reactions (PCRs) (using 1-5 μL of DNA per reaction), so it can be used for genetic screening and mapping studies.

Use of a new jumbo forceps improves tissue acquisition of Barrett's esophagus surveillance biopsies

The major risk factors for the development of esophageal adenocarcinoma remain long-standing GERD and resultant Barrett's esophagus (BE). Finding the exact method of adequate tissue sampling for surveillance of dysplasia in BE remains a dilemma. We prospectively compared standard large-capacity biopsy forceps with a new jumbo biopsy forceps for dysplasia detection in BE. Prospective, single-center investigation. We prospectively enrolled 32 patients undergoing surveillance endoscopy for BE. Biopsy samples were obtained in paired fashion alternating between the experimental (jumbo) and control (large-capacity) forceps. Each sample was assessed for histopathology, specimen size, and adequacy. A total of 712 specimens were available for analysis for this investigation. Six patients were found to have dysplasia, and in 5 of those patients, the dysplasia was only detected with the jumbo forceps. The mean width was significantly greater in the Radial Jaw 4 jumbo group (3.3 mm vs 1.9 mm [P < .005]) as was the mean depth (2.0 mm vs 1.1 mm [P < .005]). Sixteen percent of samples obtained with the standard forceps provided an adequate sample, whereas the jumbo forceps provided an adequate sample 79% of the time (P < .05). A lack of a validated index for assessment of tissue adequacy in BE. The Radial Jaw 4 jumbo biopsy forceps significantly improves dysplasia detection and adequate tissue sampling in patients undergoing endoscopy for BE.

Retrospective analysis of the utility of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in pancreatic masses, using a 22-gauge or 25-gauge needle system: a multicenter experience

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is now performed routinely in many advanced endoscopy centers and has enhanced the ability to diagnose pancreatic masses. However, there is uncertainty about which needle size is optimal for EUS-FNA of pancreatic masses. We aimed to evaluate the performance of the 22-gauge and 25-gauge needles in obtaining cytologic diagnosis of pancreatic masses. All cases that were referred for EUS-FNA for pancreatic masses between February 2001 and June 2007 were reviewed, and patients who underwent EUS-FNA using the 22-gauge and 25-gauge needle system were identified. In patients who underwent surgery, operative histopathological findings were compared with the cytopathological findings from EUS-FNA. A total of 842 patients with pancreatic masses detected on computed tomography (CT) and/or magnetic resonance imaging (MRI) and confirmed by EUS underwent EUS-FNA with the 22-gauge needle (n = 540) or the 25-gauge needle (n = 302). Results of EUS-FNA cytology findings were compared with the gold standard of surgical histopathological findings or long-term clinical follow-up. The sensitivity, specificity, PPV, and NPV of FNA were respectively 84%, 100%, 100%, and 73% [corrected] for the 22-gauge needle compared with 92%, 97%, 98%, and 87%, [corrected] respectively for the 25-gauge needle. No complications were noted in the 25-gauge needle group, compared with pancreatitis in 2% of the 22-gauge needle group. This retrospective comparative study shows that EUS-FNA with a 25-gauge needle system is a safe and reliable method for tissue sampling in pancreatic masses. The system is more sensitive and has a slightly [corrected] higher NPV than the standard 22-gauge needle. Our study suggests that perhaps the smaller caliber FNA needle causes less trauma during EUS-FNA and hence less complications. Further studies including randomized trials are needed.

Immunohistochemical Evaluation of Prostate Needle Biopsies Using Saved Interval Sections vs New Recut Sections From the Block

The best method of tissue sampling for performance of immunohistochemistry on prostate needle biopsy tissue sections has not been established. The aim of this study was to prospectively compare the usefulness of using saved interval sections vs new recut sections from the paraffin block in the immunohistochemical evaluation of prostate needle biopsy (PNB) material. Seventy (10.3%) of 682 PNB specimens consecutively examined over a 1-year period were evaluated immunohistochemically. Of these cases, 38 were concurrently evaluated using saved interval sections (2 levels) and recut sections. Identical staining results were achieved in 21 cases (55%). Loss of the atypical/ malignant focus of interest was seen in 3 (8%) of the interval sections vs 19 (50%) of the recut sections (P < .0001). The mean linear extent of the foci that were lost in the recut sections (0.75 mm) was significantly less than that of the foci that were not lost in the recuts (1.32 mm; P = .025). Fifteen (79%) of the 19 foci that were lost in the recut sections were 1 mm or less in length vs 7 (37%) of the 19 not lost in the recuts (P = .021). These findings support the practice of cutting and saving 2 interval levels of unstained sections of PNB specimens for potential immunohistochemical evaluation.

Gastric Antral Pancreatic Rest Resection Using Endoscopic Band Ligation Snare Polypectomy Technique

Background: Although gastric antral pancreatic rests (PR) have characteristic endoscopic and EUS features, confirming a histologic diagnosis may be desirable to exclude other significant pathology. Forceps biopsy and snare polypectomy are often unsuccessful due to inadequate depth of sampling. Removal with endoscopic band ligation snare polypectomy technique (EBLSP) may be a safe and effective way of obtaining a tissue diagnosis of PR. Aims: To assess the efficacy and safety of EBLSP in obtaining a tissue diagnosis of PR compared to sampling with biopsy +/- snare polypectomy, and to characterize PR endoscopic appearance. Methods: Retrospective case series in which an electronic GI endoscopic report database was searched for patients who underwent EGD between 1/00 and 10/08 at an academic medical center by a single endoscopist and were found to have gastric antral subepithelial masses. The images were reviewed for endoscopic appearance and tissue sampling technique, and final pathologic results were recorded. EBLSP was performed with rubber band ligation followed by snare polypectomy and clip placement. Results: 61 patients with subepithelial antral masses were identified. 21(34%) were histology proven PR, of which 16(76%) were obtained with EBLSP, 4(19%) with forceps biopsy +/- snare polypectomy, and 1(5%) with cap EMR technique. The median endoscopic size of histology proven PR was 10 mm (range 6-15 mm). The median distance from the pylorus was 35 mm (range 10-60 mm). The median location relative to the pylorus was at the 6 o'clock position (range 3-7 o'clock). 13(62%) displayed central umbilication. EUS was performed on 19(90%) PR with median dimensions being 8.5 by 4 mm. All PR were hypoechoic or heterogenous lesions located in the submucosal layer. Among patients with antral masses that endoscopically appeared to be PR, 16 of 18 (89%) who underwent EBLSP had a histologic diagnosis of PR, compared to 4 of 13 (31%) who had sampling with forceps biopsy +/- snare polypectomy (p=0.007). No complications occurred with any tissue sampling method used. Conclusions: 1) Endoscopic submucosal resection of gastric antral pancreatic rests can be safely and effectively performed with band ligation snare polypectomy for pathologic diagnosis. 2) EBLSP has a significantly higher diagnostic yield for suspected pancreatic rests than forceps biopsy +/- snare polypectomy (89% vs 31%, p=0.007). 3) The endoscopic appearance of histology proven pancreatic rests is a raised, 6-15 mm diameter subepithelial mass with central umbilication that is located 1-6 cm from the pylorus in the 3-7 o'clock position.

Needle and surgical biopsy techniques differentially affect adipose tissue gene expression profiles

BackgroundAdipose tissue gene expression analysis in humans now provides a tremendous means to discover the physiopathologic gene targets critical for our understanding and treatment of obesity. Clinical studies are emerging in which adipose gene expression has been examined in hundreds of subjects, and it will be fundamentally important that these studies can be compared so that a common consensus can be reached and new therapeutic targets for obesity proposed. ObjectiveWe studied the effect of the biopsy sampling methods (needle-aspirated and surgical) used in clinical investigation programs on the functional interpretation of adipose tissue gene expression profiles. DesignA comparative microarray analysis of the different subcutaneous adipose tissue sampling methods was performed in age-matched lean (n = 19) and obese (n = 18) female subjects. Appropriate statistical (principal components analysis) and bioinformatic (FunNet) functional enrichment software were used to evaluate data. The morphology of adipose tissue samples obtained by needle-aspiration and surgical methods was examined by immunohistochemistry. ResultsBiopsy techniques influence the gene expression underlying the biological themes currently discussed in obesity (eg, inflammation, extracellular matrix, and metabolism). Immunohistochemistry experiments showed that the easier to obtain needle-aspirated biopsies poorly aspirate the fibrotic fraction of subcutaneous adipose tissue, resulting in an underrepresentation of the stroma-vascular fraction. ConclusionsThe adipose tissue biopsy technique is an important caveat to consider when designing, interpreting, and, most important, comparing microarray experiments. These results will have crucial implications for the clinical and physiopathologic understanding of human obesity and therapeutic approaches.

Magnetic Resonance Imaging-Guided Breast Interventions

The use of breast magnetic resonance imaging (MRI) for screening, diagnosis, staging, and management of breast cancer is rapidly increasing. MRI is highly sensitive for the detection of benign and malignant abnormalities that are occult to physical examination, ultrasound, and mammography. However, the specificity of MRI is moderate. These attributes necessitate methods for MR-guided tissue sampling to determine the histology of MRI detected lesions. This article will review appropriate peer-reviewed data and currently accepted methods for MR-guided tissue sampling. A detailed step-by-step technique for vacuum-assisted MR-guided breast biopsy is included. We also review emerging data for percutaneous and transcutaneous MR-guided breast interventions such as tissue ablation for benign and malignant disease.