Case of severe alcoholic hepatitis following acute pancreatitis.

This report describes the clinical course of a 41 year-old African woman who presented with an episode of acute alcoholic pancreatitis followed next by severe alcoholic hepatitis (SAH). Initially admitted for pancreatitis, the patient responded promptly to comprehensive treatment with strict abstinence from alcohol. However, remarkable elevations in white blood cell count to 44,000/µL and total bilirubin level to 12.4 mg/dL were observed 5-7 weeks later. Contrast-enhanced computed tomography revealed rapidly progressing hepatosplenomegaly. Histological analysis of a liver biopsy detected ballooned hepatocytes with Mallory-Denk bodies and significant neutrophilic infiltration in the hepatic parenchyma, which confirmed the diagnosis of SAH. The patient's hepatosplenomegaly and overall condition improved with supportive care alone. The reported case reveals the unexpected fact that SAH can develop after alcoholic acute pancreatitis.

Leucine-rich repeat-containing G protein-coupled receptor 5 expression in lymph node metastases of colorectal cancer: Clinicopathological insights and prognostic implications.

Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), a significant cancer stem cell marker in colorectal cancer (CRC), lacks lymph node (LN) expression studies. In this study, we identified LGR5 expression by RNAscope, a highly sensitive RNA in situ method, and analyzed its association with clinicopathological characteristics. Tissue microarrays were generated from primary tumors (PTs) and LN metastases in paraffin-embedded blocks of 38 CRC surgical resection materials. LGR5 expression by RNAscope was evaluated by dividing the expression levels into negative and positive expression. In all but two cases of LN metastasis, LGR5-positive dots were detected in tumor cells, and there was a wide range of LGR5-positive cells. More LGR5-positive dots were identified in the gland-forming region. Twenty-three cases were classified into a high LGR5-expression group, and 15 cases were classified into a low LGR5-expression group. In the high LGR5-expression group, the histological grade was lower than in the low LGR5-expression group (p = 0.0159), while necrosis was significantly more prevalent (p = 0.0326), and the tumor, node, metastasis stage was significantly lower (p = 0.0302). There was no association between LGR5 expression levels in LN metastases and LGR5 expression levels in PT tissue. LGR5 expression in LN metastases may influence prognosis. Further analysis may lead to new therapeutic strategies.

An Immunohistochemical Analysis of Osteopontin and S100 Calcium-binding Protein P is Useful for Subclassifying Large- and Small-duct Type Intrahepatic Cholangiocarcinomas.

Intrahepatic cholangiocarcinoma (iCCA) has been newly subclassified into two different subtypes: large-duct (LD) type and small-duct (SD) type. However, many cases are difficult to subclassify, and there is no consensus regarding subclassification criteria. LD type expresses the highly sensitive diagnostic marker S100 calcium-binding protein P (S100P), while SD type lacks sensitive markers. We identified osteopontin (OPN) as a highly sensitive marker for SD type. This study aimed to develop new subclassification criteria for LD-type and SD-type iCCA. We retrospectively investigated 74 patients with iCCA and subclassified them based on whole-section immunostaining of S100P and OPN. Of the 74 cases, 41 were subclassified as LD type, 32 as SD type, and one was indeterminate. Notably, all S100P-negative cases had OPN positivity. Seventy-three of the 74 cases (98.6%) were clearly and easily subclassified as LD or SD type using only these 2 markers. We also determined the value of immunohistochemistry in cases that were difficult to diagnose based on hematoxylin-eosin and Alcian blue-periodic acid-Schiff staining. Furthermore, we analyzed the clinicopathological characteristics and prognoses of these 2 subtypes. LD type was a poor prognostic factor on univariate analysis; it had significantly worse overall survival ( P = 0.007) and recurrence-free survival ( P < 0.001) than the SD type. In conclusion, we propose new subclassification criteria for iCCA based on immunostaining of S100P and OPN. These criteria may help pathologists to diagnose subtypes of iCCA, supporting future clinical trials and the development of medications for these 2 subtypes as distinct cancers.

A preliminary study of IgG4 expression and its prognostic significance in oral squamous cell carcinoma.

BACKGROUND: IgG4, which plays a pivotal role in the progression of phenotypically diverse tumors, serves as a prognostic marker because of its influence on cancer immunity. Nevertheless, the functions of IgG4 in tongue squamous cell carcinoma (TSCC) remained to be identified. METHODS: To evaluate the significance of IgG4 expression in TSCC, we performed immunohistochemical analysis of patients with TSCC (n = 50) to evaluate the correlation of IgG4 expression with patients' clinicopathological features and prognoses. RESULTS: Higher IgG4 expression detected in TSCC tissues was associated with the less advanced mode of invasion (Yamamoto-Kohama [YK] 1-3) (P = 0.031) and with well-differentiated TSCC (P = 0.077). Kaplan-Meier analyses revealed that the higher IgG4 expression group exhibited better prognosis indicated by overall survival (OS) (P = 0.04) and recurrence-free survival (RFS) (P = 0.016). Univariate analysis of OS indicated that IgG4 expression was associated with longer OS (P = 0.061), and multivariate analysis of RFS revealed that IgG4 expression served as an independent prognostic factor for longer RFS (P = 0.005). CONCLUSION: These results indicate that relatively higher IgG4 levels serve as a favorable prognostic factor for TSCC.

Identification of Terminal ßGlcNAc on Brachyspira Species in Human Intestinal Spirochetosis.

Human intestinal spirochetosis (HIS) is a colorectal bacterial infection caused by the Brachyspira species. Griffonia simplicifolia-II (GS-II) is a lectin specific to terminal α/ßGlcNAc residues. Here, we investigated terminal ßGlcNAc residues in the context of HIS infection using GS-II-horseradish peroxidase staining and HIK1083 immunostaining specific to terminal αGlcNAc residues. Fourteen of 15 HIS cases were GS-II-positive on the bacterial body. No cases showed HIK1083 positivity. The percentage of bacterial bodies staining positively for GS-II based on comparison with anti-Treponema immunostaining was ≤30% in seven cases, 30-70% in two, and >70% in six. Of 15 HIS cases analyzed, none were comorbid with tubular adenomas, and three were comorbid with sessile serrated lesions (SSLs). To determine the species of spirochete infected, the B. aalborgi-specific or B. pilosicoli-specific NADPH oxidase genes were amplified by PCR. After direct sequencing of the PCR products, all nine cases in which PCR products were observed were found to be infected with B. aalborgi alone. These results indicate that the HIS bacterial body, especially of B. aalborgi, is characterized by terminal ßGlcNAc and also indicate that terminal ßGlcNAc on the HIS bacterial body is associated with HIS preference for SSLs.

Interleukin-6 Stromal Expression is Correlated with Epithelial-Mesenchymal Transition at Tumor Budding in Colorectal Cancer.

Background. Tumor budding is a poor prognostic factor in colorectal adenocarcinoma, but the underlying mechanism remains unclear. Interleukin-6 (IL6) is one of the main cytokines produced by cancer-associated fibroblasts. IL6 is linked with cancer progression and poor prognosis by activating cancer cells and modifying the cancer microenvironment. However, little is known about the expression of IL6 in tumor budding and its association with tumor budding in colorectal adenocarcinoma. Methods. The clinicopathological and prognostic significance of IL6 in tumor budding was examined using a tissue microarray consisting of 36 patient samples of tumor budding in colorectal adenocarcinoma. IL6 mRNA was detected by RNAscope. Patients were stratified into negative and positive IL6 expression groups. Results. IL6 expression was overwhelmingly observed in cancer stroma but was negligible in cancer cells. Tumor budding grade was higher in the IL6-positive group in cancer stroma than in the IL6-negative group (P = .0161), while the IL6-positive group significantly exhibited the epithelial-mesenchymal transition phenotype compared with the IL6-negative group in cancer stroma (P = .0301). There was no significant difference in overall survival between colorectal adenocarcinoma patients in the IL6-positive and -negative groups in cancer stroma. Conclusion. Tumor budding may be affected by IL6 expression, and IL6 expression in cancer stroma at tumor budding may be an important prognostic marker.

Thrombospondin 2 is a key determinant of fibrogenesis in non-alcoholic fatty liver disease.

OBJECTIVE: Hepatic overexpression of the thrombospondin 2 gene (THBS2) and elevated levels of circulating thrombospondin 2 (TSP2) have been observed in patients with chronic liver disease. This study aimed to identify the specific cells expressing THBS2/TSP2 in non-alcoholic fatty liver disease (NAFLD) and investigate the underlying mechanism behind THBS2/TSP2 upregulation. DESIGN: Comprehensive NAFLD liver gene datasets, including single-cell RNA sequencing (scRNA-seq), in-house NAFLD liver tissue, and LX-2 cells derived from human hepatic stellate cells (HSCs), were analysed using a combination of computational biology, genetic, immunological, and pharmacological approaches. RESULTS: Analysis of the genetic dataset revealed the presence of 1433 variable genes in patients with advanced fibrosis NAFLD, with THBS2 ranked among the top 2 genes. Quantitative polymerase chain reaction (qPCR) examination of NAFLD livers showed a significant correlation between THBS2 expression and fibrosis stage (r = .349, p < .001). In support of this, scRNA-seq data and in situ hybridization demonstrated that the THBS2 gene was highly expressed in HSCs of NAFLD patients with advanced fibrosis. Pathway analysis of the gene dataset revealed THBS2 expression to be associated with the transforming growth factor beta (TGFß) pathway and collagen gene activation. Moreover, the activation of LX-2 cells with TGFß increased THBS2/TSP2 and collagen expression independently of the TGFß-SMAD2/3 pathway. THBS2 gene knockdown significantly decreased collagen expression in LX-2 cells. CONCLUSIONS: THBS2/TSP2 is highly expressed in HSCs and plays a role in regulating fibrogenesis in NAFLD patients. THBS2/TSP2 may therefore represent a potential target for anti-fibrotic therapy in NAFLD.

Mucosal damage in pancreaticobiliary maljunction is stronger in the gallbladder than in the bile duct.

BACKGROUND: The frequency of gallbladder carcinoma is high in pancreaticobiliary maljunction (PBM), and the mechanism of carcinogenesis is not well understood. METHODS: The expression of γH2AX, the most sensitive marker for detecting DNA damage, was analyzed using immunohistochemistry in patients with PBM, in which the gallbladder and bile duct were simultaneously resected. Gallbladder and bile ducts were evaluated in non-neoplastic regions in 13 cases of PBM without cancer in the gallbladder and bile ducts. RESULTS: The median frequencies of γH2AX expression in the bile duct and gallbladder within the same case were 5.9% (range 1.7-12.05%) and 9.9% (range 2.8-25%), respectively, and were significantly higher in the gallbladder mucosa (P < 0.0004). γH2AX expression strongly correlated in the bile duct and gallbladder (r = 0.9436, P < 0.0001). PBM caused marked mucosal damage to the gallbladder. CONCLUSIONS: Mucosal damage may be involved in carcinogenesis, which may be useful for predicting malignant transformation.

Artificial intelligence for evaluating the risk of gastric cancer: reliable detection and scoring of intestinal metaplasia with deep learning algorithms.

BACKGROUND AND AIMS: Gastric cancer (GC) is associated with chronic gastritis. To evaluate the risk, the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) system was constructed and showed a higher GC risk in stage III or IV patients, determined by the degree of intestinal metaplasia (IM). Although the OLGIM system is useful, evaluating the degree of IM requires substantial experience to produce precise scoring. Whole-slide imaging is becoming routine, but most artificial intelligence (AI) systems in pathology are focused on neoplastic lesions. METHODS: Hematoxylin and eosin-stained slides were scanned. Images were divided into each gastric biopsy tissue sample and labeled with an IM score. IM was scored as follows: 0 (no IM), 1 (mild IM), 2 (moderate IM), and 3 (severe IM). Overall, 5753 images were prepared. A deep convolutional neural network (DCNN) model, ResNet50, was used for classification. RESULTS: ResNet50 classified images with and without IM with a sensitivity of 97.7% and specificity of 94.6%. IM scores 2 and 3, involved as criteria of stage III or IV in the OLGIM system, were classified by ResNet50 in 18%. The respective sensitivity and specificity values of classifying IM between scores 0 and 1 and 2 and 3 were 98.5% and 94.9%, respectively. The IM scores classified by pathologists and the AI system were different in only 438 images (7.6%), and we found that ResNet50 tended to miss small foci of IM but successfully identified minimal IM areas that pathologists missed during the review. CONCLUSIONS: Our findings suggested that this AI system would contribute to evaluating the risk of GC accuracy, reliability, and repeatability with worldwide standardization.

ARL4C is associated with epithelial-to-mesenchymal transition in colorectal cancer.

BACKGROUND: ADP-ribosylation factor-like protein 4 C (ARL4C) is a member of the ARF small GTP-binding protein subfamily. The ARL4C gene is highly expressed in colorectal cancer (CRC). ARL4C protein promotes cell motility, invasion, and proliferation. METHODS: We investigated the characteristics of ARL4C by comparing its expression at the invasion front and relationships with clinicopathological data using RNAscope, a highly sensitive RNA in situ method. RESULTS: In all cases, ARL4C expression was observed in cancer stromal cells and cancer cells. ARL4C expression in cancer cells was localized at the invasion front. In cancer stromal cells, ARL4C expression was significantly stronger in cases with high-grade tumor budding than in cases with low-grade tumor budding (P = 0.0002). Additionally, ARL4C expression was significantly increased in patients with high histological grade compared with those with low histological grade (P = 0.0227). Furthermore, ARL4C expression was significantly stronger in lesions with the epithelial-to-mesenchymal transition (EMT) phenotype compared with the non-EMT phenotype (P = 0.0289). In CRC cells, ARL4C expression was significantly stronger in cells that had the EMT phenotype compared with those with a non-EMT phenotype (P = 0.0366). ARL4C expression was significantly higher in cancer stromal cells than in CRC cells (P < 0.0001). CONCLUSION: Our analysis reinforces the possibility that ARL4C expression worsens the prognosis of patients with CRC. Further elucidation of the function of ARL4C is desired.

Increased GS-II lectin binding and SATB2 downregulation are biological features for sessile serrated lesions and microvesicular hyperplastic polyps.

Sessile serrated lesions (SSLs) and microvesicular hyperplastic polyps (MVHPs) are colorectal lesions displaying gastric differentiation. Griffonia simplicifolia-II (GS-II) is a lectin specific to terminal α/ßGlcNAc residues. Here, we assessed GS-II binding and performed immunostaining for HIK1083 (specific to terminal αGlcNAc residues), MUC5AC, MUC6, and special AT-rich sequence binding protein 2 (SATB2) in SSLs, MVHPs, and tubular adenomas (TAs). We observed MUC5AC positivity in 28 of 30 SSLs, but in only three of 23 TAs. Moreover, 24 of 30 SSLs were MUC6-positive, while none of the 23 TAs were MUC6-positive. None of the 30 SSLs or 23 TAs showed HIK1083 positivity. All 30 SSLs and 26 MVHPs were GS-II-positive, while only seven of 23 were in TAs. GS-II staining was mainly distributed in the Golgi region, but SSLs and MVHPs showed goblet cell distribution, in 20 of 30 and 19 of 26 cases, respectively. All SSLs, MVHPs, and TAs were SATB2-positive, but 21 of 30 SSLs and 12 of 26 MVHPs showed decreased staining intensity relative to adjacent mucosa, a decrease seen in only two of 23 in TAs. These results indicate overall that increased terminal ßGlcNAc and decreased SATB2 expression are characteristics of SSLs and MVHPs.

Surgical revascularization for quasi-moyamoya disease associated with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome: a case report and literature review.

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome is a rare multisystem disease characterized by plasma cell dyscrasia and overproduction of vascular endothelial growth factor, which is related to disease activity. Recent treatment strategies have improved survival of patients suffering from this disorder; however, ischemic stroke remains a poor prognostic factor. POEMS patients with ischemic stroke frequently develop cerebral large artery stenosis/occlusion, followed by progressive stroke. Post literature review, we present an ischemic stroke case of quasi-moyamoya disease linked with this syndrome that was successfully treated with surgical revascularization. A 41-year-old woman diagnosed with POEMS syndrome developed progressive ischemic stroke due to quasi-moyamoya disease, despite decreased vascular endothelial growth factor level with lenalidomide and dexamethasone treatment. She underwent superficial temporal artery to middle cerebral artery bypass with encephalo-duro-myo-synangiosis bilaterally. The postoperative course was uneventful. Two years and five months after the stroke, neuroimaging demonstrated bypass patency, neovascularization after encephalo-duro-myo-synangiosis, and no recurrence of stroke. Our case is the first to report successful surgical revascularization for a POEMS patient. Surgical revascularization may be a useful treatment option for patients with quasi-moyamoya disease associated with POEMS syndrome, especially for those who develop refractory ischemic stroke despite reduced vascular endothelial growth factor level.

IgG4 expression and IgG4/IgG ratio in the tumour invasion front predict long-term outcomes for patients with intrahepatic cholangiocarcinoma.

IgG4-positive plasma cells are reportedly increased in the tumour microenvironment, and a high number of these cells in tumours is a poor prognostic factor in several cancers. However, there are no reported analyses of IgG4 expression in intrahepatic cholangiocarcinoma (ICC). This study aimed to analyse the correlations between prognosis-related clinicopathological features of patients with ICC and IgG4 expression. We identified 37 ICC patients who underwent surgical resection between January 2010 and December 2020. The number of IgG-positive and IgG4-positive plasma cells in the tumour, invasion front, and stroma near the tumour was analysed by immunostaining. Furthermore, we examined the association of prognosis-related clinicopathological data with the number of IgG4-positive plasma cells and IgG4/IgG ratio in ICC patients. The IgG4-positive plasma cell percentages for the intra-tumour area, invasion front, and non-cancerous area (NCA) near the tumour were 91.9%, 56.8%, and 81.1%, respectively. IgG-positive plasma cells were observed in each region for all cases, except for NCA tissue in one case. A high IgG4 expression level and IgG4/IgG ratio in the invasion front were significantly associated with poor overall survival (OS) (log-rank test p=0.0438 and p=0.0338, respectively). Multivariate analysis for OS revealed that high IgG4 expression (p=0.0140), lymph node metastasis (p=0.0205), and positive surgical margin (p=0.0009) or a high IgG4/IgG ratio (p=0.0051), lymph node metastasis (p=0.0280), and positive surgical margin (p=0.0009) were independent poor prognostic factors. In conclusion, a high IgG4 expression level and IgG4/IgG ratio in the invasion front are independent poor prognostic factors for ICC. Targeted therapy for IgG4 may improve the prognosis for patients with ICC.

Clinical features of pagetoid spread: Analysis of perianal lesions associated with anal canal adenocarcinoma and perianal primary extramammary Paget disease.

Secondary extramammary Paget disease (s-EMPD) represents anal canal and rectal, bladder, and gynecological cancers, which horizontally extend within the epidermis of the anal and vulvar skin. It is necessary to distinguish this condition from primary extramammary Paget disease (p-EMPD), which occurs primarily in genital and perianal areas. This study aimed to investigate the clinical and histopathological features of these two conditions in the perianal skin and to identify useful features for differentiation. We retrospectively analyzed 16 patients who visited Shinshu University Hospital from 2009 to 2022 and presented with perianal skin lesions and suspected EMPD. Six patients had p-EMPD and 10 had s-EMPD derived from anal canal adenocarcinoma. Regarding clinical features, nine of 10 (90%) of the s-EMPD cases had symmetric skin lesions, whereas all of the p-EMPD cases had asymmetrical lesions (p = 0.0004). Furthermore, assessment of symmetry around the anus showed that s-EMPD had a significantly smaller coefficient of variation than p-EMPD (0.35 and 0.62, respectively; p = 0.048), suggesting that s-EMPD was more symmetric around the anus. The frequency of raised lesions, such as foci or nodules, was nine of 10 (90%) for s-EMPD and one of six (16%) for p-EMPD (p = 0.003). Well-defined tumor borders on the lateral margins were identified in s-EMPD (5/10, 50%); however, they were not identified in p-EMPD (0/6, 0%). The borders tended to be clearer in s-EMPD; however, the difference was not significant (p = 0.078). Based on these findings, we recommend consideration of s-EMPD when anal skin lesions are symmetrical, well-defined, or raised.

High expression of LGR6 is a poor prognostic factor in esophageal carcinoma.

BACKGROUND: Leucine-rich repeat-containing G-protein-coupled receptor 6 (LGR6) promotes carcinogenesis and progression in some cancer types. However, there are few reports of LGR6 expression in esophageal squamous cell carcinoma (ESCC). LGR6 expression and clinicopathological features in ESCC were investigated by RNAscope, a highly sensitive RNA in situ hybridization method. METHODS: Appropriate tumors were selected from 41 cases of ESCC from which tissue microarrays were generated, and LGR6 expression was identified by RNAscope. RESULTS: Thirty-seven patients had LGR6 expression. High LGR6 expression was observed in 17 cases and low LGR6 expression in 24 cases. LGR6 expression was significantly higher in high histological grade ESCC than in low histological grade ESCC (P = 0.0023). ESCC patients who received neoadjuvant chemotherapy had significantly higher LGR6 expression than those without neoadjuvant chemotherapy (P = 0.0109). Furthermore, high LGR6 expression showed a poorer prognosis than low LGR6 expression (log-rank test, P = 0.0365). CONCLUSIONS: LGR6 may be a prognostic factor and a potential new therapeutic target in ESCC.

Serum positivity of serum anti-tissue transglutaminase immunoglobulin A antibodies in Japanese children with inflammatory bowel disease.

BACKGROUND: Serum anti-tissue transglutaminase immunoglobulin A antibody (tTG-IgA) is a screening test for celiac disease (CeD). In recent years, there have several reports of combined inflammatory bowel disease (IBD) and CeD in children. The purposes of this study are to research the positivity of the tTG-IgA antibody in Japanese children, and whether IBD and CeD co-occur. METHODS: We examined tTG-IgA as a screening test for CeD in symptomatic pediatric patients with IBD (cases) and those without IBD (controls, non-IBD). Those with tTG-IgA levels of 10 U/mL or higher were considered positive. All patients had routine biopsy specimens taken from the second part and bulbus of the duodenum, and were evaluated histologically based on the Marsh classification. RESULTS: Thirty-one patients in the IBD group and 53 patients in the non-IBD group were included. The tTG-IgA was positive in five cases (5.9%) and median titer of positive cases was 12.3 U/mL (10.2-41.7). One patient in the IBD group (3.2%) and four patients in the non-IBD group (7.8%) were positive for tTG-IgA. No cases showed histological features of CeD. There were no statistically significant differences in age, sex, symptoms and laboratory tests between the tTG-IgA positive and negative groups. Patients among the IBD and the non-IBD groups that were tTG-IgA positive demonstrated symptoms after wheat consumption. CONCLUSIONS: We identified a patient who was positive for tTG-IgA antibodies who experienced abdominal symptoms due to wheat ingestion, indicative of subclinical CeD. Further investigation is needed to clarify the co-occurrence of IBD and CeD among Japanese children.

Hereditary diffuse gastric cancer in a Japanese family with CDH1 mutation three case reports.

BACKGROUND: Germline pathogenic variants in the E-cadherin gene CDH1 cause hereditary diffuse gastric cancer (HDGC), which is an autosomal dominant cancer syndrome, accounting for 1-3% of all gastric cancers. HDGC harboring a CDH 1 variant is extremely rare in Japan. METHOD: In this study we report the clinical courses of three cases with HDGC from a single Japanese family. RESULTS: The proband exhibited advanced and metastatic gastric cancer, and was found to have a previously reported heterozygous frameshift variant in CDH1 (NM_004360.3:c.1009_1010del:p.Ser337Phefs*12). Five at-risk relatives underwent presymptomatic molecular testing after careful genetic counseling, and three were molecularly diagnosed as positive for the variant. Esophagogastroduodenoscopy was performed in these relatives revealing abnormal small pale mucosal patches, small ulcerative lesion and no abnormal findings. Moreover, random and targeted biopsies were compatible with pathological diagnosis of HDGC in the three cases, all of which underwent total prophylactic gastrectomy. CONCLUSION: It is critical for the assessment and management of HDGC patients to be actively offered a multidisciplinary and familial-oriented approach. Notably, genetic screening in suspected individuals and familial members is a determining piece for a higher detection rate and the identification of clinical relevant mutations in both low and high-incidence gastric cancer countries.

Number and distribution of eosinophils and lymphocytes in the Japanese pediatric gastrointestinal tract: in search of a definition for "abnormally increased eosinophils".

BACKGROUND: Primary eosinophilic gastrointestinal disorders (EGIDs) constitute chronic allergic inflammation. The number of eosinophils is one of the diagnostic criteria; more than 20 eosinophils per high-power field (HPF) in the gastrointestinal (GI) tract are considered abnormal in Japan. However, the quantity of eosinophils considered normal varies according to anatomical location and geographical region; such values have not been reported in Japanese pediatric patients, nor have the numbers of lymphocytes in the normal pediatric stomach. To establish a reference for defining diagnostic criteria for EGIDs, we evaluated the number of eosinophils in the normal Japanese pediatric GI tract. METHODS: We examined 131 biopsy cases without significant clinical history, endoscopic abnormality, or histological abnormality. Immunohistochemical analysis of CD3 and CD20 was performed. RESULTS: The mean eosinophil density was highest in the cecum (49.5 ± 22.4 per HPF). Counts of more than 20 eosinophils per HPF were observed in the duodenum [bulb (20.0 ± 9.6) and second portion (30.0 ± 15.8)], terminal ileum (38.3 ± 22.7), cecum (49.5 ± 22.4), ascending colon (42.3 ± 25.3), transverse colon (29.4 ± 17.0), and descending colon (32.2 ± 17.9). Counts of fewer than 10 eosinophils per HPF were observed in the stomach and rectum; a count of fewer than one eosinophil per HPF was observed in the esophagus. More than 100 CD3-positive T cells per HPF were observed in the stomach. CONCLUSIONS: The mean numbers of eosinophils in the bowel were greater than 20 per HPF. For Japanese pediatrics, the current threshold eosinophil count should be revised.