Dome-type carcinoma of the rectum mimicking a submucosal tumor: a case report and literature review.

Dome-type carcinoma (DC) has been recognized as a rare variant of adenocarcinoma, which arises in gut-associated lymphoid tissue. It has a specific morphologic feature of a dome-like protrusion associated with lymphoid tissue. We report a case of a DC of the rectum in an asymptomatic 58-year-old male. A 2-cm sized, well-demarcated, round mass masquerading as a submucosal tumor (SMT) was identified in the rectum and was resected by endoscopic submucosal dissection. The tumor was revealed as an adenocarcinoma with submucosal invasion of 3,700 µm, which consisted of dilated cystic glands and the lymphoid stroma with reactive germinal centers. On immunohistochemistry, the tumor cells revealed retained expression for mismatch repair proteins. Laparoscopic surgical resection was subsequently performed. DC is considered a distinctive subtype of colorectal adenocarcinoma with characteristic morphology and low-grade malignant potential. Careful detection of the overlying mucosal lesion is crucial to differentially diagnose DC from SMT.

Expression of Insulin-like Growth Factor II mRNA-binding Protein 3 in Gallbladder Carcinoma.

BACKGROUND/AIM: Emerging evidence suggests that Insulin-like growth factor II mRNA-binding protein 3 (IMP3) promotes tumor progression in several human malignancies. We investigated whether IMP3 expression has clinicopathological and prognostic significance in gallbladder adenocarcinoma (GBAC). PATIENTS AND METHODS: We examined immunohistochemical IMP3 expression in 204 GBACs and its associations with clinicopathological parameters and patient outcomes. RESULTS: The majority (87.7%) of GBACs exhibited at least focal cytoplasmic and membranous IMP3 immunoreactivity. Tumor-specific IMP3 expression highlighted proper muscle invasion, which was not detected in the corresponding hematoxylin and eosin-stained slides. This finding upgraded pathological tumor stage (pT) from pT1a to pT1b in four well-differentiated GBACs. High IMP3 expression was associated with high histological grade, advanced stage, and lymphatic invasion, as well as worse overall survival. CONCLUSION: Tumor-specific IMP3 expression in GBAC is helpful in determining the tumor extent, especially in well-differentiated tumors. High IMP3 expression reflects aggressive oncogenic behavior of GBAC. IMP3 expression may be used as a diagnostic and prognostic marker in GBAC.

Adenocarcinoma and Neuroendocrine Collision Tumor in a Giant Gastric Hyperplastic Polyp.

Screening esophagogastroduodenoscopy of a 65-year-old man revealed a 4.7-cm polypoid in the gastric high body. Clinical and laboratory findings, including serum gastrin level (460 pg/mL) and biopsy findings, were consistent with a diagnosis of type I neuroendocrine tumor (NET). Histologically, the mass consisted of dilated tortuous glands at the surface and grade 1 NET in deeper tissue. Some hyperplastic glands exhibited a transition to adenocarcinoma, which invaded the NET, simulating a "tumor in tumor" appearance. Next-generation sequencing revealed that the adenocarcinoma component harbored a TP53 mutation, whereas the NET component showed no pathogenic mutation. To our knowledge, this unusual collision of adenocarcinoma and NET within a single gastric hyperplastic polyp has not been previously described. This case suggests that large gastric hyperplastic polyps should be carefully examined because of the possibility of underlying NET and malignant transformation of surface epithelium.

Pancreatic High-Grade Neuroendocrine Neoplasms in the Korean Population: A Multicenter Study.

PURPOSE: The most recent 2017 World Health Organization (WHO) classification of pancreatic neuroendocrine neoplasms (PanNENs) has refined the three-tiered 2010 scheme by separating grade 3 pancreatic neuroendocrine tumors (G3 PanNETs) from poorly differentiated pancreatic neuroendocrine carcinomas (PanNECs). However, differentiating between G3 Pan- NETs and PanNECs is difficult in clinical practice. MATERIALS AND METHODS: Eighty-two surgically resected PanNENs were collected from 16 institutions and reclassified according to the 2017 WHO classification based on the histological features and proliferation index (mitosis and Ki-67). Immunohistochemical stains for ATRX, DAXX, retinoblastoma, p53, Smad4, p16, and MUC1 were performed for 15 high-grade PanNENs. RESULTS: Re-classification resulted in 20 G1 PanNETs (24%), 47 G2 PanNETs (57%), eight G3 well-differentiated PanNETs (10%), and seven poorly differentiated PanNECs (9%). PanNECs showed more frequent diffuse nuclear atypia, solid growth patterns and apoptosis, less frequent organoid growth and regular vascular patterns, and absence of low-grade PanNET components than PanNETs. The Ki-67 index was significantly higher in PanNEC (58.2%± 15.1%) compared to G3 PanNET (22.6%±6.1%, p < 0.001). Abnormal expression of any two of p53, p16, MUC1, and Smad4 could discriminate PanNECs from G3 PanNETs with 100% specificity and 87.5% sensitivity. CONCLUSION: Histological features supporting the diagnosis of PanNECs over G3 PanNETs were the absence of a low-grade PanNET component in the tumor, the presence of diffuse marked nuclear atypia, solid growth pattern, frequent apoptosis and markedly increased proliferative activity with homogeneous Ki-67 labeling. Immunohistochemical stains for p53, p16, MUC1, and Smad4 may be helpful in distinguishing PanNECs from G3 PanNETs in histologically ambiguous cases, especially in diagnostic practice when only small biopsied tissues are available.

Standardized Pathology Report for Colorectal Cancer, 2nd Edition.

The first edition of the 'Standardized Pathology Report for Colorectal Cancer,' which was developed by the Gastrointestinal Pathology Study Group (GIP) of the Korean Society of Pathologists, was published 13 years ago. Meanwhile, there have been many changes in the pathologic diagnosis of colorectal cancer (CRC), pathologic findings included in the pathology report, and immunohistochemical and molecular pathology required for the diagnosis and treatment of colorectal cancer. In order to reflect these changes, we (GIP) decided to make the second edition of the report. The purpose of this standardized pathology report is to provide a practical protocol for Korean pathologists, which could help diagnose and treat CRC patients. This report consists of "standard data elements" and "conditional data elements." Basic pathologic findings and parts necessary for prognostication of CRC patients are classified as "standard data elements," while other prognostic factors and factors related to adjuvant therapy are classified as "conditional data elements" so that each institution could select the contents according to the characteristics of the institution. The Korean version is also provided separately so that Korean pathologists can easily understand and use this report. We hope that this report will be helpful in the daily practice of CRC diagnosis.

Tumor-specific Expression of Insulin-like Growth Factor II mRNA-binding Protein 3 Independently Predicts Worse Survival of Patients With Adenocarcinoma of the Ampulla of Vater.

BACKGROUND/AIM: Insulin-like growth factor II mRNA-binding protein 3 (IMP3) plays an important role in the adhesion, invasion, and metastasis of tumor cells. Although emerging evidence suggests that IMP3 promotes tumor progression in several malignancies, the expression of IMP3 and its prognostic implication in adenocarcinoma of the ampulla of Vater (AVAC) has not been clarified to date. MATERIALS AND METHODS: The IMP3 expression status in 87 AVAC tissues was examined using immunostaining, and its association with various clinicopathological features and outcome of patients with AVAC was investigated. RESULTS: The vast majority (87.4%) of AVAC cases displayed at least focal cytoplasmic and membranous IMP3 immunoreactivity in tumor cells, whereas IMP3 expression was consistently absent from normal biliary epithelial cells. Tumor-specific IMP3 expression was associated with submucosal and pancreatic invasion, which were not identified in the corresponding hematoxylin and eosin-stained slides. This finding led to up-staging of the pathological tumor stage in two cases of well-differentiated AVAC. In addition, high IMP3 expression was significantly associated with a poorly differentiated histology (p=0.026). Survival analyses revealed that high IMP3 expression independently predicted shorter recurrence-free (p=0.003) and overall (p=0.029) survival. CONCLUSION: Our study demonstrated tumor-specific IMP3 expression in AVAC, which will be helpful in determining invasion depth and tumor extent in patients with well-differentiated tumors, as well as indicating worse survival of patients with AVAC. Our data highlight IMP3 expression status as a potential diagnostic and prognostic marker for AVAC.

True cytomegalovirus colitis is a poor prognostic indicator in patients with ulcerative colitis flares: the 10-year experience of an academic referral inflammatory bowel disease center.

Background and aims: The impact of cytomegalovirus (CMV) colitis on long-term outcomes of ulcerative colitis (UC) flares remains controversial. Methods: A total of 257 UC patients with moderate-to-severe flares were observed for a mean follow-up of 41.2 months. CMV colitis was defined as histopathologic confirmation of CMV inclusions obtained from macroscopic endoscopic lesions in patients with UC flares. An independent gastrointestinal pathologist prospectively reviewed all specimens. A poor outcome was defined as any of hospitalization, colectomy or death during the follow-up period. Results: The prevalence of CMV colitis was 14% (36/257) over the 10-year study period (2007-2016). When compared to the controls, patients with CMV colitis were characterized by older age, higher disease activity, endoscopic deep ulcerations and more frequent use of immunosuppressive drugs (all p < .05). In total, 57 outcome events (50 hospitalizations, seven colectomies) were observed among the study population (44.7% in patients with CMV colitis vs. 18.9% in controls). The cumulative probability of a poor outcome was significantly greater in the patients with CMV colitis than in the controls (log-rank test p < .001). In a multivariable analysis, CMV colitis remained as an independent predictor of a poor outcome (hazard ratio; 2.27; 95% confidence interval: 1.12-4.60). Despite a generally favorable response to antiviral therapy (79%), the risk of recurrent CMV colitis remained quite high (57%). Most of the recurrences developed within 8 months (75%). Conclusions: True CMV colitis is a poor prognostic indicator among patients with UC flares. An effective strategy for managing recurrent CMV colitis is urgently needed (KCT0003296).

Stromal p16 Overexpression in Gastric-type Mucinous Carcinoma of the Uterine Cervix.

BACKGROUND/AIM: Gastric-type mucinous carcinoma (MC-G) of the uterine cervix displays distinct morphological features and an aggressive clinical course. The expression status of p16 in the stroma has not been investigated in adenocarcinoma of the uterine cervix. Stromal p16 expression was evaluated in endocervical adenocarcinomas, including usual-type endocervical adenocarcinoma (UEA), intestinal-type mucinous carcinoma (MC-I), and MC-G. Whether stromal p16 expression varied significantly according to the histological subtype and whether the expression status is associated with clinicopathological characteristics of MC-G was also investigated. MATERIALS AND METHODS: Immunostaining of p16 was performed for 24, 19, and 18 cases of UEA, MC-I, and MC-G, respectively. RESULTS: UEA and MC-I subtypes exhibited horizontally continuous, strong nuclear p16 immunoreactivity in the tumor cells, whereas none of the MC-G cases showed diffuse and strong nuclear immunoreactivity for p16 in the tumor cells. Instead, 10 (55.6%) cases of MC-G displayed moderately to strongly positive p16 expression in the stroma. Stromal p16 expression of MC-G was significantly higher than that of normal cervix, UEA, and MC-I. Metastatic MC-G had significantly higher stromal p16 expression than primary MC-G. Further, stromal p16 overexpression in MC-G was associated with advanced stage, parametrial invasion, and lymphovascular invasion. CONCLUSION: Stromal p16 expression of MC-G was significantly higher than that of normal cervix and other histological subtypes of adenocarcinoma and was associated with advanced stage, parametrial invasion, and lymphovascular invasion, reflecting the aggressive behavior of MC-G. Our observations suggest that stromal p16 expression is involved in the development and progression of MC-G.

Dynamic enhanced computed tomography imaging findings of an inflammatory fibroid polyp with massive fibrosis in the stomach.

Inflammatory fibroid polyp (IFP) is a rare benign lesion of the gastrointestinal tract. We report a case of computed tomography (CT) imaging finding of a gastric IFP with massive fibrosis. CT scans showed thickening of submucosal layer with overlying mucosal hyperenhancement in the gastric antrum. The submucosal layer showed increased enhancement on delayed phase imaging. An antrectomy with gastroduodenostomy was performed because gastric cancer was suspected, particularly signet ring cell carcinoma. The histopathological diagnosis was an IFP with massive fibrosis. The authors suggest that when the submucosal layer of the gastric wall is markedly thickened with delayed enhancement and preservation of the mucosal layer, an IFP with massive fibrosis should be considered in the differential diagnosis.

A rare, low-grade appendiceal mucinous neoplasm (Pseudomyxoma peritonei) with ossification: A case report with morphoproteomic analysis of bone formation.

Heterotopic ossification occurring to low-grade appendiceal mucinous neoplasm (LAMN) (pseudomyxoma peritonei) is extremely rare. The pathogenetic mechanism of the tumor-related heterotopic bone formation remains as yet unconfirmed. Here, we describe a rare case of LAMN with ossification in a 72-year-old woman, and concentrate on the etiology of heterotopic ossification by the immunohistochemical evaluation of the novel markers such as BMP9, osteocalcin, and osteopontin. BMP9 is one of the most effective osteogenetic proteins. However, no researches associated with BMP9 in the heterotopic ossification occurring to LAMN have been performed. Consequently, we suggest the trustworthy hypothesis of tumor-associated heterotopic bone formation through this case. When osteoblastic markers such as BMP9, osteocalcin, and osteopontin are overexpressed in tumor cells, osteoblast-like transformation of such tumor cells occurs. In turn, these tumor cells increase secretion of interactive osteogenetic factors, such as BMP9, osteocalcin, and osteopontin, thus contributing to heterotopic bone formation through a microenvironmental change to mesenchymal stromal cells (osteoblastic differentiation). This phenomenon is considered a type of EMT. Patients should be followed closely because EMT-like transformed tumors have shown a tendency toward local recurrence. Our findings provide insight into the pathogenetic etiology of the heterotopic ossification in LAMN (pseudomyxoma peritonei).

Downregulation of osteoprotegerin expression in metastatic colorectal carcinoma predicts recurrent metastasis and poor prognosis.

We recently reported the downregulation of osteoprotegerin expression in primary colorectal carcinoma and its significant association with aggressive oncogenic behavior, which suggest that this process contributes to colorectal carcinoma development and progression. In this study, we used immunohistochemical staining to evaluate osteoprotegerin expression in 81 colorectal liver metastasis tissue samples and investigated its possible association with the clinicopathological characteristics and outcomes of patients with colorectal liver metastasis. These tissues exhibited significantly reduced expression of osteoprotegerin compared to primary colorectal carcinomas and normal colorectal mucosa. This reduced expression was significantly associated with the extent of colorectal liver metastasis, including multiplicity of metastatic tumors, involvement of the bilateral hepatic lobes, and higher histological grade. In addition, reduced osteoprotegerin expression was an independent significant predictor of recurrent liver metastasis and prognostic factor for reduced patient survival. These findings suggest that osteoprotegerin expression may be a novel predictor of recurrent liver metastasis and a prognostic biomarker in patients with colorectal liver metastasis. Patients harboring colorectal liver metastasis with reduced osteoprotegerin expression should be carefully monitored after hepatic resection for colorectal liver metastasis to enable early detection of potentially resectable metastatic recurrences.

A Rare Colon Cancer with Ossification: Pathogenetic Analysis of Bone Formation.

Heterotopic ossification occurring in colon cancer is an exceedingly rare event. The pathogenetic mechanism of tumor-related heterotopic bone formation remains unclear. Herein, we describe a rare case of colon cancer with ossification in a 76-year-old woman. We also highlight the etiology of heterotopic ossification by immunohistochemical evaluation of novel markers such as bone morphogenetic protein 9 (BMP9), osteocalcin, osteopontin, and ß-catenin. BMP9 is one of the most potent osteogenetic BMPs. However, no previous research has been performed concerning BMP9 in heterotopic ossification arising in colon cancer. Subsequently, we suggest a hypothesis of tumor-associated heterotopic bone formation through this case. When osteoblastic indicators including BMP9, osteocalcin, and osteopontin are upregulated in tumor cells, osteoblast-like transformation of such tumor cells occurs. These tumor cells augment the release of interactive osteogenetic factors (BMP9, osteocalcin, and osteopontin) and stimulate uncommitted mesenchymal stromal cells into specific osteoblastic differentiation, contributing to heterotopic bone formation. This transformation of tumor cells is considered a type of epithelial-mesenchymal transition (EMT) because of overexpression of BMP9 and ß-catenin. Patients should be followed closely because EMT has a tendency toward local recurrence. Our findings provide insight into the pathogenetic etiology of heterotopic ossification in colon cancer.

Clinicopathological implications of GNAS in Ewing sarcoma.

The objective of the present study was to determine whether guanine nucleotide-binding protein α stimulating (GNAS) gene expression correlates with pathognomonic signs by analyzing the mutations, methylation status and G-protein α subunit (Gsα) expression of GNAS in Ewing sarcoma (ES). Formalin-fixed paraffin-embedded tissue samples from 77 patients with primary ES were obtained in South Korea, Argentina and Brazil, and were studied via methylation chip assay and direct sequencing of the GNAS gene and immunohistochemical analysis of Gsα. The mutation and methylation statuses of the GNAS gene were examined. Immunohistochemical results were measured with respect to proportion and staining intensity. The results revealed that GNAS genes in ES tumor samples were less methylated compared with normal controls. No mutations were detected at exons 8 or 9 of the GNAS locus complex on chromosome 20q13.3, indicating that the pathogenesis of ES was not associated with GNAS mutation. Gsα expression correlated well with the methylation status of the GNAS gene. Notably, high Gsα expression was detected more frequently in samples from living patients than from decedents, although this was not statistically significant (P=0.055). In conclusion, GNAS mutation is not associated with the pathogenesis of ES tumors. This finding may be used to differentiate ES tumors from metastatic bone lesions with morphological similarity to ES tumors. Analysis of the methylation status of the GNAS gene and immunohistochemical Gsα expression suggests that hypermethylated GNAS (low Gsα expression) in ES may be associated with unfavorable progression with a non-significant trend.

Prognostic value of ERG, PTEN, CRISP3 and SPINK1 in predicting biochemical recurrence in prostate cancer.

The established prognostic factors associated with prostatic adenocarcinoma are the Gleason score, pathological T staging and serum prostatic-specific antigen (PSA) level. However, these prognostic factors alone are not sufficient for predicting prognostic characteristics, including early stage or advanced prostate cancer, presence of metastasis or disease-related mortality. The purpose of the present study was to simultaneously evaluate the prognostic value and associations of four biomarkers, namely, transcriptional regulator ERG (ERG), phosphatase and tensin homolog (PTEN), cysteine-rich secretory protein 3 (CRISP3) and serine protease inhibitor Kazal type I (SPINK1), and to conduct risk stratification of prostate cancer for use in patient management. A total of 68 formalin-fixed, paraffin-embedded, prostate cancer samples from radical prostatectomies were obtained in the Kyung Hee University Hospital (Seoul, Korea) and were studied immunohistochemically for ERG, PTEN, CRISP3 and SPINK1 to determine the proportion and intensity of staining. SPINK1 expression was mutually exclusive of ERG expression (P=0.001). The loss of PTEN and high CRISP3 expression are unfavorable indicators for prostate cancer, as PTEN loss was associated with shorter biochemical recurrence (BCR) (P=0.039), and high CRISP3 expression was associated with increased BCR (P<0.001) and cancer-related mortalities (P=0.011). Using the combination of low PTEN and high CRISP3 expression enables attention to be focused on patients who exhibit a poor prognosis. Subgrouping of patients, into high-risk and low-risk categories, was correlated with BCR-free survival in prostate cancer upon multivariate analysis (P=0.030). Overall, low PTEN and high CRISP3 expression significantly characterize the subgroups of prostate cancer that have a poor prognosis for BCR.

EGFR, COX2, p-AKT expression and PIK3CA mutation in distal extrahepatic bile duct carcinoma.

Distal extrahepatic bile duct (EBD) carcinoma is a rare but highly aggressive malignant neoplasm. Some in vitro studies have shown that EGFR and PI3K-Akt pathway play an important role in the carcinogenesis of bile duct carcinoma. The aim of the present study is to investigate the expression of EGFR, p-AKT, and COX-2 and the mutation of PIK3CA in distal EBD carcinoma and evaluate the association with clinicopathological factors. Ninety cases of distal extrahepatic bile duct (EBD) carcinoma specimens were studied. Immunohistochemistry (IHC) using antibodies against EGFR, p-AKT, and COX-2 was performed on TMA blocks. The PIK3CA mutation was evaluated using the PNAClamp Detection Kit from DNA samples extracted from formalin fixed, paraffin embedded tissue. EGFR expression of distal EBD carcinomas was 61.9%, 26.2%, 6.0% and 6.0% in the negative, weakly positive, moderately positive, and strongly positive groups, respectively. Positive EGFR expression showed significant relationships with high T stage (p = 0.024). In Kaplan-Meier analysis, EGFR expression was associated with shorter cancer-specific overall survival (p = 0.005). Multivariate analysis also showed that moderate or strong (2+ or 3+) EGFR expression was a significant prognostic factor in distal EBD carcinoma: HR 5.286; p = 0.001. Ninety cases of EBD carcinoma tissue were analysed for hotspot mutations (exon 9 and 20) in the PIK3CA gene. Only one mutation was detected: a missense mutation of H1047 at exon 20. The expression levels of p-AKT and COX-2 showed no association with any clinicopathological parameters, including survival rate. Moderate and strong EGFR expressions demonstrate a direct link to poor prognosis. Although further study is warranted to understand the clinicopathological significance, our finding suggests EGFR is a useful prognostic marker of patients with distal EBD carcinoma. A low prevalence of PIK3CA mutation exists in the distal EBD carcinoma of Korean patients, indicating that mutation screening may not be useful in determining prognosis or in formulating a treatment response to targeted inhibition in Korea.

Down-regulation of osteoprotegerin expression as a novel biomarker for colorectal carcinoma.

A better understanding of tumor biology is important in the identification of molecules that are down-regulated in malignancy and in determining their role in tumor suppression. The aim of this study was to analyze osteoprotegerin (OPG) expression in colorectal carcinoma (CRC) and to investigate the underlying mechanism for changes in the expression of OPG. OPG expression was assessed in CRC tissue samples and cell lines. The methylation status of the OPG promoter region was determined, and the effects of demethylation on OPG expression were analyzed. The effects of recombinant OPG (rOPG) administration on cellular functions were also investigated. Clinical and prognostic implications of OPG protein expression in CRC patients were analyzed. The CRC tissues and cells showed significantly lower OPG expression. Pyrosequencing of OPG-silenced CRC cells revealed that the OPG gene promoter was highly methylated. Treatment with demethylating agent significantly elevated OPG mRNA and protein expression. rOPG significantly decreased cell viability and MMP-2 and VEGF-A production in CRC cells. Reduced OPG immunoreactivity was associated with aggressive oncogenic behavior in CRC. Also, OPG expression was found to be an independent predictor of recurrent hepatic metastasis and independent prognostic factor for worse survival rates. We demonstrated that OPG silencing in CRC occurs through epigenetic repression, and is involved in the development and progression of CRC. Our data suggest that OPG is a novel prognostic biomarker and a new therapeutic target for the treatment of patients with CRC.

Suppression of GLTSCR2 expression in renal cell carcinomas.

Nucleolar protein PICT-1/GLTSCR2 (GLTSCR2) has both tumor suppressive and oncogenic activities, depending on the types of cancer tissue and its expression level. The role of GLTSCR2 in renal cell carcinoma (RCC) has not yet been addressed. The aims of this study were to evaluate GLTSCR2 expression in RCC tissue and to determine pathological significance of GLTSCR2 in terms of tumor grade. RCC and adjacent normal tissue from 84 different patients was retrieved from nephrectomy specimens. The expression level of GLTSCR2 in RCC tissues was determined via immunohistochemical staining and invasion was determined using transwell chambers with Matrigel-coated membranes. The expression of GLTSCR2 was suppressed in about 80% of the carcinoma specimens compared to noncancerous renal tissue and inversely correlated with Fuhrman nuclear grade (r=-0.40, p<0.05). Knockdown of GLTSCR2 expression increased the invasiveness of SNU267 RCC cells. The expression of GLTSCR2 was suppressed in RCCs and its downregulation accentuated the malignant phenotype.