Primary EGIST of the greater omentum - a rare presentation.

Extragastrointestinal stromal tumors (EGISTs) are rare mesenchymal neoplasms, which develop in the retroperitoneum, mesentery, and omentum, lacking continuity to the stomach or intestines. Authors hereby present a female patient with a large heterogeneous abdominal mass as a case of an omental EGIST. A 46-year-old woman was referred to our hospital due to an insidious enlargement and colicky pain in the right iliac fossa. Abdominal palpation revealed a voluminous, freely mobile, and non-pulsatile mesoabdominal bulge expanding to the hypogastrium. On exploratory midline laparotomy, the tumor was densely fused to the greater omentum, not connected to the stomach, without gross involvement of adjacent structures. The large mass was completely excised after adequate mobilization. Immunohistochemical techniques showed strong and diffuse expression of WT1, actin and DOG-1, as well as multifocal c-KIT marking. Mutational study concluded a double mutation of KIT exon 9 and a mutation of PDGFRA exon 18. The patient was submitted to adjuvant treatment with imatinib mesylate 800 mg/day. Despite an extremely diverse presentation, omental EGISTs often remain clinically silent for a long time having enough space to grow before becoming symptomatic. These tumors have a consistent pattern of metastasis that typically spares lymph nodes unlike epithelial gut neoplasms. Surgery remains the preferred treatment for non-metastatic EGISTs of the greater omentum. It is possible that DOG-1 will supplant KIT as the leading marker in the future. The scarcity of knowledge on omental EGISTs implies a close monitoring of these patients to detect local relapse or distant metastasis.

The clinical importance of the host anti-tumour reaction patterns in regional tumour draining lymph nodes in patients with locally advanced resectable gastric cancer: a systematic review and meta-analysis.

BACKGROUND: The status of regional tumour draining lymph nodes (LN) is crucial for prognostic evaluation in gastric cancer (GaC) patients. Changes in lymph node microarchitecture, such as follicular hyperplasia (FH), sinus histiocytosis (SH), or paracortical hyperplasia (PH), may be triggered by the anti-tumour immune response. However, the prognostic value of these changes in GaC patients is unclear. METHODS: A systematic search in multiple databases was conducted to identify studies on the prognostic value of microarchitecture changes in regional tumour-negative and tumour-positive LNs measured on histopathological slides. Since the number of GaC publications was very limited, the search was subsequently expanded to include junctional and oesophageal cancer (OeC). RESULTS: A total of 28 articles (17 gastric cancer, 11 oesophageal cancer) met the inclusion criteria, analyzing 26,503 lymph nodes from 3711 GaC and 1912 OeC patients. The studies described eight different types of lymph node microarchitecture changes, categorized into three patterns: hyperplasia (SH, FH, PH), cell-specific infiltration (dendritic cells, T cells, neutrophils, macrophages), and differential gene expression. Meta-analysis of five GaC studies showed a positive association between SH in tumour-negative lymph nodes and better 5-year overall survival. Pooled risk ratios for all LNs showed increased 5-year overall survival for the presence of SH and PH. CONCLUSIONS: This systematic review suggests that sinus histiocytosis and paracortical hyperplasia in regional tumour-negative lymph nodes may provide additional prognostic information for gastric and oesophageal cancer patients. Further studies are needed to better understand the lymph node reaction patterns and explore their impact of chemotherapy treatment and immunotherapy efficacy.

Digital Examination of LYmph node CYtopathology Using the Sydney system (DELYCYUS): An international, multi-institutional study.

BACKGROUND: After a series of standardized reporting systems in cytopathology, the Sydney system was recently introduced to address the need for reproducibility and standardization in lymph node cytopathology. Since then, the risk of malignancy for the categories of the Sydney system has been explored by several studies, but no studies have yet examined the interobserver reproducibility of the Sydney system. METHODS: The authors assessed interobserver reproducibility of the Sydney system on 85 lymph node fine-needle aspiration cytology cases reviewed by 15 cytopathologists from 12 institutions in eight different countries, resulting in 1275 diagnoses. In total, 186 slides stained with Diff-Quik, Papanicolaou, and immunocytochemistry were scanned. A subset of the cases included clinical data and results from ultrasound examinations, flow cytometry immunophenotyping, and fluorescence in situ hybridization analysis. The study participants assessed the cases digitally using whole-slide images. RESULTS: Overall, the authors observed an almost perfect agreement of cytopathologists with the ground truth (median weighted Cohen κ = 0.887; interquartile range, κ = 0.210) and moderate overall interobserver concordance (Fleiss κ = 0.476). There was substantial agreement for the inadequate and malignant categories (κ = 0.794 and κ = 0.729, respectively), moderate agreement for the benign category (κ = 0.490), and very slight agreement for the suspicious (κ = 0.104) and atypical (κ = 0.075) categories. CONCLUSIONS: The Sydney system for reporting lymph node cytopathology shows adequate interobserver concordance. Digital microscopy is an adequate means to assess lymph node cytopathology specimens.

Renal involvement in Behçet´s Disease: a rare clinical challenge.

Although Behçet´s disease (BD) is a systemic inflammatory disease, renal involvement is uncommon and ranges from mild asymptomatic urinary abnormalities to severe disease with progressive renal failure. We describe the case of a 30 years-old woman with multiorgan BD, under ustekinumab, who presented with proteinuria, hematuria and impaired renal function. Kidney biopsy revealed histological findings of active renal vasculitis in the context of IgA nephropathy and tubulointerstitial nephritis and the patient was treated with corticosteroids and cyclophosphamide with excellent response. Our case highlights the importance of recognizing a possible renal involvement in BD patients, reinforcing the need for monitoring renal function and urinalysis in these patients.

Searching for SARS-CoV-2 in Cancer Tissues: Results of an Extensive Methodologic Approach based on ACE2 and Furin Expression.

SARS-CoV-2 pandemics have been massively characterized on a global scale by the rapid generation of in-depth genomic information. The main entry gate of SARS-CoV-2 in human cells is the angiotensin-converting enzyme 2 (ACE2) receptor. The expression of this protein has been reported in several human tissues, suggesting a correlation between SARS-CoV-2 organotropism and ACE2 distribution. In this study, we selected (a series of) 90 patients who were submitted to surgery for tumor removal between the beginning of the SARS-CoV-2 pandemic and the closure of operating rooms (by the end of March 2020) in two different countries-Portugal and Brazil. We evaluated the expressions of ACE2 and furin (another important factor for virus internalization) in colon (n = 60), gastric (n = 19), and thyroid (n = 11) carcinomas. In a subseries of cases with PCR results for SARS-CoV-2 detection in the peri-operatory window (n = 18), we performed different methodological approaches for viral detections in patient tumor samples. Our results show that colon and gastric carcinomas display favorable microenvironments to SARS-CoV-2 tropism, presenting high expression levels of ACE2 and furin. From the subseries of 18 cases, 11 tested positive via PCR detection performed in tumor blocks; however, a direct association between the ACE2 expression and SARS-CoV-2 infection was not demonstrated in cancer cells using histology-based techniques, such as immunohistochemistry or in situ hybridization. This study raises the possibility of ACE2-mediated viral tropism in cancer tissues to be clarified in future studies.

Decellularized Colorectal Cancer Matrices as Bioactive Scaffolds for Studying Tumor-Stroma Interactions.

More than a physical structure providing support to tissues, the extracellular matrix (ECM) is a complex and dynamic network of macromolecules that modulates the behavior of both cancer cells and associated stromal cells of the tumor microenvironment (TME). Over the last few years, several efforts have been made to develop new models that accurately mimic the interconnections within the TME and specifically the biomechanical and biomolecular complexity of the tumor ECM. Particularly in colorectal cancer, the ECM is highly remodeled and disorganized and constitutes a key component that affects cancer hallmarks, such as cell differentiation, proliferation, angiogenesis, invasion and metastasis. Therefore, several scaffolds produced from natural and/or synthetic polymers and ceramics have been used in 3D biomimetic strategies for colorectal cancer research. Nevertheless, decellularized ECM from colorectal tumors is a unique model that offers the maintenance of native ECM architecture and molecular composition. This review will focus on innovative and advanced 3D-based models of decellularized ECM as high-throughput strategies in colorectal cancer research that potentially fill some of the gaps between in vitro 2D and in vivo models. Our aim is to highlight the need for strategies that accurately mimic the TME for precision medicine and for studying the pathophysiology of the disease.

Peripheral T-Cell Lymphoma, Not Otherwise Specified - a case report and short literature review.

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) is the most common subgroup of peripheral T-cell lymphomas (PTCL), and constitutes a diagnosis of exclusion. At presentation, most patients exhibit B symptoms and generalized lymphadenopathy, with or without concomitant extra-nodal involvement. We present a case of a man admitted to the hospital with B symptoms, generalized lymphadenopathy and a pruritic exanthema. Laboratory workup reveled persistent eosinophilia and malignant hypercalcemia. The excisional lymph node biopsy diagnosed PTCL-NOS, and the skin biopsy demonstrated a lichenoid dermatitis, compatible with the presumptive clinical diagnosis of a drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. The patient was treated with topical betamethasone with good overall response, and initiated the first cycle of chemotherapy before discharge. This case report describes a PTCL-NOS with a concomitant non-lymphoproliferative disease, the challenging diagnostic workup of the two diseases and reinforces the most important features of the lymphoproliferative neoplasm.

Role of liver biopsy in the era of clinical prediction scores for "drug-induced liver injury" (DILI): experience of a tertiary referral hospital.

The clinical implications of the biopsy findings in cases of drug-induced liver injury (DILI) are not fully elucidated. The aim of this study was to evaluate the histopathological findings of cases diagnosed as DILI and to correlate them with clinical and biochemical findings (such as causality assessment algorithms). We searched our department database for all cases of liver biopsy with findings consistent with toxic liver disease and selected those with a clinical diagnosis of DILI. The causative relationships were established according to Roussel Uclaf Causality Assessment Method (RUCAM). A total of 53 cases of DILI were reviewed, most of them diagnosed in hospitalized patients (83%). The analytical toxicity profile was hepatocellular (R > 5) in 60% of the cases and cholestatic (R < 2) in 26.4% of cases. The group of drugs most implicated was the anti-microbials (18, 34%). The predominant histological patterns were "necroinflammation" (67.9%) and "cholestasis" (28.3%). The hepatocellular biochemical pattern was not associated with the presence of predominantly necroinflammatory findings in the biopsy (p = 0.44), and the biochemical cholestatic pattern was not associated with the presence of predominantly cholestatic findings in the biopsy (p = 0.51). This study supports that a better insight into the pathologic mechanisms associated with DILI should be based on liver biopsy due to the lack of a uniform correlation between clinical and biochemical patterns. Also, a liver biopsy may be used in those cases where clinical suspicion of DILI persists despite a low score on current causality assessment algorithms.

Arteriolar C4d in IgA Nephropathy: A Cohort Study.

RATIONALE & OBJECTIVE: Glomerular C4d (C4dG) as an indicator of the lectin pathway of complement activation in immunoglobulin A nephropathy (IgAN) has been associated with more severe kidney damage. Recent studies have suggested that vascular lesions in IgAN biopsy specimens with complement deposition are also associated with disease progression. We aimed to study the clinical significance of arteriolar C4d (C4dA) in IgAN kidney biopsy tissue. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Kidney biopsy specimens from 126 adults with IgAN diagnosed by Oxford classification criteria were stained using immunohistochemistry and classified according to C4dG and C4dA deposition. Additionally, vascular lesions including acute and chronic microangiopathy, arteriolar hyalinosis, and arterial intima fibrosis were characterized. PREDICTOR: C4dA. OUTCOME: Progressive kidney disease, defined as a decline in estimated glomerular filtration rate by≥50% or occurrence of kidney failure. ANALYTICAL APPROACH: The association of C4dA and C4dG with baseline clinical and histologic characteristics, as well as progressive kidney disease, were assessed with survival analysis using multivariable Cox regression analysis. RESULTS: C4dA was identified in 21 (17%) patients and was associated with mean arterial pressure, arterial intima fibrosis, and chronic microangiopathy. C4dA was also significantly associated with C4dG and both were associated with progressive kidney disease. In regression analysis, C4dA remained significantly associated with progressive kidney disease after adjusting for other significant predictors, including baseline estimated glomerular filtration rate, mean arterial pressure, and the presence of crescents. LIMITATIONS: Findings based on the retrospective evaluation of a single center's experience, limited number of events, a small number of patients with a broad range of kidney disease stages, and use of immunohistochemistry rather than immunofluorescence to detect C4d. CONCLUSIONS: C4dA is a potential biomarker for disease progression in IgAN. It should be further investigated in larger cohorts to determine the value of C4dA in improving prediction of IgAN disease progression.

Eosinophils in the gastrointestinal tract: how much is normal?

The normal density of eosinophils in the digestive mucosa of children has been rarely addressed despite being important to provide baseline counts for the diagnosis of eosinophilic gastrointestinal disorders (EGID). Histopathological criteria for EGID remain undefined and there has been little consistency of results in different populations. We aimed to establish the eosinophil density of the normal digestive mucosa in a paediatric population submitted to endoscopic procedures with normal histological features. Biopsies from endoscopies of 33 patients were evaluated. Quantification of eosinophils was performed manually. Review of the pathology reports confirmed absence of abnormality in the biopsy specimens. Counts were expressed in eosinophils per high power field and per mm2. Oesophagus (n = 33): eosinophils were uniformly absent in all biopsies. Stomach: counting was performed, separately, in the superficial and deep lamina propria of the fundus (n = 13), corpus (n = 13) and antrum (n = 16). Mean eosinophilic density was higher in the deep lamina propria. Small intestine: eosinophil counts revealed 18.1 ± 17.0, 14.4 ± 12.0, and 51.5 ± 35.3 in the lamina propria of the bulb (n = 13), D2 (n = 13), and ileum (n = 16), respectively. Large intestine: the highest peak count was observed in the caecum (125 mm2; n = 16) with a mean of 51.8 ± 33.5. The eosinophil counts were lower in the ascending (n = 16; 40.9 ± 27.4), transverse (n = 14; 34.3 ± 21.9), descending (n = 15; 40.0 ± 26.6), and sigmoid (n = 17; 25.8 ± 17.8) colon and in the rectum (n = 17; 13.9 ± 10.1). These data provide a baseline count and distribution of eosinophils in the gastrointestinal tract of paediatric patients with normal mucosa, thus expanding the scarce published data.