Signet-ring cell change versus signet-ring cell carcinoma: a comparative analysis

Diagnostic Pitfall of Gastric Signet-Ring Cells: How to Diagnose a Benign Signet-Ring Cell From a Malignant One

Sometimes non-neoplastic changes of the gastric mucosa mimic diffuse-type gastric carcinoma, specifically signet-ring cell adenocarcinoma. In fact, gastric epithelial cells undergoing signet-ring cell change have a cellular morphology that is almost identical to signet-ring cell adenocarcinoma, often leading to misdiagnosis. Accurate recognition of signet-ring cell change is essential to avoid overdiagnosis and overtreatment of signet-ring cell adenocarcinoma. Research on this topic is limited and clinicians lack formal diagnostic tools when signet-ring cells are detected in biopsy specimens. The aims of this study are 3-fold. Firstly, to increase the awareness of both clinicians and pathologists of this rare but highly significant entity. Secondly, to report 4 additional examples of signet-ring cell change and analyze them alongside signet-ring cell adenocarcinoma to compare their morphological and phenotypic features and their evolution over time. Finally, to highlight the potential utility of endoscopic resection to confirm the diagnosis. Cells in signet-ring cell change strongly express E-cadherin, show a wild-type p53 expression, and have a low Ki67 index. In contrast, cells in signet-ring cell adenocarcinoma strongly express p53, have high proliferation rates, and show either no or weak E-cadherin staining. Genetic analysis may be useful in identifying patients at risk of hereditary early diffuse gastric adenocarcinoma, which can mimic signet-ring cell change.

A Rare Case of Signet Ring Cell Colon Cancer Presenting as Adult Colorectal Intussusception

Signet ring cell carcinoma of the rectum is rare and typically presents with advanced disease. We report a case of a 68-year-old man who presented with left lower quadrant pain and was found to have signet ring cell carcinoma with intussusception. This case is unusual because of its polypoid growth pattern and apparent early pathological stage. We discuss the differential diagnoses and prognosis.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Incidental morphological findings in colorectal adenomas

Owing to a sharp increase in the frequency of diagnosis of colorectal adenomas in the current era of population screening, distinctive morphological features are increasingly being observed. These may present diagnostic challenges and cause clinical management issues. Paneth cell metaplasia is a more common occurrence, but the incidence rates of squamous metaplasia, clear cell metaplasia, osseous metaplasia, neuroendocrine differentiation and signet‐ring cell‐like lesion are low, and they can be seen in <1% of colorectal adenomas. Their histomorphological characteristics are quite unique; ancillary studies are not very helpful and often not needed. In this review, we give an overview and describe the potential clinical consequences of such incidental and special morphological findings in colorectal adenomas.

Hereditary Gastric and Breast Cancer Syndromes Related to CDH1 Germline Mutation: A Multidisciplinary Clinical Review

E-cadherin (CDH1 gene) germline mutations are associated with the development of diffuse gastric cancer in the context of the so-called hereditary diffuse gastric syndrome, and with an inherited predisposition of lobular breast carcinoma. In 2019, the international gastric cancer linkage consortium revised the clinical criteria and established guidelines for the genetic screening of CDH1 germline syndromes. Nevertheless, the introduction of multigene panel testing in clinical practice has led to an increased identification of E-cadherin mutations in individuals without a positive family history of gastric or breast cancers. This observation motivated us to review and present a novel multidisciplinary clinical approach (nutritional, surgical, and image screening) for single subjects who present germline CDH1 mutations but do not fulfil the classic clinical criteria, namely those identified as-(1) incidental finding and (2) individuals with lobular breast cancer without family history of gastric cancer (GC).

Knowledge gaps in the appendix: a multi-institutional study from seven academic centers

Appendix pathology represents uncommonly encountered specimens with unique diagnostic challenges. To delineate common knowledge gaps, extramural consults submitted to seven institutions between 2016-2017 were reviewed. All appendix consults were resections (100%, n = 43), and the majority were directed for consultation by the originating pathologist (95%, n = 41) with no additional studies performed by the consultant (65%, n = 28). This study was dominated by inquiries related to low grade appendiceal mucinous neoplasms (44%, n = 19) and goblet cell carcinoid related neoplasms (19%, n = 8). Of the 43 appendiceal consults, 19 were submitted by the contributing pathologist as low grade appendiceal mucinous neoplasm, but only half of these were diagnosed by the consultant as such (n = 9). Low grade appendiceal mucinous neoplasm-related consultation themes included diverticular disease, criteria for invasion, high grade atypia, extra-appendiceal mucin, and staging. Examples of major disagreements that were downgraded included consults submitted as low grade appendiceal mucinous neoplasm and diagnosed by the consultant as serrated polyp (n = 3), appendicitis (n = 1), and benign appendix (n = 1). Examples of major disagreements-upgraded included cases submitted as low grade appendiceal mucinous neoplasm and diagnosed by the consultant as low grade appendiceal mucinous neoplasm with high-risk features (n = 2) and mucinous adenocarcinoma (n = 2). One case contained both a major disagreement-upgrade (low grade appendiceal mucinous neoplasm changed to high grade appendiceal mucinous neoplasm) and a major disagreement-downgrade (pT3 changed to Tis). Of the 15 cases diagnosed by the consultants as low grade appendiceal mucinous neoplasm, submitted diagnoses included low grade appendiceal mucinous neoplasm (n = 9), adenocarcinoma (n = 5), and one case was submitted without a diagnosis. For goblet cell carcinoid-related consults, the usual inquiry related to distinguishing goblet cell carcinoid from goblet cell carcinoid with adenocarcinoma (adenocarcinoma ex-goblet cell carcinoid). Of the 38 overall consults with a submitted diagnosis, 53% (n = 20) were disagreements, and most of these were major disagreements-downgraded (n = 13).

Dystrophic Adipocytes Mimicking Metastatic Signet Ring Cell Adenocarcinoma: A Diagnostic Pitfall in a Cachectic Patient

Cachexia is a debilitating condition and complex syndrome commonly associated with a variety of chronic diseases. It is caused by metabolic dysregulation and characterized by profound loss of adipose tissue and skeletal muscles. While pathological changes of cachectic conditions on adipose tissue have been studied and documented in tumor-bearing animal models, similar morphological changes in human surgical specimens are rare. Here we report a case of a cachectic patient with pancreatic adenocarcinoma whose adipocytes underwent dramatic lipodystrophy mimicking signet ring cell adenocarcinoma. The patient had presented with a large bowel obstruction, a mass extending between the pancreas and colon, and radiographic concern for carcinomatosis. A moderately differentiated adenocarcinoma was identified invading externally into the colon, with extensive signet ring-like cells throughout the specimen, including those adjacent to the colon and lymph nodes and around nerves. These signet ring-like cells were round with variably clear to eosinophilic cytoplasm and a peripherally displaced round to oval nucleus. Immunohistochemical staining demonstrated that these signet ring-like cells were negative for AE1/AE3, CD138, or Kreyberg staining, while they were positive for S-100 staining, confirming these as dystrophic adipocytes. Here we examine dystrophic adipocytes in a cachetic patient, examining the differential diagnosis and potential ancillary studies.

Signet-ring Cells in the Skin: A Case of Late-onset Cutaneous Metastasis of Gastric Carcinoma and a Brief Review of Histological Approach

Up to 10% of patients with visceral malignancies develop skin metastases during their clinical course and these metastases constitute about 2% of all skin cancers. Skin metastasis may be the first sign of a clinically silent visceral cancer or represent recurrence of an internal malignancy. In both situations, they are associated with poor prognosis, which can partly be attributed to underdiagnosis. In this paper, a case of relapsing gastric adenocarcinoma, which manifested itself as asymptomatic cutaneous papules and nodules on a patient's head and neck, is reported and histopathological approach to the cutaneous lesions containing signet-ring cell is briefly reviewed.

Reacquisition of E-cadherin expression in metastatic deposits of signet-ring cell carcinoma of the upper gastrointestinal system: a potential anchor for metastatic deposition

AIMS

To examine the expression of E-cadherin in paired primary and metastatic signet-ring cell carcinomas (SRCC) of various organ systems in order to explore the potential role of the molecule in metastatic dissemination of this unique tumour type.

METHODS

Thirty-seven consecutive cases of SRCC from various organs with paired primary and metastatic tumorous tissue available were retrieved. The intensity of membranous E-cadherin expression was semiquantitatively scored on a scale of 0-3+.

RESULTS

Reduced E-cadherin expression was a distinct feature of primary SRCC and was observed in 78% of primary tumours. Interestingly, the E-cadherin reduction was less frequently seen in metastatic SRCC when compared with their primary counterparts, and was only found in 57% of tumours in lymph node metastases or at distant sites of relapse. Furthermore, the mean score of E-cadherin expression of primary SRCC was significantly lower than that of their metastatic counterparts (2.3 vs 1.8; p=0.008). When divided by organ systems, the reacquisition of E-cadherin expression in the metastatic deposits was most remarkable in the SRCC of upper gastrointestinal tract origin (2.3 vs 1.4; p=0.003), whereas no significant difference was observed in other organ systems.

CONCLUSIONS

While the reduction of E-cadherin in primary SRCC supports its pivotal role in epithelial-mesenchymal transition, a process crucial in tumour progression and metastatic dissemination, the re-expression of this molecule in metastatic SRCC cells implies a reversal to their epithelial phenotype (thus mesenchymal-epithelial transition) which, in turn, theoretically helps tumour cells to anchor and form cohesive metastatic deposits.

Identification of Signet Ring Cell Change in Colonic Subserosa in the Setting of Clostridium difficile Colitis

Signet ring cell change of intestinal epithelial cells is a rare but well-known mimicker of signet ring cell carcinoma and is often associated with ischemic and/or pseudomembranous colitis. Instead, signet ring cell change involving nonepithelial cells in the subserosa of the intestine is an extremely rare finding with only a single case report in the literature to date. We report a new case of benign signet ring cell change localized in the subserosa of the large bowel incidentally identified in a resection specimen for Clostridium difficile colitis mimicking a metastatic signet ring cell carcinoma. Based on the morphologic features and immunohistochemical profile, we propose that these signet ring cells may possibly represent modified/degenerated fat cells. Furthermore, we discuss how to differentiate benign signet ring cells from a signet ring cell carcinoma.

Hereditary diffuse gastric cancer: updated clinical guidelines with an emphasis on germline CDH1 mutation carriers

Germline CDH1 mutations confer a high lifetime risk of developing diffuse gastric (DGC) and lobular breast cancer (LBC). A multidisciplinary workshop was organised to discuss genetic testing, surgery, surveillance strategies, pathology reporting and the patient's perspective on multiple aspects, including diet post gastrectomy. The updated guidelines include revised CDH1 testing criteria (taking into account first-degree and second-degree relatives): (1) families with two or more patients with gastric cancer at any age, one confirmed DGC; (2) individuals with DGC before the age of 40 and (3) families with diagnoses of both DGC and LBC (one diagnosis before the age of 50). Additionally, CDH1 testing could be considered in patients with bilateral or familial LBC before the age of 50, patients with DGC and cleft lip/palate, and those with precursor lesions for signet ring cell carcinoma. Given the high mortality associated with invasive disease, prophylactic total gastrectomy at a centre of expertise is advised for individuals with pathogenic CDH1 mutations. Breast cancer surveillance with annual breast MRI starting at age 30 for women with a CDH1 mutation is recommended. Standardised endoscopic surveillance in experienced centres is recommended for those opting not to have gastrectomy at the current time, those with CDH1 variants of uncertain significance and those that fulfil hereditary DGC criteria without germline CDH1 mutations. Expert histopathological confirmation of (early) signet ring cell carcinoma is recommended. The impact of gastrectomy and mastectomy should not be underestimated; these can have severe consequences on a psychological, physiological and metabolic level. Nutritional problems should be carefully monitored.

Impact of aggressive histology and location of primary tumor on the efficacy of surgical therapy for peritoneal carcinomatosis of colorectal origin

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) for peritoneal carcinomatosis (PC) of colorectal origin increases survival (OS) compared to systemic chemotherapy alone. Signet ring histology demonstrates aggressive behavior with poor survival. We sought to determine whether CRS/HIPEC increases survival in this subset of patients.

METHODS

We reviewed 67 patients with PC of appendiceal (AP, n = 37) or colorectal origin (CRC, n = 30) with signet cell histology from a prospective database between May 2001 and August 2011. Survival analysis and multivariate Cox regression were used to determine prognostic factors for survival.

RESULTS

Complete CRS (CC-0/1) was achieved in 77 % (CRC) and 73 % (AP) of patients. Progression-free survival (PFS) and OS were 9 and 12 months in CRC and 12 and 21 months in AP patients. In the CRC group, univariate predictors of poor survival included female gender, age, American Society of Anesthesiologists score, preoperative albumin, completeness of cytoreduction, and morbidity. In a multivariate Cox regression model, incomplete cytoreduction (CC-2/3) and female gender were joint significant predictors of poor survival. In the AP group, significant univariate predictors of poor survival included higher EBL and PCI score. In a multivariate Cox regression model, blood loss of >500 ml and a body mass index of <25 kg/m(2) were joint significant predictors of poor survival.

CONCLUSIONS

AP signet cell tumors demonstrate a more favorable outcome than CRC signet cell tumors after CRC/HIPEC for carcinomatosis, suggesting an underlying difference in biology. CRS/HIPEC does not confer survival benefit in colorectal signet ring carcinomatosis unless complete cytoreduction can be achieved, whereas appendiceal signet ring carcinomatosis may benefit, regardless of resectability.

Nonneoplastic signet-ring cell change in gastrointestinal and biliary tracts: a pitfall for overdiagnosis

Nonneoplastic signet-ring cell change (SRCC) is a rare but known phenomenon in gastrointestinal and biliary tracts and is always associated with underlying mucosal ulceration/erosion secondary to infection, ischemia, or other etiology. Because nonneoplastic SRCC closely mimics signet-ring cell adenocarcinoma (SRCA), differentiation of these 2 entities is critical because misdiagnosis of nonneoplastic SRCC as SRCA can lead to intense therapeutic interventions such as surgery and/or chemoradiation therapy. In this review, a brief overview on nonneoplastic SRCC in gastrointestinal and biliary tracts, including the spectrum of clinical presentation, important histologic features, and immunohistochemical markers that are useful in differentiating nonneoplastic SRCC from SRCA, is provided. The pathogenesis of nonneoplastic SRCC in gastrointestinal and biliary tracts is discussed.

Biopsy interpretation of colonic biopsies when inflammatory bowel disease is excluded

The interpretation of colonic biopsies related to inflammatory conditions can be challenging because the colorectal mucosa has a limited repertoire of morphologic responses to various injurious agents. Only few processes have specific diagnostic features, and many of the various histological patterns reflect severity and duration of the disease. Importantly the correlation with endoscopic and clinical information is often cardinal to arrive at a specific diagnosis in many cases.

Metastatic gallbladder adenocarcinoma with signet-ring cells: A case report

INTRODUCTION

Signet-ring cell carcinoma is a rare and aggressive variant of mucinous adenocarcinoma. Only a few cases of gallbladder adenocarcinoma with signet-ring cells have been reported and because of this there is a lack of knowledge about the behavior and biology of this pathology.

CASE PRESENTATION

We present the case of a 63-year-old Arab man with gallbladder signet-ring cell adenocarcinoma. He had an elective cholecystectomy and refused chemotherapy. Two months later, a small hepatic metastatic nodule was found, and nine months later he presented with multiple metastases in the liver, lymphatic nodes, both pleuras, peritoneum and subcutaneous tissue.

CONCLUSION

The proliferation of signet-ring cells in a gallbladder adenocarcinoma worsens the prognosis of an already adverse neoplasm. New lines of treatment in chemotherapy, such as cisplatin, or new biological therapy, such as monoclonal antibody c-myc oncogene, should be encouraged to improve the survival and life quality of these oncologic patients.

Pseudoneoplasms of the gastrointestinal tract

CONTEXT

The pathologist plays the leading role in distinguishing pseudoneoplasms from truly neoplastic lesions in the gastrointestinal tract.

OBJECTIVE

This review was conducted to heighten awareness of pseudoneoplasms, to help differentiate among the various types of pseudoneoplasms, and to help distinguish pseudoneoplasms from malignancies.

DATA SOURCES

This review is based on the medical literature on pseudoneoplasms in MEDLINE and the authors' own experiences. Reference lists of retrieved articles were also reviewed to identify additional articles.

CONCLUSIONS

A classification of pseudoneoplasms, according to the mechanism of injury to the gastrointestinal tract, morphologic patterns, and heterotopia, may be useful in providing a diagnostic framework in which ancillary techniques often have a diagnostic role. Several pseudoneoplasms may be closely associated with true neoplasms (eg, malakoplakia, prolapsetype lesions) because of the nonspecific nature of the response of the intestine to injury.

Absence of E-cadherin expression distinguishes noncohesive from cohesive pancreatic cancer

PURPOSE

The role of E-cadherin in carcinogenesis is of great interest, but few studies have examined its relevance to pancreatic carcinoma.

EXPERIMENTAL DESIGN

We evaluated E-cadherin protein expression by immunohistochemistry in pancreatobiliary cancers having a noncohesive histologic phenotype (21 undifferentiated adenocarcinomas and 7 signet ring carcinomas), comparing the results with pancreatic cancers having a cohesive phenotype (25 moderately differentiated and 14 poorly differentiated adenocarcinomas).

RESULTS

Twenty of 21 undifferentiated cancers had complete absence of E-cadherin expression, as did two signet ring carcinomas. In contrast, cohesive cancers (n = 39) had E-cadherin labeling at the plasma membrane (P < 0.001). Subsets of cancers were also evaluated for beta-catenin expression. All of the cohesive lesions (n = 28) showed a membranous beta-catenin expression pattern, whereas noncohesive foci (n = 7) were characterized by either cytoplasmic labeling or complete absence of beta-catenin protein expression, suggestive of a deficient zonula adherens in noncohesive cancers. E-cadherin promoter hypermethylation was observed in an undifferentiated pancreatic cancer cell line, MiaPaCa-2, whereas two pancreatic cancer cell lines derived from differentiated lesions lacked any evidence of E-cadherin promoter methylation. No pattern of E-cadherin promoter methylation could be determined in three primary cancers having mixed histologic patterns (contained both cohesive and noncohesive foci). No somatic mutations in E-cadherin were identified in noncohesive pancreatic cancers having inactivated E-cadherin.

CONCLUSIONS

Noncohesive pancreatic cancers were characterized by the loss of E-cadherin protein expression. Promoter hypermethylation is a possible mechanism of E-cadherin gene silencing in a subset of these cancers.

Signet ring cell differentiation in mucinous colorectal carcinoma

Approximately 10% of all colorectal carcinomas are mucinous carcinomas, characterized by extracellular mucin. Occasionally, mucin accumulates intracellularly in these tumours, causing signet ring cell differentiation. We hypothesized that signet ring cells arise from a separate genetic pathway. In this study the molecular background of signet ring cell differentiation was investigated by analysing genetic changes, changes in the expression of adhesion molecules, and mucin content. Furthermore, its clinical relevance was addressed. Cell lines of colorectal tumours with non-mucinous (AC), mucinous (MC), and signet ring cell phenotype (MCSRC) were used for Multiplex Ligation-dependent Probe Amplification to detect deletions and amplifications in specific oncogenes and tumour suppressor genes. Furthermore, the expression of E-cadherin, beta-catenin, ITF (intestinal trefoil factor), and MUC2 in signet ring cells was studied by immunohistochemistry, immunofluorescence, and mRNA in situ hybridization. Results were validated using a large cohort of rectal carcinomas from which clinicopathological data were available. Specific amplifications and deletions in cell lines of AC, MC, and MCSRC were detected. Bcl-2 was amplified in MCSRC and MC cell lines, but not in AC cell lines. Bcl-2 FISH analysis confirmed this in patient material. Signet ring cells had decreased expression of adhesion molecules (E-cadherin, beta-catenin) and were strongly positive for ITF and MUC2, two peptides which are normally only produced by goblet cells. RNA in situ hybridization confirmed the production of ITF. Mucinous carcinomas with signet ring cell differentiation presented at a higher T stage than adenocarcinomas and mucinous carcinomas (16% pT4 versus 3-5%, p<0.001) and were more frequently node positive (77% vs 39-44%; p<0.001). Prognosis was significantly worse. In conclusion, the presence of signet ring cells in carcinomas with mucinous differentiation correlates with increased T-stage and poor prognosis. These cells, characterized by ITF and MUC2 production, show disruption of the E-cadherin/beta-catenin complex, as well as amplification of Bcl-2.

Post-Gastric Endoscopic Mucosal Resection Surveillance Biopsies: Evaluation of Mucosal Changes and Recognition of Potential Mimics of Residual Adenocarcinoma

Endoscopic mucosal resection (EMR) offers curative treatment for patients with node-negative early gastric carcinoma of less than 2 cm without ulceration or ulceration scar. Follow-up biopsies are frequently performed to ensure the absence of residual neoplasia. We performed a retrospective analysis of post-EMR biopsies from 33 patients who underwent gastric EMR. Histologic changes included inflammation (100%), stromal edema (97.0%), foveolar hyperplasia (78.8%), ectatic vessels (66.7%), epithelial atypia (60.6%), increased glandular mitoses (57.6%), epithelial anisonucleosis (54.5%), fibrinopurulent materials (51.5%), ischemia (48.5%), stromal hemorrhage (33.3%), mucin depletion (12.1%), clear cell degeneration (15.2%), and signet-ring cell-like change (6.1%). Especially, clear cell degeneration and signet-ring cell-like change were conspicuous in the area of ischemia. Residual adenocarcinomas were noted in 4 of 33 cases, and consistently showed high nuclear-to-cytoplasmic ratio with high glandular density. Glandular clear cell degeneration and/or signet-ring cell-like change were worrisome and sometimes difficult to be distinguished from residual neoplastic glands. However, these degenerative glands were usually embedded in a nondesmoplastic stroma and showed anisonucleosis of glandular epithelia. Mimics of residual adenocarcinoma, namely clear cell degeneration and signet-ring cell-like change should be judiciously assessed to avoid unnecessary surgery.

Signet ring cell infiltration in tubular adenoma of ascending colon

We present a case of signet ring cell infiltration in an adenomatous polyp of the ascending colon and review the literature. The patient had undergone resection of a mucin-producing adenocarcinoma of the proximal sigmoid colon seven months before the findings were reported. We presume that the signet ring cell aggregates are of metastatic origin.