Clinicopathologic Features of Gastrointestinal Tract Langerhans Cell Histiocytosis.

Gastrointestinal (GI) tract involvement by Langerhans cell histiocytosis (LCH) is rare and its clinicopathologic characteristics have only been described in case reports and small series. We reviewed hematoxylin and eosin and CD1a, S100, and Langerin immunohistochemical-stained slides from 47 patients with well-documented demographic and clinical findings. Our cases included 8 children and 39 adults, with a mean follow-up of 63 months. All pediatric patients had concurrent multisystem LCH, presented with GI symptoms, and showed nonpolypoid lesions. Seven (88%) showed multifocal GI disease, including 5 with multiple GI organ involvement. All sampled lesions from children exhibited infiltrative growth. More than half had died of the disease or manifested persistent LCH at last follow-up. Twenty-five of 39 (64%) adults had LCH involving only the GI tract (single system), with the remaining 14 (36%) exhibiting multisystem disease. Adult single-system GI LCH was typically encountered incidentally on screening/surveillance endoscopy (72%). Most exhibited isolated colorectal involvement (88%) as a solitary polyp (92%), with a well-demarcated/noninfiltrative growth pattern (70%), and excellent prognosis (100%). In comparison, adult patients with multisystem LCH more frequently presented with GI symptoms (92%, P < .001), noncolorectal GI site involvement (50%, P = .02), multifocal GI lesions (43%, P = .005), nonpolypoid lesions (71%, P < .001), infiltrative histologic growth pattern (78%, P = .04), and persistent disease (57%, P < .001). Adult patients with multisystem LCH appear to exhibit similar clinicopathologic features to those of pediatric patients. These results demonstrated that adults with single-system LCH involving the GI tract have an excellent prognosis, whereas multisystem LCH occurring at any age carries an unfavorable prognosis. High-risk features of GI LCH include pediatric age, GI symptomatology, noncolorectal GI involvement, multifocal GI disease, nonpolypoid lesions, and infiltrative growth pattern.

Exacerbated ischemia-reperfusion injury in fatty livers is mediated by lipid peroxidation stress and ferroptosis.

BACKGROUND: Ischemia-reperfusion injury is a common problem in liver surgery and transplantation. Although ischemia-reperfusion injury is known to be more pronounced in fatty livers, the underlying mechanisms for this difference remain poorly understood. We hypothesized that ferroptosis plays a significant role in fatty liver ischemia-reperfusion injury due to increased lipid peroxidation in the presence of stored iron in the fatty liver. To test this hypothesis, the ferroptosis pathway was evaluated in a murine fatty liver ischemia-reperfusion injury model. METHODS: C57BL6 mice were fed with a normal diet or a high fat, high sucrose diet for 12 weeks. At 22 weeks of age, liver ischemia-reperfusion injury was induced through partial (70%) hepatic pedicle clamping for 60 minutes, followed by 24 hours of reperfusion before tissue harvest. Acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal were quantified in the liver tissues. In separate experiments, liproxstatin-1 or vehicle control was administered for 7 consecutive days before liver ischemia-reperfusion injury. RESULTS: Exacerbated ischemia-reperfusion injury was observed in the livers of high fat, high sucrose diet fed mice. High fat, high sucrose diet + ischemia-reperfusion injury (HDF+IRI) livers had a significantly greater abundance of acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal compared with normal diet + ischemia-reperfusion injury (ND+IRI) livers or sham fatty livers, which indicated an increase of ferroptosis. HFD fed animals receiving liproxstatin-1 injections had a significant reduction in serum aspartate transaminase and alanine transaminase after ischemia-reperfusion injury, consistent with attenuation of ischemia-reperfusion injury in the liver. CONCLUSION: Ferroptosis plays a significant role in ischemia-reperfusion injury in fatty livers. Inhibiting ferroptotic pathways in the liver may serve as a novel therapeutic strategy to protect the fatty liver in the setting of ischemia-reperfusion injury.

Clinical Significance and Prognostic Implications of Discontinuous Growth Pattern in Esophageal Adenocarcinoma: A Multi-Institutional Study.

The significance of discontinuous growth (DG) of the tumor to include tumor deposits and intramural metastasis in esophageal adenocarcinoma (EAC) is unclear. Esophagectomy specimens from 151 treatment-naïve and 121 treated patients with EAC were reviewed. DG was defined as discrete (≥2 mm away) tumor foci identified at the periphery of the main tumor in the submucosa, muscularis propria, and/or periadventitial tissue. Patients' demographics, clinicopathologic parameters, and oncologic outcomes were compared between tumors with DG versus without DG. DGs were identified in 16% of treatment-naïve and 29% of treated cases ( P =0.01). Age, gender, and tumor location were comparable in DG+ and DG- groups. For the treatment-naïve group, DG+ tumors were larger with higher tumor grade and stage and more frequent extranodal extension, lymphovascular/perineural invasion, and positive margin. Patients with treated tumors presented at higher disease stages with higher rates of recurrence and metastasis compared with treatment-naïve patients. In this group, DG was also associated with TNM stage and more frequent lymphovascular/perineural spread and positive margin, but not with tumor size, grade, or extranodal extension. In multivariate analysis, in all patients adjusted for tumor size, lymphovascular involvement, margin, T and N stage, metastasis, neoadjuvant therapy status, treatment year, and DG, DG was found to be an independent adverse predictor of survival outcomes in EAC. DG in EAC is associated with adverse clinicopathologic features and worse patient outcomes. DG should be considered throughout the entire clinicopathologic evaluation of treatment-naïve and treated tumors as well as in future staging systems.

Incidental findings during donor liver assessment: Single center experience.

Intraoperative consultation of donor liver is an important part of transplant evaluation and determination of liver eligibility. In this study, we describe incidental pathologic findings discovered during the pretransplant evaluation of liver donors in our Institution from 1/2010 to 12/2022. During this 13-year period 369 intraoperative consultations from 262 liver donors were performed. Of those cases, incidental findings were identified in 22 cases (5.9 %) from 19 donors (7.3 %); two donors had more than one lesion. The median age of this subset of patients was 53 years (range: 18-70) and females predominated (63 %). Sixteen of the donors had abnormal findings in the liver: 6 bile duct hamartoma (BDH), 5 hyalinized nodule with Histoplasma capsulatum, 5 focal nodular hyperplasia (FNH), 2 bile duct adenomas (BDA), 1 biliary cyst and 1 hemangioma. One donor had both FNH and a BDH. One BDH and 1 BDA case was misdiagnosed as malignancy during the frozen section evaluation. Three donors had extrahepatic pathologies: a pancreatic tail schwannoma, a low-grade appendiceal mucinous neoplasm, and a lymph node with metastatic endometrial endometrioid adenocarcinoma. Of the 19 livers, the final organ disposition was available for 9: 6 were transplanted (67 %) and 3 were discarded (33 %). Two of the 3 discarded organs were misdiagnosed BDH and BDA cases, and one was incorrectly reported as having 90 % microvesicular steatosis during the frozen assessment. We present the clinicopathologic characteristics of liver donors with incidental findings during the pre-transplant evaluation which could lead to unwarranted graft dismissal if misdiagnosed. Additionally, incidental fungal infections can have implications for immunosuppressive therapy and the decision to use or reject the graft.

Histology Shift in Esophageal Cancer Between Biopsies and Resections After Neoadjuvant Therapy: A Pilot Study.

Preoperative neoadjuvant therapy followed by resection is the mainstay treatment for locally advanced esophageal adenocarcinoma. We recently observed the histology shift from predominant esophageal adenocarcinoma in the biopsy to neuroendocrine neoplasm with or without adenocarcinoma in the post-treatment resection. The underlying mechanism of this finding is uncertain, and there is limited information in the literature. A total of 11 patients were identified: 10 patients received presurgical chemoradiation and 1 with chemotherapy. All biopsies were diagnosed with adenocarcinoma. When neuroendocrine immunomarkers were retrospectively performed on 5 biopsies, 2 showed focal positivity, although the classic neuroendocrine morphology was not readily appreciated. All resections contained neuroendocrine neoplasm, including 8 of well-differentiated type and 3 of neuroendocrine carcinomas. Two post-treatment esophagectomies consisted of neuroendocrine neoplasm only without residual adenocarcinoma. Upon follow-up, 8 patients died of the disease (median survival = 26 months), and 3 patients were alive after a median follow-up of 14 months. The overall median survival time was better than the reported esophageal neuroendocrine carcinoma (15 months). The 5-year observed survival rate was 11.3%, which was lower than the Surveillance, Epidemiology, and End Results 5-year survival rate of adenocarcinoma (21.8%). We reported a small series of esophageal adenocarcinoma that showed histology shift between biopsy and esophagectomy after neoadjuvant therapy. Our limited data suggest that prognosis of this group is different than the conventional adenocarcinoma. Awareness of this morphological change reminds pathologists to examine the biopsy specimens thoroughly, because recognition of neuroendocrine neoplasm, especially high-grade neuroendocrine component, might potentially affect pre- and post-surgical regimens.

Colitis as the Initial Presentation of Eosinophilic Granulomatosis with Polyangiitis.

A male patient in his early sixties with recurrent diarrhea was transferred to our hospital. The patient did not have any pulmonary or upper respiratory symptoms. He was noted to have peripheral eosinophilia. Further workup revealed a negative antineutrophilic cytoplasmic antibody titer but a positive myeloperoxidase antibody and positive proteinase 3 antibodies. A colon biopsy also revealed eosinophilic-rich granulomas in the mucosa, confirming a diagnosis of eosinophilic granulomatosis with polyangiitis. On cardiac imaging, eosinophilic myocarditis was also discovered. To treat active severe EGPA, the patient received high-dose corticosteroids and intravenous cyclophosphamide. The occurrence of gastrointestinal involvement as an initial manifestation of eosinophilic granulomatosis with polyangiitis is infrequent, emphasizing the significance of its recognition. This case underscores the importance of identifying and diagnosing such atypical presentations to facilitate timely and appropriate management.

Primary and secondary angiosarcomas of the liver: a multi-institutional study of 32 cases.

Angiosarcomas involving the liver can be hepatic primary or metastasis from another anatomic site, which have not been systematically compared. We analyzed a series of liver biopsy or resection specimens carrying a diagnosis of angiosarcoma collected between 2005 and 2022 at 3 tertiary medical centers. The cohort included 32 patients (20 M and 12 F) with a median age of 64 years. Nineteen were primary hepatic angiosarcoma (PHA) and 13 metastatic angiosarcoma to liver (MA). Males were predominant in PHA (15/19, 78%) compared to MA (5/13, 38%, P = .025). There was no age difference between the 2 groups. Five cases had background hepatic cirrhosis, which more likely harbored PHA (4/5, 80%). Multifocality and multiorgan involvement were common in both groups. Tumor size was significantly larger in PHA than in MA (10.4 versus 4.7 cm, P < .01). Histologically, there were no differences in terms of tumor morphology (spindled versus epithelioid) and growth patterns (vasoformative versus solid) between the 2 groups. Immunohistochemically, all tumor cells were positive for CD31 (28/28, 100%) and ERG (18/18, 100%). Molecular analysis in 5 cases demonstrated different mutation profiles involving different genes, including MTOR, PIK3CA, ARID1A, CDKN2A, PTEN, TP53, ATRX, KDR/VEGFR2, and so forth. On follow-up, 30 patients (93%) died of disease, with a median survival of 114 days. Univariate and multivariate analyses revealed PHA and epithelioid morphology to be associated with worse survival (P < .05), while treatment was associated with better survival (P < .001). Our results confirmed that angiosarcoma, particularly PHA, is extremely aggressive. Epithelioid morphology is an adverse prognosticator and may be used for tumor subclassification.

Adenovirus-Related Fulminant Liver Failure After Kidney Transplantation.

BACKGROUND Human adenovirus is a well-known pathogen that can potentially lead to severe infection in immunocompromised patients. Adenovirus infections in solid-organ transplant recipients can range from asymptomatic to severe, prolonged, disseminated disease, and have a significant impact on morbidity, mortality, and graft survival. The clinical manifestations vary from asymptomatic and flu-like illness to severe life-threatening viremia with multi-organ failure. Post-transplant adenovirus infection is well described in kidney recipients, but in adult liver transplant recipients the impact of the virus is not well described. In this report, a case of disseminated adenovirus infection with subsequent fatal acute liver failure in a post-kidney transplant patient is presented. CASE REPORT A 51-year-old man underwent a deceased kidney transplantation for focal segmental glomerulosclerosis. Shortly after the kidney transplantation, he received multiple plasmapheresis with additional steroid treatments for cellular rejection and reoccurrence of his primary kidney disease. Three weeks after the kidney transplant, he developed a disseminated adenovirus infection with subsequent acute liver failure. Despite the early diagnosis and aggressive treatment, the patient died. CONCLUSIONS Patients with organ transplantation with autoimmune background etiology are usually over-immunosuppressed to avoid early rejection. In this population, opportunistic infections are not rare. Fever, general malaise, and transplant organ dysfunction are the first signs of bacterial or viral infection. Early infectious diseases work-up, including tissue biopsy, is fundamental to establish a diagnosis. Broad antibiotic and possible antiviral aggressive treatment are mandatory.

Nrf2 deficiency causes hepatocyte dedifferentiation and reduced albumin production in an experimental extrahepatic cholestasis model.

The transcription factor Nrf2 modulates the initiation and progression of a number of diseases including liver disorders. We evaluated whether Nrf2 mediates hepatic adaptive responses to cholestasis. Wild-type and Nrf2-null mice were subjected to bile duct ligation (BDL) or a sham operation. As cholestasis progressed to day 15 post-BDL, hepatocytes in the wild-type mice exhibited a tendency to dedifferentiate, indicated by the very weak expression of hepatic progenitor markers: CD133 and tumor necrosis factor-like weak induced apoptosis receptor (Fn14). During the same period, Nrf2 deficiency augmented this tendency, manifested by higher CD133 expression, earlier, stronger, and continuous induction of Fn14 expression, and markedly reduced albumin production. Remarkably, as cholestasis advanced to the late stage (40 days after BDL), hepatocytes in the wild-type mice exhibited a Fn14+ phenotype and strikingly upregulated the expression of deleted in malignant brain tumor 1 (DMBT1), a protein essential for epithelial differentiation during development. In contrast, at this stage, hepatocytes in the Nrf2-null mice entirely inhibited the upregulation of DMBT1 expression, displayed a strong CD133+/Fn14+ phenotype indicative of severe dedifferentiation, and persistently reduced albumin production. We revealed that Nrf2 maintains hepatocytes in the differentiated state potentially via the increased activity of the Nrf2/DMBT1 pathway during cholestasis.

Metastatic Cancer of Apparent Colon Origin With No Intraluminal Cancer After Resection of Colorectal Lateral Spreading Lesions.

We report a case of metastatic adenocarcinoma to the liver that presented 5 months after piecemeal endoscopic mucosal resection of 3 benign lateral spreading adenomas in the cecum. The pathologic features of the metastatic cancer indicated a probable colonic origin. However, when the cancer was identified, there was no endoscopic evidence of recurrent polyp or another primary lesion in the colon.

The Histopathologic Features of Sickle Cell Hepatopathy: A Multi-Institutional Study.

OBJECTIVES: Recent data on hepatic histopathology in patients with sickle cell disease (SCD) are lacking. METHODS: A total of 39 liver biopsies from SCD patients from 4 medical institutes were systematically evaluated. RESULTS: The average age of patients was 27 years; 23 were female. The majority of the patients had hemoglobin SS (33), 3 had hemoglobin SC, and 3 sickle cell trait. Elevated liver functional tests and evaluation for cirrhosis were the main indications for biopsy. At the time of biopsy, most had elevated liver transaminases or hepatomegaly. The most common histopathologic abnormalities were Kupffer cell erythrophagocytosis (76.9%), hemosiderosis (74.4%), sinusoidal dilatation (71.8%), and intrasinusoidal sickled red cells (69.3%). Portal inflammation, lobular inflammation, and bile duct injury were mild to minimal and present in a minority of cases. Advanced fibrosis was present in 28.2% of the cases. CONCLUSIONS: The typical histopathologic features seen in patients with SCD include Kupffer cell erythrophagocytosis, hemosiderosis, sinusoidal dilatation, and intrasinusoidal sickled red cells in a pauci-inflammatory or uninflamed background. Necrosis is less common than reported in older literature. Pathologists should be aware that significant portal and lobular inflammation, interface activity, and bile duct injury are unusual and may be suggestive of other etiologies.

Splenic-vasculature involvement is associated with poor prognosis in resected distal pancreatic cancer.

BACKGROUND: Distal pancreatic carcinoma is one of the most lethal cancers largely due to its high incidence of distant metastasis. This study aims to assess the prognostic value of splenic-vasculature involvement in resected distal pancreatic carcinoma. METHODS: In this retrospective study, we collected the clinicopathologic information of 454 patients with pancreatic cancer and performed univariate and multivariate analyses to identify factors associated with progression-free survival (PFS) and overall survival (OS), with an emphasis on the prognostic value of splenic-artery and -vein involvement. RESULTS: Univariate analysis revealed that larger tumor size, non-intraductal papillary mucinous neoplasm (non-IPMN)-associated adenocarcinoma, poor differentiation, stage pT3, nodal metastasis, lymphovascular invasion, perineural invasion, and pathologic and radiographic evidence of splenic-vein invasion were significantly associated with shorter PFS and OS (all P < 0.05). Multivariate analysis confirmed non-IPMN-associated adenocarcinoma, stage pT3, stage pN1-2, and post-operative adjuvant chemotherapy as independent risk factors for both PFS and OS, and larger tumor size and radiographic evidence of splenic-artery invasion as predictors of PFS only. CONCLUSION: Guidelines should be developed for a uniform approach with regard to the examination and reporting of the status of the splenic vasculature when dealing with distal-pancreatic-cancer specimens.

Characterization of Chronic Gastritis in Lynch Syndrome Patients With Gastric Adenocarcinoma.

BACKGROUND: Gastric cancer is one of the Lynch syndrome (LS)-associated malignancies. Previous studies have suggested that LS patients with gastric cancer also had chronic atrophic gastritis in the background mucosa, but further histologic characterization was not attempted. This study aims to understand the histologic features of background chronic gastritis in LS patients with gastric adenocarcinoma. METHODS: Eleven LS-associated gastric cancer cases were collected from five institutions. Demographics and clinical features were retrieved by review of medical charts. Pathological material was reviewed for tumor location and histologic type. In addition, non-neoplastic gastric mucosa was assessed for inflammation (chronic and active), atrophy, intestinal metaplasia (IM) in the antrum and body, as well as pyloric gland metaplasia and enterochromaffin-like (ECL) cell hyperplasia in the body. RESULTS: Eleven LS patients with gastric cancer (four male and seven female) with a mean age of 63 years (range: 23 - 83) were included. Ten (90.9%) had personal cancer histories; however none of the patients had family history of gastric cancer. Eight (72.7%) patients underwent gastrectomy and three had endoscopic resection. Nine (81.8%) patients had tumor in the fundus and/or body and two had tumor present in the antrum. Seven (63.6%) cases were intestinal type or mixed type carcinoma, and the remaining four were signet ring cell carcinoma. Eight (of 11, 72.7%) patients had chronic gastritis, five (45.4%) had atrophy, and four (36.3%) had intestinal metaplasia. Four of five patients with both antrum and body mucosa available for evaluation (80%), demonstrated body-predominant chronic gastritis. Four patients had germline MLH1 alterations and all of these patients had chronic gastritis, including one Helicobacter pylori (H. pylori) gastritis and three H. pylori-negative gastritis. CONCLUSIONS: None of LS patients with gastric cancer in our cohort had a family history of gastric cancer. Gastric adenocarcinomas in LS patients were primarily located in the fundus and/or body. Two-thirds of these tumors were of intestinal type and had a background chronic, H. pylori-negative gastritis. These results support a chronic atrophic gastritis with intestinal metaplasia-dysplasia-carcinoma sequence in LS-related gastric tumorigenesis, particularly in MLH1-mutated LS patients.

Allograft Necrosis in Liver Biopsy Is Predictive for Organ Outcome and Patient Survival.

AIM: To evaluate if any association existed between the extent of allograft necrosis in liver biopsy and patient survival. METHODS: Sixty-nine patients who had 70 liver transplantations with allograft necrosis were included in the study. Correlations of necrosis, the Model for End-Stage Liver Disease (MELD) score, and allograft survival were analyzed. RESULTS: Allograft failure rate within 1 month after index biopsy was worse in patients with a higher extent of necrosis (2.5%, 12.5%, 25%, and 40% in groups with allograft necrosis of 1-25%, 26-50%, 51-75%, and >75%, respectively). Adequate biopsy with more than 50% necrosis is associated with significant allograft failure (P <.001). The MELD scores did not always accurately predict fatality that was caused by massive necrosis. In the absence of substantial clinical changes, repetition of allograft biopsy within a short period of time did not provide additional value. Among patients with more than 75% allograft necrosis, one who received an immediate second transplantation survived and 3 out of 9 patients who had not received those deceased within 1 month. CONCLUSIONS: Allograft necrosis demonstrates strong predictive power in organ and patient survival. Additionally, biopsy-proven allograft necrosis unequivocally pinpoints ischemia as the direct cause of allograft failure, which facilitates clinical management. Immediate retransplantation is crucial for patients with substantial allograft necrosis.

Reproducibility of AJCC Criteria for Classifying Deeply Invasive Colon Cancers Is Suboptimal for Consistent Cancer Staging.

The eighth edition of the American Joint Committee on Cancer (AJCC) Staging Manual attempts to address ambiguity in the pT category assignment for colon cancer from prior editions. Despite modifications, the distinction between the pT3 and pT4a categories continues to be a source of diagnostic confusion. In this study, we assessed interobserver agreement among pathologists from different institutions in the application of AJCC eighth edition criteria for categorizing deeply invasive colonic adenocarcinomas. We identified morphologic patterns that produce diagnostic confusion. We assessed 47 colon cancers that closely approached the serosal surface. Six pathologists with interest in gastrointestinal pathology and 4 focused in other subspecialties classified each case as pT3 or pT4a, based on examination of low-magnification and high-magnification images of the most deeply invasive area. Interobserver agreement was assessed using Fleiss' κ. Cases displayed 3 morphologic patterns at the advancing tumor edge, namely, (1) continuous invasion through an inflammatory focus, (2) pushing border, and (3) infiltrative glands and cell clusters with serosal reaction. Gastrointestinal pathologists achieved slight (κ=0.21) or moderate (κ=0.46) and (κ=0.51) agreement in each category, whereas agreement among nongastrointestinal pathologist was fair (0.31) and (0.39), or moderate (0.57) for each category, respectively. In 10 (21%) cases, the distinction between pT3 and pT4a would have changed the overall clinical stage. We conclude that histologic criteria for serosal penetration is a persistent source of diagnostic ambiguity for gastrointestinal and general pathologists in the pT categorization of colon cancers. Clarification of these criteria will help ensure uniform reporting of pathologic and clinical stage.

Feasibility, Process, and Effects of Short-Term Calorie Reduction in Cancer Patients Receiving Chemotherapy: An Integrative Review.

Recent preclinical studies have shown the potential benefits of short-term calorie reduction (SCR) on cancer treatment. In this integrative review, we aimed to identify and synthesize current evidence regarding the feasibility, process, and effects of SCR in cancer patients receiving chemotherapy. PubMed, Cumulative Index to Nursing and Allied Health Literature, Ovid Medline, PsychINFO, and Embase were searched for original research articles using various combinations of Medical Subject Heading terms. Among the 311 articles identified, seven studies met the inclusion criteria. The majority of the reviewed studies were small randomized controlled trials or cohort study with fair quality. The results suggest that SCR is safe and feasible. SCR is typically arranged around the chemotherapy, with the duration ranging from 24 to 96 h. Most studies examined the protective effects of SCR on normal cells during chemotherapy. The evidence supports that SCR had the potential to enhance both the physical and psychological wellbeing of patients during chemotherapy. SCR is a cost-effective intervention with great potential. Future well-controlled studies with sufficient sample sizes are needed to examine the full and long-term effects of SCR and its mechanism of action.

Validation of American Joint Committee on Cancer 8th edition of TNM staging in resected distal pancreatic cancer.

BACKGROUND: In order to improve risk stratification and clinical management of the pancreatic ductal adenocarcinoma (PDAC), the American Joint Committee on Cancer (AJCC) has published its eighth edition staging manual. Some major changes have been introduced in the new staging system for both T and N categories. Given the rarity of resectable disease, distal pancreatic cancer is likely underrepresented in the published clinical studies, and how the impact of the staging system actually reflects on to clinical outcomes remain unclear. AIM: To validate the AJCC 8th edition of TNM staging in distal PDAC. METHODS: A retrospective cohort study was performed in seven academic medical centers in the United States. Clinicopathological prognostic factors associated with progression-free survival (PFS) and overall survival (OS) were evaluated through univariate and multivariate analyses. RESULTS: Overall, 454 patients were enrolled in the study, and were divided into 2 subgroups: Invasive intraductal papillary mucinous neoplasms (IPMN) (115 cases) and non-IPMN associated adenocarcinoma (339 cases). Compared to invasive IPMN, non-IPMN associated adenocarcinomas are more common in relatively younger patients, have larger tumor size, are more likely to have positive lymph nodes, and are associated with a higher tumor (T) stage and nodal (N) stage, lymphovascular invasion, perineural invasion, tumor recurrence, and a worse PFS and OS. The cohort was predominantly categorized as stage 3 per AJCC 7th edition staging manual, and it's more evenly distributed based on 8th edition staging manual. T and N staging of both 7th and 8th edition sufficiently stratify PFS and OS in the entire cohort, although dividing into N1 and N2 according to the 8th edition does not show additional stratification. For PDAC arising in IPMN, T staging of the 7th edition and N1/N2 staging of the 8th edition appear to further stratify PFS and OS. For PDAC without an IPMN component, T staging from both versions fails to stratify PFS and OS. CONCLUSION: The AJCC 8th edition TNM staging system provides even distribution for the T staging, however, it does not provide better risk stratification than previous staging system for distal pancreatic cancer.

STAT6 Expression in Solitary Fibrous Tumor and Histologic Mimics: a Single Institution Experience.

STAT6 stain has proved to be a good surrogate marker for the genetic alteration (NAB2-STAT6 gene fusion) in solitary fibrous tumor (SFT). This study aims to validate the use of STAT6 rabbit monoclonal antibody in differentiating SFT from its histologic mimics. Forty-five cases of SFT and 110 cases from 9 other spindle cell tumors were collected for STAT6 immunostaining. Positive nuclear STAT6 staining was present in all 45 SFT cases (100% sensitivity). No nuclear staining was identified in other spindle cell neoplasms (0/13, dedifferentiated liposarcoma; 0/17, synovial sarcoma; 0/16, malignant peripheral nerve sheath tumors; 0/25, undifferentiated pleomorphic sarcoma; 0/10, dermatofibrosarcoma protuberans; 0/9, low-grade fibromyxoid sarcoma; 0/6, angiofibroma; 0/5, deep fibromatosis; 0/9, gastrointestinal tumor). The STAT6 staining in SFT was usually diffuse (5+ in 19 cases; 4+ in 17 cases) and strong (40 cases). Monoclonal STAT6 stain is highly sensitive and specific for SFTs and particularly useful in the diagnosis of difficult SFT cases.