Gastrointestinal cancers accompanied by a dense lymphoid component: an overview with special reference to gastric and colonic medullary and lymphoepithelioma-like carcinomas

Prognosis of EBV-positive gastric cancer with lymphoid stroma: systematic review and meta-analysis

BACKGROUND

Although gastric cancer with lymphoid stroma (GCLS) presents better prognosis, uncertainty still exists regarding the association of Epstein-Barr virus (EBV) infection with prognosis of GCLS. Therefore, it is urgent to evaluate the outcome and characteristics of EBV-positive GCLS via a systematic review and meta-analysis.

METHODS

Three medical databases, with a period ranging from 2000 to so far, were searched for observational studies on EBV infection, clinical characteristics and prognosis. Odds ratio (OR) was used to evaluate the mortality and clinical characteristics of EBV-positive GCLS patients. Egger's test and subgroup analysis were conducted to identify the source of heterogeneity.

RESULTS

Nine retrospective studies were finally identified, which involved 618 EBV-positive and 153 EBV-negative GCLS patients. The forest plot indicated that EBV-positive GCLS patients had lower mortality (p = .009; 95% CI: 0.15-0.77; I2 = 48.6%). Both of funnel plot and Egger's tests suggested that there was no publication bias. Nonetheless, subgroup analysis indicated that T1-2 stage ratio more than 50% (p < .001; I2 = 6.7%) and male ratio more than 80% (p < .001; I2 = 0.0%) were valuable for eliminating the heterogeneity. Seven studies including valid information showed that TNM stage of EBV-positive and negative GCLS patients was not statistically different (p = .644; 95% CI: 0.50-1.53; I2 = 0.0%).

CONCLUSIONS

EBV-positive GCLS tends to have lower mortality, suggesting that detection of EBV infection is necessary to predict prognosis of GCLS.

Molecular Pathology of Gastric Cancer

Gastric cancer (GC) is one of the most common lethal malignant neoplasms worldwide, with limited treatment options for both locally advanced and/or metastatic conditions, resulting in a dismal prognosis. Although the widely used morphological classifications may be helpful for endoscopic or surgical treatment choices, they are still insufficient to guide precise and/or personalized therapy for individual patients. Recent advances in genomic technology and high-throughput analysis may improve the understanding of molecular pathways associated with GC pathogenesis and aid in the classification of GC at the molecular level. Advances in next-generation sequencing have enabled the identification of several genetic alterations through single experiments. Thus, understanding the driver alterations involved in gastric carcinogenesis has become increasingly important because it can aid in the discovery of potential biomarkers and therapeutic targets. In this article, we review the molecular classifications of GC, focusing on The Cancer Genome Atlas (TCGA) classification. We further describe the currently available biomarker-targeted therapies and potential biomarker-guided therapies. This review will help clinicians by providing an inclusive understanding of the molecular pathology of GC and may assist in selecting the best treatment approaches for patients with GC.

Surgical treatment of Epstein-Barr virus-associated lymphoepithelioma-like carcinoma occurring in both the posterior mediastinum and liver: Case report

RATIONALE

Lymphoepithelioma-like carcinoma (LELC) is a rare malignant tumor that can occur in many areas of the body. The pathogenesis of LELC remains unknown, but Epstein-Barr virus (EBV) has been shown to be strongly correlated with LELC at several anatomic sites, including the lungs and thymus. To the best of our knowledge, EBV-associated LELC has never been reported in both the posterior mediastinum and liver. Herein, we report the case of a 41-year-old female diagnosed with LELC in both the posterior mediastinum and liver and discuss whether it is beneficial to perform surgery on advanced LELC when resectable metastases are found.

PATIENT CONCERNS

The patient was a 41-year-old woman who had been suffering from intermittent pain in the upper right quadrant for 3 months without obvious cause and was admitted to our hospital with occasional nausea without vomiting.

DIAGNOSIS

Her cancer antigen 125 and cytokeratin 19 fragment levels were elevated, whereas alpha-fetoprotein and alanine aminotransferase were normal. Computed tomography (CT) and magnetic resonance imaging revealed a mass in the S6 segment of the liver. Whole-body positron emission tomography/computed tomography (PET/CT) revealed a 3.2-cm mass in the posterior mediastinum and a 6.7-cm mass on the right side of the liver. We made a diagnosis of LELC based on the histological and immunohistochemical findings of specimens obtained by operation. However, it was difficult to determine the primary origin of the tumor.

INTERVENTIONS

The patient underwent mediastinal tumor resection, hepatectomy, and diaphragmatic repair. Thereafter, she was administered paclitaxel and cisplatin as adjuvant chemotherapy.

OUTCOMES

The postoperative course was uneventful, and the patient was discharged 10 days later. Although she was administered paclitaxel and cisplatin as adjuvant chemotherapy, we noted recurrence during the 4-month follow-up examination. Then, the patient passed away 5 months after surgery.

LESSONS

We present the first case of LELC found in both the posterior mediastinum and liver and describe the functionality of PET/CT for finding occult carcinomas and identifying their primary tumor origin. Additional studies are urgently needed to discover whether it is beneficial to perform surgery on advanced LELC when resectable metastases are revealed by PET/CT.

Clinicopathological Features and Prognostic Implication of Gastric Carcinoma with Lymphoid Stroma

Methods

This study included 34 eligible studies and 1757 GCLSs. The clinicopathologic characteristics of GCLS were investigated from eligible studies, and the meta-analysis was performed. In addition, we compared the survival rates between GCLS and non-GCLS.

Results

The estimated rate of GCLS was 0.062 (95% confidence interval (CI) 0.040-0.097). GCLS was significantly correlated with the diffuse type of Lauren's classification, proximal tumor location, less-frequent lymphatic invasion, and lower pTNM stage. However, there was no significant difference in age, sex, tumor differentiation, vascular invasion, perineural invasion, pT stage, lymph node metastasis, and distant metastasis between GCLS and non-GCLS patients. EBV positive rates in GCLS and non-GCLS patients were 0.723 (95% CI 0.643-0.791) and 0.064 (95% CI 0.039-0.103), respectively. HER2 expression in GCLS was significantly lower than that in non-GCLS. GCLS patients had a more favorable prognosis than that of non-GCLS patients (hazard ratio 0.500, 95% CI 0.305-0.821).

Conclusion

GCLS comprised 6.2% of overall GC and more frequent in the proximal portion of the stomach. Since GCLS was associated with better prognosis, the histologic finding can be useful for predicting the patient's prognosis.

SSTR2a is constantly expressed in lymphoepithelioma-like carcinoma with squamous differentiation other than that with glandular differentiation

AIMS

Somatostatin receptor 2a (SSTR2a) is an important diagnostic marker of meningioma and neuroendocrine tumours and is frequently expressed in primary and metastatic non-keratinising nasopharyngeal carcinoma (NK-NPC). Since NK-NPC cases are considered a kind of lymphoepithelioma-like carcinoma (LELCs) which originate from the nasopharynx, information on the expression profile of SSTR2a in LELC in other sites with squamous and glandular differentiations is still lacking. This study aimed to assess the expression of SSTR2a in LELC of various organs and clarify its expression profile.

METHODS

Expression of SSTR2a in 164 cases of LELC was retrospectively analysed by immunohistochemistry in paraffin-embedded tissues, including 146 cases of LELC with squamous differentiation (120 cases of the nasopharynx, 21 cases of the lung and 5 cases of the parotid gland) and 18 cases of LELC with glandular differentiation (15 cases of the stomach and 3 cases of the liver).

RESULTS

We found that all (100%) cases of LELC of the lung (21/21) and parotid gland (5/5), and 93.3% (112/120) cases of LELC of the nasopharynx showed a diffused and strong expression of SSTR2a, while cases of gastric (0/15) and biliary (0/3) showed no SSTR2a expression.

CONCLUSION

SSTR2a is constantly expressed in LELC with squamous differentiation, but not expressed in LELC with glandular differentiation. However, the selective expression mechanism of SSTR2a remains unknown, which needs further investigation. Our novel findings might provide potential therapeutic approaches for the treatment of LELC with squamous cell differentiation.

Pancreatic ductal adenocarcinoma with mismatch repair deficiency resected after long-term observation

Pancreatic ductal adenocarcinoma (PDAC) with mismatch repair (MMR) deficiency is a rare subtype, clinicopathological features of which have not been fully understood. A 70-year-old woman was admitted for the investigation of a 20-mm pancreatic tumor in the pancreatic head, detected during the cause scrutiny of exacerbation of diabetes mellitus and panhypopituitarism. The tumor decreased in size after administration of hydrocortisone for panhypopituitarism. Autoimmune pancreatitis, complicated with hypophysitis, was suspected, and prednisolone treatment was administered. The tumor did not show enlargement for 3 years during which a dose of prednisolone was maintained. However, 1.5 years after the cessation of prednisolone administration, the tumor size increased again. On endoscopic ultrasonography, the tumor was found to be a 25.2-mm mass lesion with almost uniformly low echogenicity and blood flow signal, and anisonucleosis on cytodiagnosis was revealed. Pancreatoduodenectomy was performed, and on histological analysis, moderately differentiated tubular adenocarcinoma with massive lymphocytic infiltration was observed. Immunohistochemistry revealed a concomitant loss of MSH2 and MSH6 in the tumor cells, which implicated mutant MSH2 gene. She has remained well with no recurrence for 2.9 years since her surgery. We herein report a case of PDAC with MMR deficiency, resected after long-term observation.

A Rare Case of Moderately Differentiated Adenocarcinoma With PD-L1 Overexpression and a Heterogeneous LELC Component in the Ascending Colon

Background

Lymphoepithelioma-like carcinomas (LELCs), especially colorectal cancers (CRCs), are uncommon pathological phenotypes generally associated with poor aggressiveness and a preferable prognosis. However, PD-L1 overexpression in CRCs is associated with poor outcomes. We report a case of moderately differentiated adenocarcinoma with PD-L1 overexpression, an LELC component, and Crohn’s-like lymphoid reaction (CLR) presenting with extreme locoregional aggression and complete remission with chemotherapy after noncurative excision.

Case presentation

A 69-year-old man was referred to our hospital for abdominal fullness and pain. Computed tomography (CT) showed a circumferential tumor in the ascending colon, accompanied by bulky swollen lymph nodes. Under the preoperative diagnosis of T4N2M1 (lymph nodes) ascending colon cancer, we performed a right hemicolectomy; however, paracaval and parailiac vein lymph nodes were abandoned. Pathological findings showed moderate to poorly differentiated adenocarcinoma invading the subserosa accompanied by an LELC component invading the superficial muscularis propria. Lymph node metastases were found in a neighboring tumor and in retroperitoneal lymph nodes with glandular differentiation. No relation to microsatellite instability (MSI) or Epstein-Barr virus (EBV) was observed. In the component with glandular differentiation, PD-L1 overexpression was revealed. CLR findings were also observed. The tumor was diagnosed as T3N2M1 cancer that was moderately to poorly differentiated and had an LELC component. The patient was treated with chemotherapy, and the metastasized lymph nodes ultimately disappeared. He was alive without tumor recurrence 5-years post-operation.

Conclusion

This is a very rare case of moderately differentiated adenocarcinoma with PD-L1 overexpression and a heterogeneous LELC component that developed in the ascending colon. Unlike the previously reported weak aggressive properties of LELCs, the present case showed an extremely aggressive locoregional extent, but complete remission was finally achieved with chemotherapy. This type of LELC with CLR could be associated with a good response to chemotherapy and a good prognosis in CRC patients.

A case of poorly differentiated adenocarcinoma with lymphoid stroma originated in the ascending colon diagnosed as lymphoepithelioma-like carcinoma

An 86-year-old woman’s stool sample was positive for blood. Computed tomography (CT) showed wall thickening of the ascending colon at the hepatic flexure. Colonoscopy showed near-complete obturation by colon cancer. Since she was asymptomatic, elective surgery was planned. Laparoscopic right hemicolectomy was performed. Histopathological examination showed poorly differentiated carcinoma cells proliferating in a solid pattern with marked lymphocyte infiltration. The diagnosis was lymphoepithelioma-like carcinoma (LELC) associated with Epstein-Barr virus (EBV) infection; however, EBV-encoded small RNA–in situ hybridization was negative. Microsatellite instability was not assessed. The postoperative course was uneventful and she was discharged on the 15th postoperative day. She remains recurrence-free at 2 years after surgery. Past reports note that colorectal carcinomas with dense lymphoid stroma may be related to LELC or medullary carcinoma (MC). Gastrointestinal LELC is rare, with some reports on LELC of the esophagus and stomach. Reports on LELC of the large intestine are very rare. MC of the large intestine is relatively new concept, firstly described in the WHO Classification of Tumours of the Digestive System 3rd Edition in 2000. We herein present a case of lymphoepithelioma-like carcinoma of the ascending colon and relevant case reports about LELC and MC of the large intestine.

Gastric Carcinomas With Lymphoid Stroma: An Evaluation of the Histopathologic and Molecular Features

Gastric carcinoma with lymphoid stroma is an uncommon variant enriched for mutually exclusive Epstein-Barr virus (EBV) positivity and mismatch repair (MMR) deficiency. We performed this study to evaluate molecular alterations in this morphologically homogeneous subtype and compare them with 295 conventional gastric cancers analyzed in The Cancer Genome Atlas study. We identified 31 study cases and subjected them to in situ hybridization for EBV-encoded RNAs and assessment for MMR status. Immunostains for PD-L1, β-catenin, and HER2 were performed; extracted DNA was sequenced with a Comprehensive Cancer Panel. Most study patients were older adult men with stage I or II disease (76%). Tumors were classified as EBV/MMR-proficient (MMR-P) (n=7), EBV/MMR deficient (n=12), and EBV/MMR-P (n=12). EBV/MMR-P tumors were usually located in the proximal stomach (83%) and showed heterogenous growth patterns with glandular differentiation (83%). Tumors in all groups showed numerous tumor infiltrating lymphocytes and PD-L1 expression, infrequent nuclear β-catenin accumulation (10%), and lacked both membranous HER2 staining and HER2 amplification. EBV/MMR-deficient tumors showed significantly higher tumor mutation burden (P=0.001) and KRAS alterations (56%) compared with EBV/MMR-P tumors (9%, P=0.05). TP53 variants were more common among EBV/MMR-P tumors (82%) compared with EBV/MMR proficient (0%, P=0.01) and EBV/MMR-deficient (11%, P<0.01) tumors. Alterations in KRAS, ARID1A, PIK3CA, and TP53 followed similar patterns of distribution compared with The Cancer Genome Atlas dataset. We conclude that gastric carcinomas with lymphoid stroma show a spectrum of molecular changes and frequent PD-L1 expression, raising the possibility that this subgroup of tumors may be susceptible to checkpoint inhibitors and/or agents that target receptor tyrosine kinase-mediated signaling.

Molecular Diagnostics in Esophageal and Gastric Neoplasms: 2018 Update

Esophageal cancer (EC) is rapidly increasing in incidence in the United States. Genetic changes associated with the development of EC involve the p16, p53, and APC genes. Human epidermal growth factor 2 (HER-2) overexpression is seen in gastroesophageal junction carcinoma and a subset gastric carcinoma (GC). Interestingly, up to 50% cases of GC are related to Helicobacter pylori infection and up to 16% are related to EBV infection. Microsatellite instability is observed in up to 39% of GC and cell free nucleic acid analysis provides additional opportunities for diagnosis and prognosis of disease.

Gut-associated lymphoid tissue or so-called “dome” carcinoma of the colon: Review

AIM

To present a comprehensive review of the etiology, clinical features, macroscopic and pathological findings, and clinical significance of Gut-associated lymphoid tissue or “dome” carcinoma of the colon.

METHODS

The English language medical literature on gut- or gastrointestinal-associated lymphoid tissue (GALT) or “dome” carcinoma of the colon was searched and appraised.

RESULTS

GALT/dome-type carcinomas of the colon are thought to arise from the M-cells of the lymphoglandular complex of the intestine. They are typically asymptomatic and have a characteristic endoscopic plaque- or “dome”-like appearance. Although the histology of GALT/dome-type carcinomas displays some variability, they are characterized by submucosal localization, a prominent lymphoid infiltrate with germinal center formation, tumor-infiltrating lymphocytes, absence of desmoplasia, and dilated glands lined by columnar epithelial cells with bland nuclear features and cytoplasmic eosinophilia. None of the patients reported in the literature with follow-up have developed metastatic disease or local recurrence.

CONCLUSION

Increased awareness amongst histopathologists of this variant of colorectal adenocarcinoma is likely to lead to the recognition of more cases.

Isolated Gastric Metastasis of Endometrial Adenocarcinoma: First Case Report and Review of Pertinent Literature

Upper gastrointestinal metastasis of endometrial carcinoma rarely occurs in the absence of locoregional disease and other distant metastases. We describe herein the unique case of an isolated gastric metastasis of a stage I endometrial adenocarcinoma. Because the metastatic tumor was initially misdiagnosed clinically and pathologically as a primary gastric carcinoma, we illustrate the histopathology and review the pertinent literature. A 42-year-old woman with Lynch syndrome underwent treatment of endometrial adenocarcinoma at an outside hospital comprising clinical and radiological staging including a positron emission tomography-computed tomography (PET-CT) scan followed by a total intra-abdominal hysterectomy, bilateral salpingoophorectomy and pelvic and paraaortic lymphadenectomy. The preoperative and pathology findings were consistent with a stage I tumor. Three months postoperatively, a PET-CT scan revealed a new 4.4 cm hypermetabolic lesion in the stomach. A biopsy of the lesion was interpreted pathologically as gastric adenocarcinoma with lymphoid stroma. Upon referral of the patient to our center for management, the biopsy was reviewed in consultation and the pathology materials from the hysterectomy procedure were retrieved for comparison. Based on the morphological and immunohistochemical similarities between the tumors the gastric tumor was diagnosed as metastatic endometrial adenocarcinoma. To our knowledge, this is the first documented case of an isolated gastric metastasis complicating stage I endometrial adenocarcinoma. Awareness of the potential for this occurrence and of the associated diagnostic pitfalls is crucial for accurate diagnosis and therapy.

Lymphoepithelioma-Like Carcinoma of the Uterine Cervix: A Pathologic Study of Eight Cases With Emphasis on the Association With Human Papillomavirus

Objectives

Lymphoepithelioma-like carcinoma (LELC) of the uterine cervix is a rare tumor. The goal of this study was to evaluate a series of cases of cervical LELC and to investigate possible association with human papillomavirus (HPV) and/or Epstein-Barr virus (EBV).

Methods

Immunohistochemistry for p63, p16, human leukocyte antigen-D related (HLA-DR), and B-cell lymphoma 2 (BCL-2); in situ hybridization (ISH) for EBV and HPV; and polymerase chain reaction (PCR) genotyping were performed. Mismatch repair (MMR) studies and PD-L1 status were obtained.

Results

We found eight cases of LELC. Tumors demonstrated sheets of cells containing vesicular nuclei, amphiphilic cytoplasm, and dense peri- and intratumoral lymphocytic infiltrates. All tumors stained for p63, p16, and HLA-DR; two also stained for BCL-2. When combining ISH and PCR results, seven tumors were HPV positive; they were all Epstein-Barr encoding region negative. All cases were MMR intact, and most overexpressed PD-L1.

Conclusions

This study shows that cervical LELCs are associated with HPV and not EBV.

Cytomorphological Study of Medullary Carcinoma of Breast in Comparison to Infiltrating Ductal Carcinoma

Introduction:

Medullary breast carcinoma (MBC) is one of the rare variants of breast carcinoma, accounting for less than 5% of invasive breast carcinoma. MBCs relatively appear a decade earlier when compared to invasive ductal carcinoma (IDC NOS), which is more prevalent in the elderly age.

Subjects and Methods:

A retrospective study was conducted in the Department of Pathology from 2009 to 2016. Fine needle aspiration cytology slides of MBCs and IDCs were retrieved, studied microscopically, and reviewed to compare the cytological features.

Results:

During the study period, MBC cases were 12 and IDC were 319. Random 12 cases of IDC NOS were taken up for comparative cytological evaluation. Various cytological features are assessed and compared using chi square test and independent t test ratio. On comparison of IDC NOS and MBC cases in relation to the parameters like: syncytial clusters and nature of inflammatory infiltrate; the number of positive category was higher in MBC group (83.3%). In contrast, parameters like three-dimensional clusters, acinar pattern, and necrosis; the number of positive category was higher in IDC NOS group with a percentage of 91.7%, 100%, and 67%, respectively. Ratio of lymphoplasmacytic cells to tumor cells between the two showed that the ratio was higher in MBC group. This comparison was statistically significant with a P value of <0.001.

Conclusion:

Though few variants of breast carcinoma contain lymphoplasmacytic infiltrate, the intensity and pattern of distribution of these lymphocytes and plasma cells in relation to tumor cells helps in distinguishing MBC from other breast carcinomas commonly IDC NOS on cytology. Also MBCs have a better prognosis when compared to IDC NOS.

Gastric Carcinomas With Lymphoid Stroma: Categorization and Comparison With Solid-Type Colonic Carcinomas

OBJECTIVES

To determine whether histologic features could help identify gastric carcinomas with lymphoid stroma associated with microsatellite instability (MSI) (ie, "medullary carcinomas"), Epstein-Barr virus (EBV) infection (termed lymphoepithelioma-like carcinomas in other organ systems), or neither.

METHODS

We identified 17 solid-type gastric carcinomas with lymphoid stroma, assessed EBV and MSI status, and compared features across groups. We also compared them with 51 solid-type colorectal adenocarcinomas.

RESULTS

In the stomach, EBV-associated carcinomas (n = 8) contained intratumoral germinal centers (P = .024) and eosinophils (P = .030) and lacked necrosis (P = .019) compared with MSI-associated carcinomas (n = 5) and non-EBV, non-MSI carcinomas (n = 4). In the colon, MSI-driven carcinomas (n = 40) more frequently contained intratumoral lymphocytes (P = .017) and neutrophils (P = .0050) and less often metastasized to distant sites (P = .0040) than poorly differentiated carcinomas lacking MSI (n = 11).

CONCLUSIONS

Morphology may help classify gastric carcinomas with lymphoid stroma, although ancillary testing appears more reliable. Lymphoepithelioma-like carcinoma and medullary carcinoma should not be used interchangeably.

Small bowel carcinomas in celiac or Crohn's disease: distinctive histophenotypic, molecular and histogenetic patterns

Non-familial small bowel carcinomas are relatively rare and have a poor prognosis. Two small bowel carcinoma subsets may arise in distinct immune-inflammatory diseases (celiac disease and Crohn's disease) and have been recently suggested to differ in prognosis, celiac disease-associated carcinoma cases showing a better outcome, possibly due to their higher DNA microsatellite instability and tumor-infiltrating T lymphocytes. In this study, we investigated the histological structure (glandular vs diffuse/poorly cohesive, mixed or solid), cell phenotype (intestinal vs gastric/pancreatobiliary duct type) and Wnt signaling activation (β-catenin and/or SOX-9 nuclear expression) in a series of 26 celiac disease-associated small bowel carcinoma, 25 Crohn's disease-associated small bowel carcinoma and 25 sporadic small bowel carcinoma cases, searching for new prognostic parameters. In addition, non-tumor mucosa of celiac and Crohn's disease patients was investigated for epithelial precursor changes (hyperplastic, metaplastic or dysplastic) to help clarify carcinoma histogenesis. When compared with non-glandular structure and non-intestinal phenotype, both glandular structure and intestinal phenotype were associated with a more favorable outcome at univariable or stage- and microsatellite instability/tumor-infiltrating lymphocyte-inclusive multivariable analysis. The prognostic power of histological structure was independent of the clinical groups while the non-intestinal phenotype, associated with poor outcome, was dominant among Crohn's disease-associated carcinoma. Both nuclear β-catenin and SOX-9 were preferably expressed among celiac disease-associated carcinomas; however, they were devoid, per se, of prognostic value. We obtained findings supporting an origin of celiac disease-associated carcinoma in SOX-9-positive immature hyperplastic crypts, partly through flat β-catenin-positive dysplasia, and of Crohn's disease-associated carcinoma in a metaplastic (gastric and/or pancreatobiliary-type) mucosa, often through dysplastic polypoid growths of metaplastic phenotype. In conclusion, despite their common origin in a chronically inflamed mucosa, celiac disease-associated and Crohn's disease-associated small bowel carcinomas differ substantially in histological structure, phenotype, microsatellite instability/tumor-infiltrating lymphocyte status, Wnt pathway activation, mucosal precursor lesions and prognosis.

Gastric Medullary Carcinoma with Sporadic Mismatch Repair Deficiency and a TP53 R273C Mutation: An Unusual Case with Wild-Type BRAF

Medullary carcinoma has long been recognized as a subtype of colorectal cancer associated with microsatellite instability and Lynch syndrome. Gastric medullary carcinoma is a very rare neoplasm. We report a 67-year-old male who presented with a solitary gastric mass. Total gastrectomy revealed a well-demarcated, poorly differentiated carcinoma with an organoid growth pattern, pushing borders, and abundant peritumoral lymphocytic response. The prior cytology was cellular with immunohistochemical panel consistent with upper gastrointestinal/pancreaticobiliary origin. Overall, the histopathologic findings were consistent with gastric medullary carcinoma. A mismatch repair panel revealed a mismatch repair protein deficient tumor with loss of MLH1 and PMS2 expression. BRAF V600E immunostain (VE1) and BRAF molecular testing were negative, indicating a wild-type gene. Tumor sequencing of MLH1 demonstrated a wild-type gene, while our molecular panel identified TP53 c.817C>T (p.R273C) mutation. These findings were compatible with a sporadic tumor. Given that morphologically identical medullary tumors often occur in Lynch syndrome, it is possible that mismatch repair loss is an early event in sporadic tumors with p53 mutation being a late event. Despite having wild-type BRAF, this tumor is sporadic and unrelated to Lynch syndrome. This case report demonstrates that coordinate ancillary studies are needed to resolve sporadic versus hereditary rare tumors.

Programmed Death-Ligand 1 Expression Is Common in Gastric Cancer Associated With Epstein-Barr Virus or Microsatellite Instability

Blockade of the programmed death 1 (PD-1) pathway has emerged as a novel therapy for cancer. Therefore, development of biomarkers for response prediction, such as PD-ligand 1 (PD-L1) expression by immunohistochemistry, may help to stratify patients. Solid tumors with CD8 T-cell rich tumor microenvironment have been implicated to be associated with increased PD-L1 expression. We hypothesized that gastric cancers associated with Epstein-Barr virus infection (EBV+) or microsatellite instability (MSI), both of which are known to harbor such tumor microenvironment, are associated with increased PD-L1 expression. Forty-four resected gastric cancers including 7 EBV+, 16 MSI, and 21 microsatellite stable cancers without EBV (EBV-/MSS) were studied for PD-L1 expression and T-cell subpopulations by immunohistochemistry. Positive PD-L1 expression (PD-L1+), defined as membranous staining in either tumor cells or tumor immune infiltrates, was seen in 32 (72%) gastric cancers. EBV+ or MSI cancers showed significantly higher rates of PD-L1+ compared with EBV-/MSS cancers (7/7, 100%; 14/16, 87%; 11/21, 52%; P=0.013). PD-L1+/EBV+ and PD-L1+/MSI cancers had significantly more CD8 T cells at tumor invasive front than PD-L1+/EBV-/MSS cancers (P<0.001). PD-L1+ was not associated with the depth of invasion or nodal metastasis (P=0.534, 0.288). Multivariate analysis showed PD-L1+ was not an independent predictor of disease-free survival while MSI was (P=0.548, 0.043). In summary, EBV+ or MSI gastric cancers are more likely to express PD-L1 and have increased CD8 T cells at tumor invasive front than EBV-/MSS cancers. Our results suggest EBV infection and MSI should be investigated for predicting response to PD-1 blockade.

Molecular Testing for Gastrointestinal Cancer

With recent advances in molecular diagnostic methods and targeted cancer therapies, several molecular tests have been recommended for gastric cancer (GC) and colorectal cancer (CRC). Microsatellite instability analysis of gastrointestinal cancers is performed to screen for Lynch syndrome, predict favorable prognosis, and screen patients for immunotherapy. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor has been approved in metastatic CRCs with wildtype RAS (KRAS and NRAS exon 2-4). A BRAF mutation is required for predicting poor prognosis. Additionally, amplification of human epidermal growth factor receptor 2 (HER2) and MET is also associated with resistance to EGFR inhibitor in metastatic CRC patients. The BRAF V600E mutation is found in sporadic microsatellite unstable CRCs, and thus is helpful for ruling out Lynch syndrome. In addition, the KRAS mutation is a prognostic biomarker and the PIK3CA mutation is a molecular biomarker predicting response to phosphoinositide 3-kinase/AKT/mammalian target of rapamycin inhibitors and response to aspirin therapy in CRC patients. Additionally, HER2 testing should be performed in all recurrent or metastatic GCs. If the results of HER2 immunohistochemistry are equivocal, HER2 silver or fluorescence in situ hybridization testing are essential for confirmative determination of HER2 status. Epstein-Barr virus-positive GCs have distinct characteristics, including heavy lymphoid stroma, hypermethylation phenotype, and high expression of immune modulators. Recent advances in next-generation sequencing technologies enable us to examine various genetic alterations using a single test. Pathologists play a crucial role in ensuring reliable molecular testing and they should also take an integral role between molecular laboratories and clinicians.

The prognostic value and pathobiological significance of Glasgow microenvironment score in gastric cancer

PURPOSE

To evaluate the prognostic value and pathobiological significance of Glasgow microenvironment score (GMS), a parameter based on tumor stroma percentage and inflammatory cell infiltration, in gastric cancer.

METHODS

A total of 225 cases of gastric cancer were histologically reviewed, and GMS was evaluated for each case. The association between GMS and patients' survival was investigated. Then the relationship between GMS and mismatch repair (MMR) status, Epstein-Barr virus (EBV) infection were determined using immunohistochemistry (IHC) and in situ hybridization, and the expression of PD1/PD-L1 was examined. Furthermore, the amount of cancer-associated fibroblasts (CAFs), the content and maturity of collagen components were detected using IHC, Picrosirius Red staining and second harmonic generation imaging.

RESULTS

GMS was significantly associated with clinical outcomes of gastric cancer, and multivariate analysis indicated that GMS was an independent factor (HR 1.725, P = 0.002). Low GMS was a manifestation of better prognosis and inflammatory tumor microenvironment, which was related to MMR deficiency (P = 0.042) and EBV infection (P = 0.032), and within this microenvironment, expression of PD-L1 in carcinoma cells (P = 0.030) or in inflammatory cells (P = 0.029) was significantly higher. In contrast, high GMS linked to a poorer survival and desmoplastic stroma, in which there existed markedly increased CAFs and collagen deposition.

CONCLUSION

GMS can serve as a useful prognostic factor for gastric cancer, and according to GMS, the tumor microenvironment in this cancer type may be partially classified as inflammatory or desmoplastic microenvironment that possesses different pathobiological features.

Gastric Medullary Carcinoma: A Rare Case Report

A case of 64-year-old female patient with early stage gastric medullary carcinoma has been presented, along with a review of the literature.

Epstein-Barr virus infection serves as an independent predictor of survival in patients with lymphoepithelioma-like gastric carcinoma

BACKGROUND

The pathogenesis and clinicopathologic characteristics of Epstein-Barr virus (EBV)-negative lymphoepithelioma-like gastric carcinoma (LELC) are still unclear. In addition, it remains controversial whether EBV infection itself affects the prognosis of LELC.

METHODS

Between 1995 and 2011, 145 LELC patients (124 patients with EBV infection and 21 patients without EBV infection) underwent radical gastrectomy with D2 lymph node dissection. The clinicopathologic features and prognosis of EBV-negative LELC cases were compared with those of EBV-positive LELC cases. The median duration of follow-up after surgery was 55 months. Microsatellite instability (MSI) analysis was performed on 20 EBV-negative LELC cases.

RESULTS

EBV-negative LELC accounted for 14.5 % of the total LELC cases. EBV-negative LELC was significantly associated with older age, female sex, advanced T stage, and advanced American Joint Committee on Cancer (AJCC) tumor stage compared with EBV-positive LELC. In univariate analysis, patients with EBV-negative LELC had significantly shorter overall, disease-specific, and recurrence-free survival than those with EBV-positive LELC. The 5-year overall survival rates were 81.0 % for patients with EBV-negative LELC and 96.2 % for patients with EBV-positive LELC. In a Cox proportional hazards model, EBV infection, age, and AJCC tumor stage were identified as independent predictors of overall survival. MSI-high, MSI-low, and microsatellite-stable tumors accounted for 25, 10, and 65 % of EBV-negative LELC cases, respectively. MSI status did not affect the prognosis of EBV-negative LELC cases.

CONCLUSIONS

EBV infection serves as an independent predictor of survival in patients with LELC. EBV-negative LELC exhibited clinicopathologic features and prognosis distinct from those of EBV-positive LELC.

Lymphoepithelioma-like gastric carcinoma: A case report and review of the literature

Lymphoepithelioma-like gastric carcinoma is a rare type of gastric cancer characterized by a carcinoma with intense stromal lymphocytic infiltration. Although lymphocytic infiltration is closely associated with Epstein-Barr virus (EBV) infection, concomitant occurrence with differentiated adenocarcinoma is relatively rare. The clinical manifestations of lymphoepithelioma-like gastric carcinoma (including EBV-positive and -negative forms) are similar to those of gastric cancer, and the diagnosis is based on pathologic, histologic, and immunohistochemical findings. This report describes the case of a 55-year-old female patient who presented with a 10-year history of recurrent and worsening abdominal pain and melena that had been occurring for 2 mo. An ulcerative lesion was detected in the stomach by endoscopic examination, which raised suspicion of early gastric cancer. A subsequent preoperative endoscopic biopsy showed adenocarcinoma, but the postoperative pathologic, histologic, and immunohistochemical analyses of the resected specimen revealed a final diagnosis of lymphoepithelioma-like gastric carcinoma.

DOME/GALT type adenocarcimoma of the colon: a case report, literature review and a unified phenotypic categorization

Several types of colorectal cancers are associated with a prominent lymphoid component, which is considered a positive prognostic factor. We report a case of a dome-type carcinoma of the cecum in a 57 year old female. The sessile, non-polypoid lesion histologically consisted of a tubulovillous adenoma with low-grade dysplasia. The submucosal invasive component showed low-grade architectural features that included cystically dilated glands containing eosinohilic debris. Immunohistochemical studies displayed retention of the four mistmach repair proteins, consistent with a stable phenotype. After 3 years, the patient remains free of recurrence. A literature review highlighted striking similarities between dome-type carcinoma and the gut-associated lymphoid tissue carcinoma, the two sharing an intimate association with the gut associated lymphoid tissue.The two variants might therefore be grouped into a unified category.

Is gastric lymphoepithelioma-like carcinoma a special subtype of EBV-associated gastric carcinoma? New insight based on clinicopathological features and EBV genome polymorphisms

BACKGROUND

Gastric lymphoepithelioma-like carcinoma (LELC) is a rare entity that is closely associated with Epstein-Barr virus (EBV). However, the EBV latency pattern and genome polymorphisms in gastric LELC have not been systematically explored.

METHODS

The clinicopathological features, EBV latency pattern and genome polymorphisms of EBV-positive gastric LELC in Guangzhou, southern China were investigated and compared with those of ordinary EBV-associated gastric carcinoma (EBVaGC) in the same area.

RESULTS

Ten (1.42%) of 702 gastric carcinoma cases were identified as gastric LELC, in which eight (80%) cases were EBV-positive. The clinicopathological characteristics and EBV latency pattern of EBV-positive gastric LELC were similar to those of ordinary EBVaGC. In EBV genotype analysis, type A strain, type F, I, mut-W1/I, XhoI- and del-LMP1 variants were predominant among EBV-positive gastric LELCs, accounting for eight (100%), six (75%), eight (100%), seven (87.5%), five (62.5%) and six (75%) cases, respectively, which are similar to those in ordinary EBVaGC. For EBNA1 polymorphisms, the V-leu and P-ala subtypes were predominant in EBV-positive gastric LELC, which is different from the predominant V-val subtype in ordinary EBVaGC. EBV-positive gastric LELC has a favorable prognosis when compared to ordinary EBVaGC (median survival time 43.0 vs. 18.0 months).

CONCLUSIONS

Gastric LELC is strongly associated with EBV and EBV-positive gastric LELC should be regarded as a special subtype of EBVaGC. This, to our best knowledge, is the first time in the world that the EBV latency pattern and genome polymorphisms of EBV-positive gastric LELC are systematically revealed.

Medullary colon cancer presenting with total necrosis of all regional lymph node metastases: morphologic description of a presumed immune-mediated event

Medullary carcinoma is a rare type of colon cancer with characteristic clinical and molecular features. Notably, despite its high-grade histology, the prognosis is generally better than for colonic adenocarcinoma of the usual type. We present herein a singular case of medullary colon cancer in which all of numerous lymph node metastases in the surgical resection specimen were completely necrotic in the face of a wholly viable primary tumor. Possible mechanisms are discussed with emphasis on immune-mediated factors.

Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_204

Prognostic stratification of colorectal cancer patients: current perspectives

Tumor staging according to the American Joint Committee on Cancer/Union for International Cancer Control tumor, node, metastasis (TNM) system is currently regarded as the standard for staging of patients with colorectal cancer. This system provides the strongest prognostic information for patients with early stage disease and those with advanced disease. For patients with intermediate levels of disease, it is less able to predict disease outcome. Therefore, additional prognostic markers are needed to improve the management of affected patients. Ideal markers are readily assessable on hematoxylin and eosin-stained tumor slides, and in this way are easily applicable worldwide. This review summarizes the histological features of colorectal cancer that can be used for prognostic stratification. Specifically, we refer to the different histological variants of colorectal cancer that have been identified, each of these variants carrying distinct prognostic significance. Established markers of adverse outcomes are lymphatic and venous invasion, as well as perineural invasion, but underreporting still occurs in the routine setting. Tumor budding and tumor necrosis are recent advances that may help to identify patients at high risk for recurrence. The prognostic significance of the antitumor inflammatory response has been known for quite a long time, but a lack of standardization prevented its application in routine pathology. However, scales to assess intra- and peritumoral inflammation have recently emerged, and can be expected to strengthen the prognostic significance of the pathology report.