Faculty Bibliography

CONTEXT.—/UNASSIGNED:Cytomegalovirus (CMV) immunohistochemistry (IHC) is the most widely used method to diagnose CMV infection/reactivation in tissues in a pathology laboratory. OBJECTIVE.—/UNASSIGNED:To improve the efficiency of CMV IHC testing by evaluating immunopositive staining trends of tissue-invasive CMV in the gastrointestinal system. DESIGN.—/UNASSIGNED:A total of 1479 individual orders for CMV IHC on gastrointestinal biopsy specimens from 2016 to 2018 were included. The analysis was performed to identify the significant factors contributory to CMV-positive test results. RESULTS.—/UNASSIGNED:The overall positivity rate of CMV IHC in our institution was 4.73% (70 of 1479). The positivity rate from physician-requested and pathologist-initiated tests was significantly different (7.54% versus 3.83%, P = .004). Cases with severe inflammation showed a higher positive CMV rate than those with mild inflammation (5.37% versus 2.60%, P = .04). Cytomegalovirus positivity in biopsies from posttransplant patients, inflammatory bowel disease, human immunodeficiency virus (HIV)/common variable immunodeficiency (CVID), cancer, and others was 19.69%, 3.84%, 23.33%, 9.00%, and 2.84%, respectively. The positivity rate among posttransplant, HIV/CVID, or cancer patients was significantly higher than in other populations. Cases tested with multiple tissue blocks generated a higher positivity rate than those with a single block (7.77% versus 3.23%, P < .001). Testing 3 to 4 blocks per case almost tripled the positive CMV detection rate (9.04%). Interestingly, using 5 or more blocks did not further ameliorate the positive CMV detection rate. CONCLUSIONS.—/UNASSIGNED:The data revealed that physician request, immunosuppression, multiple blocks, and severe inflammation were strongly related to positive CMV IHC detection rate. These findings might provide value in helping pathologists manage CMV IHC testing more efficiently.

BACKGROUND:Recent studies have suggested the important roles of CD47 and tumor-associated macrophages in the prognosis and immunotherapy of various human malignancies. However, the clinical significance of CD47 expression and CD163+ TAMs in pancreatic neuroendocrine tumor (PanNET) remains unclear. METHODS:In this study, 47 well-differentiated PanNET resection specimens were collected. CD47 expression and CD163+ macrophages were evaluated using immunohistochemistry and correlated with clinicopathologic properties. RESULTS:Positive CD47 staining was seen in all PanNETs as well as adjacent normal islets. Compared to normal islets, CD47 overexpressed in PanNETs (p = 0.0015). In the cohort, lymph node metastasis (LNM), lymphovascular invasion (LVI), and perineural invasion (PNI) were found in 36.2, 59.6, and 48.9% of the cases, respectively. Interestingly, PanNETs with LNM, LVI, or PNI had significantly lower H-score of CD47 than those without LNM (p = 0.035), LVI (p = 0.0005), or PNI (p = 0.0035). PanNETs in patients with disease progression (recurrence/death) also showed a significantly lower expression of CD47 than those without progression (p = 0.022). In contrast, CD163+ macrophage counts were significantly higher in cases with LNM, LVI, and PNI. CONCLUSIONS:Our data suggest relative low CD47 expression and high CD163+ TAMs may act as indicators for poor prognosis of PanNETs.

Background: Digestive symptoms are often seen in COVID-19 patients with poor outcomes. The Viral RNA is mostly positive in the stool of these patients, and has a longer delay before viral clearance. However, its diagnostic value and significance for guiding clinical treatment remain unknown. And the pathologic alterations in the GI tract in COVID-19 patients have not been well defined. We evaluated rectal swab SAS-CoV-2 test and histopathologic changes in the small intestine in autopsy patients.
Design(s): 18 autopsy cases with confirmed SAS-CoV2 infection were included. Nasal, bronchial, and rectal swab SARS-CoV-2 PCR were performed at the time of autopsy. Clinical information included demographics, comorbidities, presenting symptoms, related laboratory tests were collected. Histopathologic evaluation was performed and correlated with clinical properties.
Result(s): 83% (15/18) of patients were male. Median age is 50 years. 7/18 (38.9%) patients had diarrhea in addition to cough, fever and other symptoms. Except in one case, all patients had underlying comorbidities of diabetes, hypertension and /or obesity. In the small intestine, acute inflammation was not seen in any cases. 5/18 displayed mild and one showed moderate chronic inflammation. Hypermucinous change was found in six patients but not associated with diarrhea. 3 cases had microthrombi identified in the sections. Notably, obviously increased D dimer in lab tests were noticed in all patients. Postmortem 17/17 (100%) nasal, 18/18 (100%) bronchial and 7/16 (43.8%) rectal swabs showed SARS-CoV-2 PCR positivity. 3 of 7 (42.9%) patients with diarrhea are positive in rectal swab for SARS-CoV-2.
Conclusion(s): There are no specific COVID-19 changes in the small intestine. More investigations are needed, especially on tissues from different locations of the GI tract. Data from rectal swab testing suggests that it is not ideal for diagnosing COVID-19, guiding treatment, or predicting small intestinal pathology

Background: In addition to respiratory distress, GI symptoms have been reported in COVID-19 patients at various stages of the disease. Among the GI symptoms that have been reported, diarrhea, nausea, vomiting, abdominal pain and GI bleeding were often seen. Age and comorbid conditions such as obesity, HTN, DM and/or CAD have been considered as risk factors for COVID-19 patients for severe disease. GI manifestations in COVID-19 patients appeared to act as a sign for a serious condition. The virus has been identified in the stool and in rectal swabs of some infected patients, even after a negative nasopharyngeal test. There is a lack of reports on pathological alterations of the GI tract in COVID-19 infected patients.
Design(s): 16 PCR confirmed COVID-19 patients (11 males and 5 females) were included in the study. Biopsy or resection specimens were taken from the esophagus (4), stomach (6), small intestine (5), appendix (3), colon (5) and gallbladder (3). Clinical information including demographics, comorbidities, GI symptoms, related laboratory tests were collected. Histopathologic evaluation was performed and correlated with clinical properties.
Result(s): The age of the patients ranged from 10 to 84 years old, with an average of 47 years. Eight (50%) patients had at least one comorbid condition, two patients (12.5%) had prior history of cancer, and six patients had no significant medical history. Abdominal pain and GI bleeding were the most common presenting symptoms. Histologically, acute and chronic inflammation was seen in 14 of 16, and 15 of 16 cases, respectively. Eight cases showed severe acute inflammation with ulceration. The mucosal changes included nonspecific reactive change, hypermucinous, atrophic/ischemic changes, and necrosis, were indiscriminately noticed in these cases. Four cases showed intraepithelial lymphocytosis. Viral like inclusions were found in four cases. Microthrombi were identified in 5 cases with an average patient age of 60 years. Notably, microthrombi were seen in about 5 out of 8 (62%) patients with comorbidities. The patients with microthrombi had a higher D dimer test value than those without thrombus. Three patients died shortly after operation, and two of them showed microthrombi in the tissue specimens.
Conclusion(s): Acute and chronic inflammation were indiscriminately seen in these cases. Microthrombi were dominantly found in aging patients with comorbidities, suggesting microthrombi in the GI tract may be a histologic indication for severe COVID-19 patients with GI symptoms

Gastrointestinal (GI) symptoms of SARS-CoV-2/COVID-19 in the form of anorexia, nausea, vomiting, abdominal pain and diarrhea are usually preceded by respiratory manifestations and are associated with a poor prognosis. Hematochezia is an uncommon clinical presentation of COVID-19, and we hypothesize that older patients with significant comorbidities (obesity and cardiovascular) and prolonged hospitalization are susceptible to ischemic injury to the bowel. We reviewed the clinical course, key laboratory data including acute-phase reactants, and drug/medication history in 2 elderly male patients admitted for COVID-19 respiratory failure. Both patients had a complicated clinical course and suffered from hematochezia, acute blood loss, and anemia which led to hemodynamic instability requiring blood transfusion around day 40 of their hospitalization. Colonoscopic impressions were correlated with the histopathological findings in the colonic biopsies that included changes compatible with ischemia and nonspecific acute inflammation, edema, and increased eosinophils in the lamina propria. Both patients were hemodynamically stable, on prophylactic anticoagulants, multiple antibiotics, and antifungal agents due to respiratory infections at the time of lower GI bleeding. Hematochezia resolved spontaneously with supportive care. Both patients eventually recovered and were discharged. Elderly patients with significant comorbid conditions are uniquely at risk for ischemic injury to the bowel. This case report highlights hematochezia as an uncommon GI manifestation of spectrum of COVID-19 complications. The causes of bleeding in these COVID-19 associated cases are likely multifactorial and can be attributed to concomitant etiologies based on their age, multiple comorbid conditions, prolonged hospitalization compounded by lung injury, and hypoxia precipitated by the virus. We hypothesize that rather than a direct viral cytopathic effect, ischemia and hypoperfusion may be unleashed due to the cytokine storm orchestrated by the virus that leads to abnormal coagulation profile. Additional factors that may contribute to ischemic injury are prophylactic use of anticoagulants and polypharmacy. There were no other causes to explain the brisk lower GI bleeding. Presentation of hematochezia was followed by hemodynamic instability that may further increase the mortality and morbidity of COVID-19 patients, and prompt consultation and management by gastroenterology is therefore warranted.

Although coronavirus disease 2019 (COVID-19) is transmitted via respiratory droplets, there are multiple gastrointestinal and hepatic manifestations of the disease, including abnormal liver-associated enzymes. However, there are not many published articles on the pathological findings in the liver of patients with COVID-19. We collected the clinical data from 17 autopsy cases of patients with COVID-19 including age, sex, Body mass index (BMI), liver function test (alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), alkaline phosphatase (ALP), direct bilirubin, and total bilirubin), D-dimer, and anticoagulation treatment. We examined histopathologic findings in postmortem hepatic tissue, immunohistochemical (IHC) staining with antibody against COVID-19 spike protein, CD68 and CD61, and electron microscopy. We counted the number of megakaryocytes in liver sections from these COVID-19-positive cases. Abnormal liver-associated enzymes were observed in 12 of 17 cases of COVID-19 infection. With the exception of three cases that had not been tested for D-dimer, all 14 patients' D-dimer levels were increased, including the cases that received varied doses of anticoagulation treatment. Microscopically, the major findings were widespread platelet-fibrin microthrombi, steatosis, histiocytic hyperplasia in the portal tract, mild lobular inflammation, ischemic-type hepatic necrosis, and zone 3 hemorrhage. Rare megakaryocytes were found in sinusoids. COVID-19 IHC demonstrates positive staining of the histiocytes in the portal tract. Under electron microscopy, histiocyte proliferation is present in the portal tract containing lipid droplets, lysosomes, dilated ribosomal endoplasmic reticulum, microvesicular bodies, and coronavirus. The characteristic findings in the liver of patients with COVID-19 include numerous amounts of platelet-fibrin microthrombi, as well as various degrees of steatosis and histiocytic hyperplasia in the portal tract. Possible mechanisms are also discussed.

BACKGROUND AND AIMS/OBJECTIVE:Collagenous colitis (CC) is an inflammatory bowel disorder with unknown etiopatogenesis involving human leukocyte antigen (HLA)-related immune-mediated responses, environmental and genetic risk factors. We carried out an array-based genetic association study in a cohort of CC patients and investigated the common genetic basis between CC and Crohn's disease (CD), ulcerative colitis (UC) and celiac disease. METHODS:DNA from 804 CC formalin-fixed, paraffin-embedded tissue samples was genotyped with Illumina Immunochip. Matching genotype data on controls and CD, UC and celiac disease cases were provided by the respective Consortia. A discovery association study followed by meta-analysis with an independent cohort, polygenic risk score (PRS) calculation, and cross-phenotype analyses were performed. Enrichment of regulatory expression quantitative trait loci (eQTLs) among the CC variants was assessed in hemopoietic and intestinal cells. RESULTS:Three HLA alleles (HLA-B*08:01, HLA-DRB1*03:01, and HLA-DQB1*02:01), related to the ancestral haplotype 8.1, were significantly associated with increased CC risk. We also identified an independent protective effect of HLA-DRB1*04:01 on CC risk. PRS quantifying the risk across multiple susceptibility loci was strongly associated with CC risk. An enrichment of eQTLs was detected among the CC susceptibility variants in various cell types. The cross-phenotype analysis identified a complex pattern of polygenic pleiotropy between CC and other immune-mediated diseases. CONCLUSION/CONCLUSIONS:In this largest genetic study of CC to date with histologically confirmed diagnosis, we strongly implicated the HLA locus and proposed potential non-HLA mechanisms in disease pathogenesis. We also detected a shared genetic risk between CC, celiac disease, CD and UC, which supports clinical observations of comorbidity.

Background: Cytomegalovirus (CMV) infection of gastrointestinal organs (GI) is the most common manifestation of tissue-invasive disease, especially in immunocompromised individuals. It is often seen in patients with IBD, post transplantation, HIV and cancer. The histopathologic diagnosis of CMV infection relies on histologic evaluation of viral inclusions and immunohistochemistry (IHC) confirmation. To avoid missing CMV infection in patients, numerous CMV IHC test requests are submitted by physicians or pathologists each year. However, more than 90% percent of cases are reported negative. The high volume of test requests not only negatively impact the efficiency of CMV test resource, but also increase the cost burden for hospital and patients. We analyzed the CMV IHC test data and related clinical information in order to improve the practices by eliminating the unnecessary use of resources.
Design(s): CMV IHC test orders from 2017 to 2018 were retrieved from surgical pathology computerized database to find CMV IHC results, physician or pathologist requests, tissue inflammatory status, blocks tested, and other related clinical information. After excluding the cases from non-gastrointestinal sources, cytology, autopsy and resection specimens, 1025 individual orders of CMV IHC on GI biopsy specimens were included. Analysis was performed to find out the significant factors contributory to positive test results.
Result(s): The overall CMV IHC positive rate is 4.1% (43/1025) in our institution. The positive rate from physician request and pathologist order was not significantly different (5.5% vs 3.7%).Cases with multiple tissue blocks generated a higher positive rate as compared to single block (6.8% vs 2.6%, p=0.0019).Cases with severe inflammation showed significant higher positive CMV staining than that with moderate or less inflammation (5.3% vs 2%).CMV positivity in biopsies from post-transplant patients, IBD, cancer or others was 13.6%, 3.5%, 4.4% or 3.9%, respectively. Positive rate in post-transplantation patients was higher than other populations.
Conclusion(s): Significant number of negative CMV stains could be cut down through optimizing the test orders. While ordering CMV IHC on GI biopsy specimens, clinical history and severity of tissue inflammation should be considered. For high risk cases such as post transplantation, multiple blocks may need to be submitted. IBD patients did not have higher CMV positive rate than other patient population, perhaps due to recently improving therapeutic approach

Background: Pancreatic neuroendocrine tumors (pNETs), originating from diffuse neuroendocrine cells, are a clinically rare and heterogeneous disease of the pancreas which have increased significantly in incidence over the past few decades. As the therapeutic options continue to expand, it is necessary to define robust prognostic markers to guide clinical decision making and improve patient outcome. Although several biomarkers for NETs exist, sensitive and specific markers that diagnose tissue-specific NETs and predict tumor growth and behavior are generally lacking. CD47 is a transmembrane ligand which inhibits phagocytosis. Overexpression of CD47 has been associated with increased tumor growth and metastasis in a variety of malignancies. In this study, we examine the prognostic implications of CD47 expression in pNETs.
Design(s): 44 well differentiated pNET resection specimens (17 G1, 23 G2, and 4 G3) were selected and analyzed using CD47 immunohistochemistry. Staining intensity and percentage of positive tumor cells was quantified using the H-score method. Statistical analysis was utilized to correlate H-score with various clinicopathologic parameters.
Result(s): Membranous and cytoplasmic staining of CD47 was seen in pNETs and normal endocrine cells. High expression of CD47 was seen in all samples of pNETs compared to the surrounding noncancerous pancreatic tissues. H-score of CD47 in pNETs with lymph node metastasis was significantly lower than in pNETs without lymph node metastasis (128.2+/-9.0 and 161.7+/-11.0, P=0.038). CD47 expression inversely correlate with perineural invasion (127.4+/-7.7 vs 170.0+/-11.6, P=0.004), and lymphovascular invasion (128.8+/-7.6 vs 178.8+/-13.6, P=0.002). Further analysis revealed that CD47 expression in pNETs was also inversely related to mitotic count (P=0.045). CD47 expression did not correlate with patient's age, gender, tumor size, stage, grade, or Ki-67 proliferation index.
Conclusion(s): CD47 was overexpressed in all pNETs. CD47 expression significantly correlated with lymph node metastasis, perineural invasion, lymphovascular invasion, and mitosis. The data indicated that CD47 may be a promising marker for predicting pNET prognosis