Background: Most testicular germ cell tumors arise from intratubular germ cell neoplasia unclassified (IGCNU, also referred to as carcinoma in situ), which is thought to originate from a transformed primordial germ cell (PGC)/gonocyte, the fetal germ cell. Analyses of the molecular profile of IGCNU and seminoma show similarities to the expression profile of fetal germ cells/gonocytes. In murine PGCs, expression and interaction of Blimp1 and Prmt5 results in arginine 3 dimethylation of histone H2A and H4. This imposes epigenetic modifications leading to transcriptional repression in mouse PGCs enabling them to escape the somatic differentiation program during migration, while expressing markers of pluripotency. Results: In the present study, we show that BLIMP1 and PRMT5 were expressed and arginine dimethylation of histones H2A and H4 was detected in human male gonocytes at weeks 12–19 of gestation, indicating a role of this mechanism in human fetal germ cell development as well. Moreover, BLIMP1/PRMT5 and histone H2A and H4 arginine 3 dimethylation was present in IGCNU and most seminomas, while downregulated in embryonal carcinoma (EC) and other nonseminomatous tumors. Conclusion: These data reveal similarities in marker expression and histone modification between murine and human PGCs. Moreover, we speculate that the histone H2A and H4 arginine 3 dimethylation might be the mechanism by which IGCNU and seminoma maintain the undifferentiated state while loss of these histone modifications leads to somatic differentiation observed in nonseminomatous tumors.

Background Occasionally patients undergoing resection for presumed malignancy of the pancreatic head are diagnosed postoperatively with benign disease. Autoimmune pancreatitis (AIP) is a rare disease that mimics pancreatic cancer. We aimed to determine the prevalence of benign disease and AIP in patients who underwent pancreatoduodenectomy (PD) over a 9-year period, and to explore if and how surgery could have been avoided. Methods All patients undergoing PD between 2000 and 2009 in a tertiary referral centre were analyzed retrospectively. In cancer-negative cases, postoperative diagnosis was reassessed. Preoperative index of suspicion of malignancy was scored as non-specific, suggestive, or high. In AIP patients, diagnostic criteria systems were checked. Results A total of 274 PDs were performed for presumed malignancy. The prevalence of benign disease was 8.4 %, overall prevalence of AIP was 2.6 %. Based on preoperative index of suspicion of malignancy, surgery could have been avoided in 3 non-AIP patients. All AIP patients had sufficient index to justify surgery. If diagnostic criteria would have been checked; however, surgery could have been avoided in one to five AIP patients. Conclusions The prevalence of benign disease in patients who underwent PD for presumed malignancy was 8.4 %, nearly one-third attributable to AIP. Although misdiagnosis of AIP as carcinoma is a problem of limited quantitative importance, every effort to establish the correct diagnosis should be undertaken considering the major therapeutic consequences. IgG4 measurement and systematic use of diagnostic criteria systems are recommended for every candidate patient for PD when there is no histological proof of malignancy.

Background and study aims: Serrated polyps of the large intestine comprise a heterogeneous group of lesions with distinct histological and malignant features. The aim of the study was to estimate the prevalence of serrated polyp subtypes in a cohort of individuals undergoing screening colonoscopy, and to identify associations between the detection of serrated polyp subtypes and advanced neoplasia. Patients and methods: Data on serrated polyps, adenomas, and cancers were collected from participants of a randomized screening trial that compared colonoscopy with computed tomography colonography. Only data from participants in the colonoscopy arm were used. Logistic regression analyses were performed to identify associations between patients’ age, sex, and prevalence of the different types of serrated polyps and to identify associations between the detection of these polyps and advanced neoplasia (defined as an adenoma ≥ 10 mm, villous component, high grade dysplasia or colorectal cancer). Results: A total of 1426 screen-naïve individuals (51 % male) with a median age of 60 years (IQR 55 – 65) were included. The prevalence of hyperplastic polyps, sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs) was 23.8 %, 4.8 %, and 0.1 %, respectively. SSA/Ps comprised 7.3 % of all polyps. No differences based on age or sex were observed in the prevalence of SSA/Ps. Proximal and large (≥ 10 mm) hyperplastic polyps, as well as proximal and large (≥ 10 mm) SSA/Ps, were associated with synchronous advanced neoplasia. Conclusions: Serrated polyps, including SSA/Ps, were frequently encountered in routine screening colonoscopies. Large and proximal hyperplastic polyps, as well large and proximal SSA/Ps, were associated with advanced neoplasia.

OBJECTIVE: Several diagnostic scoring systems for autoimmune pancreatitis (AIP) have been proposed including the Asian, HISORt (Histology, Imaging, Serology, Other organ involvement and Response to therapy), and International Consensus Diagnostic Criteria (ICDC), which have been compared by a few studies. We evaluated the diagnostic performance of these criteria in patients diagnosed with AIP between May 1992 and August 2011. METHODS: Scoring systems were applied retrospectively using data obtained in the initial evaluation period, before pancreatic resection was performed. RESULTS: One hundred fourteen cases with AIP were included. Eighty-two percent met the diagnostic criteria for AIP according to either the Asian, HISORt, or ICDC criteria. Only 33% met the Asian criteria, probably mainly related to a low rate of diagnostic pancreatography. In 18%, all scoring systems failed to confirm the diagnosis, even though these patients were considered to have a firm diagnosis of AIP. CONCLUSIONS: In this cohort of AIP patients, the 3 major diagnostic scoring systems for AIP proved to be complementary rather than overlapping. Our data indicate that one-fifth of our AIP patients do not meet any of these scoring systems. The ICDC, Asian, and HISORt criteria should be considered as useful clinical tools but not as criterion standard for the diagnosis. Copyrigh

Endoscopic Ultrasound, Official publication of Euro-EUS Scientific Committee, Asia-Pacific EUS Task Force,China