Undifferentiated Gastric Carcinoma Research Articles

Gastrointestinal Stromal Tumor (GIST) masquerading as undifferentiated gastric carcinoma; a potential diagnostic pitfall

Abstract Introduction/Objective Epithelioid variant of the GIST can mimic carcinoma and misdiagnosis has grave implications in patient management. The purpose of this report is to describe such a case and to remind pathologists to keep epithelioid GIST in the differential. Methods/Case Report A 66-year-old male presented with melena for 2 weeks. Endoscopy showed a large, infiltrative, and ulcerated mass in the gastric fundus. CT imaging showed a 16 x 12 cm mass-like gastric wall thickening, most compatible with gastric carcinoma. The mass was biopsied, which showed sheets and clusters of anaplastic, large to medium sized polygonal epithelioid cells with areas of rhabdoid phenotype characteristic of an undifferentiated gastric carcinoma. Initial immunohistochemical stains including pancytokeratin and p40 showed negativity, prompting additional stains including Cam5.2, SOX10, CD45, synaptophysin, INSM1, EMA, CK7 and CK20- all of which were also negative. At this point the main diagnostic consideration was undifferentiated gastric carcinoma. However, for completion purposes, DOG1 stain was added that came back positive. Since rhabdoid morphology is a bit unusual, even for epithelioid GISTs, and literature review suggested that DOG1 positivity can be seen in up to 11% of carcinomas, confirmatory NGS testing was performed. This demonstrated a KIT W557R gene mutation, confirming the diagnosis of GIST. The patient was treated with imatinib and subsequent imaging showed decreased size and hypermetabolism of the gastric mass. Patient is alive with disease 6 months after the diagnosis. Results (if a Case Study enter NA) NA Conclusion Using a panel of appropriate immunohistochemical stains and keeping epithelioid GIST in the differential can help avoid this diagnostic pitfall.

SMARCA4-deficient undifferentiated gastric carcinoma: a case series and literature review.

Undifferentiated gastric carcinoma, characterized by anaplastic cells lacking distinct features of cytological or architectural differentiation, poses diagnostic and therapeutic challenges. Recent studies have suggested an association between this carcinoma and deficiencies in the SWI/SNF complex, particularly mutations in subunits such as SMARCA4. We herein report six cases of SMARCA4-deficient undifferentiated gastric carcinoma with molecular findings, highlighting the rarity and diagnostic pitfalls of this malignancy. Predominantly occurring in males over 50years, these cases presented with nonspecific symptoms and were often diagnosed at an advanced stage. Histologically, the tumors exhibited a sheet-like growth pattern, reduced or absent epithelial markers, and loss of BRG-1 expression, with molecular analysis confirming SMARCA4 gene mutations. The response to conventional chemotherapy was poor, underscoring the importance of complete surgical resection and the development of alternative treatment modalities.

Histogenetic insights and genetic landscape of fibromatosis-like undifferentiated gastric carcinoma: a focused study

BackgroundThe aim of this study was to elucidate the histogenesis and genetic underpinnings of fibromatosis-like undifferentiated gastric carcinoma (FLUGC), a rare pathological entity.MethodThrough a detailed analysis of seven cases, including histopathological evaluation, CTNNB1 gene mutation screening, human epidermal growth factor receptor 2 (HER2) protein level quantification, and HER2 gene amplification assessment to identify the pathological and molecular characteristics of FLUGC.ResultsOf the seven patients in this study, five were male and two were female (age: 39–73 years). Four patients presented with lesions in the gastric antrum and three had lesions in the lateral curvature of the stomach. Histopathologically, over 90% of the tumor consisted of aggressive fibromatosis-like tissue, including proliferating spindle fibroblasts and myofibroblasts and varying amounts of collagenous fibrous tissues. Undifferentiated cancer cells, accounting for less than 10%, were dispersed among the aggressive fibromatosis-like tissues. These cells were characterized by their small size and were relatively sparse without glandular ducts or nested mass-like structures. Immunophenotyping results showed positive expression of CKpan, CDX2, villin, and p53 in undifferentiated cancer cells; positive expression of vimentin in aggressive fibromatosis-like tissue; positive cytoplasmic expression of β-catenin; and focal cytoplasmic positive expression of smooth muscle actin (SMA). Genetic analysis did not reveal any mutations in the CTNNB1 gene test, nor was there amplification in the HER2 gene fluorescence in situ hybridization (FISH) test. Additionally, the Epstein-Barr encoding region (EBER) of in situ hybridization was negative; and the mismatch repair (MMR) protein was positive. Programmed cell death-1 (PD-1) was < 1–5%; programmed cell death ligand 1 (PD-L1): TPS = 1–4%, CPS = 3–8.ConclusionThe study highlights the significance of CTNNB1, HER2, EBER, and MMR as pivotal genetic markers in FLUGC, underscoring their relevance for diagnosis and clinical management. The rarity and distinct pathological features of FLUGC emphasize the importance of accurate diagnosis to prevent underdiagnosis or misdiagnosis and to raise awareness within the medical community.

Enhancement Patterns in Differentiated and Undifferentiated Gastric Carcinoma: Multiphasic Contrast-Enhanced Computed Tomography Versus Histopathology.

Background Gastric adenocarcinoma (GCA) poses a significant global health burden due to its prevalence and high morbidity and mortality rates. GCA is classified into three main histological types: well-differentiated (intestinal type), poorly differentiated (diffuse type), and mixed or indeterminate forms. These types vary in causes, epidemiology, and genetics, with the diffuse type often associated with the worst prognosis. Endoscopic biopsy is the primary method for characterization, but it has its limitations. There is potential in using contrast-enhanced computed tomography (CT) to differentiate between histological subtypes of gastric adenocarcinoma, which could aid subtype differentiation. Building on this, our study aims to assess CT's effectiveness in distinguishing between broad histological groups of gastric adenocarcinoma based on enhancement patterns, contributing to improved diagnostic accuracy Objective Our research focuses on evaluating the effectiveness of multiphasic contrast-enhanced computed tomography (CECT) in distinguishing between the three broad histopathological subtypes of gastrointestinal cancers. Methods This study was a prospective, analytical observational study that was approvedand carried out in our institutional tertiary care hospital. Consecutive individuals who had undergone endoscopic-guided biopsy and demonstrated histological evidence of GCA were taken into consideration for participation in the study. In order to complete the clinical staging process, further multiphasic CT scans were carried out on each of the fifty patients and were categorised accordingly based on the findings of histopathology. Results In the differentiated type, segmental distribution was: 5.5% upper segment, 16.7% middle segment, 66.7% lower segment, and 11.1% diffuse type. Esophageal involvement was 5.6%, duodenal involvement was similar, and lymph node involvement was approximately 38.8%. TNM staging: 38.8% IIIB, 22.2% III, 27.8% IVA, and 11.1% IVB. In the undifferentiated type, segmental distribution: 6.2% upper segment, 31.2% middle segment, 50.0% lower segment, and 12.5% diffuse type. Esophageal involvement was around 6.25%, duodenal involvement was 18.75%, and lymph node involvement was about 71.8%. TNM staging: 34.4% IIIB, 21.8% III, 28.1% IVA, and 15.6% IVB. Conclusion Multiphasic CT evaluations provide valuable insights into the prognostic aspects of gastric carcinomas by assessing peak enhancement. Differentiated tumors typically exhibit arterial phase enhancement, while undifferentiated tumors show venous phase enhancement, reflecting their microvascular architecture. Recent studies emphasize the importance of understanding gastric carcinoma characteristics for diagnosis and prognosis. Our research aligns with this, revealing distinct contrast enhancement patterns between differentiated and undifferentiated types. However, discrepancies in histological classifications and contrast enhancement patterns across studies warrant further investigation. Integrating histopathological and radiological insights is essential for accurate diagnosis and treatment planning.

Prognostic Factors and Survival Analysis in Undifferentiated Gastric Carcinoma

Prognostic Factors and Survival Analysis in Undifferentiated Gastric Carcinoma

S4129 An Extraordinarily Rare Case of SMARCA4-Deficient Undifferentiated Gastric Carcinoma

S4129 An Extraordinarily Rare Case of SMARCA4-Deficient Undifferentiated Gastric Carcinoma

S4147 SMARCA4 Deficient Undifferentiated Gastric Carcinoma with Metastasis

S4147 SMARCA4 Deficient Undifferentiated Gastric Carcinoma with Metastasis

Clinicopathological and prognostic significance of SWI/SNF complex subunits in undifferentiated gastric carcinoma

BackgroundThe switch/sucrose nonfermentable (SWI/SNF) complex is an evolutionarily conserved chromatin remodeling complex that displays dysfunction in many tumors, especially undifferentiated carcinoma. Cancer stem cells (CSC), a special type of undifferentiated cancer cells with stem cell-like properties, play an essential role in tumor cell proliferation, invasion, and metastasis. In undifferentiated gastric carcinomas, the association of SWI/SNF complexes with clinicopathological features, CSC phenotype, and the prognosis is not fully understood.MethodsWe collected a cohort of 21 patients with undifferentiated/dedifferentiated gastric carcinoma. We next performed immunohistochemistry staining for the five subunits of the SWI/SNF complex (ARID1A, ARID1B, SMARCA2, SMARCA4, and SMARCB1), and four mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6), as well as other markers such as p53, PD-L1, and cancer stem cell (CSC) markers (SOX2, SALL4). Then, we investigated the correlation of SWI/SNF complex subunits with clinicopathological characters and performed prognostic analysis.ResultsWe observed SMARCA2 loss in 12 cases (57.14%), followed by ARID1A (5 cases, 23.81%) and SMARCA4 (3 cases, 14.29%). Fourteen cases (66.67%) lost any one of the SWI/SNF complex subunits, including 3 cases with SMARCA2 and ARID1A co-loss, and 3 cases with SMARCA2 and SMARCA4 co-loss. Correlation analysis revealed that the CSC phenotype occurred more frequently in the SWI/SNF complex deficient group (P = 0.0158). Survival analysis revealed that SWI/WNF complex deficiency, undifferentiated status, CSC phenotype, and the loss of SMARCA2 and SMARCA4 resulted in worse survival. Univariate and multivariate Cox regression analyses screened out three independent factors associated with worse prognosis: undifferentiated status, SWI/SNF complex deficiency, and lymph node metastasis.ConclusionsThe SWI/SNF complex deficiency was more likely to result in a CSC phenotype and worse survival and was an independent prognostic factor in undifferentiated/dedifferentiated gastric carcinoma.

Successful treatment of immune-related cystitis by Chai-Ling-Tang (Sairei-To) in a gastric carcinoma patient: Case report and literature review

Immune checkpoint inhibitors (ICIs) have changed the landscape of advanced cancer treatment. However, immune checkpoint inhibitors can trigger effector T cells against self-antigens as well as tumor antigens, resulting in immune-related toxicities in normal organs, referred to as immune-related adverse events (irAEs). A 56-year-old man with undifferentiated gastric carcinoma received sintilimab plus paclitaxel and tegafur therapy. After five cycles of treatment, the patient was referred to the hospital for sudden onset urinary frequency, micturition pain, and urinary incontinence. Cystoscopy revealed the entire bladder mucosa was red and edematous but there was no evidence of tumor. Oral administration of Chai-Ling-Tang (Sairei-To) alleviated lower urinary tract symptoms (LUTS). Histological analysis revealed numerous infiltrates of CD3-positive and CD8-positive cells into the urothelium but no atypia, indicating a diagnosis of immune-related cystitis. Interestingly, the urothelial epithelium infiltrated by lymphocytes and subepithelial inflammatory cells strongly expressed cell boundary PD-L1. The dose of Chai-Ling-Tang was maintained and stopped 2 months later without recurrence of LUTS. Since recovering from cystitis, the patient remains alive with no disease progression. This report shows that Chai-Ling-Tang is safe and effective for treating immune-related cystitis. The detailed mechanism of action requires further investigation.

Enhancement pattern of differentiated and undifferentiated gastric carcinoma on multiphasic contrast-enhanced computed tomography.

PurposeTo study the enhancement pattern of differentiated and undifferentiated gastric carcinoma on multiphasic contrast-enhanced computed tomography (CT).Material and methodsSeventy patients with biopsy-proven gastric cancer underwent multiphasic contrast-enhanced CT. The CT protocol include plain, arterial, portal venous, and hepatic venous phase. Tumour size, location, peak-enhancement characteristics, and staging were evaluated.ResultsThe peak-enhancement type was ‘arterial’ in 20 out of 28 within the differentiated-type GCAs and ‘portalvenous’ in 37 out of 42 within the undifferentiated-type GCAs (c2 statistic with Yates correction = 23.3981, p < 0.00001). The maximum attenuation value was statistically significant for the arterial phase between differentiated and undifferentiated GCAs (p < 0.05).ConclusionsAssessing peak-enhancement in a multiphasic CT can help identify the histological subcategory of gastric carcinomas that has prognostic significance. Arterial phase peak-enhancement is frequently seen in differentiated carcinomas whereas venous phase peak-enhancement is seen in undifferentiated carcinomas.

S2931 A Rare Histologic Sub-Type of Mucinous Gastric Adenocarcinoma (MGC) in Liver Transplant Recipient

INTRODUCTION: The relationship between solid organ transplant recipients and development of de novo malignancies has been well established in the literature. Liver transplant recipients have a 20% risk of developing de novo malignancies at 10 years post-transplant, which increases to 55% at 15 years post-transplant. Most commonly, de novo malignancies in liver transplant recipients include lymphoproliferative disorder, non-Hodgkin Lymphoma, head and neck cancer, Kaposi Sarcoma, and esophageal carcinoma. CASE DESCRIPTION/METHODS: A 73 yo M from West Africa, non-smoker, with no reported EtoH/IVD use, h/o liver transplant in a setting of HBV liver disease on immunosuppressive therapy, h/o prostate cancer s/p prostatectomy, presented with complaint of dizziness, fatigue and tarry black stool for 1–2 weeks. The patient was found to have microcytic anemia with Hgb of 4.6 g/dL. He was admitted to ICU and pRBC transfusion. EGD showed likely malignant gastric tumor in the gastric antrum involving the incisura and extending to the pylorus and proximal duodenal bulb causing luminal narrowing (see images below). Labs were positive for slightly elevated CEA of 6.2 ng/mL. CT abdomen/pelvis showing thickening of gastric wall and enlarged celiac lymph node. Biopsy revealed MGC negative for HER2. DISCUSSION: MGC is a very rare subtype of undifferentiated gastric carcinoma, constituting 2–6% of all gastric cancers. WHO defines MGC as adenocarcinoma with >50% of extracellular mucin within tumors. Of the several mucin types, MUC2 was found to be strongly associated to MGC. It has been known that HER-2 and EGFR are poor prognostic indicators in stomach cancer patients, their clinical importance have not been investigated. The tumor size, macroscopic type, depth of invasion, lymph node metastasis, peritoneal metastasis and hepatic metastasis but not histological type, are significant predictive factors for survival. On review of the literature, we found that patients with MCG had more metastatic lymph node involvements and venous invasion compared to NMGCs. In addition to surgery, therapeutic agents that target oncogenes have attracted much attention. Anti-HER-2 monoclonal antibody(mAb) and an anti-EGFR mAb, have reached the clinical trial stage for gastric cancer treatments.Reports of gastric adenocarcinoma in liver transplant recipients appear in the literature as case reports or case series. This case highlights the importance of increasing index of suspicion for gastric malignancy in liver transplant recipients.Figure 1Figure 2

Risk Factors for Lymph Node Metastasis in Undifferentiated Early Gastric Cancer

The indication for endoscopic resection is differentiated gastric cancer ≤ 2 cm in size without an ulcer, of which the depth of invasion is clinically diagnosed as tumor confined to the mucosa. Endoscopic resection is not indicated for undifferentiated gastric intramucosal carcinoma, which is associated with a high rate of lymph node metastasis. This study aimed to analyze the factors associated with lymph node metastasis and to determine the validity of endoscopic resection in patients with undifferentiated early gastric cancer (EGC). This study included 141 patients who underwent gastrectomy with lymph node dissection for undifferentiated EGC. The clinicopathological findings were retrospectively analyzed to identify the factors associated with lymph node metastasis. According to the depth of tumor invasion, lymph node metastasis was observed in 13 patients (9.2%), including three with intramucosal carcinoma (3.6%) and ten with submucosal invasive carcinoma (17.2%). Univariate analysis identified tumor size (p = 0.038), depth of tumor invasion (p = 0.008), and lymphovascular invasion (LVI) (p = 0.0002) as risk factors for lymph node metastasis. On multivariate analysis, LVI (p = 0.002) was identified as the only independent risk factor for lymph node metastasis. The use of endoscopic resection for the undifferentiated EGC should be considered carefully for patients with LVI because of the risk for lymph node metastasis.

H. pylori infection and gastric cancer in Bangladesh: a case-control study.

Background:Like that of other Asian countries gastric cancer (GC) is also a leading cancer in Bangladesh and also a cause for cancer-related mortality. Infection with Helicobacter pylori (H. pylori) is the strongest recognized risk factor for gastric adenocarcinoma. The infection is also prevalent in common people. This case-control study was carried out to find an association between GC and H. pylori infection in the community.Materials and Methods:To evaluate association of H. pylori and carcinoma of stomach this study was conducted at National Institute of Cancer Research & Hospital, Dhaka from January 2013 to December 2014. H. pylori status was determined serologically by using H. pylori kit in the department of Biochemistry laboratory of Bangabandhu Sheikh Mujib Medical University. In total, 114 patients with GC and 520 patients not having GC were studied as controls. Logistic regression method was used to calculate the odds ratio.Results:Significantly more patients in the case group (86.8%) were found to be seropositive for H. pylori antigen in contrast to the control group (67.5%). All of the cases in the present study were in advanced stage. No significant association between H. pylori seropositivity and tumor location was found. It was noted that undifferentiated gastric carcinoma had slightly more association with H. pylori infection. Younger H. pylori–infected patients had been found to be at higher relative risk for GC than older patients.Conclusion:As there is a strong association found between GC and H. pylori infection special emphasis to eradicate H. pylori infection might reduce the incidence of this dreadly disease.

Gastric metastases mimicking primary gastric cancer: A brief literature review

Gastric cancer is the fifth most common cancer worldwide, with most cases presenting in the form of primary tumors. In this paper, we performed a literature review on the incidence and particularities of extragastric metastases. These lesions are rare in clinical practice and can be misdiagnosed as primary undifferentiated gastric carcinomas as the differential diagnosis between primary and secondary malignancy is difficult to make. As per the literature, the most common malignancies which can present gastric metastases are lung cancer, followed by carcinoma of the breast, esophagus, kidney, and head and neck carcinomas. Malignant melanoma, ovarian cancer, prostate cancer, and adrenal gland carcinomas are rarely described as presenting metastases in the stomach. In most cases, the literature addressed poorly differentiated tumors with high-grade malignancy. The most common feature was the ulcerated tumor with depressed area, associated with identifiable extragastric tumor cells in the gastric submucosa. The linitis plastica-like feature is unusual and is more characteristic of breast lobular carcinoma. The accurate diagnosis of such rare extragastric metastatic cases depends on the appropriate clinical history and precise pathological diagnosis, which is mandatory for initiating the best therapeutic options.

Epstein-Barr virus and carcinomas: rare association of the virus with gastric adenocarcinomas.

We have analysed 174 gastric carcinomas from the United Kingdom and from Japan for the presence of Epstein-Barr virus (EBV) using in situ hybridisation for the small EBV-encoded nuclear RNAs (EBERs). EBV was detected in the tumour cells in all of six undifferentiated gastric carcinomas with prominent lymphoid stroma (undifferentiated carcinomas of nasopharyngeal type, UCNT) but only in three of the remaining 168 typical gastric adenocarcinomas (1.8%). No differences were observed between the British and the Japanese cases. One case with an EBV-positive UCNT showed adjacent areas of EBV-negative typical adenocarcinoma. It is uncertain whether these patterns represent two independent carcinomas or whether they are the result of heterogeneous EBV infection in a single tumour. In the remaining EBV-positive carcinomas, viral transcripts were detected in virtually all tumour cells, indicating that EBV infection must have taken place early in the neoplastic process and suggesting that the virus is likely to be of pathogenetic significance for the virus-associated tumours. Immunohistology demonstrated absence of detectable levels of the EBV-encoded latent membrane protein, LMP1, and nuclear antigen, EBNA2. The BZLF1 protein which induces the switch from latent to lytic infection was demonstrated in a small proportion of the tumour cells in three cases. The close association of EBV with undifferentiated gastric carcinomas compared to the variable association with gastric adenocarcinomas suggests fundamentally different roles for the virus in the aetiology of these two malignancies.

Characteristics and prognosis of mucinous gastric carcinoma.

Mucinous gastric carcinoma (MGC) is a rare histological subtype of undifferentiated gastric carcinoma, accounting for ~2.6-6.6% of all gastric cancer cases. The clinicopathological characteristics and prognosis of MGC are controversial. The present study aimed to determine the clinicopathological characteristics and prognosis of patients with MGC. We retrospectively compared the characteristics and postoperative survival of 70 patients with MGC and 2,492 non-MGC (NMGC) cases who underwent surgical resection between 1990 and 2010. MGC was characterised by larger tumor size, macroscopic Borrmann type 2 and 3, T4 invasion of the gastric wall, positive N2 and N3 lymph node metastasis, positive lymphatic vessel invasion, positive venous invasion, peritoneal metastasis and advanced tumor stage III and IV. The prognosis of MGC patients was worse compared to that of NMGC patients, as the former group consisted of more advanced-stage cases. When patients with similar disease stages were compared, the incidence of peritoneal metastasis was significantly higher among MGC patients. However, hepatic metastasis was found significantly more often in NMGC patients. Otherwise, the prognosis of MGC and NMGC patients with similar disease stages was not significantly different. Therefore, our findings indicated that, although MGC is more rare and mostly detected at an advanced stage, the diagnosis of the mucinous histological subtype was not an independent prognostic factor.

Our experience of treating undifferentiated gastric carcinoma: report of four cases

Undifferentiated gastric carcinoma is a rare histopathological type of cancer that does not show any differentiation toward adenocarcinoma or squamous cell carcinoma. It is thought to be highly malignant, and is associated with a poor prognosis. However, its clinical behavior has not yet been fully analyzed because of its rarity. We herein review the clinical characteristics and prognoses of patients with undifferentiated gastric carcinoma treated at our institutions. Among 2,651 gastric cancer patients, four (0.2 %) were histopathologically diagnosed to have undifferentiated carcinoma. These four patients included three males and one female. The median age of the patients was 60-year old (range 47-75). Three cases had distant metastases at diagnosis. One of these three cases was treated with chemotherapy alone, and the other two were treated with palliative gastrectomy and chemotherapy. The patient with no distant metastasis underwent curative gastrectomy and adjuvant chemotherapy. All patients died of cancer at a median of 5.4 (range 3.5-7.1) months after their diagnoses.

Pyruvate Kinase M2 Plays a Dual Role on Regulation of the EGF/EGFR Signaling via E-Cadherin-Dependent Manner in Gastric Cancer Cells

Background and AimsEGFR activation and PKM2 expression are instrumental in tumorigenesis. EGFR activation regulates PKM2 functions in a subcellular compartment-dependent manner and promotes gene transcription and tumor growth. In addition, PKM2 is upregulated in EGFR-induced pathways in glioma malignancies. However, we found that PKM2 could also regulate the activity of the EGF/EGFR signaling pathway in gastric cancer cells. We aimed to define the biological mechanisms for PKM2 in regulating the cell motility and invasion.MethodsWe employed stable transfection with short hairpin RNA to stably silence the expression of PKM2 in the BGC823, SGC7901 and AGS gastric cancer cell lines. The effects of PKM2 in vitro were determined by assessing cell migration and invasion. Immunohistochemical analysis was used to explore the relationship among PKM2 and other proteins.ResultsOur results indicate that the knockdown of PKM2 decreased the activity of E-cadherin and enhanced the EGF/EGFR signaling pathway in the gastric cell lines BGC823 and SGC7901 that were positive for E-cadherin expression. However, in the undifferentiated gastric carcinoma cell line AGS, which lacks E-cadherin expression, PKM2 promoted cell migration and invasion. Immunohistochemical analyses showed that the levels of E-cadherin expression, ERK1/2 phosphorylation, and cytoplasmic PKM2 expression were correlated with each other.Conclusion:PKM2 may play different roles in differently differentiated gastric cancer cell types, and this finding would be consistent with the previous clinical research. The results of our study reveal an important link between PKM2 and E-cadherin during EGFR-stimulated gastric cancer cell motility and invasion.

Gastric Cancer Staging with Dual Energy Spectral CT Imaging

PurposeTo evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers.Materials and Methods96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings.ResultsThe overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP.ConclusionThe monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes.

Clinicopathological characteristics and prognosis of signet ring cell carcinoma of the stomach

Signet ring cell carcinoma (SRC) of the stomach is a histological type based on microscopic characteristics. Although the distinctive clinicopathological features of SRC have been reported, results are inconsistent and survival outcomes are uncertain. We retrospectively studied 769 patients with gastric carcinoma who underwent gastrectomy in our institute from 1999 to 2009. Among them, 326 patients (42.4 %) had early gastric cancer (EGC) and 443 patients (57.6 %) had advanced gastric cancer (AGC). Sex, age, tumor location, macroscopic type, tumor size, microscopic invasion, and survival rate were compared between patients with SRC, differentiated-, and undifferentiated-type gastric carcinomas. Fifty-one patients (15.6 %) had SRC in EGC; there were significant differences in sex, age, location, macroscopic type, and size between SRC and the differentiated histological type. However, there was no difference between SRC and undifferentiated-type gastric carcinoma, except for the macroscopic type. Fifty-seven patients (12.9 %) had SRC in AGC. Sex, age, location, size, macroscopic type, perineural invasion, N stage, and hepatic metastasis were significantly different between SRC and the differentiated histological type. Undifferentiated-type gastric carcinoma differed in sex, macroscopic type, and hepatic metastasis. The overall survival rate differed between SRC and other cell types (P < 0.001). Among all the study patients, age [hazard ratio (HR) 1.013, P = 0.041] and tumor, node, and metastasis (TNM) stage (HR 2.350, P < 0.001) were important factors for predicting survival. Omitting patients with palliative resection or metastases, TNM stage was still an important factor for survival (HR 2.077, P < 0.001). Patients with SRC showed similar clinicopathological features with undifferentiated histology. The survival of patients with SRC reflected a better prognosis in patients with undifferentiated gastric carcinoma. However, when narrowing the patients to those with EGC only, survival in EGC patients exhibited no difference between histological types. Among AGC patients, SRC patients had a worse prognosis than other cell types.