The pathogenesis of cryptoglandular anal fistula: New insight into the immunological profile.

AIM: The aetiology of cryptoglandular anal fistula (AF) is poorly understood. Evidence suggests that persistence and/or recurrence of the disease is more related to inflammatory than infectious factors. The aim of this study was to investigate the immune profile of cryptoglandular AF and to perform a histopathological characterization. METHOD: Fistulectomy was performed in all patients; healthy ischioanal fat from the same patients was used as a control. Samples were evaluated by the Luminex xMAP system for the detection of 27 analytes. AF tissues were analysed using immunofluorescence. Staining was performed using primary antibodies to identify M1 inflammatory and M2 anti-inflammatory macrophages. Selective staining of total T lymphocytes and different T lymphocyte subsets was performed. RESULTS: Twenty patients with AF underwent a fistulectomy. Specific cytokine pathways differentiated AF from healthy tissue: pro-inflammatory cytokines interleukin (IL)-1ß, IL-4, IL-8 and IL-17 and the anti-inflammatory cytokine IL-10 were overexpressed in AF compared with controls. Chemokines involved in macrophage recruitment (CCL2, CCL3, CCL4) were higher in AF than in healthy fatty tissue. Moreover, we showed that Tc17 cells characterize AF patients, thus confirming the enzyme-linked immunosorbent assay data. Furthermore, elevated infiltration of CD68+ myeloid cells and a reduction of the M1/M2 ratio characterize AF patients. CONCLUSION: A combination of inflammatory cytokines, chemokines and growth factors reside in the wound microenvironment of AF patients. For the first time an important prevalence of Tc17 cells and a reduction in the M1/M2 ratio was observed, thus suggesting new insights into the immunological characterization of AF patients.

Human herpesvirus 8-associated colonic Kaposi's sarcoma during vedolizumab treatment in ulcerative colitis: a case report and review of the literature.

BACKGROUND: Kaposi's sarcoma (KS) is a rare vascular tumor associated with human herpesvirus (HHV)-8 infection. One of the variants of KS is defined iatrogenic and is overall reported in transplanted patient but also, although less frequently, in patients treated with long-standing immunosuppressive therapy, such as in inflammatory bowel disease including ulcerative colitis and Crohn's disease. CASE PRESENTATION: Herein, we report the first case of KS in a human immunodeficiency virus (HIV)-negative 47-year old male with UC after treatment with the α4-ß7 integrin inhibitor vedolizumab (VDZ). The patient underwent to colectomy for a medical refractory disease and the histological examination of the surgical specimen showed the typical findings of KS together with the HHV-8 positivity. The patient achieved a good health status, without any sign of disease recurrence. CONCLUSIONS: In the present case, we can assume that VDZ may have promoted the reactivation of a latent HHV-8 infection endowed with oncogenic potentialities and, in turn, the onset of KS. We also briefly reviewed all the cases of KS in HIV-negative patients with inflammatory bowel disease.

Total mesopancreas excision for periampullary malignancy: a single-center propensity score-matched comparison of long-term outcomes.

PURPOSE: Few comparative studies are available on the long-term prognostic role of mesopancreas (MP) excision after pancreaticoduodenectomy (PD). We compared the long-term outcomes of patients undergoing standard PD (sPD) and PD with MP excision (PD-MPe). METHODS: Sixty sPDs were compared to 60 matched PD-MPe patients for intraoperative and postoperative data, histopathological findings, and long-term outcomes. RESULTS: R0 rate was similar in the two groups (p = 0.17). However, PD-MPe related to a lower rate of MP resection margin positivity (16.7% vs 5%; p = 0.04) and to a higher harvested lymph nodes number (19.8 ± 7.6 vs 10.1 ± 5.1; p < 0.0001). Local tumor recurrence was more frequent in the sPD cohort (55.5% vs 26.8% in the PD-MPe group; p = 0.002), with a consequent worse disease-free survival (DFS) (14.8% vs 22.3%; p = 0.04). An inferior 5-year overall survival (OS) was noted in case of MP margin positivity compared with MP margin negativity (0% vs 29%; p < 0.0001). MP positivity resulted as an independent prognostic factor for both a worse OS and DFS at the multivariate analysis. CONCLUSION: PD-MPe offers clinical advantages in terms of MP resection margin status, local recurrence, long-term mortality, and DFS. The lower MP positivity rate, achieved with PD-MPe, leads to better outcomes both in terms of OS and DFS.

Telocytes are the physiological counterpart of inflammatory fibroid polyps and PDGFRA-mutant GISTs.

PDGFRA mutations in the gastrointestinal (GI) tract can cause GI stromal tumour (GIST) and inflammatory fibroid polyp (IFP). Hitherto no cell type has been identified as a physiological counterpart of the latter, while interstitial Cajal cells (ICC) are considered the precursor of the former. However, ICC hyperplasia (ICCH), which strongly supports the ICC role in GIST pathogenesis, has been identified in germline KIT-mutant settings but not in PDGFRA-mutant ones, challenging the precursor role of ICC for PDGFRA-driven GISTs. Telocytes are a recently described interstitial cell type, CD34+/PDGFRA+. Formerly considered fibroblasts, they are found in many organs, including the GI tract where they are thought to be involved in neurotransmission. Alongside IFPs and gastric GISTs, GI wall "fibrosis" has been reported in germline PDGFRA-mutants. Taking the opportunity offered by its presence in a germline PDGFRA-mutant individual, we demonstrate that this lesion is sustained by hyperplastic telocytes, constituting the PDGFRA-mutant counterpart of germline KIT mutation-associated ICCH. Moreover, our findings support a pathogenetic relationship between telocyte hyperplasia and both IFPs and PDGFRA-mutant GISTs. We propose the term "telocytoma" for defining IFP, as it conveys both the pathogenetic (neoplastic) and histotypic ("telocytary") essence of this tumour, unlike IFP, which rather evokes an inflammatory-hyperplastic lesion.

Emergency surgery for colorectal cancer does not affect nodal harvest comparing elective procedures: a propensity score-matched analysis.

PURPOSE: About 30% of colorectal cancers (CRCs) present with acute symptoms. The adequacy of oncologic resections is a matter of concern since few authors reported that emergency surgery in these patients results in a lower lymph node harvest (LNH). In addition, emergency resections have been reported with a longer hospital stay and higher morbidity rate. We thus conducted a propensity score-matched analysis with the aim of investigating LNH in emergency specimens comparing with elective ones. Secondary aim was the comparison of morbidity and hospital stay. METHODS: Eighty-seven consecutive R0 emergency surgical procedures were matched with elective CRCs using the propensity score method and the following covariates: age, sex, stage, and localization. Groups were compared using univariate and multivariate analyses. Outcome measures were LNH, nodal ratio, Clavien's morbidity grades, and hospital stay. RESULTS: Emergency patients presented more metastatic nodes compared with elective ones (p 0.017); however, both presented a comparable mean LNH. Multivariate analysis documented that a T stage ≥3 was the only variable correlated with a nodal positivity (OR 6.3). On univariate analysis, emergency CRCs had a longer mean hospital stay compared with elective resections (p 0.006) and a higher rate of Clavien ≥4 events (p 0.0173). Finally, emergency resection and an age >66 years were variables independently correlated with a mean hospital stay >10 days (OR, respectively, 3.7 and 3.5). CONCLUSIONS: Emergency CRC resections were equivalent to the elective procedures with respect to LNH. However, emergency surgery correlated with a longer mean hospital stay. Graphical abstract Emergency and Elective resections for CRC provide similar LNH.

Peculiarity of Autoimmune Hepatitis Triggered by SARS-CoV-2 Infection.

Introduction: Recently, medical interest has been growing in SARS-CoV-2 infection and its multiorgan involvement, including the liver. Up until now, a few reports have described autoimmune hepatitis (AIH) triggered by SARS-CoV-2 infection, but no data are available about the specific liver inflammatory infiltrate and cluster of differentiation. We report a case of AIH triggered by SARS-CoV-2 infection, with a particular focus on its histological and mainly immunohistochemical features. Case description: A 60-year-old man, with a history of paucisymptomatic SARS-CoV-2 infection that occurred one month earlier, was admitted for alterations of hepatocellular necrosis and cholestasis indexes. He completed vaccination for SARS-CoV-2 a year earlier. The serologies for hepatotropic viruses were negative. The anti- smooth muscle antibodies (ASMA) and antinuclear antibodies (ANA) results were positive. Anti-liver kidney microsome (anti-LKM) antibodies and antimitochondrial (AMA) were negative. By liver biopsy, haematoxylin-eosin staining highlighted severe portal inflammation with a rich CD38+ plasma cell component, while immunohistochemical staining showed low cell CD4+ count and prevalence of CD8+ and CD3+. After biopsy, the patient started an immunosuppressant regimen, with benefit. Discussion: We can conclude that the patient developed a type 1 AIH triggered by SARS-CoV-2 infection. The presence of CD8 T-cells at immunohistochemical examination suggests different mechanisms from classic AIH. Similar cases are described after AIH triggered by SARS-CoV-2 vaccination. Conclusion: The AIH after SARS-CoV-2 infection developed by the patient showed a histological picture similar to a classic AIH for the abundant presence of plasma cells, and immunohistochemical features similar to those described after SARS-CoV-2-vaccination. LEARNING POINTS: Recently, medical interest has been growing in SARS-CoV-2 infection and its multiorgan involvement, including the liver. Underlying mechanisms are not still clear, more likely consisting of an inflammatory and immune mediated process rather than a direct cytopathic damage.Our report describes a rare case of type 1 AIH triggered by SARS-CoV-2 infection, showing a peculiar histological pattern, different from classic AIH, conversely similar to AIH triggered by SARS-CoV-2 vaccination.The mechanisms underlying liver involvement in SARS-CoV-2 infection are still under investigation. Further studies should be encouraged to improve understanding on this focus and to support physicians in its management.

Histopathological Spectrum and Molecular Characterization of Liver Tumors in the Setting of Fontan-Associated Liver Disease.

PURPOSE: Univentricular heart is corrected with the Fontan procedure (FP). In the long term, so-called Fontan-associated liver diseases (FALDs) can develop. The aim of this study is to analyze the molecular profile of FALDs. METHODS: FALDs between January 1990 and December 2022 were reviewed for histology and immunohistochemistry, laboratory data, and images. Targeted next generation sequencing (NGS), performed on the DNA and RNA of both neoplastic and non-lesional liver tissue, was applied. RESULTS: A total of 31/208 nodules > 1 cm in diameter were identified on imaging, but a liver biopsy was available for five patient demonstrating the following: one hepatocellular adenoma (HA), two hepatocellular carcinomas (HCCs), one fibrolamellar carcinoma (FLC), and one intrahepatic cholangiocarcinoma (ICC). Molecular analysis showed a copy number alteration involving FGFR3 in three cases (two HCCs and one ICC) as well as one HCC with a hotspot mutation on the CTNNB1 and NRAS genes. Tumor mutational burden ranged from low to intermediate. A variant of uncertain significance in GNAS was present in two HCCs and in one ICC. The same molecular profile was observed in a non-lesional liver. A DNAJB1-PRKACA fusion was detected only in one FLC. CONCLUSIONS: Neoplastic FALDs show some unusual molecular profiles compared with non-Fontan ones. The presence of the same alterations in non-lesional cardiac cirrhosis could contribute to the development of FALD.

Solute Transporter OCTN1/Slc22a4 Affects Disease Severity and Response to Infliximab in Experimental Colitis: Role of Gut Microbiota and Immune Modulation.

BACKGROUND: Inflammatory bowel diseases are chronic disabling conditions with a complex and multifactorial etiology, still incompletely understood. OCTN1, an organic cation transporter, could have a role in modulating the inflammatory response, and some genetic polymorphisms of this molecule have been associated with increased risk of inflammatory bowel diseases. Until now, limited information exists on its potential in predicting/modulating patient's response to therapies. The aim of this study was to evaluate the role of OCTN1 in modifying gut microbiota and mucosal immunity in response to infliximab therapy in murine colitis. METHODS: A dextran sodium sulphate model of colitis was used to assess the clinical efficacy of infliximab administered intravenously in ocnt1 gene knockout mice and their C57BL/6 controls. Stool, colon, and mesenteric lymph node samples were collected to evaluate differences in gut microbiota composition, histology, and T cell populations, respectively. RESULTS: Octn1 -/- influences the microbiota profile and is associated with a worse dysbiosis in mice with colitis. Infliximab treatment attenuates colitis-associated dysbiosis, with an increase of bacterial richness and evenness in both strains. In comparison with wild type, octn1-/- mice have milder disease and a higher baseline percentage of Treg, Tmemory, Th2 and Th17 cells. CONCLUSIONS: Our data support the murine model to study OCTN1 genetic contribution to inflammatory bowel diseases. This could be the first step towards the recognition of this membrane transporter as a biomarker in inflammatory conditions and a predictor of response to therapies.

In this article, we evaluated the role of OCTN1, an organic cation transporter, in modifying gut microbiota and immune T cell populations, as well as its effects on experimental colitis and the response to infliximab treatment.

Focus on Immune Checkpoint Inhibitors-related Intestinal Inflammation: From Pathogenesis to Therapeutical Approach.

Recently, antitumor immunotherapies have witnessed a breakthrough with the emergence of immune checkpoint inhibitors (ICIs) including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors. Unfortunately, the use of ICIs has also led to the advent of a novel class of adverse events that differ from those of classic chemotherapeutics and are more reminiscent of autoimmune diseases, the immune-related adverse events (IRAEs). Herein, we performed an insight of the main IRAEs associated with ICIs, focusing on gastroenterological IRAEs and specifically on checkpoint inhibitor colitis, which represents the most widely reported IRAE to date. We comprehensively dissected the current evidence regarding pathogenesis, diagnosis, and management of ICIs-induced colitis, touching upon also on innovative therapies.

Immune checkpoint inhibitors (ICIs)-induced colitis is the most widely reported immune-related adverse event following the use of ICIs. In this review, we comprehensively discuss current evidence regarding pathogenesis, diagnosis, and management of ICIs-induced colitis, including a focus on innovative therapies.

Cytomegalovirus Infection: An Underrated Target in Inflammatory Bowel Disease Treatment.

CMV infection is still a matter of concern in IBD patients, especially regarding the disease's relapse management. Why IBD patients, particularly those affected by ulcerative colitis, are more susceptible to CMV reactivation is not totally explained, although a weakened immune system could be the reason. Various techniques, ranging from serology to histology, can be employed to detect intestinal CMV infection; however, there is currently disagreement in the literature regarding the most effective diagnostic test. Furthermore, CMV involvement in steroid resistance has been broadly discussed, but whether CMV infection is a cause or consequence of the disease severity and, consequently, steroid refractoriness is still debated. Its potential contribution to the lack of response to advanced therapy and small molecules must be more valued and wholly explored. In this review, we look at the actual literature on CMV in IBD patients, and we suggest a pragmatic algorithm for clinical practice management of CMV infection.

Multifocal hepatic small vessel neoplasm with spleen dissemination.

Among liver vascular tumours, hepatic small vessel neoplasm (HSVN) has been recently identified as a rare infiltrative vascular neoplasm whose malignant potential is yet to be fully ascertained. About 30 cases of HSVN have been described so far. The most common clinical presentation is an asymptomatic solitary liver lesion. Multifocal disease has been described in literature; however, to date, there are no reports of disease dissemination to other organs. Here we report a case of multifocal HSVN with synchronous spleen secondary lesions.

Collagenous colitis and atezolizumab therapy: an atypical case.

Immune checkpoint inhibitors such as anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), anti-PD-1 (programmed cell death protein 1), and PD-L1 (programmed cell death protein-ligand 1) are emerging drugs that have radically changed treatment and prognosis of different types of tumors. However, despite their considerable benefits, immune checkpoint inhibitors are associated with numerous side effects involving several organs. Gastrointestinal toxicities represent some of these most common adverse events. While clinical presentation usually ranges from mild diarrhea to life-threatening colitis, typical endoscopic and histologic findings of immune-mediated colitis often resemble those of inflammatory bowel diseases. However, less common patterns are lymphocytic colitis and, rarely, collagenous colitis. Physician and pathologists must be aware of the wide spectrum of clinical and histological findings that may be encountered in immune-related gastro-intestinal toxicities. We report a rare and atypical case of collagenous colitis occurred in a woman affected by stage IV lung adenocarcinoma, on atezolizumab therapy.

Mesothelioma in Familial Mediterranean Fever With Colchicine Intolerance: A Case Report and Literature Review.

A 65-year-old Italian physician affected by Familial Mediterranean fever (FMF) was hospitalized due to progressive abdominal enlargement, which had begun 6 months before admission. Physical examination revealed ascites and bilateral leg edema. Abdominal CT scan showed ascitic fluid and extensive multiple peritoneal implants; peritoneal CT-guided biopsy revealed an epithelial-type malignant mesothelioma. The patient's past medical history revealed recurrent episodes of abdominal pain and fever from the age of 2. Clinical diagnosis of FMF was suspected at the age of 25, while genetic analysis, performed at the age of 50, confirmed homozygosity for the M694I mutation in the MEFV gene. Treatment with the first line FMF drug colchicine was started and stopped several times because of worsened leukopenia. The patient in fact had a history of asymptomatic leukopenia/lymphopenia from an early age; the intake of colchicine aggravated his pre-existing problem until the definitive suspension of the drug. As for second-line drugs, canakinumab was first prescribed, but due to prescription issues, it was not possible to be administered. When he was given anakinra, there was a worsening of leukopenia leading to septic fever. Systematic literature review indicates that, in most cases, recurrent peritoneal inflammation results in benign peritoneal fibrosis or less commonly in encapsulating peritonitis. There are only a few reported cases of recurrent peritoneal inflammation progressing from FMF to peritoneal mesothelioma (MST). In such cases, intolerance to colchicine or its erratic intake may lead to long-term recurrent inflammation, which usually precedes the development of the tumor, while pre-existing leukopenia, as in our patient, could also be a factor promoting or accelerating the tumor progression. In conclusion, we suggest that in the presence of intolerance or resistance to colchicine, interleukin (IL)-1 inhibition could suppress peritoneal inflammation and prevent MSTs.

Gastrointestinal juvenile-like (inflammatory/hyperplastic) mucosal polyps in neurofibromatosis type 1 with no concurrent genetic or clinical evidence of other syndromes.

Gastrointestinal "juvenile-like (inflammatory/hyperplastic) mucosal polyps" (JLIHMPs) have been proposed as a neurofibromatosis type 1 (NF1)-specific gastrointestinal manifestation. Juvenile polyposis syndrome (JPS) has also been reported in a NF1 patient, harboring concurrent NF1 and SMAD4 germline mutations. Additionally, NF1-like cafe-au-lait spots have been described in biallelic mismatch repair deficiency, another condition featuring gastrointestinal polyps. The SMAD4 and BMPR1A genes that are involved in 50-60% of JPS cases have not been investigated in the ~ 20 published cases of NF1-associated JLIHMPs with the exception of the abovementioned patient with concomitant JPS and NF1. NF1 defects have been found in the only two cases exhaustively tested. Therefore, JLIHMP has been questioned as an independent, NF1-specific entity. Incidental associations between NF1 and gastrointestinal polyposes at risk for gastrointestinal carcinoma should not be overlooked, given their implications in terms of clinical surveillance. We describe two patients featuring JLIHMPs in clinically/genetically proven NF1, in the absence of SMAD4 and BMPR1A mutations. In one case, the intervening mucosa was markedly inflamed, unlike JPS. We suggest that JLIHMP probably represents a gastrointestinal lesion specific to NF1.

Correction to: Gastrointestinal juvenile-like (inflammatory/hyperplastic) mucosal polyps in neurofibromatosis type 1 with no concurrent genetic or clinical evidence of other syndromes.

The authors regret that the original version of this article, unfortunately, contained an error. The values "1/3 (33%)" reported in the second to last sentence of the Discussion are wrong; the correct values are "2/2 (100%)". These are presented correctly in this article.

Left-sided early-onset vs late-onset colorectal carcinoma: histologic, clinical, and molecular differences.

OBJECTIVES: Carcinomas of the left colon represent a neoplasm of older patients (late onset), but epidemiologic evidence has been showing an increasing incidence in patients 50 years or younger (early onset). In this study, we investigate pathologic and molecular features of early- and late-onset carcinoma of the left colon. METHODS: We selected 22 patients 50 years or younger and 21 patients 70 years or older with left-sided colorectal carcinoma (CRC). All samples were evaluated for pathologic features, microsatellite instability, and KRAS and BRAF mutations. Moreover, both groups were analyzed to identify CpG island methylator phenotype features and assessed with restriction landmark genome scanning (RLGS) to unveil differential DNA methylation patterns. RESULTS: Early-onset patients had advanced pathologic stages compared with late-onset patients (P = .0482). All cases showed a microsatellite stable profile and BRAF wild-type sequence. Early-onset patients (43%) more frequently had mutations at KRAS codon 12 compared with late-onset patients (14%) (P =.0413). RLGS showed that patients younger than 50 years who had CRC had a significantly lower percentage of methylated loci than did patients 70 years or older (P = .04124), and differential methylation of several genomic loci was observed in the two groups. CONCLUSIONS: Our results suggest that left-sided CRCs may present differential patterns of aberrant DNA methylation when they are separated by age.