Risk factors for clinical relapse in patients with ulcerative colitis who are in clinical remission but with endoscopic activity.

Background and Aim: The treatment strategy for patients with ulcerative colitis (UC) in clinical remission who have not achieved mucosal healing is unclear. This study aimed to determine the risk factors of relapse in patients in clinical remission with endoscopic activity. Methods: This retrospective, single-center study included patients with UC who underwent colonoscopy (CS) and were in clinical remission with endoscopic activity. Characteristics were compared between patients who relapsed within 2 years after CS and those who did not. A Cox proportional hazards regression model was used to identify risk factors contributing to clinical relapse. Recent worsening in bowel symptoms was defined as increase in bowel frequency and/or increase in abdominal pain within approximately 1 month based on the descriptions in the medical charts. Results: This study regarded 142 patients in clinical remission with an endoscopic activity of Mayo endoscopic subscore (MES) of ≥1 as eligible, and 33 (23%) patients relapsed during the observation period. Recent worsening of bowel symptoms was a significant risk factor for clinical relapse (hazard ratio [HR]: 3.02, 95% confidence interval [CI]: 1.34-6.84). This was particularly evident in patients with MES of 2 (HR: 5.16, 95% CI: 1.48-18.04), whereas no risk factors were identified in patients with MES of 1. The presence or absence of therapeutic intervention just after CS did not significantly affect clinical relapse. Conclusion: Recent worsening in bowel symptoms was a significant risk factor for clinical relapse in patients with UC who were in clinical remission with endoscopic activity.

Clinical outcomes and reintervention after endoscopic retrograde cholangiopancreatography in primary sclerosing cholangitis in absence of cholangitis.

BACKGROUND AND AIM: Endoscopic retrograde cholangiopancreatography (ERCP) may help detect cholangiocarcinoma in patients with primary sclerosing cholangitis (PSC), but it may be associated with complications. This study was aimed at determining the prognostic impact of ERCP on patients with PSC without cholangitis. METHODS: Patients with PSC without cholangitis were divided into two groups: those who underwent ERCP within three years after diagnosis (ERCP-performed group) and those who did not (non-ERCP group). These groups were compared in terms of clinical outcomes (liver-related death or liver transplantation, endoscopic treatment requirement and repeated cholangitis) and the composite outcome. RESULTS: Of 99 patients with PSC with detailed medical history, 49 were included in the ERCP-performed group and 21 in the non-ERCP group. In Kaplan-Meier analysis, the non-ERCP group was less likely to achieve the three outcomes and the composite outcome, showing statistical significance (endoscopic treatment requirement; p = 0.017 and composite outcome; p = 0.014). A Cox proportional hazards model indicated that ERCP in the asymptomatic state was a significant predictor of endoscopic treatment requirement (hazard ratio [HR]: 4.37, 95% confidence interval [CI]: 1.03-18.59) and the composite outcome (HR: 4.54, 95% CI: 1.07-19.28). CONCLUSION: ERCP in patients with PSC without cholangitis is likely to require further endoscopic treatment and may be associated with poor prognosis.

Intensive triamcinolone acetonide injection regimen can highly prevent stricture after extensive esophageal endoscopic submucosal dissection.

BACKGROUND: This study aimed to investigate the utility of intensive triamcinolone acetonide (TA) injections after extensive esophageal endoscopic submucosal dissection (ESD). METHODS: This retrospective study included 27 lesions in 27 consecutive patients who underwent ESD (ulcers encompassing ≥3/4 of the esophageal circumference) and received TA injections without oral steroid administration. Groups A and B included patients undergoing ESD with and without complete circumferential resection, respectively. All patients received TA injections (100 mg/session) immediately after ESD. In Group A, weekly based TA injections were performed until near-complete ulcer epithelialization. In Group B, patients did not receive additional injections or received weekly or biweekly TA injections. The primary outcome was stricture rate, and the secondary outcomes were the proportion of patients requiring endoscopic balloon dilation (EBD) and the number of TA injections. RESULTS: Group A included 7 lesions, and Group B included 20 lesions. The median (range) tumor lengths were 40 (30-90) and 45 (30-110) mm in Groups A and B, respectively. In Group A, the median circumferential resection diameter was 40 (20-80) mm. The stricture rate and the proportion of patients requiring EBD were 0 (0%) in Group A and 1 (5.0%) in Group B. The number of TA injection sessions was significantly higher in Group A than in Group B (8 [5-25] vs 1.5 [1-3]; p < 0.001). CONCLUSIONS: Intensive weekly or biweekly based TA injections might aid in preventing post-ESD stricture and the need for EBD in patients undergoing extensive resection involving the entire esophageal circumference.

Characteristics of factors contributing to follow-up for suspected delayed bleeding after colorectal endoscopic submucosal dissection.

BACKGROUND AND AIMS: Delayed bleeding (DB) is a major adverse event associated with colorectal endoscopic submucosal dissection (ESD) that sometimes causes difficulties in making decisions regarding endoscopic hemostasis. This study identified the factors that contribute to follow-up without endoscopic hemostasis when DB is suspected after colorectal ESD. METHODS: In total, 583 patients (603 tumors) who underwent ESD or hybrid ESD for colorectal tumors at Chiba University Hospital between June 2009 and January 2022 were retrospectively registered. Of these, 141 cases (141 tumors) with DB, and hematochezia or hemoglobin decrease ≥2 g/dL after colorectal ESD, were analyzed. The DB group was divided into the Hemostasis group (H group; endoscopic hemostasis performed) and no-Hemostasis group (no-H group; no endoscopy performed, or endoscopy performed but no hemostasis performed after hematochezia or hemoglobin decrease). Univariate and multivariate logistic regression analyses were conducted to assess the factors contributing to follow-up. RESULTS: Thirty-one patients with 31 tumors were categorized into the H group, and 110 patients with 110 tumors were in the no-H group. Multivariate regression analysis revealed that date from ESD to first hematochezia ≤Day 3 (odds ratio, 4.55; 95% confidence interval, 1.44-14.33; P = .010) and bleeding duration ≤1 day (odds ratio, 3.35; 95% confidence interval, 1.35-8.34; P = .009) contributed to follow-up. CONCLUSIONS: In cases of DB after colorectal ESD, a bleeding duration ≤1 day or date from ESD to first hematochezia ≤Day 3 may contribute to follow-up observation without endoscopic hemostasis.

Differences in Mucosal Permeability Among Patients With Ulcerative Colitis Classified Based on the Colonic Location and Disease Activity.

INTRODUCTION: Factors affecting mucosal permeability (MP) in ulcerative colitis (UC) are largely unknown. We aimed to investigate the difference in MP among patients with UC classified according to the colonic locations and to evaluate the correlations between local MP and endoscopic or histological activity of UC. METHODS: The transepithelial electrical resistance (TER), which is inversely proportional to permeability, of tissue samples from the mucosa of the ascending colon, descending colon, and rectum of patients with UC and healthy individuals (HIs) was measured by using the Ussing chamber. TERs were compared between patients with UC and HIs and evaluated according to colonic locations and disease activity of UC. RESULTS: Thirty-eight patients with UC and 12 HIs were included in this study. Both in HIs and patients with UC, MP tends to be higher in the anal side. TER in the ascending colon was significantly lower in patients with UC than in HIs (45.3 ± 9.0 Ω × cm 2 vs 53.5 ± 9.7 Ω × cm 2 , P = 0.01). The increased permeability in UC was observed also in the descending colon, only when the inflammation involved the location. A significant correlation between TER and endoscopic activity was found in the rectum only ( r = -0.49, P = 0.002). There were no significant correlations between TERs and UC histology. DISCUSSION: The MP in the colon differs according to the colonic location. The ascending colon among patients with UC showed disease-specific changes in MP, whereas the MP is increased in proportion to the endoscopic activity in the rectum.

Utility of prophylactic clipping after colorectal cold snare polypectomy in patients on oral antithrombotic agents.

BACKGROUND AND AIMS: There is no consensus on the effectiveness of prophylactic clipping after colonic cold snare polypectomy (CSP). This study aimed to evaluate the utility of prophylactic clipping in preventing delayed bleeding (DB) after colorectal CSP in patients on antithrombotic agents. METHODS: We retrospectively recruited consecutive patients on antithrombotic agents who underwent colorectal CSP in Chiba University Hospital. The DB rate was compared between patients with and without prophylactic clipping. RESULTS: The study included 133 patients (422 polyps) requiring prophylactic clipping and 85 patients (282 polyps) not requiring prophylactic clipping. There were no significant differences in DB and hematochezia rates between the groups. By weighted logistic regression analysis, the odds ratio of hematochezia was 0.557 (95% confidence interval, 0.225-1.378; P = .205) in patients without clipping compared to those with clipping. CONCLUSIONS: Prophylactic clipping may not be necessary to prevent DB after colorectal CSP in patients on antithrombotic agents.

Investigation of risk factors for metachronous recurrence in patients with early gastric adenocarcinoma by miRNA-mRNA integral profiling.

The mechanism of metachronous recurrence (MR) after performing endoscopic treatment for early gastric adenocarcinoma (GAC) and eradicating Helicobacter pylori (H. pylori) is unknown. To elucidate the mechanism and risk factors of MR, we analyzed gene expression at multiple locations of the gastric mucosa. We selected each five patients with MR and without MR (control), after early GAC treatment and eradication of H. pylori. Mucosal tissue was collected from four sites in the stomach of each patient as biopsy specimens for mRNA sequencing, gene set enrichment analysis, and microRNA (miRNA) sequencing. We also performed correlation analysis and target prediction on pathways. As a result, endoscopically, the MR group had more intestinal metaplasia and enlarged folds. A total of 384 mRNAs presented changes in expression and 31 gene sets were enriched in the MR group. Immune-related pathways were enriched in the entire stomach, and the IFN-α response had the highest enrichment score. Additionally, 32 miRNAs revealed changes in their expression. Correlation analysis and target prediction with genes in the gene set of IFN-α response revealed that 10 miRNA-mRNA pairs presented a significant correlation. Immune-related pathways with miRNAs in the gastric mucosa after H. pylori eradication may be a risk factor for MR.

[A case of irreversible metronidazole encephalopathy during liver abscess treatment].

Metronidazole (MNZ) is a widely used drug for protozoan and anaerobic infections. The continuous use of MNZ causes various neurological symptoms, such as cerebellar ataxia, visual disturbance, vestibulocochlear symptoms, gait disturbance, dysarthria, and epileptic seizures of unknown cause, named MNZ-induced encephalopathy (MIE), in rare cases. MIE is a reversible disease that often improves within a few days of MNZ discontinuation, but irreversible neurological symptoms rarely remain. Herein, we report a case of MIE that developed during MNZ administration for a liver abscess, causing prolonged unconsciousness and death even after drug discontinuation. An 85-year-old female patient complained of fever, elevated liver enzymes, and a multifocal abscess in the right hepatic lobe, as seen on computed tomography. Percutaneous transhepatic abscess drainage and antibiotic therapy were initiated. The causative agent of the liver abscess could not be identified, thus meropenem was started, which demonstrated no inflammation improvement, thus oral MNZ was added. The inflammation recurred when MNZ was discontinued, and the patient continued taking MNZ. Vomiting, upper limb tremors, consciousness disturbance, and convulsions appeared on day 46 (total dose of MNZ 73.5mg), and the patient was hospitalized. T2-weighted, diffusion-weighted, and FLAIR head magnetic resonance imaging (MRI) revealed symmetrical abnormal high-signal areas in the cerebellar dentate nucleus, corpus callosum, cerebral white matter, and periventricular areas. MIE was diagnosed based on the patient's course and MRI images, and MNZ was discontinued. The patient continued to suffer from impaired consciousness and convulsions after MNZ discontinuation and died due to aspiration pneumonia. Suggestively, MIE development is related to long-term MNZ administration, poor nutrition, liver disease, underlying diseases (such as advanced cancer), and serious complications. A systematic review of MIE cases revealed that 4.8-5.9% of the patients demonstrated little improvement of symptoms after MNZ discontinuation, and some deaths were reported. Patients with poor prognosis were often suffering from impaired consciousness and convulsions. Furthermore, impaired consciousness was the most common residual symptom. Abnormal signals in characteristic areas, such as the dentate nucleus cerebri and corpus callosum, on head MRI are useful for MIE diagnosis, especially in patients with abnormal findings in the cerebral white matter, which is associated with a poor prognosis. We should pay close attention to the onset of MIE when MNZ is administered.

Treatment strategy changes for inflammatory bowel diseases in biologic era: results from a multicenter cohort in Japan, Far East 1000.

Many molecular targeted agents, including biologics, have emerged for inflammatory bowel diseases (IBD), but their high prices have prevented their widespread use. This study aimed to reveal the changes in patient characteristics and the therapeutic strategies of IBD before and after the implementation of biologics in Japan, where the unique health insurance system allows patients with IBD and physicians to select drugs with minimum patient expenses. The analysis was performed using a prospective cohort, including IBD expert and nonexpert hospitals in Japan. In this study, patients were classified into two groups according to the year of diagnosis based on infliximab implementation as the prebiologic and biologic era groups. The characteristics of therapeutic strategies in both groups were evaluated using association analysis. This study analyzed 542 ulcerative colitis (UC) and 186 Crohn's disease (CD). The biologic era included 53.3% of patients with UC and 76.2% with CD, respectively. The age of UC (33.9 years vs. 38.8 years, P < 0.001) or CD diagnosis (24.3 years vs. 31.9 years, P < 0.001) was significantly higher in the biologic era group. The association analysis of patients with multiple drug usage histories revealed that patients in the prebiologic era group selected anti-tumor necrosis factor (TNF)-α agents, whereas those in the biologic era group preferred biologic agents with different mechanisms other than anti-TNF-α. In conclusion, this study demonstrated that both patient characteristics and treatment preferences in IBD have changed before and after biologic implementation.

Clinical Features Focusing on Extraintestinal Manifestations in Japanese Patients with Inflammatory Bowel Diseases: Far East 1000.

BACKGROUND: Patients with inflammatory bowel diseases (IBD) can develop extraintestinal manifestations (EIMs) during the disease course, which sometimes impact their quality of life. OBJECTIVES: This study aimed to clarify the prevalence and types of EIMs using a hospital-based IBD cohort in Japan. METHODS: A patient cohort with IBD was established in 2019, as participated by 15 hospitals in Chiba Prefecture of Japan. Using this cohort, the prevalence and types of EIMs, which are defined based on previous reports and the Japanese guidelines, were investigated. RESULTS: This cohort enrolled 728 patients, including 542 ulcerative colitis (UC) and 186 Crohn's disease (CD). Of these patients with IBD, 10.0% were identified with one or more EIMs (57 (10.5%) with UC and 16 (8.6%) with CD). Arthropathy and arthritis were the most common EIM in 23 (4.2%) patients with UC, followed by primary sclerosing cholangitis (PSC) (2.6%). Arthropathy and arthritis were also the most common in patients with CD, but no cases of PSC were observed. EIMs were more frequently observed in patients with IBD treated by specialists than in those treated by non-specialists (12.7% vs. 5.5%, p = 0.011). The incidence of EIMs in patients with IBD was not significantly different over time. CONCLUSIONS: The prevalence and types of EIMs in our hospital-based cohort in Japan did not significantly differ from those reported in previous or Western studies. However, the incidence might be underestimated due to the limited ability of non-IBD specialists to discover and describe EIMs in patients with IBD.

Long-term course of gastric submucosal tumors: growth speed and size-increasing factors.

BACKGROUND AND AIMS: Gastric submucosal tumors (SMTs) are treated or monitored according to GI stromal tumor guidelines, but the adequacy of the guidelines has not been thoroughly examined. We investigated the long-term course of gastric SMTs to determine the validity of guideline-based follow-up methods and the factors contributing to their size increase. METHODS: This study included gastric SMTs diagnosed as GI mesenchymal tumors (GIMTs) by using EUS and followed up with EUS. The percentage and speed of GIMT enlargement and factors associated with the enlargement were investigated by using the Cox proportional hazards model. RESULTS: From January 1994 to May 2022, a total of 925 gastric SMTs were evaluated with EGD, and 231 SMTs were diagnosed as GIMTs. Of the 231 GIMTs, 145 were examined by EUS more than twice and were followed up for >6 months. The mean ± standard deviation follow-up period was 5.20 ± 4.04 years (range, 0.5-17.3 years), with 39 (26.9%) of 145 GIMTs increasing in size with a mean doubling time of 3.60 ± 3.37 years. A multivariate analysis of factors influencing tumor growth revealed that irregular extraluminal borders were an increasing factor (hazard ratio, 3.65; 95% confidence interval, 1.26-10.52), initial tumor size ≤9.5 mm (hazard ratio, .23; 95% confidence interval, 0.07-0.77) was a nonincreasing factor, and GIMTs with calcification (n = 13) did not increase in size. CONCLUSIONS: Tumor growth in gastric GIMTs <9.5 mm in diameter and/or with calcification is rare. Follow-up intervals for these lesions could be extended.

Anti-TNFα antibody versus non-anti-TNFα molecular agents for ulcerative colitis patients who failed initial anti-TNFα therapy.

BACKGROUND AND AIM: Anti-tumor necrosis factor (TNF)α antibody (ATA) and biologics/molecular targeted agents with other mechanisms (non-ATA) are currently available for refractory ulcerative colitis (UC). However, the knowledge about optimal drug selection after the initial treatment with ATA failure is lacking. This study assessed whether the response to the initial ATA could be a basis for selecting subsequent agents in UC patients. METHODS: Ulcerative colitis patients treated with ATA or non-ATA as the subsequent biologic after the failure of initial ATA were retrospectively analyzed. The efficacy at 14 weeks was examined according to the response to initial ATA. RESULTS: Of 163 patients treated with the first ATA, the efficacy of subsequent ATA and non-ATA was evaluated in 63 and 36, respectively. Remission and response to subsequent-line therapy, regardless of ATA or non-ATA, were lower in patients with primary nonresponse (PNR) to initial ATA than in patients with efficacy to initial ATA (33.3% vs 69.2%, P < 0.01). In patients with PNR to initial ATA, the remission rate with subsequent ATA was significantly lower than with subsequent non-ATA (4.3% vs 26.3%, P = 0.04). In patients who showed efficacy to initial ATA, the remission rate with subsequent ATA was also lower than that with subsequent non-ATA (30.6% vs 56.3%, P = 0.08). PNR with initial ATA was the predictor of PNR to subsequent ATA (odds ratio: 5.62, 95% confidence interval: 1.50-21.7). CONCLUSION: Non-ATA may be suitable in UC patients as the subsequent biologics regardless of the outcome of the first ATA.

Evaluation of Usability and Learning Motivation of e-Learning Courses for People With Chronic Kidney Disease.

Nurses need to increase patient education opportunities so that more people with chronic kidney disease can understand the disease accurately from its early stages. We developed an e-learning course based on the Dick and Carey system approach model and the attention, relevance, confidence, satisfaction model for people with chronic kidney disease. People with chronic kidney disease, on average, are aged around 50 to 60 years, and this population tends to lack perceived susceptibility toward and concern for the disease owing to the asymptomatic nature of early chronic kidney disease. Therefore, e-learning should be easy to use and motivate learning. This study aimed to evaluate the usability and learning motivation of this course. The participants included 10 outpatients (mean age, 51.2 years) with chronic kidney disease whose mastery percentage of learning objectives was compared by the knowledge tests immediately before and after the course. We also observed the participants' operation status and measured their motivation for using instructional materials with a questionnaire. The results demonstrated that this course facilitates independent operation, improves postcourse performance, and motivates participants in all areas of learning motivation. Thus, this e-learning course can be recommended as easy to use and motivating for people with chronic kidney disease.

Clinical Characteristics of Esophageal Motility Disorders in Patients With Heartburn.

BACKGROUND/AIMS: Esophageal motility disorders (EMDs) contribute to the pathophysiology of gastroesophageal reflux disease. However, the causes of EMDs and their impact on gastroesophageal reflux disease-associated symptoms remain unknown. This study aims to elucidate clinical features associated with various types of EMDs in patients with heartburn symptoms. METHODS: Of the 511 patients who underwent high-resolution manometry, 394 who were evaluated for heartburn symptoms were examined. Patients subjected to high-resolution manometry were classified into 4 groups: outflow obstruction group, hypermotility group, hypomotility group, and normal motility group. Symptoms were evaluated using 3 questionnaires. Patient characteristics and symptoms for each EMD type were compared with those of the normal motility group. RESULTS: Of the 394 patients, 193 (48.9%) were diagnosed with EMDs, including 71 with outflow obstruction, 15 with hypermotility, and 107 with hypomotility. The mean dysphagia score was significantly higher in each of the 3 EMD groups compared with those with normal motility. The mean acid reflux and dyspepsia scores were significantly lower in the outflow obstruction group (P < 0.05). The mean body mass index and median Brinkman index were significantly higher in the hypermotility group (P = 0.001 and P = 0.018, respectively), whereas the mean diarrhea and constipation scores were significantly lower in the hypomotility group (P < 0.05). CONCLUSIONS: The results of our study indicate that different EMDs have distinct characteristics. Cigarette smoking and high body mass index were associated with esophageal hypermotility. Assessment of the dysphagia symptom scores may help identify patients with EMDs.

Methotrexate-induced Transient Encephalopathy in an Adolescent and Young Adult Patient with Acute Lymphoblastic Leukemia.

A 17-year-old girl was diagnosed with acute lymphoblastic leukemia (ALL). After the administration of high-dose methotrexate (MTX) or intrathecal MTX, the patient experienced transient hemiparesis and motor aphasia. Diffusion-weighted magnetic resonance imaging showed a high-intensity lesion in the bilateral centrum semiovale, and a vasospasm was detected in the proximal segment of bilateral A1 on magnetic resonance angiography. Edaravone was administered, and leucovorin rescue treatment was continued; eventually, the patient's neurological symptoms completely resolved. This finding suggested that vasospasm might be a mechanism underlying MTX-induced transient encephalopathy in adolescent and young adult patients with ALL.

CD7-Positive Diffuse Large B-Cell Lymphoma Presenting as an Intranasal Tumor.

We report a case of a 74-year-old man with a cluster of differentiation (CD) 7-positive diffuse large B-cell lymphoma (DLBCL) in the right nasal cavity. Flow cytometry analyses showed CD7 and CD20 positivity in tumor cells. The patient received 6 cycles of R-CHOP plus local radiation therapy because positron emission tomography-computed tomography after R-CHOP revealed an intranasal lesion. The patient achieved complete remission (CR) after radiation therapy. The frequency of CD7-positive DLBCL is rare, and only 11 cases with follow-up of clinical course have been reported thus far. CR or partial response was noted in 8 of 11 cases after receiving rituximab combined with chemotherapy. In total, 9 of 12 cases involved the development of extranodal lesions, which occurred as an intranasal tumor in 3 cases. It is important to examine the clinical features by accumulation of further cases.

[Refractory CD20-positive peripheral T-cell lymphoma showing loss of CD20 expression after rituximab therapy and gain of CD20 expression after administration of vorinostat and gemcitabine].

A 79-year-old male patient presented with systemic lymphadenopathy. A lymph node biopsy revealed effacement of the normal nodal architecture with diffuse proliferation of medium-sized atypical lymphoid cells. Southern blot analyses demonstrated rearrangement of the T-cell receptor gene but not the immunoglobulin heavy chain gene. He was diagnosed with CD20-positive peripheral T-cell lymphoma (PTCL), NOS. Although he achieved partial remission after six cycles of R-CHOP, he relapse occurred after 2 months. CD20-negative conversion was confirmed in the lymph node, which was positive for CCR4, and the skin at the time of relapse. The patient received the GDP regimen as salvage therapy with the addition of vorinostat for skin involvement; however, he failed to respond, and the disease systemically progressed. Furthermore, he also exhibited progression in the skin after stopping vorinostat due to hematologic toxicity. A lymph node biopsy at progression revealed CD20 re-expression by immunohistochemistry. At progression, the patient received mogamulizumab but failed to respond, and he died owing to disease progression 8 months after relapse. In this case, we demonstrated CD20-negative conversion following rituximab and CD20-positive reversion after using vorinostat and gemcitabine.

Non-Hodgkin lymphoma diagnosed by a percutaneous trans-hepatic needle biopsy of portal vein tumor emboli.

A 58-year-old woman was admitted to our hospital for evaluation of left flank pain. Abdominal computed tomography showed a greatly enlarged splenic tumor with a massive portal vein tumor thrombosis (PVTT). We suspected non-Hodgkin lymphoma (NHL) based on the high values of serum soluble interleukin-2 receptor and lactate dehydrogenase. Because there was no superficial lymph node enlargement, ultrasound-guided percutaneous trans-hepatic needle biopsy was performed to obtain a pathological diagnosis of PVTT, instead of a splenectomy, after the patient had provided informed consent. This procedure was thought to be less invasive than splenectomy. Histologic examination revealed CD20-positive NHL. A complete response was achieved after six courses of R-CHOP and it was confirmed by splenectomy. A PVTT due to NHL is extremely rare as compared with that due to hepatocellular carcinoma, gastric cancer, and colon cancer. However, NHL should be considered in the differential diagnosis for a patient with a PVTT, because B cell-NHL tends to have a good prognosis when rituximab combined chemotherapy is administered. We suggest that a percutaneous trans-hepatic needle biopsy may be useful for diagnosing PVTT due to NHL.

KIT-negative gastrointestinal stromal tumor of the abdominal soft tissue: a clinicopathologic and genetic study of 10 cases.

Gastrointestinal stromal tumor (GIST) typically occurs in the gastrointestinal (GI) tract, and expresses KIT protein that is associated with KIT or platelet-derived growth factor receptor-α (PDGFRA) gene mutation. Extragastrointestinal stromal tumors (EGISTs) are a minor subset of GIST that occurs in the soft tissue outside the GI tract, and in very rare cases, these tumors can be KIT negative. We examined the clinicopathologic and molecular characteristics of 10 cases of KIT-negative EGIST by using immunohistochemical staining and gene mutation analysis. The tumors occurred in the omentum (n=5), mesentery (n=2), retroperitoneum (n=1), pelvic cavity (n=1), and not otherwise specified regions of the abdominal cavity (n=1). They ranged from 4 to 33 cm (median, 15 cm) in maximum diameter with relatively low mitotic counts (median, 3.5 per 50 high-power fields). Morphologically, most cases were of epithelioid cell (n=9) or mixed epithelioid and spindle cell (n=1) type, accompanied by variable amounts of myxoid stroma. By immunohistochemical staining, the tumors were positive for CD34 (80%), protein kinase C (PKC) θ (90%), and discovered on GIST-1 (DOG1) (90%), but were negative for KIT (0%). The majority of the examined cases (7 of 9 cases; 78%) had PDGFRA mutations in exon 12 (n=1) or exon 18 (n=6). One case (11%) had a mutation in KIT exon 11, and the remaining 1 had no mutation in either KIT or PDGFRA. Distant metastasis and local recurrence occurred in 1 (10%) and 2 (20%) patients, respectively, and adverse outcome was correlated with larger (>10 cm) tumor size and high mitotic counts (>5/50 high-power fields). Therefore, KIT-negative EGISTs can be characterized by preferential omental origin, epithelioid cell type, low mitotic activity, and mutation of the PDGFRA gene, and these features are similar to those of KIT-negative gastric GISTs. As KIT-negative EGISTs should be considered to be a potential abdominal soft tissue neoplasm, immunohistochemical staining panel and molecular analysis are necessary not only to confirm the diagnosis but also to determine the therapeutic strategy.