Retrospective analysis of pathological types and imaging features in pancreatic cancer: A comprehensive study

BACKGROUND Pancreatic cancer remains one of the most lethal malignancies worldwide,with a poor prognosis often attributed to late diagnosis.Understanding the correlation between pathological type and imaging features is crucial for early detection and appropriate treatment planning.AIM To retrospectively analyze the relationship between different pathological types of pancreatic cancer and their corresponding imaging features.METHODS We retrospectively analyzed the data of 500 patients diagnosed with pancreatic cancer between January 2010 and December 2020 at our institution.Pathological types were determined by histopathological examination of the surgical spe-cimens or biopsy samples.The imaging features were assessed using computed tomography,magnetic resonance imaging,and endoscopic ultrasound.Statistical analyses were performed to identify significant associations between pathological types and specific imaging characteristics.RESULTS There were 320(64%)cases of pancreatic ductal adenocarcinoma,75(15%)of intraductal papillary mucinous neoplasms,50(10%)of neuroendocrine tumors,and 55(11%)of other rare types.Distinct imaging features were identified in each pathological type.Pancreatic ductal adenocarcinoma typically presents as a hypodense mass with poorly defined borders on computed tomography,whereas intraductal papillary mucinous neoplasms present as characteristic cystic lesions with mural nodules.Neuroendocrine tumors often appear as hypervascular lesions in contrast-enhanced imaging.Statistical analysis revealed significant correlations between specific imaging features and pathological types(P<0.001).CONCLUSION This study demonstrated a strong association between the pathological types of pancreatic cancer and imaging features.These findings can enhance the accuracy of noninvasive diagnosis and guide personalized treatment approaches.

Unusual histopathological findings in appendectomy specimens from patients with suspected acute appendicitis

AIM: To investigate the prevalence and implications of unusual histopathological findings in appendectomy specimens from patients with suspected acute appendicitis. METHODS: The demographic and histopathological data of 1621 patients (≥ 16 years-old) who underwent appendectomy to treat an initial diagnosis of acute appendicitis between January 1999 and November 2011 were retrospectively assessed. Microscopic findings were used to classify the patients under six categories: appendix vermiformis, phlegmonous appendicitis, gan- grenous appendicitis, perforated appendicitis, supurative appendicitis, and unusual histopathologic findings. The demographic and clinicopathologic characteristics of patients with unusual histopathologic findings were evaluated in detail, and re-analysis of archived resected appendix specimens was carried out. RESULTS: A total of 912 males and 709 females, from16 to 94 years old, were included in the study and comprised 789 cases of suppurative appendicitis, 370 cases of appendix vermiformis, 243 cases of perforated gangrenous appendicitis, 53 cases of flegmaneous appendicitis, 32 cases of gangrenous appendicitis, and 134 (8.3%) cases of unusual histopathological findings. The unusual histopathological findings included fibrous obliteration (n = 62), enterobius vermicularis (n = 31), eosinophilic infiltration (n = 10), mucinous cystadenoma (n = 8), carcinoid tumor (n = 6), granulomatous inflammation (n = 5), adenocarcinoma (n = 4; one of them mucinous), and mucocele (n = 3), adenomatous polyp (n = 1), taenia sup (n = 1), ascaris lumbricoides (n = 1), appendiceal diverticula (n = 1), and B cell non-hodgkin lymphoma (n = 1). None of the 11 patients with subsequent diagnosis of tumor were suspected of cancer prior to the appendectomy. CONCLUSION: Even when the macroscopic appearance of appendectomy specimens is normal, histopathological assessment will allow early diagnosis of many unusual diseases.

Endoscopic findings and clinicopathologic characteristics of colonic schistosomiasis:A report of 46 cases

AIM:To make a retrospective analysis of endoscopy findings and clinicopathologic characteristics of colonic schistosomiasis in order to further improve our understanding of the disease and decrease its misdiagnosis. METHODS:Endoscopy findings and clinicopathologic characteristics of 46 intestinal schistosomiasis patients were retrospectively analyzed.All the patients underwent colonoscopy and all biopsy specimens stained with hematoxylin and eosin were observed under a light microscope. RESULTS:Of the 46 colonic schistosomiasis patients,1 was diagnosed as acute schistosomal colitis,16 as chronic schistosomal colitis and 29 as chronic active schistosomal colitis according to their endoscopic findings and pathology.Not all patients were suspected of or diagnosed as colonic schistosomiasis.Of the 12 misdiagnosed patients,4 were misdiagnosed as ulcerativecolitis,1 as Crohn's disease,and 7 as ischemic colitis.The segments of rectum and sigmoid colon were involved in 29 patients(63.0%) .Intact Schistosoma ova were deposited in colonic mucosa accompanying infiltration of eosinocytes,lymphocytes,and plasma cells in acute schistosomal colitis patients.Submucosal fibrosis was found in chronic schistosomal colitis patients.Among the 17 patients with a signal polyp,hyperplastic polyp,canalicular adenoma with a low-grade intraepithelial neoplastic change,tubulovillous adenoma with a highgrade intraepithelial neoplastic change were observed in 10,5,and 2 patients,respectively.Eight out of the 46 patients were diagnosed as colonic carcinoma. CONCLUSION:Endoscopy contributes to the diagnosis of colonic schistosomiasis although it is nonspecific. A correct diagnosis of colonic schistosomiasis can be established by endoscopy in combination with its clinicopathologic characteristics.

Non-alcoholic steatohepatitis and influence of age and gender on histopathologic findings

AIM:To characterize the histopathologic specifications of non-alcoholic steatohepatitis(NASH)according to age and gender.METHODS:An analytical cross-sectional study was conducted in two private gastroenterology clinics on biopsy proven patients suffering from NASH.Biopsy histopathologic findings as well as demographic and laboratory data of the patients at the time of biopsy were gathered retrospectively from clinical records.The grading and staging of histopathologic findings were performed according to the Brunt method after reevaluation of the slides by a pathologist.Patients were divided into two groups according to age(belowand above 55 years).Mean quantitative grade of all pathologic findings were also calculated according to Brunt scoring values.RESULTS:A total number of 77 NASH patients,consisting of 58 males(75.3%)and 19(24.7%)females with a mean age of 41.99±11.80 years(range,18-70 years),were enrolled.The mean age(48.72±13.99 years vs 39.74±10.16 years,P=0.004)and aspartate aminotransferase level(75.11±29.68 U/L vs 52.78± 25.00 U/L,P=0.002)was significantly higher in female patients.Mean quantitative grade of hepatosteatosis was significantly higher in females(2.00±0.82 vs 1.59 ±0.68,P=0.031)compared to males.Fifty four percent(34/65)of young patients had mild hepatosteatosis (GradeⅠ)while only one patient(11.2%)in the older group had gradeⅠhepatosteatosis.Patients aged≥55 had significantly more severe hepatosteatosis(GradeⅢ) (44.4%vs 9.5%,P=0.007)and the mean quantitative grade of hepatosteatosis was significantly higher among them(2.33±0.71 vs 1.56±0.67,P=0.002).Multivariate analysis after omitting the confounding role of age revealed a higher grade of hepatosteatosis in female patients(P=0.010).CONCLUSION:These findings point toward the possible influence of age in the severity of steatohepatitis,portal and lobar inflammation in patients suffering from NASH while gender independently might contribute to the level of steatohepatitis.

Pancreatic schwannoma: Imaging features and pathological findings

To the Editor:Schwannoma is an infrequent tumor originating from Schwann cells of the peripheral nerve sheath and was first reported as a true neoplasm originating from Schwann cells in 1910 [1] . The ma- jority of schwannomas are detected as a solitary tumor from the peripheral nerves of the face, neck, trunk, extremities, or retroperi- toneal region. Based on a previous study [2] , merely 3% of schwan- nomas are retroperitoneal, accounting for approximately 4% of all retroperitoneal tumors. Furthermore, pancreatic schwannomas that stem from either parasympathetic or sympathetic fibers of the pancreas are especially rare. Schwannomas are generally encapsu- lated, and over 90% are benign [3] . Considering its benign biolog- ical behavior, it is essential to accurately diagnose schwannomas in order to apply reasonable surgical methods and postoperative surveillance. Herein, we report four cases of pancreatic schwan- noma in our center to update the data on the clinicopathological traits about this type of tumor.

Immune checkpoint inhibitor-induced diarrhea/colitis: Endoscopic and pathologic findings

The indications of immune checkpoint inhibitors(ICPIs)for cancer treatment have rapidly expanded,and their use is increasing in clinical settings worldwide.Despite the considerable clinical benefits of ICPIs,frequent immune-related adverse events(ir AEs)have become nonnegligible concerns.Among ir AEs,ICPIinduced colitis/diarrhea is frequent and recognized not only by oncologists but also by gastroenterologists or endoscopists.The endoscopic findings show similarity to those of inflammatory bowel disease to a certain extent,particularly ulcerative colitis,but do not seem to be identical.The pathological findings of ICPI-induced colitis may vary among drug classes.They show acute or chronic inflammation,but it may depend on the time of colitis suggested by colonoscopy,including biopsy or treatment intervention.In the case of chronic inflammation determined by biopsy,the endoscopy findings may overlap with those of inflammatory bowel disease.Here,we provide a comprehensive review of ICPIinduced colitis based on clinical,endoscopic and pathologic findings.

Hepatic malignancies:Correlation between sonographic findings and pathological features

Ultrasonography(US) findings are inevitably based on pathological features.Knowledge of the pathological features of hepatic malignancies such as hepatocellular carcinoma(HCC),liver metastasis and intrahepatic cholangiocarcinoma is essential for correct US diagnosis and appropriate management.One type of hepatocarcinogenesis is step-wise development from a low-grade dysplastic nodule(DN),high-grade DN,high-grade DN with malignant foci,and well-differentiated HCC,to classical HCC.The intranodular blood supply changes in accordance with this progression.Moreover,the malignant potential tends to change as the macroscopic configuration progresses.Therefore,typical US findings of advanced HCC are a mosaic pattern,septum formation,peripheral sonolucency(halo),lateral shadow produced by fibrotic pseudocapsule,posterior echo enhancement,arterial hypervascularity with dilated intratumoral blood sinusoids,and perinodular daughter nodule formation.Bull's eye appearance is a common presentation of metastases from gastrointestinal(GI) adenocarcinomas,and represents histological findings that show an area of central necrosis surrounded by a zonal area of viable tumor.Thick zonal area reflects the layer of viable cells that are fed by minute tumor vessels.US imaging features of liver metastases from the GI tract are as follows:Bull's eye appearance,multiple masses,irregular tumor border,arterial rim-like enhancement,and hypoenhancement in the late vascular phase.Most intrahepatic cholangiocarcinomas are ductal adenocarcinomas.The bile ducts peripheral to the tumor are usually dilated because of obstruction by tumors.US imaging features of mass-forming cholangiocarcinoma are as follows:peripheral bile duct dilatation,irregular tumor border,arterial enhancement due to minute intratumoral blood sinusoids,and hypoenhancement in the late vascular phase.

Unusual histopathological findings in appendectomy specimens:A retrospective analysis and literature review

AIM: To document unusual findings in appendectomy specimens. METHODS: The clinicopathological data of 5262 patients who underwent appendectomies for presumed acute appendicitis from January 2006 to October 2010 were reviewed retrospectively. Appendectomies performed as incidental procedures during some other operation were excluded. We focused on 54 patients who had unusual findings in their appendectomy specimens. We conducted a literature review via the PubMed and Google Scholar databases of English language studies published between 2000 and 2010 on unusual findings in appendectomy specimens. RESULTS: Unusual findings were determined in 54 (1%) cases by histopathology. Thirty were male and 24 were female with ages ranging from 15 to 84 years (median, 32.2 ± 15.1 years). Final pathology revealed 37 cases of enterobiasis, five cases of carcinoids, four mucinous cystadenomas, two eosinophilic infiltrations, two mucoceles, two tuberculosis, one goblet-cell carcinoid, and one neurogenic hyperplasia. While 52 patients underwent a standard appendectomy, two patients who were diagnosed with tuberculous appendicitis underwent a right hemicolectomy. All tumors were located at the distal part of the appendix with a mean diameter of 6.8 mm (range, 4-10 mm). All patients with tumors were alive and disease-free during a mean follow-up of 17.8 mo. A review of 1366 cases reported in the English literature is also discussed. CONCLUSION: Although unusual pathological findings are seldom seen during an appendectomy, all appendectomy specimens should be sent for routine histopathological examination.

Histopathological findings in cholecystectomies specimens:A single institution study of 20 584 cases

Background: The histopathological examination of cholecystectomy specimens has not been standardized with a debate concerning the routine and the selective approach. The aim of this study was to assess the information obtained from routine histopathological examination of cholecystectomy specimens.Methods: All histopathological reports of cholecystectomy specimens between January 2003 and December 2016 were analyzed, including a clinical diagnosis of benign gallstone disease or cholecystitis.Results: A total of 20,584 reports were examined. The mean age of patients was 54.2 years. Patients aged more than 60 years represent 37.6% of the study population. Of all patients, 15,973(77.6%) were females.Incidental gallbladder cancers(GBC) were present in 155 cholecystectomies specimens(0.8%). 67.1% of GBC are at T2 and T3 stage. Granulomatous cholecystitis was diagnosed in only 19 cases(0.1%). GBC were more prevalent in older patients(P < 10-6) and cholesterolosis was more prevalent in young patients(P < 10-6). There was no gender predilection for GBC(P = 0.739).Conclusions: The rate of incidental gallbladder carcinoma in our study is low, yet, we found a higher proportion of T2 and T3 carcinomas stage. Granulomatous cholecystitis may need further investigations and treatments. When a selective approch of histopathological examination of cholecystectomy specimens is used, it is important to take into account that clinical parameters are significantly associated with gallbladder cancer.

Endoscopic findings and pathologic characteristics of gastric eosinophilic granuloma:A report of 18 patients

AIM: To investigate the endoscopic findings and patholo- gic characteristics of gastric eosinophilic granuloma (GEG). METHODS: A retrospective study of 18 cases of gastric eosinophilic granulomas was conducted. Gastroscopy was performed and all specimens of biopsies were stained by H&E and observed under light microscopy. RESULTS: Ulcer was the most frequent endoscopic appearance. The others included deformed pylorus and/or duodenal bulb, esophagitis, mucous hyperemia and/or mucosal erosion. Eosinophilic cell infiltration and generous hyperplasia of arterioles, venules and lymph vessels were found in the lesions of the patients. Interstitium had massive eosinophilic infiltrates and was made up of collagen fibers and fibroblasts. Lymphoid follicles were revealed in some sections of biopsies. CONCLUSION: GEG is lack of specific symptoms and physical signs. It can be misdiagnosed as gastric ulcer in most cases before biopsies. Endoscopy and endoscopic multiple deep biopsies in suspected areas are indispensable for correct diagnosis of GEG.

Clinical Significance of Pathological and Anatomical Findings in Cone Beam CT Scans of the Maxillary Sinus

Objective: To determine the range and prevalence of pathological conditions and demonstration of significant anatomical structures in the maxillary sinuses using the cone beam computerized tomographic (CBCT) scan. Methodology: Case series of 60 CBCT scans of the maxillae. Results: Forty (67%) of the scans were of female patients while the rest (20, 33%) were of males. Remarkably, the majority of the scans were requested for those patients who sought dental implant fabrication. Overall, 35 (58%) scans demonstrated pathological features while 8 (13%) demonstrated significant anatomical structures. Pathological features included mucosal thickening in 26 (43%), polypoid lesions in 9 (15%), total antral opacification in 1 (2%) and foreign body in 1 (2%). The commonest anatomic feature was dental root protrusion into the maxillary sinuses in 8 (13%). Conclusion: The CBCT imaging is an important tool for investigating the maxillary sinuses for pathology and the demonstration of the associated anatomic relations.

Recurrence in node-negative advanced gastric cancer:Novel findings from an in-depth pathological analysis of prognostic factors from a multicentric series

AIM To analyze the clinicopathological characteristics of patients with both node-negative gastric carcinoma and diagnosis of recurrence during follow-up. METHODS We enrolled 41 patients treated with curative gastrectomy for p T2-4 a N0 gastric carcinoma between 1992 and 2010,who developed recurrence(Group 1). We retrospectively selected this group from the prospectively collected database of 4 centers belonging to the Italian Research Group for Gastric Cancer,and compared them with 437 p T2-4 a N0 patients without recurrence(Group 2). We analyzed lymphatic embolization,microvascular infiltration,perineural infiltration,and immunohistochemical determination of p53,Ki67,and HER2 in Group 1 and in a subgroup of Group 2(Group 2 bis) of 41 cases matched with Group 1 according to demographic and pathological characteristics. RESULTS T4 a stage and diffuse histotype were associated with recurrence in the group of p N0 patients. In-depth pathological analysis of two homogenous groups of p N0 patients,with and without recurrence during longterm follow-up(groups 1 and 2 bis),revealed two striking patterns: lymphatic embolization and perineural infiltration(two parameters that pathologists can easily report),and p53 and Ki67,represent significant factors for recurrence.CONCLUSION The reported pathological features should be considered predictive factors for recurrence and could be useful to stratify node-negative gastric cancer patients for adjuvant treatment and tailored follow-up.

Atypical clinical and pathological findings in a patient with isolated cortical vein thrombosis

Isolated cortical vein thrombosis often produces a focal lesion. Because of the rapid development of collateral circulation, increased intracranial pressure has never been reported in a patient with isolated cortical vein thrombosis. The diagnosis of isolated cortical vein thrombosis is based mainly on MRI, catheter digital subtraction angiography, and histological findings, but may be challenging. We report a patient who presented with intermittent seizures and left-sided limb weakness. Her symptoms gradually progressed, and she eventually developed signs of increased intracranial pressure. Imaging studies showed a space-occupying lesion in the right frontal lobe of the brain. As we could not diagnose isolated cortical vein thrombosis based on the preoperative findings, surgical excision of the lesion was performed under general anesthesia. Histological examination showed destruction of the brain parenchyma with infiltration of macrophages, proliferation of reactive astrocytes and small vessels, and foci of hemorrhage. Further examination found that a number of small vessels in both the subarachnoid space and brain parenchyma were filled with thrombus, some of which was organized. Elastic fiber staining showed that the obstructed vessels were veins. We diagnosed isolated cortical vein thrombosis with atypical clinical features.

Clinical pathological characteristics of“crawling-type”gastric adenocarcinoma cancer:A case report

BACKGROUND Gastric cancer(GC)is a significant health problem worldwide,and early detection and accurate diagnosis are crucial for improving patient outcomes.Crawling-type gastric adenocarcinoma is a rare subtype of GC that has unique histopathological and clinical characteristics,and its diagnosis and management can be challenging.This pathological type of GC is also rare.CASE SUMMARY Here,we report the case of a patient who underwent ordinary endoscopy,na-rrow-band imaging,and endoscopic ultrasonography intending to determine the extent of tumor invasion and upper abdominal enhanced computed tomography and whether there was tumor metastasis.Then,endoscopic submucosal dissection was performed.After pathological and immunohistochemical examination,the pathological diagnosis was crawling-type gastric adenocarcinoma.This is a very rare and special pathological type of tumor.This case highlights the importance of using advanced endoscopic techniques and pathological examination in diagnosing and managing gastric crawling-type adenocarcinoma.Moreover,the findings underscore the need for continued research and clinical experience in this rare subtype of GC to improve patient outcomes.CONCLUSION The“crawling-type”GC is a rare and specific tumor pathology.It is difficult to identify and diagnose gliomas via endoscopy.The tumor is ill-defined,with a flat appearance and indistinct borders due to the lack of contrast against the background mucosa.Pathology revealed that the tumor cells were hand-like,so the patient has diagnosed with“crawling-type”gastric adenocarcinoma.

MRI Features of Intracranial Primitive Neuroectodermal Tumors in Adults:Comparing with Histopathological Findings

The MRI appearances of 7 adult patients with pathologically proven intracranial primitive neuroectodermal tumors (PNET) were retrospectively analyzed. The MRI features were compared with findings in pathology and surgery. In this group, the tumor masses were most commonly found in the semisphere of cerebrum and in the vermis of cerebellum. They were relatively large and 4 were in lobulated shape. All of them had well defined margins. MR images showed the tumors to be mildly or obviously hypointense on T 1 weighted images and hyperintense on T 2 weighted images. Most masses had heterogeneous appearances with some cystic and necrotic areas. Intratumoral haemorrhage and focal calcification were occasionally seen. Mostly, there was no or only mild surrounding edema. Marked inhomogeneous contrast enhancement on MRI was seen in 6 cases except one. Two patients with multiple intracranial metastases were revealed on MR images. In this series, there was good correlation between MRI features and findings in pathology and surgery. These results showed that certain MRI features might suggest the diagnosis of intracranial PNET in adults. MRI is an effective technique to detect these tumors and is helpful to treatment planning and follow up.

Consistency between magnetic resonance diffusion-weighted images and pathological findings in a hyperacute cerebral infarction rabbit model

BACKGROUND： Because magnetic resonance diffusion-weighted imaging is sensitive to water molecule movement, it has particular advantages for early diagnosis of cerebral infarction. However, the relationship between apparent diffusion coefficient changes with ischemia time, particularly relative apparent diffusion coefficient and tissue pathological changes remains controversial. OBJECTIVE： To explore the correlation between apparent diffusion coefficient changes and pathologic changes in hyperacute cerebral infarction. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment of neuroimaging. The study was performed at the Laboratory of Radiology Department, Longgang Central Hospital of Shenzhen from October 2007 to October 2008. MATERIALS： Magnetic resonance scanner was purchased from Philips Medical Systems, Best, the Netherlands. METHODS： A total of 42 healthy, adult, New Zealand rabbits were randomly assigned into sham-operation, ischemia 0.5-, 1-, 2-, 3-, 4-, and 6-hour groups, with six animals in each group. Local cerebral ischemia model was established by right middle cerebral artery occlusion, and cranial MRI scanning and pathologic observation were performed, respectively, at 0.5, 1,2, 3, 4, and 6 hours following ischemia. The middle cerebral artery of sham-operation group was only exposed, but not occluded. Images at the above-mentioned time points were also collected. MAIN OUTCOME MEASURES： Apparent diffusion coefficient and relative apparent diffusion coefficient values of abnormal signal on diffusion-weighted imaging were calculated and compared with pathological changes in the ischemic region. RESULTS： No abnormal diffusion-weighted imaging signals or pathological changes were observed in the sham-operation group. Abnormal signal intensity on diffusion-weighted imaging was first observed in the 0.5-hour group. Apparent diffusion coefficient and relative apparent diffusion coefficient values decreased in all middle cerebral artery occlusion rabbits and reached lowest levels at 3 hours, followed by a gradual increase. The right ischemic basal ganglia region with high signal intensity on diffusion-weighted imaging extended with increasing time of occlusion, and the pathologic outcome corresponded with MRI changes. CONCLUSION： Relative apparent diffusion coefficient values changed regularly with ischemia time and displayed good correspondence to pathological manifestations.

Contrast investigation of multi-slice spiral CT perfusion imaging and pathological findings in VX2 soft-tissue tumor of rabbits

Objective: To perform a contrast investigation of multi-slice spiral CT (MSCT) perfusion imaging and pathological findings in VX2 soft-tissue tumor of rabbits, and discuss the applicative value of multi-slice spiral CT perfusion imaging in soft-tissue tumors. Methods: 8 Newzealand white rabbits were implanted with 0.1 ml VX2 tumor tissue suspension in bilateral proximal thighs. 14 days and 21 days later, CT plain scan and perfusion scan were performed on these rabbits respectively, then the images were transmitted to AW4.0 workstation, the functional maps and perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were computed and analyzed. Subsequently, the rabbits were sacrificed, the tumors of which were taken out for pathological examination. The correlation between MSCT functional parametric images and pathological findings was analyzed. Results: All the values of BF, BV and PS of VX2 soft-tissue tumors were obviously higher while the MTT-values were lower than those of the normal muscular tissues significantly (P<0.001). Conclusion: Multi-slice spiral CT perfusion imaging is an accurate, convenient and relatively safe functional imaging technique, which can give a quantitative assessment to blood perfusion and angiogenesis of soft-tissue tumors.

Duodenal Endoscopic and Histopathologic Findings in a COVID-19 Patient: A Case Report and Literature Review

Although COVID-19 clinical manifestations are mostly respiratory gastrointestinal manifestations may also be encountered in some instances. However, at the time of our writing, little is known about COVID-19, associated pathologic changes in the digestive system. We describe a case of COVID-19 disease with digestive manifestations that demonstrated specific pathologic changes in the gastrointestinal tract. Histological examination of endoscopic biopsy samples from duodenum was performed in combination with a review of the literature. According to our literature review, digestive histopathologic changes have been reported in 14 cases of COVID-19 patients. Pathological findings were generally nonspecific in all these cases and ranged from epithelial damage, lymphoplasmacytic and macrophages infiltrates, prominent endothelitis and ischemic enterocolitis. In our patient, histological features were more specific, characterized by several viral cytopathic effects associated with mucosal damage, numerous microthrombi and positive staining of ACE2 on various enterocytes. Histological analysis is not a practical option for the diagnosis of SARS-CoV-2 infections but could help to elucidate pathophysiology of the disease. Those changes may be specific in the GI tract and related clinical manifestations should not be overlooked. Furthermore, preventive measures for oral-fecal transmission should not be minimized.

Histopathologic findings of keratoconus corneas underwent penetrating keratoplasty according to topographic measurements and keratoconus severity

AIM： To investigate the histopathologic and morphological changes of the corneas with keratoconus（KC） undergoing penetrating keratoplasty（PKP） according to topographic findings and severity of KC.METHODS： The corneal tissue of 35 samples with KC was retrospectively evaluated with conventional light microscopy. Topographic and pachymetric parameters of keratoconus corneas by means of Pentacam such as mean keratometry（K） and central corneal thickness（CCT） were recorded. Severity of KC was graded according to Amsler-Krumeich classification. RESULTS： Epithelial thinning and breaks in Bowman＇s layer are the most common findings in keratoconus corneas（94.3% and 82.9% corneas, respectively）. The results revealed statistically significant higher mean K value and lower CCT in the keratoconus corneas that were affected by epithelial thinning, breaks in the Bowman＇s layer, folds in the Descemet＇s membrane, epithelial scars, breaks in Descemet＇s membrane, and stromal scars than those corneas without these findings（P〈0.05）. Moreover, those corneas with epithelial thinning, breaks in the Bowman＇s layer, folds in Descemet＇s membrane, epithelial scars, and stromal scars had significantly more severe disease than those corneas without these findings（P〈0.05）. The presence of the stromal and epithelial scars were associated with the higher KC severity, in which, respectively, 87.5% and 80.0% of the corneas with stromal and epithelial scars had stage 4 of the KC severity. CONCLUSION： It seems that there are some specific patterns in histologic changes of the keratoconus corneas. The presence of pathologic findings was correlatedwith thinner and steeper corneas. Epithelial or stromal scars were associated with the highest disease severity. The description of histopathologic findings of KC may help in elucidating the pathogenesis of the disease and help pathologist in differentiating KC from other corneal diseases.

Comparative analysis of CT and pathological findings of peripheral nerve sheath tumors

Objective: To improve the qualitative diagnosis of peripheral nerve sheath tumors by computed tomography (CT). Methods: CT findings of 64 cases of pathologically confirmed nerve sheath tumors were compared with the pathological findings of the tumors. Results: Low density of the tumors shown in plain CT images was related to dominating reticular structure in the tumor as found pathologically. Tumors with intact capsule found by pathological findings were shown with smooth margin in CT images. Inhomogeneous density and enhancement of the tumors in CT images was related to tumor necrosis, liquefaction and cystic degeneration, and inhomogeneous enhancement also involved the reticular structure. Conclusion: Nerve sheath tumors are characterized by distribution along the nerves, lower density than that of muscles in plain CT images, and inhomogeneous enhancement in enhanced CT, which can help differentiate nerve sheath tumors from other soft tissue tumors. When nerve sheath tumors lack distinctive CT features, the diagnoses have to depend on their pathological findings.