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TGF-α inhibits gastric acid secretion andmay play an important role in epithelial repair. Wequantitated regional levels of TGF-α in the humanproximal gastrointestinal tract and determined whether they are affected by acid suppression oraspirin-induced injury. Ten healthy volunteers werestudied. After baseline endoscopy with biopsy, fiverandomly received no treatment, aspirin, omeprazole, orcimetidine for one week. Endoscopy was repeated and priorunhealed biopsy sites quantitated. TGF-α levelswere measured by RIA. Five additional subjects thencompleted an extended protocol of three weeks' duration. All subjects were free of H. pylori infection.TGF-α levels in the antrum, 34.76 ± 5.54 pgTGF-α/μg DNA were threefold higher than in thegastric body and duodenum (11.03 ± 2.60 and 10.41± 1.64 respectively, P < 0.01). The number of unhealed sites inthe aspirin group was significantly greater than in thecontrol or acid inhibition groups; however, TGF-αlevels were not different from the surrounding mucosa. TGF-α increased in the controls afterbiopsy; the increase was significant in the body at week2 only. Aspirin significantly increased TGF-αlevels in the gastric body and duodenum after one week. The rise in antral TGF-α appeared delayedand blunted by the aspirin treatment compared tocontrol. There was no relationship between the number ofvisible biopsy sites, degree of aspirin-induced injury, and the TGF-α level. Acid suppression wasassociated with a significant increase in TGF-α inthe gastric body and antrum at one week. Immunochemicalstaining did not demonstrate differences inproliferation in any treatment group compared to controls.TGF-α levels vary by location in the proximalgastrointestinal tract, with significantly greaterlevels in the antrum. After biopsy, TGF-α levelsincrease; short-term aspirin and acid inhibitors modulatethis effect. Aspirin significantly impaired the healingof endoscopic biopsies in the antrum; however, this wasnot associated with changes in TGF-α levels. TGF-α levels did not change in responseto acid secretory state. Further studies of mucosallevels of TGF-α in response to aspirin-inducedinjury in humans appear warranted. [ABSTRACT FROM AUTHOR]

Objective: To investigate occult enteric infections and morphologic changes in the small intestine in patients with advanced human immunodeficiency virus (HIV) infection and chronic diarrhea of undefined cause.Design: Case-control study.Setting: Referral-based clinic and hospital in tertiary care center.Patients: Twenty-two patients with advanced HIV infection (19 with the acquired immunodeficiency syndrome [AIDS], 3 with AIDS-related complex) with chronic diarrhea, selected because of previously negative stool evaluations for bacterial or parasitic pathogens, were compared with 13 patients with advanced HIV infection (9 with AIDS, 4 with AIDS-related complex) without diarrhea by analysis of endoscopic biopsies using light and electron microscopy, viral culture, and morphometric studies. Both groups were convenience samples and had at least 7 months follow-up.Measurements and Main Results: Eleven of twenty-two patients with HIV infection and chronic diarrhea but only 1 of 13 patients without diarrhea showed occult enteric pathogens (that is, undetected by routine studies) after extensive evaluation of duodenal and colorectal biopsies. Mycobacterium avium-intracellulare and microsporidia were the most common occult agents in study patients with diarrhea (5 each). Patients with diarrhea and occult enteric infections had greater weight loss (mean, 14.3 kg compared with 6.2 kg; P less than 0.05) and shorter survival (1 of 11 compared with 8 of 11 still alive; P less than 0.004) than those with diarrhea but no identified pathogens (defined as "AIDS enteropathy"). Duodenal morphometry showed decreased villus-to-crypt ratios because of villus atrophy and crypt elongation in HIV-infected patients both with and without diarrhea compared with normal controls (P less than 0.001 for each). All three groups showed comparable frequencies of epithelial mitoses.Conclusions: Further endoscopic biopsy evaluation of patients with AIDS who had unexplained chronic diarrhea showed an occult infectious cause in half of the cases. However, altered villus and crypt architecture in advanced HIV infection was independent of the presence of diarrhea or enteric infection and therefore did not correlate with AIDS enteropathy. Subnormal epithelial proliferation in response to injury could be a factor, but the underlying cause of the architectural changes remains obscure. We suggest that T-cell dysfunction may play a role. [ABSTRACT FROM AUTHOR]

Discusses a case of fulminant hepatic failure in a patient shortly after switching to sustained-release nicotinic acid after having taken ordinary nicotinic acid for over one year without side effects. Features suggesting fulminant hepatic to be resulted from use of sustained-release nicotinic acid; Cause of hepatic necrosis; Awareness regarding side effects of nicotinic acid.

Background: The antibody-drug conjugate (ADC) trastuzumab emtansine (T-DM1) combines the antitumor activities of trastuzumab with intracellular delivery of the cytotoxic agent DM1 and represents a new approach to therapy for HER2-positive MBC. Recently, the first phase 3 data have been reported with significant improvements in PFS (9.6 vs 6.4 months; HR=0.650; P<0.0001) and lower incidence of grade ≥ 3 adverse events (AEs) (57% vs 41%) vs capecitabine + lapatinib (Blackwell 2012). This pooled analysis reports the overall safety profile of T-DM1 3.6 mg/kg q3w in 882 patients treated with T-DM1. Methods: Data were included from treated patients in 7 studies of single-agent T-DM1 3.6 mg/kg q3w: 1 phase 1 study in previously treated MBC (TDM3569g, Krop 2010, n=15 treated at 3.6 mg/kg q3w); 3 phase 2 single-arm studies in previously treated MBC (TDM4258g, Burris 2011, N=112; TDM4374g, Krop 2012, N=110; TDM4688g, Gupta 2011, n=51); 1 randomized phase 2 study in previously untreated MBC (Hurvitz 2011, TDM4450g/BO21976, n=69); 1 extension study (TDM4529/BO25430, n=43 from parent studies); and 1 phase 3 study in MBC previously treated with trastuzumab and a taxane (EMILIA, Blackwell 2012, n=490). Data were analyzed in 4 groups: (1) all T-DM1-treated pts (7 studies, N=882), (2) pts originally enrolled in single-arm studies (n = 288), (3) T-DM1 pts from TDM4450g (n = 69), and (4) T-DM1 pts from EMILIA (n = 490). Results: Among all pts (N = 882), median age was 53 years (range 25-85 years); 52.7% had ≥3 metastatic sites; 81.7% had received prior treatment for MBC; and the median number of prior non-endocrine agents for MBC was 3.0 (range 0-19). All-grade AEs occurring in ≥ 25% of patients were fatigue (45.4%), nausea (42.3%), headache (28.7%), thrombocytopenia (28.7%), and constipation (25.5%). Grade ≥3 AEs occurring in 2% were thrombocytopenia, increased AST, increased ALT, fatigue, hypokalemia, and anemia. Table 1 describes the grade ≥ 3 incidence of these AEs, as well as selected AEs with known association to T-DM1 or potential risk based on the components of T-DM1 or on preclinical data. Conclusions: The safety profile of T-DM1 3.6 mg/kg q3w was consistent across the studies and the different patient populations with HER2-positive MBC. Additional analyses on hepatic transaminase increases and those exploring potential associations between thrombocytopenia and hemorrhage will be presented. [ABSTRACT FROM AUTHOR]

Background: Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds., Method: We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities., Results: Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies., Interpretation: When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling., Competing Interests: Disclosure JNK declares consulting services for Owkin, France and Panakeia, UK. TJB reports owning a company that develops mobile apps, outside the scope of the submitted work (Smart Health Heidelberg GmbH, Handschuhsheimer Landstr. 9/1, 69120 Heidelberg). PQ has had paid roles in the English NHS bowel cancer screening programme over the course of this study. SBG is co-founder of Brogent International LLC with equity, outside the scope of the submitted work. All other authors have declared no conflicts of interest., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Bright red linear marks in the right colon are occasionally seen but have never been described in the medical literature. We have termed this finding "cat scratch" colon., Methods: This was a prospective examination of 8277 colonoscopies at a single endoscopy center in a private practice setting. All cases of cat scratch colon were biopsied, and the results read by two pathologists., Results: A total of 21 cases of cat scratch colon were identified, all in the ascending colon and cecum, with a prevalence of 0.25%. The majority of cases were in women. Although the colon was histologically normal in most cases, there was a significantly higher proportion of collagenous colitis in patients with cat scratch colon compared with the total cohort (14% vs. 0.15%)., Conclusions: The prevalence of bright red linear markings (cat scratch colon) in the cecum and ascending colon is 0.25%. These markings appear to be superficial breaks in the mucosa possibly secondary to barotrauma. Patients tend to be older women with higher proportion of collagenous colitis.

With the exception of angiodysplasia, vascular abnormalities of the intestines are unusual. We describe a florid benign vascular proliferation of the colon in five adult patients, three of whom presented with idiopathic intussusception. In all cases, the proliferation was sufficiently exuberant to raise the possibility of angiosarcoma as a diagnostic consideration. The group included 2 males and 3 females with a median age of 43 years. Two patients were HIV positive. Four patients presented with a colonic mass; other symptoms at presentation included abdominal pain, diarrhea, bleeding, and bowel obstruction. In all cases, a florid lobular proliferation of small vascular channels lined by plump endothelial cells extended from the submucosa through the entire thickness of the bowel wall. The endothelial cells showed minimal nuclear atypia, and mitotic figures were infrequent. The overlying mucosa showed ulceration with ischemic-type changes, and had features of mucosal prolapse. A possible underlying arteriovenous malformation was identified in two cases. All patients were alive and well at last follow-up (interval, 6 months to 5 years). The presence of intussusception or mucosal prolapse in all of the cases suggests repeated mechanical forces applied to the bowel wall as a possible etiologic factor. The role of HIV infection in the pathogenesis of these lesions remains to be determined.

Molecular classification of tumors based on their gene expression profiles promises to significantly refine diagnosis and management of cancer patients. The establishment of organ-specific gene expression patterns represents a crucial first step in the clinical application of the molecular approach. Here, we report on the gene expression profiles of 154 primary adenocarcinomas of the lung, colon, and ovary. Using high-density oligonucleotide arrays with 7129 gene probe sets, comprehensive gene expression profiles of 57 lung, 51 colon, and 46 ovary adenocarcinomas were generated and subjected to principle component analysis and to a cross-validated prediction analysis using nearest neighbor classification. These statistical analyses resulted in the classification of 152 of 154 of the adenocarcinomas in an organ-specific manner and identified genes expressed in a putative tissue-specific manner for each tumor type. Furthermore, two tumors were identified, one in the colon group and another in the ovarian group, that did not conform to their respective organ-specific cohorts. Investigation of these outlier tumors by immunohistochemical profiling revealed the ovarian tumor was consistent with a metastatic adenocarcinoma of colonic origin and the colonic tumor was a pleomorphic mesenchymal tumor, probably a leiomyosarcoma, rather than an epithelial tumor. Our results demonstrate the ability of gene expression profiles to classify tumors and suggest that determination of organ-specific gene expression profiles will play a significant role in a wide variety of clinical settings, including molecular diagnosis and classification.

Background: Pancreatic cancer is the fifth leading cause of cancer-related mortality in the United STATES: Although smoking and age are known risk factors for pancreatic cancer, several case reports and case-control studies have suggested that there is also a familial risk. We evaluated whether a family history of pancreatic cancer increases the risk of pancreatic cancer in first-degree relatives and whether smoking and younger age at cancer diagnosis further increase this risk., Methods: We conducted in-person interviews with 247 patients ("case probands") with pancreatic cancer and 420 population-based control probands to collect risk factor data and pancreatic cancer family history for 1816 first-degree relatives of the case probands and 3157 first-degree relatives of the control probands. We analyzed the data by unconditional logistic regression models, with adjustment for correlated data by use of generalized estimating equations. All statistical tests were two-sided., Results: A positive family history of pancreatic cancer (i.e., being related to a case proband) or ever-smoking cigarettes approximately doubled the risk of pancreatic cancer (relative risk [RR] = 2.49; 95% confidence interval [CI] = 1.32 to 4.69; RR = 2.04; 95% CI = 1.09 to 3.83, respectively). The RR increased to 8.23 (95% CI = 2.18 to 31.07) for relatives who ever smoked and were related to a case proband who was diagnosed before age 60 years., Conclusion: Routine questioning of patients about a family history of pancreatic cancer, the age of onset of this cancer in their relatives, and the patient's smoking status may identify individuals at high risk of pancreatic cancer. Future research exploring the genetic and environmental interactions associated with the risk of pancreatic cancer is critically important.

The objective of endoscopic surveillance in Barrett esophagus (BE) is to assess the risk of subsequent development of invasive carcinoma. Criteria for morphologic evaluation of dysplasia, the presumed precursor lesion, have been established, although there are surprisingly few data in the literature correlating biopsy diagnosis of dysplasia with outcome. We collected follow-up information on 138 patients with BE whose initial endoscopic biopsy specimens had been selected for submission in an interobserver variability study performed by 12 pathologists with special interest in gastrointestinal pathology and reviewed blindly twice each by all the participants. Cases were scored as BE with no dysplasia, atypia indefinite for dysplasia (IND), low-grade dysplasia (LGD), high-grade dysplasia (HGD), intramucosal carcinoma, and frankly invasive carcinoma, thus generating 24 scores on each biopsy specimen. Clinical follow-up was obtained and correlated with both the submitting diagnoses and majority diagnoses. Kaplan-Meier statistics were used to compare both the submitting and majority diagnoses with outcome using detection or documentation of invasive carcinoma as the endpoint. Using the submitting diagnoses, no invasive carcinomas were detected in 44 cases diagnosed as BE (median follow-up, 38.5 months). Carcinomas were detected in 4 of 22 (18%) cases submitted as IND (median progression-free survival of 62 months), in 4 of 25 (15%) cases of LGD (median progression-free survival of 60 months), in 20 of 33 cases of HGD (median progression-free survival, 8 months), and all 13 (100%) cases submitted as adenocarcinoma. Grade on initial biopsy correlated significantly with progression to invasive carcinoma (log-rank P =.0001). Majority diagnosis was achieved in 99 of the cases. Using the majority diagnoses, no invasive carcinomas were found in 50 cases of BE (median follow-up, 48 months), and carcinomas were detected in 1 of 7 (14%) IND cases (80% progression-free survival at 2 months), 3 of 15 (20%) LGD (median progression-free survival, 60 months), 9 of 15 (60%) HGD (median progression-free survival, 7 months), and all 12 (100%) carcinoma. Initial grading again correlated significantly with progression to invasive carcinoma (log-rank P =.0001). However, there were 39 cases without a majority diagnosis. Among these, no carcinomas developed in 8 cases with an average score between BE and IND. Carcinomas were detected in 9 of 21 (43%) cases with an average score between IND and LGD, and 7 of 10 (70%) cases with an average score between LGD and HGD. There were ulcers in 8 of 39 cases (20%) of the "no-majority" group and in 13 of 99 (13%) of the majority cases. Of 21 total ulcerated cases, cancer was demonstrated in 15 (71%) of these on follow-up. These data support combining the IND and LGD categories for surveillance purposes. Cases without dysplasia may be followed up conservatively. The data obtained from submitted diagnoses as opposed to those from blind review suggest that knowledge of the clinical findings aids in diagnosis. The data also support the assertion that HGD is strongly associated with invasive carcinoma. Rebiopsy of ulcerated areas should be considered because they may harbor malignancy. Histologic grading of dysplasia using established criteria is a powerful prognosticator in BE. HUM PATHOL 32:379-388., (Copyright 2001 by W.B. Saunders Company)

Morphologic assessment of dysplasia in Barrett esophagus, despite limitations, remains the basis of treatment. We rigorously tested modified 1988 criteria, assessing intraobserver and interobserver reproducibility. Participants submitted slides of Barrett mucosa negative (BE) and indefinite (IND) for dysplasia, with low-grade dysplasia (LGD) and high-grade dysplasia (HGD), and with carcinoma. Two hundred fifty slides were divided into 2 groups. The first 125 slides were reviewed, without knowledge of the prior diagnoses, on 2 occasions by 12 gastrointestinal pathologists without prior discussion of criteria. Results were analyzed by kappa statistics, which correct for agreement by chance. A consensus meeting was then held, establishing, by group review of the index 125 slides, the criteria outlined herein. The second 125-slide set was then reviewed twice by each of the same 12 pathologists, and follow-up kappa statistics were calculated. When statistical analysis was performed using 2 broad diagnostic categories (BE, IND, and LG v HG and carcinoma), intraobserver agreement was near perfect both before and after the consensus meeting (mean kappa = 0.82 and 0.80). Interobserver agreement was substantial (kappa = 0.66) and improved after the consensus meeting (kappa = 0.70; P =.02). When statistical analysis was performed using 4 clinically relevant separations (BE; IND and LGD; HGD; carcinoma), mean intraobserver kappa improved from 0.64 to 0.68 (both substantial) after the consensus meeting, and mean interobserver kappa improved from 0.43 to 0.46 (both moderate agreement). When statistical analysis was performed using 4 diagnostic categories that required distinction between LGD and IND (BE; IND; LGD; HGD and carcinoma), the pre-consensus meeting mean intraobserver kappa was 0.60 (substantial agreement), improving to 0.65 after the meeting (P <.05). Interobserver agreement was poorer, with premeeting and postmeeting mean values unchanged (kappa = 0.43 at both times). Interobserver agreement was substantial for HGD/carcinoma (kappa = 0.65), moderate to substantial for BE (kappa = 0.58), fair for LGD (kappa = 0.32), and slight for IND (kappa = 0.15). The intraobserver reproducibility for the diagnosis of dysplasia in BE was substantial. Interobserver reproducibility was substantial at the ends of the spectrum (BE and HG/carcinoma) but slight for IND. Both intraobserver and interobserver variation improved overall after the application of a modified grading system developed at a consensus conference but not in separation of BE, IND, and LGD. The criteria used by the group are presented. HUM PATHOL 32:368-978., (Copyright 2001 by W.B. Saunders Company)

Granulomatous appendicitis is an enigmatic entity. Purported causes include Crohn's disease, foreign body reactions, sarcoidosis, and infectious agents; however, most cases remain idiopathic. Yersinia enterocolitica (YE) and Y. pseudotuberculosis (YP) have been implicated as causes of appendicitis, ileocolitis, and mesenteric adenitis. The authors examined the potential role of YE and YP in granulomatous appendicitis using histologic and molecular methods. Forty cases of granulomatous appendicitis were evaluated for histologic features including transmural inflammation, number and character of granulomas, and mucosal changes. Twort Gram, Grocott methenamine-silver (GMS), and Ziehl-Neelsen stains were evaluated, and polymerase chain reaction (PCR) analysis was performed to identify pathogenic YP and YE. Twenty-five percent (10 of 40) of the cases were positive for pathogenic Yersinia by PCR (four YE, four YP, and two with both species). Prominent histologic features included epithelioid granulomas with lymphoid cuffing, transmural inflammation with lymphoid aggregates, mucosal ulceration, and cryptitis. One Yersinia-positive case contained mural Gram-negative bacilli; fungal and acid-fast bacilli stains were all negative. Except for one culture-negative case, serologies and cultures were not done or results were unavailable. Two Yersinia-positive patients were diagnosed subsequently with Crohn's disease, suggesting a possible relationship between the two entities. No other patients developed significant sequelae. YE and YP are important causes of granulomatous appendicitis, and Yersinia infection may mimic Crohn's disease. No histologic features distinguish reliably between Yersinia species, or between Yersinia-positive and Yersinia-negative cases. Because special stains and cultures are often not diagnostic, PCR analysis is an excellent technique for the diagnosis of Yersinia.

Backwash ileitis and postcolectomy pouchitis are well-recognized complications of ulcerative colitis (UC), whereas inflammation of the proximal small intestine is not. In contrast, small intestinal disease at any level is common in Crohn's disease (CD). Despite this well-established and accepted dogma, rare cases of histologically proven diffuse duodenitis (DD) associated with UC appear in the literature. In this study, we report our experience with similar cases exhibiting this unusual inflammatory phenomenon. Routine histologic sections from four cases of DD associated with well-documented UC were reviewed and the findings correlated with all available medical records. Multiple endoscopic biopsies showing histologic features of UC and colectomy specimens confirming severe ulcerative pancolitis were available for all cases. Varying degrees of active chronic inflammation and architectural mucosal distortion identical to UC were observed in pre- and postcolectomy duodenal biopsies of one of four and four of four cases, respectively. Similar inflammatory patterns were present postoperatively in the ileum in three of four cases and in the jejunum in one case. Endorectal pull-through (ERPT) procedures were performed in three of four patients and an end-to-end ileorectal anastomosis was done in one patient. Despite extensive upper gastrointestinal tract involvement, none of the patients developed postsurgical Crohn's-like complications during a follow-up period of 12 to 54 months. This suggests that patients with pancolitis and DD do not necessarily have CD, but rather may have UC and, most importantly, that successful ERPT procedures may be performed in these patients.

Stromal tumors of the anorectum are a rare group of mesenchymal tumors that often have a protracted clinical course. We sought to determine which clinical, morphologic, and immunophenotypic features correlated with an adverse outcome in 22 patients with anorectal stromal tumors. An adverse outcome, defined as either tumor recurrence or metastasis, occurred in nine patients. Seven patients had metastases, two of whom also had local recurrences. Four of these patients also died from their disease. One patient had one local recurrence, and one patient had two local recurrences; neither of these patients had metastases. Recurrences were found as long as 103 months and metastases as late as 117 months after initial presentation. However, for patients without an adverse outcome, maximum follow-up was only 84 months. Thus both recurrence and metastasis may not appear until several years after treatment, indicating that a long-term follow-up period, probably longer than available for many tumors without an adverse outcome in this study, is needed before a patient can be considered to be cured. Tumor size greater than five centimeters correlated with an adverse outcome. However, given the protracted course of these tumors and the relatively limited follow-up available, other features such as location within the muscularis propria, mitotic activity, necrosis, and pleomorphism that did not significantly correlate with an adverse outcome may become significant with longer follow-up periods. We also found that on the basis of morphologic appearance and whether tumors were confined to the submucosa or located within the muscularis propria, anorectal stromal tumors could be divided into three groups, and that the behavior of anorectal stromal tumors may also depend upon their phenotype. The largest group of 17 tumors was located within the muscularis propria, mitotically active, and composed of densely cellular spindle-shaped cells. A second group of two tumors was also located within the muscularis propria and was composed of spindle-shaped cells, but lacked dense cellularity and mitotic activity. The third group was composed of three submucosal, polypoid tumors.

Stromal tumors of the abdominal colon, the least common of all gastrointestinal stromal tumors, have not been well characterized. They have often been lumped with stromal tumors of the anorectum in order to achieve significant numbers for analysis, yet there are no data to prove that stromal tumors from these two sites are the same. In this study, we evaluated 20 colonic stromal tumors to identify clinical, morphologic, and immunophenotypic features that were useful in discriminating between those that had metastasized or caused death from those that had not metastasized or caused death. We found that colonic stromal tumors are morphologically heterogeneous, and the malignant ones are clinically aggressive. They often have metastases at presentation, and cause death in a short time. An infiltrative growth pattern in the muscularis propria, invasion of the mucosa, and high mitotic counts correlated significantly both with metastases and with death from tumor. We also found that dense cellularity correlated significantly with metastases, but not with death, and that coagulative necrosis correlated with death, but not with metastases.

Telepathology (TP) is the practice of pathology at a distance using videomicroscopy and telecommunication tools. We explore the use of "virtual microscopy" techniques and the Internet as tools for TP gastrointestinal biopsy consultations. Thirty-five gastrointestinal biopsy specimens were photographed in Los Angeles by using a high-resolution digital camera, a light microscope, and a Pentium 166 microcomputer. Several (2-8) digital photomicrographs were collected at 40x or 100x optical magnification, using 2,700 x 3,400 pixel resolution. The photomicrographs illustrated all the tissue fragments present in 1 of the biopsy levels. They were saved in medium compression JPEG image format. These images can be magnified digitally up to 600% without visible degradation and scrolled at different magnifications on a video monitor, simulating examination under a light microscope. The images files (281 to 3,324 KB) were attached to e-mail messages containing patient information and sent through the Internet to Michigan for interpretation using a Power Macintosh 7100 system. The e-mail process was successful in 100% of instances; 2 files were corrupted owing to user error and had to be resent. Additional photos were requested in 1 case. In 33 of 35 cases, there was diagnostic concordance between the original and the TP diagnoses. The 2 discrepancies were due to diagnostic disagreement. This technology offers pathologists relatively inexpensive and effective tools for gastrointestinal TP consultations.

DNA mismatch repair is an important mechanism involved in maintaining the fidelity of genomic DNA. Defective DNA mismatch repair is implicated in a variety of gastrointestinal and other tumors; however, its role in hepatocellular carcinoma (HCC) has not been assessed. Formalin-fixed, paraffin-embedded archival pathology tissues from 46 primary liver tumors were studied by microdissection and microsatellite analysis of extracted DNA to assess the degree of microsatellite instability, a marker of defective mismatch repair, and to determine the extent and timing of allelic loss of two DNA mismatch repair genes, human Mut S homologue-2 (hMSH2) and human Mut L homologue-1 (hMLH1), and the tumor suppressor genes adenomatous polyposis coli gene (APC), p53, and DPC4. Microsatellite instability was detected in 16 of the tumors (34.8%). Loss of heterozygosity at microsatellites linked to the DNA mismatch repair genes, hMSH2 and/or hMLH1, was found in 9 cases (19.6%), usually in association with microsatellite instability. Importantly, the pattern of allelic loss was uniform in 8 of these 9 tumors, suggesting that clonal loss had occurred. Moreover, loss at these loci also occurred in nonmalignant tissue adjacent to 4 of these tumors, where it was associated with marked allelic heterogeneity. There was relatively infrequent loss of APC, p53, or DPC4 loci that appeared unrelated to loss of hMSH2 or hMLH1 gene loci. Loss of heterozygosity at hMSH2 and/or hMLH1 gene loci, and the associated microsatellite instability in premalignant hepatic tissues suggests a possible causal role in hepatic carcinogenesis in a subset of hepatomas.

Background & Aims: Allelic loss of a portion of chromosome 18q and lack of expression of deleted in colorectal cancer (DCC) protein has been reported as an adverse prognostic indicator for stage II (i.e., Dukes' B2) colorectal cancer. Our aim was to assess whether the DCC gene locus was responsible., Methods: We amplified five DNA microsatellite markers located on chromosome 18q21 surrounding or within the DCC gene locus, including a DCC intragenic (TA)n microsatellite, from DNA microdissected and isolated from paraffin-embedded, formalin-fixed specimens of 70 patients with stage II colorectal cancer. Epidemiological and survival data were blinded from the microsatellite analysis to avoid bias., Results: The average follow-up time was 63.3 months for all patients. Eleven patients died of colorectal cancer by the end of the study. Loss of heterozygosity of 18q21 was present in 30 of 70 (43%) tumors. After adjustment for all other evaluated factors, 18q21 allelic loss was not a predictor of survival (hazard ratio, 1.17; 95% confidence interval, 0.27-5.10; P = 0.84)., Conclusions: Loss of heterozygosity of 18q21 does not seem to predict a survival disadvantage in stage II colorectal cancer in our patient population, and its proposed use as a prognosticator of survival or chemotherapy stratification marker for stage II tumors is not substantiated.

To further understand the role of the peptide hormone gastrin in the development and function of the stomach, we have generated gastrin-deficient mice by gene targeting in embryonic stem cells. Mutant mice were viable and fertile, without obvious visible abnormalities. However, gastric function was severely affected by the loss of gastrin. Basal gastric acid secretion was abolished and could not be induced by histamine, carbachol, or gastrin. Histological analysis revealed alterations in the two cell types primarily involved in acid secretion, parietal and enterochromaffin-like (ECL) cells. Parietal cells were reduced in number with an accumulation of immature cells lacking H(+)-K(+)-adenosinetriphosphatase (H(+)-K(+)-ATPase). ECL cells were positioned closer to the base of the gastric glands, with markedly lower expression of histidine decarboxylase. Gastrin administration for 6 days reversed the effects of the gastrin deficiency, leading to an increase in the number of mature, H(+)-K(+)-ATPase-positive parietal cells and a partial restoration of acid secretion. The results show that gastrin is critically important for the function of the acid secretory system.

Histologic features of low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) have been extensively described, and transformation to a large cell (high-grade) lymphoma can occur. We characterize high-grade gastric lymphoma histologically in an attempt to distinguish between MALT-type and non-MALT-type lesions. We studied a series of 60 gastric lymphomas and characterized them clinically, histopathologically, and immunophenotypically. Low-grade gastric lymphomas were classified according to established criteria. High-grade lymphomas were classified in three groups based on the presence or absence of a low-grade component and lymphoepithelial lesions (LELs): 1) high-grade MALT lymphomas appearing in low-grade MALT lymphomas (LG/HG MALT lymphoma); 2) large cell lymphoma with LELs composed of large cells (high-grade LELs) but without a low-grade component (HG MALT lymphoma); and 3) diffuse large cell lymphoma without a low-grade MALT lymphoma component or LELs (DLCL). Twenty-two lymphomas were classified as low-grade MALT lymphomas, 16 as LG/HG MALT lymphomas, 10 as HG MALT lymphomas, and 12 as DLCL. B-cell immunophenotype was confirmed in all 55 cases in which immunophenotyping was performed. Low-grade LELs were seen in all low-grade MALT lymphomas, and CD20(L26) expression confirmed B-cell phenotype in the LELs in 20 of 20 cases. Clinical follow-up was available for 56 patients (range, 1-264 months; mean, 57 months). Actuarial analysis of disease-specific survival and relapse-free survival showed that clinical stage was highly statistically significant (P < 0.0001), whereas histologic type and grade approached statistical significance. Multivariate analysis showed that clinical stage was the only significant factor in relapse-free and disease-specific survival.

Focal crypt injury by neutrophils (cryptitis/crypt abscesses), or focal active colitis (FAC), is a common isolated finding in endoscopic colorectal biopsies. Focal active colitis is often thought of as a feature of Crohn's disease, but may also be seen in ischemia, infections, partially treated ulcerative colitis, and as an isolated finding in patients undergoing endoscopy to exclude neoplasia. Clinical, endoscopic, and pathological data were retrospectively reviewed from 49 patients with focal active colitis, who had no other diagnostic findings on colorectal biopsy and no history of chronic inflammatory bowel disease. The histological findings were correlated with clinical diagnoses. Follow-up information was available for 42 of 49 focal active colitis patients. None developed inflammatory bowel disease; however, 19 patients had an acute self-limited colitis-like diarrheal illness, 11 had incidental focal active colitis (patients without diarrhea that were endoscoped to exclude colonic neoplasia and found to have asymptomatic FAC), 6 had irritable bowel syndrome, 4 had antibiotic-associated colitis, and 2 had ischemic colitis. Twenty patients were immunosuppressed, and 19 were taking nonsteroidal anti-inflammatory drugs. No histological features predicted final diagnoses. FAC did not predict the development of chronic colitis, even when mild crypt distortion or slight basal plasmacytosis was present. The preponderance of acute self-limited colitis and antibiotic-associated colitis among the FAC patients, along with the high number of immunosuppressed patients, support the conclusion that most FAC cases are infectious. The incidental detection of FAC in patients undergoing endoscopy to exclude colonic neoplasia was not clinically significant. The role of nonsteroidal anti-inflammatory drugs in FAC deserves further study.

Pseudomembranous colitis is often caused by Clostridium difficile; however, it may also be due to ischemia. To determine if any histologic features could be used to differentiate C difficile from ischemia, 49 biopsies of pseudomembranous colitis (25 from patients with C difficile colitis and 24 from patients with ischemic colitis) were coded, randomized, and evaluated for the presence of numerous variables, including the amount and distribution of mucosal necrosis, lamina propria hyalinization, and atrophic "micro-crypts." Hyalinization of the lamina propria was seen in 19 cases of ischemia but not in C difficile colitis (p < 0.0001). Atrophic-appearing micro-crypts were seen in 18 ischemic cases and 6 C difficile cases (p < 0.0006). Lamina propria hemorrhage, full-thickness mucosal necrosis, and a diffuse microscopic distribution of pseudomembranes were significantly more common in ischemia than C difficile. Endoscopic examination identified pseudomembranes significantly more often with C difficile than ischemia, while the endoscopic appearance of masses or polyps was seen exclusively in cases of ischemia. The presence of a hyalinized lamina propria appeared to be a specific and sensitive marker for ischemia in colon biopsies with pseudomembranes. The presence of atrophic micro-crypts, lamina propria hemorrhage, full-thickness mucosal necrosis, diffuse involvement of all the surface of all biopsies by pseudomembranes, and the endoscopic impression of a localized process, polyp, or mass were also markers of ischemia, while the endoscopic identification of diffuse pseudomembranes favored the diagnosis of C difficile.

The histopathologic alterations of hepatitis C virus (HCV) infection of the liver overlap with those of other diseases, making interpretation of liver biopsy specimens in some cases insufficient to render a diagnosis. Although HCV infection can be confirmed by detection of circulating anti-HCV antibodies, immunocompromised liver transplant recipients are often unable to mount an immunologic response to the virus, resulting in false-negative serologic testing. We describe the comparison of reverse transcription-polymerase chain reaction (RT-PCR) with histopathology, serology, and immunohistochemistry for the diagnosis of HCV. Sixty-three formalin-fixed, paraffin-embedded tissue samples (40 needle biopsy specimens and 23 native liver resection specimens) from 35 transplant patients were analyzed by use of a novel method of RNA extraction followed by nested PCR for HCV as well as albumin mRNA as an internal control. HCV was detected by RT-PCR in 50 of 51 (98%) paraffin sections of liver from transplant patients with circulating anti-HCV antibodies, 15 of which lacked characteristic histologic features of HCV infection. Overall, there were no false-negative results in 36 needle biopsy specimens from patients with hepatitis C infection, but three negative results were seen in end-stage cirrhotic native livers resected from HCV-infected patients. No false-positive test results were seen among 21 negative controls (10 liver samples from immunocompetent patients with abnormalities unrelated to hepatitis C and 11 liver biopsies from immunocompetent patients without histologic evidence of liver disease). In comparison, immunohistochemistry using antibody TORDJI-22 was positive for HCV in only 15 of 32 (47%) needle biopsies positive by RT-PCR. Our results indicate that RT-PCR is a more sensitive and specific method of detecting hepatitis C in routinely processed paraffin sections of formalin-fixed liver biopsy specimens than histopathologic examination or immunohistochemistry.

Gastrointestinal stromal tumors (GISTs), as currently defined, are mesenchymal tumors of the gastrointestinal tract composed of spindled and/or epithelioid stromal cells that are neither mature Schwann cells nor smooth muscle cells. Many studies have lumped GISTs from all gut sites, when in fact these tumors differ histologically by location. In this study, we evaluated a set of parameters by both univariate and multivariate analysis to determine which parameters correlated with metastases in 36 GISTs from the jejunum and ileum, exclusively. The parameters included organoid architecture, cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, tumor size, skeinoid fibers, nuclear pleomorphism, ischemic necrosis, immunohistochemical differentiation, and proliferating cell nuclear antigen labeling. We evaluated these retrospectively without knowledge as to the metastatic outcome of the tumors. By univariate analysis, dense cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, and size were statistically significant correlates with metastases. By multivariate analysis, only dense cellularity and mitotic counts were independent correlates with metastases. Whether these features are useful predictors of behavior remains to be tested.