Omental Lesions Research Articles

6688 Clinical Presentation and Management of Highly Differentiated Follicular Carcinoma Arising from Struma Ovarii with DICER1 Mutation: A Case Report

Abstract Disclosure: S.M. Seav: None. J. Shah: None. C. Dosiou: None. Background: Struma ovarii (SO) is a rare type of ovarian teratoma comprised of > 50% thyroid tissue. Extra-ovarian spread of SO, called peritoneal strumosis, was previously considered benign given the lack of histological malignant features. The 2020 WHO Classification of Female Genital Tumors has reclassified this as highly differentiated follicular carcinoma arising from struma ovarii (HDFCO), highlighting its low-grade malignant potential.[1] We report a case of HDFCO with extensive peritoneal disease and discuss its management. Clinical Case: A 38-year-old female presented to her OBGYN for irregular menses. Pelvic MRI showed an 8 cm right ovarian mass. Right salpingo-oopherectomy and pelvic peritoneal biopsies revealed well-differentiated thyroid tissue. Thyroid ultrasound demonstrated a multinodular goiter with ATA high risk nodules; 4 of 5 biopsied with benign results. Her thyroglobulin (Tg) was 170 ng/mL (normal 2 – 35 ng/ml). No further intervention was recommended. Two years later she was referred to our clinic. CT of abdomen/pelvis showed multifocal residual disease. We recommended more aggressive management, given the diagnosis of HDFCO. All visible disease was resected in a diagnostic laparoscopy with pelvic and omental biopsies. Pathology showed well-differentiated thyroid tissue. Molecular testing for the FGFR4 mutation associated with HDFCO was negative, but there was a DICER1 mutation c.5428 G>T of undetermined significance. DICER1 mutations are associated with thyroid cancers2. A total thyroidectomy and radioactive iodine ablation (RAI) were recommended. Thyroid pathology was benign. Tg was 9 ng/mL one month post-op. MRI six months post-laparoscopy revealed only one 6 mm omental lesion. Withdrawal I-123 whole body scan (WBS) showed multiple peritoneal implants. Tg was 214 ng/mL and TSH was 72 ulU/mL. The patient was treated with 157 mCi of oral I-131. Given the extensive peritoneal disease, she received prophylactic oral dexamethasone for 2 weeks after RAI to decrease the risk of peritoneal inflammation and bowel obstruction potentially mediated by local inflammation from radiation-related tissue injury. Her Tg three months post-RAI was 4 ng/mL. The surveillance plan is to alternate between RAI WBS and MRI abdomen/pelvis every 6 months. Conclusions: Peritoneal strumosis, previously considered benign, has recently been reclassified as HFDCO, an extremely rare low-grade malignancy with no standardized treatment. We report the first case of extensive HFDCO with a DICER1 mutation. Given the significant peritoneal involvement, our case was treated with total thyroidectomy, surgical excision of all implants, RAI, and prophylactic steroids post-RAI. Further research into the prognostic factors and optimal treatment of HFDCO is needed. Reference: [1]Giovanopoulou et al. Curr Oncol. 2022; 29(12): 9105-9116. 2Sauer et al. Head Neck Pathol. 2022; 16(1): 190–199. Presentation: 6/1/2024

Determination of the diagnostic accuracy of peritoneal biopsy with an 18G cutting needle under ultrasonography guidance and the contribution of CT findings to diagnosis before biopsy (our 8-year clinical experience)

Ultrasound-guided percutaneous core needle biopsy is an important technique in diagnosing mesenteric involvement. Diagnostic results were compared with pre-biopsy CT findings. The purpose of this study was to determine the diagnostic efficiency of omental lesion biopsies performed under ultrasound guidance and to investigate the relationship between pre-biopsy diagnostic CT findings. Demographic data of 70 patients who underwent omental biopsy under ultrasound guidance in our clinic between August 2015 and July 2023, the presence of a primary malignancy focus during the investigations conducted during the research, biopsy histopathology results, and pre-biopsy CT findings were retrospectively reviewed. This retrospective study included who underwent omental biopsy under ultrasound guidance, 48 (69%) were female, and 22 (31%) were male, with an average age of 61 (age range 15-95), and an average body mass index [BMI] of 27.7±6.9. Five (7%) of the 70 biopsy procedures were not pathologically diagnostic. Diagnostic results were compared with pre-biopsy CT findings. In all omental lesions, the percentage of omental infiltrative involvement in diagnostic CT was subjectively evaluated by two radiologists. 65 patients diagnosed pathologically, 47 (67%) were malignant, and 18 (26%) were benign. No complications occurred. Peritoneal biopsies under ultrasound guidance for mesenteric diseases detected on CT are a reliable procedure that can be easily applied. Ultrasonography imaging helps identify appropriate locations for targeted biopsies before deep percutaneous biopsy, increasing diagnostic accuracy, especially when omental lesions appear as infiltrative thickenings.

Important Predictive Factors for the Prognosis of Patients With Peritoneal Metastasis of Gastric Cancer.

This study investigated predictive factors for patients with peritoneal metastases of gastric cancer (PMGC) who underwent conversion cytoreductive surgery (C-CRS) and hyperthermic intraperitoneal intraoperative chemotherapy (HIPEC) after responding to induction chemotherapy (laparoscopic HIPEC [LHIPEC]) followed by concomitant systemic and intraperitoneal chemotherapy (bidirectional intraperitoneal and systemic chemotherapy [BIC]). Diagnostic laparoscopy was performed for 62 patients with PMGC between January 2017 and December 2022. The patients underwent LHIPEC and BIC induction chemotherapy using intraperitoneal docetaxel (30mg/m2) and cisplatin (30mg/m2), and intravenous chemotherapy for three cycles. The predictive parameters for progression-free and overall survival were analyzed using Kaplan-Meier and Cox regression analyses. The optimal cutoff values for Ki-67 parameters were assessed using receiver operating characteristic curve analysis. The study retrospectively examined 36 (58 %) of 62 patients who responded to induction therapy and underwent C-CRS or HIPEC. A Ki-67 index lower than 10 (p = 0.000), lymph node involvement (LNI) less than 2 (p = 0.039), and an omental lesion size score lower than 0.5 cm (p = 0.002) were predictive of recurrence-free and overall survival in addition to completeness of cytoreduction and the peritoneal cancer index. Cox regression analysis showed that the independent factors associated with recurrence-free survival were decreased Ki-67 expression (≥10 % vs <10 %) (hazard ratio [HR] 4.7; 95 % confidence interval [CI] 1.6-5.210; p = 0.020) and LNI higher than 2 (HR 1.92; 95% CIS 0.923-4.0; p = 0.023). Lymph node involvement and decreased Ki-67 expression are independent predictive factors of recurrence-free survival for patients with PMGC after induction chemotherapy.

Deep learning-based segmentation of multisite disease in ovarian cancer

PurposeTo determine if pelvic/ovarian and omental lesions of ovarian cancer can be reliably segmented on computed tomography (CT) using fully automated deep learning-based methods.MethodsA deep learning model for the two most common disease sites of high-grade serous ovarian cancer lesions (pelvis/ovaries and omentum) was developed and compared against the well-established “no-new-Net” framework and unrevised trainee radiologist segmentations. A total of 451 CT scans collected from four different institutions were used for training (n = 276), evaluation (n = 104) and testing (n = 71) of the methods. The performance was evaluated using the Dice similarity coefficient (DSC) and compared using a Wilcoxon test.ResultsOur model outperformed no-new-Net for the pelvic/ovarian lesions in cross-validation, on the evaluation and test set by a significant margin (p values being 4 × 10–7, 3 × 10–4, 4 × 10–2, respectively), and for the omental lesions on the evaluation set (p = 1 × 10–3). Our model did not perform significantly differently in segmenting pelvic/ovarian lesions (p = 0.371) compared to a trainee radiologist. On an independent test set, the model achieved a DSC performance of 71 ± 20 (mean ± standard deviation) for pelvic/ovarian and 61 ± 24 for omental lesions.ConclusionAutomated ovarian cancer segmentation on CT scans using deep neural networks is feasible and achieves performance close to a trainee-level radiologist for pelvic/ovarian lesions.Relevance statementAutomated segmentation of ovarian cancer may be used by clinicians for CT-based volumetric assessments and researchers for building complex analysis pipelines.Key points• The first automated approach for pelvic/ovarian and omental ovarian cancer lesion segmentation on CT images has been presented.• Automated segmentation of ovarian cancer lesions can be comparable with manual segmentation of trainee radiologists.• Careful hyperparameter tuning can provide models significantly outperforming strong state-of-the-art baselines.Graphical

Direct trocar insertion vs. Veress needle technique in laparoscopic surgeries. A systematic review and meta-analysis

To compare the safety and efficacy between Veress needle insertion and direct trocar insertion in laparoscopic surgeries. Relevant clinical trials were retrieved from major databases; Web of Science, Cochrane CENTRAL, PubMed, and SCOPUS. The following outcomes were pooled for analysis: failed entry, extraperitoneal insufflation, vascular lesion, omental lesion and visceral lesion, site bleeding, reintervention, subcutaneous emphysema, solid organ lesion, and infection of the trocar site. A fixed-effects model was used to analyze homogeneous outcomes, whereas random-effects models were used to analyze heterogeneous outcomes. We included a total of twelve clinical trials. The pooled analysis showed that the Veress needle was accompanied by a significant increase in the incidences of extraperitoneal insufflation (RR=0.204; 95% Cl [0.136, 0.307], P=0.001), omental lesion (RR=0.444 95% Cl [0.239, 0.825], P=0.01), and failed entry (RR=0.169 95% Cl [0.101, 0.284], P=0.001). There is no significant difference between both cohort regarding the vascular lesion (RR=0.847 95% Cl [0.259, 2.777), P=0.7), infection of the trocar site (RR=0.583 95%Cl [0.106, 3.216], P=0.5, and visceral lesion (RR=1.308 95% Cl [0.314, 5.438], P=0.7. The DTI was accompanied by a significantly lower incidence of complications such as extraperitoneal insufflation, failed entry, omental lesion, and subcutaneous emphysema. On the other hand, both cohorts showed similar results regarding; vascular lesions, visceral lesions, reintervention, site bleeding, and solid organ lesion.

Spatial heterogeneity of infiltrating T cells in high-grade serous ovarian cancer revealed by multi-omics analysis

Tumor-infiltrating lymphocytes (TILs), especially CD8+ TILs, represent a favorable prognostic factor in high-grade serous ovarian cancer (HGSOC) and other tumor lineages. Here, we analyze the spatial heterogeneity of different TIL subtypes in HGSOC. We integrated RNA sequencing, whole-genome sequencing, bulk Tcell receptor (TCR) sequencing, as well as single-cell RNA/TCR sequencing to investigate the characteristics and differential composition of TILs across different HGSOC sites. Two immune "cold" patterns in ovarian cancer are identified: (1) ovarian lesions with low infiltration of mainly dysfunctional Tcells and immunosuppressive Treg cells and (2) omental lesions infiltrated with non-tumor-specific bystander cells. Exhausted CD8 Tcells that are preferentially enriched in ovarian tumors exhibit evidence for expansion and cytotoxic activity. Inherent tumor immune microenvironment characteristics appear to be the main contributor to the spatial differences in TIL status. The landscape of spatial heterogeneity of TILs may inform potential strategies for therapeutic manipulation in HGSOC.

Diagnostic Value of CT Window Technique for Primary Omentum Infarction.

Objective The diagnostic value of CT window width technique in primary omentum infarction was evaluated by this study. Methods The abdominal CT data of 32 patients with clinically diagnosed abdominal omentum infarction were retrospectively selected and analyzed. The fixed window position was 50 HU, and the window width was 135 HU, 250 HU (abdomen), 350 HU (mediastinum), and 500 HU, respectively. The detection rate of lesions was analyzed and compared. Results Window widths of 135 HU, 250 HU (abdomen), 350 HU (mediastinum), and 500 HU have a detection rate of 12.5% (4 cases), 62.5% (20 cases), 100% (32 cases), 100% (32 cases) for abdominal omental lesions, respectively. However, 500 HU showed worse abdominal bowel and parenchymal organs than 350 HU. Conclusion According to the comprehensive image quality, the ideal window width for diagnosis of primary omentum infarction is 350HU (mediastinal) window width.

Multi-omics analysis reveals spatial heterogeneity of infiltrating T cells in high-grade serous ovarian cancer.

e17603 Background: The effect of spatial immunologic variation, especially in T cell infiltration, recognition and expansion, across various tumor foci in the ovary (primary) and distant metastatic foci in the peritoneal cavity and their contribution to the limited response to immune therapy in High-Grade Serous Ovarian Cancer(HGSOC) remains unexplored. We aim to provide a detailed analysis of the landscape of heterogeneity of infiltrating T cells in primary and metastatic lesions and their differential characteristics in HGSOC. Methods: We performed multi-site sampling and simultaneous RNA sequencing (RNA-seq), whole-genome sequencing (WGS) and bulk T cell receptor (TCR) sequencing as well as single cell RNA sequencing (scRNA-seq) and paired TCR sequencing (scTCR-seq) in 9 patients (48 sites, including 19 ovarian, 11 omental, 18 other metastasis lesions) with untreated primary HGSOC. Validation by IHC, flow cytometry, another scRNA-seq data from 7 patients (32 sites, including 9 ovarian, 6 omental, 6 ascites and 11 other metastasis lesions) and spatial transcriptomics. Results: CD8 exhausted clusters that are enriched in ovarian tumors exhibited high exhaustion, tumor-specific score and low bystander score, whereas CD8 transition and NK-like clusters that are enriched in omental tumors exhibited the opposite characteristics, which was confirmed by flow cytometry. Of note, the exhausted CD8+ T cells exhibited GZMB, PRF1, FASLG and IFNG effector genes despite the expression of exhaustion markers, developing from an early differentiation state with high proliferative capacity and the process preferentially occurs in primary ovarian sites. Besides, T cells corresponding to the selected TCRs that had the same distribution as neoantigens were enriched in ovarian lesions, while the virus-specific TCR preferentially enriched in omentum samples. The association of TMB, HRD score, and COSMIC mutational signatures with antigen-engaged T cell subsets was not observed at the site level within individual patients. STARTRAC-migration analysis showed that T cell clusters in blood or other sites migrating to ovarian was extremely low or vice versa. The expression of MHC-I processing and presentation genes and MHC-I protein were higher in omental lesions, along with T cells were preferentially located in tumor region of ovarian tumors. Conclusions: We identify two different immune patterns in ovarian cancer: 1) ovarian lesions with low infiltration of mainly dysfunctional T cells and immunosuppressive Treg cells. These exhausted CD8 T cells with cytotoxic function are clonal expanded; 2) omental lesions infiltrated with non-tumor-specific bystander cells. Decreased major histocompatibility complex (MHC)-I antigen presentation ability and failure of T cell infiltration into omental tumors may contribute to lack of tumor-specific T cells in omental metastasis.

The role of cytology as an effective tool in management of omental and peritoneal lesions: Experience of a large health care system.

The aim of this study is to assess the efficacy of cytology in omental or peritoneal lesions. A retrospective review of the pathology database for cytology cases of peritoneal or omental nodules over a 3-year period (2016-2018) was conducted. The cases consisted of either FNA only (FO); FNA and Core biopsy (FCB) or Touch prep and core biopsy (TCB). Cases were further divided based on the prior history of carcinoma. Concordance rates of cytologic diagnosis with histologic diagnosis were studied. Out of 104 cytology cases reviewed, 60 (57.7%) had prior history of cancer (PHC) and 44 (42.3%) had no prior history of cancer (NPHC). Of the cases with PHC, 43(71.66%) were recurrence, 10 (16.66%) were second cancer, and 7 (11.66%) were non-neoplastic lesions. Of the cases with NPHC, 38 (86.4%) had a second cancer diagnosis, while 6 (13.6%) were non-neoplastic. For FO only cases, 11 of 35 (31.4%) had follow up and 9 of 11 (81.8%) were concordant. For FCB cases, 6 out of 39 (15.4%) had follow up and 6 (100%) were concordant. For TCB cases, 9 out of 30 (30%) had follow up and 9 (100%) were concordant. A definite diagnosis was reached in 30/35, 39/39, and 29/30 cases in FO, FCB, and TCB, respectively. In summary, cytologic evaluation of omental lesions is an effective tool in providing accurate diagnosis and guiding further management. Also, the results based on our study show that the combined techniques are superior at reaching a definitive diagnosis.

Endoscopic ultrasound guided fine needle biopsy (EUS-FNB) from peritoneal lesions: a prospective cohort pilot study

BackgroundDiagnostic laparoscopy is often a necessary, albeit invasive, procedure to help resolve undiagnosed peritoneal diseases. Previous retrospective studies reported that EUS-FNA is feasible on peritoneal and omental lesions, however, EUS-FNA provided a limited amount of tissue for immunohistochemistry stain (IHC).AimThis pilot study aims to prospectively determine the effectiveness of EUS-FNB regarding adequacy of tissue for IHC staining, diagnostic rate and the avoidance rate of diagnostic laparoscopy or percutaneous biopsy in patients with these lesions.MethodsFrom March 2017 to June 2018, patients with peritoneal or omental lesions identified by CT or MRI at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand were prospectively enrolled in the study. All Patients underwent EUS-FNB. For those with negative pathological results of EUS-FNB, percutaneous biopsy or diagnostic laparoscopy was planned. Analysis uses percentages only due to small sample sizes.ResultsA total of 30 EUS-FNB passes were completed, with a median of 3 passes (range 2–3 passes) per case. For EUS-FNB, the sensitivity, specificity, PPV, NPV and accuracy of EUS-FNB from peritoneal lesions were 63.6%, 100%, 100%, 20% and 66.7% respectively. Adequate tissue for IHC stain was found in 25/30 passes (80%). The tissues from EUS results were found malignant in 7/12 patients (58.3%). IHC could be done in 10/12 patients (83.3%). Among the five patients with negative EUS results, two underwent either liver biopsy of mass or abdominal paracentesis, showing gallbladder cancer and adenocarcinoma. Two patients refused laparoscopy due to advanced pancreatic cancer and worsening ovarian cancer. The fifth patient had post-surgical inflammation only with spontaneous resolution. The avoidance rate of laparoscopic diagnosis was 58.3%. No major adverse event was observed.ConclusionsEUS-FNB from peritoneal lesions provided sufficient core tissue for diagnosis and IHC. Diagnostic laparoscopy can often be avoided in patients with peritoneal lesions.

Abstract 3000: Zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in ovarian cancer patients

Abstract Precision medicine approaches based on DNA or RNA analyses, are often not identifying actionable mutations in the patients, and have not been established for predicting presonse to commonly used drugs such as platins and taxols. In epithelial ovarian cancer (EOC), where paclitaxel and carboplatin is the most commonly used first-line treatment, however, local practice and a host of clinical studies have/are evaluating combinations with other drugs, implying that first line treatment regimens may vary in different countries and regions. As EOC patients that respond to first-line treatment have much better prognosis that those who don't, there is an urgent need for methods to predict the outcome to various available first line therapies, prior to treatment onset, so that the optimal treatment can be identified and offered to every patient. Zebrafish tumor xenograft (ZTX) models have recently been used to predict treatment outcome to first line therapy in multiple myeloma, neuroendocrine cancer, colorectal cancer and gastric cancer, but these studies have been small case studies including only a few patients. Furthermore, EOC, and the main drugs used to treat them have, however, not been studied in ZTX models in the past. Here we present results from the first 81 patients in an ongoing clinical study to delineate the sensitivity and specificity of ZTX models to predict treatment outcome to paclitaxel and carboplatin. Of these 81 patients, 21 presented with a primary tumor only, whereas 60 had metastatic disease. To date, 25 patient-derived tumor xenograft models have been developed by random selection of samples from this patient cohort, of which 12 were from paired primary and metastatic lesions from 6 patients. We show that tumors generated from metastatic omental lesions exhibited similar growth and metastatic dissemination as those generated from samples taken from ovarian lesions. Among the 25 patient models generated, 15 were analyzed for efficacy of paclitaxel and carboplatin in the ZTX models. We found that 11 of 15 responded to paclitaxel, 12 of 15 to carboplatin and 10 of 15 to both drugs. In conclusion, ZTX EOC models established from surgical samples allow prediction of treatment outcomes to 1st line treatment and thereby may aid treatment planning in the future. Citation Format: Karthik Selvaraj, Malin Vildevall, Lina Wirestam, Zaheer Ali, Anna Erkstam, Annelie Abrahamsson, Åsa Rydmark Kersley, Preben Kjölhede, Stig Linder, Charlotta Dabrosin, Anna Fahlgren, Lasse Jensen. Zebrafish tumor-derived xenograft-models for improved diagnosis and treatment planning in ovarian cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3000.

Greater Omentum Imaging-Reporting and Data System: establishing the grade of benign and malignant lesions of the greater omentum using ultrasonography

ObjectiveTo establish Greater Omentum Imaging-Reporting and Data System (GOI-RADS) to evaluate the possibility of omental diseases being malignant.MethodA retrospective analysis was made of 883 patients who had undergone biopsy of the greater omentum in our center from October 2009 to October 2019. Twelve parameters of ultrasonographic images were evaluated, and the odds ratio of each group calculated. We assigned scores for the direct signs (omental echo, omental structure, and omental nodules) and indirect signs (separation of ascites, echo of ascites, mesenteric lymph nodes, and thickening of parietal peritoneum) of omental lesions. We created an omental score (OS) for each patient and receiver operating characteristic (ROC) curve to analyze its effectiveness in the differential diagnosis of benign and malignant omental diseases.ResultsThe OS was divided into ≤5, 6, 7, 8, 9, 10, 11, 12, 13, and ≥ 14 points, and the malignant rate was 0, 1.85, 5.56, 30.36, 37.25, 87.72, 96.72, 98.28, 99.08, and 100%, respectively. The area under the ROC curve (AUC) was 0.976. When taking 10 points as the cutoff value to diagnose benign and malignant omental diseases, the sensitivity and specificity was 93.85 and 98.21%, respectively. A grading system was established: grade 1: omental score ≤ 5, malignant rate 0%; grade 2: omental score 6–7, malignant rate ≤ 5.56%; grade 3: omental score 8-–9, malignant rate ≤ 37.25%; grade 4: omental score ≥ 10, malignant rate ≥ 87.72.ConclusionGOI-RADS had high sensitivity and specificity in the differential diagnosis of benign and malignant omental lesions. We believe that GOI-RADS will aid the diagnosis of omental diseases based on objective and accurate interpretation of ultrasound features, and also to promote the ultrasonography of omental diseases in clinical application.

The Role of Cytology as an Effective Tool in Management of Omental and Peritoneal Lesions: Experience of a Large Health Care System

The Role of Cytology as an Effective Tool in Management of Omental and Peritoneal Lesions: Experience of a Large Health Care System

Immune Heterogeneity Between Primary Tumors and Corresponding Metastatic Lesions and Response to Platinum Therapy in Primary Ovarian Cancer.

CD3+ and CD8+ lymphocytes are well known prognostic markers in primary ovarian cancer. In contrast, the predictive value of the immune infiltrate concerning treatment response and the involvement of immune heterogeneity between primary and metastatic lesions are poorly understood. In this study, the immune infiltrate of 49 primary tumors and 38 corresponding lesions in the omentum (n = 23) and the peritoneum (n = 15) was immunohistochemically analyzed and correlated with clinicopathological factors and platinum-sensitivity. Immune heterogeneity was observed between paired primary and metastatic lesions for all immune cell phenotypes. The stromal immune infiltrate was higher in the omental lesions than in the primary tumors, which was reflected by CD45 (p = 0.007), CD3 (p = 0.005), CD8 (p = 0.012), and PD-1 (programmed cell-death protein 1) (p = 0.013). A higher stromal infiltrate of both CD45+ and CD3+ cells in the omental lesions was associated with the detection of lymph node metastasis (CD45, p = 0.018; CD3, p = 0.037). Platinum-sensitive ovarian cancers revealed a higher intratumoral CD8+ infiltrate in the peritoneal lesions compared to the primary tumors (p = 0.045). In contrast, higher counts of stromal PD-1+ cells in the peritoneal lesions have been associated with reduced platinum-sensitivity (p = 0.045). Immune heterogeneity was associated with platinum response and might represent a selection marker for personalized therapy.

B-mode ultrasound and contrast-enhanced ultrasound (CEUS) ofhistological confirmed omental lesions: retrospective analysis ofn = 44 patients.

Little is known about the imaging of omental pathologies. The aim of the current study was to determine the value of B-mode ultrasound (B-US), contrast-enhanced ultrasound (CEUS), and ultrasound-guided core needle biopsy for the differential diagnosis of benign and malignant omental pathologies. A retrospective evaluation (2008-2017) was performed in 44 patients (median 65,5 years, mean 64 years [47-83], 27male, 17 female) with histological (40/44 [91 %]) or cytological (4/44 [9 %]) proven omental lesions. Clinical signs and final diagnosis, size, B-US and CEUS findings, and complications were analyzed. Omental thickening was in n = 36 (81.8 %) of the cases malignant (mOL) and in n = 8 (18.2 %) benign (bOL). Twenty-six (59.1 %) patients had ascites (n = 24 [66.7 %] mOL, n = 2 [25 %] bOL). The average tumor thickness was 23 mm (24 mm in mOL, 20 mm in bOL). Interventional complications were not observed. The majority of omental lesions are malignant. The differentiation between a malignant or benign cause of thickening is not possible by any imaging method. CEUS is helpful to determine vital tissue before biopsy. Ultrasound-guided core-needle biopsy allows final diagnosis of omental thickening if > 10 mm and should be performed prior to the more invasive and complicative diagnostic laparoscopy.

Prognostic predictive value of preoperative intratumoral 2-deoxy-2-(18F)fluoro-D-glucose uptake heterogeneity in patients with high-grade serous ovarian cancer.

This study aimed to explore the clinical and prognostic significance of pretreatment positron-emission tomography/computed tomography (PET/CT) parameters, especially 2-deoxy-2-(F)fluoro-D-glucose-based heterogeneity, in high-grade serous ovarian cancer (HGSC). We retrospectively investigated 56 patients with HGSC who underwent PET/CT before primary surgery at our hospital between January 2010 and June 2015. None of these patients received neoadjuvant chemotherapy. PET/CT parameters, including maximum and mean standardized uptake value (SUVmax and SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and intratumoral heterogeneity index (HI), were measured for all patients. Differences of each PET/CT parameter between primary tumors (-P) and omental metastatic lesions (-M) were compared by paired t tests. Progression-free survival (PFS) and overall survival were analyzed by the Kaplan-Meier method and log-rank tests in univariate analyses. Cox regression analyses were used for multivariate analysis. SUVmean-P was higher than SUVmean-M (P=0.001). However, there were no statistical differences of SUVmax, MTV, TLG, or HI between primary and omental lesions. Chemosensitive patients tended to have higher levels of SUVmax-P (P=0.011), MTV-P (P=0.014), TLG-P (P=0.035), and HI-P (P=0.002), respectively. In univariate analyses, higher HI-P was associated with better PFS (P=0.007). However, in multivariate analysis, HI-P was not an independent predictor of PFS (P=0.581). Neither HI-P nor HI-M was the prognostic predictor for overall survival (P=0.078 and 0.063, respectively). 2-Deoxy-2-(F)fluoro-D-glucose-based heterogeneity appears to be a predictive and prognostic factor for patients with HGSC. Parameters of primary tumors have predominant value compared with omental metastatic lesions.

PEG Push versus Pull Technique: Patient Safety at Stake

There are 2 commonly used techniques for Peroral Endoscopic Gastrostomy (PEG) placement, the push technique and the pull technique. We report a case of equipment malfunction using the push method (Sachs-Vine). A 50 year old female with a history of metastatic endocervical adenocarcinoma was admitted for small bowel obstruction. She was also found to have new abdominal wall and omental lesions on CT. PEG tube placement was scheduled for decompression. After the endoscopic evaluation, the location of the incision was identified by transillumination as well as finger indentation and ballottement. Through sterile methods, a scout needle was used to define the tract. A trocar was introduced through the gastric wall. A guide string was then introduced and snared. The endoscope was removed with the wire in place. Gastrostomy tube was fed over the wire until the tip reached the abdominal wall. As the tubing was being pulled through and the dilator reached the level of the abdominal wall, it broke causing the bumper end to become lodged in the back of the oropharynx. This caused airway compromise and transient desaturation down to 60%. The broken tubing was located and removed with rat tooth forceps and a new PEG placed successfully using the Pull method (Ponsky). There are multiple percutaneous techniques used for PEG tube placement including the Pull method, Push method, introducer (Russell) method, and the Versa which uses T-fasteners. With the pull method, the tube is tapered at the end with a loop that is connected and it is pulled down and out through the abdominal wall with the wire. With the Push method, the tube is fed over the wire, this requires the tube to be much longer and is made of two pieces connected together with a small dilator. Both the Push and Pull method are used regularly with no significant difference in complications reported. Although this may be a rare complication, considering the already deteriorated state of many patients getting PEG tube placement and the possible deadly consequences of this complication, choosing the Pull method over the Push method is something to be considered especially in patients with abdominal wall abnormalities.

Tumor bulk as an independent marker of anti-EGFR therapeutic benefit in metastatic colorectal cancer.

e15054 Background: Molecular testing and location of the primary tumor (right-sided (R) versus (vs) left-sided (L)) are useful in predicting the clinical benefit of the anti-epidermal growth factor receptor (EGFR) antibodies, cetuximab (cet) and panitumumab (pan), in metastatic colorectal cancer (mCRC). We hypothesized that tumor bulk might also be predictive of treatment benefit given the potential for increased intra-tumor heterogeneity and reduced penetration of antibodies into bulkier lesions. Methods: A single institution retrospective cohort of 69 patients (pts) with KRAS wild-type mCRC were identified who received either cet or pan in the late-line setting +/- chemotherapy. Metastatic sites were cataloged including independent review of CT imaging prior to initiation of anti-EGFR therapy. Disease bulk was defined categorically as single metastatic lesion with diameter measuring &gt; 3.0 cm. Results: This cohort represents a diverse group having received varying prior lines of therapy and having assorted disease sites including mediastinal, pulmonary, hepatic, omental, and osseous lesions. When treated with anti-EGFR therapies, pts with pre-treatment metastases ≤3.0 cm in diameter had significant improvement in median progression free survival (mPFS) (6.2 months (mos)) vs pts with metastases &gt; 3.0 cm (3.9 mos, p &lt; 0.01). A trend towards improvement in overall survival was observed for pts with non-bulky (15.8 mos) vs bulky disease (8.6 mos, p = 0.08). A trend towards increased mPFS existed in L (5.1 mos) vs R cancers (2.5 mos, p = 0.11). In R cancers, no significant difference in mPFS was noted between bulky (2.5 mos) and non-bulky disease (2.9 mos, p = 0.53). Non-bulky L cancers had a significantly improved mPFS of 7.5 mos compared to 3.9 mos with L bulky disease (p &lt; 0.01). Non-bulky L cancers trended towards improved overall survival of 17.0 mos compared to 9.6 mos with L bulky disease (p = 0.08). Conclusions: Despite limited small sample size, these data indicate that tumor bulk is a potential predictor of the therapeutic benefit of anti-EGFR agents in left-sided mCRCs across a heterogeneous pt population. Disease bulk deserves further evaluation in larger datasets of mCRC across targeted therapeutics.

Grain Foreign Body Embedded in the Spleen and Immune-Mediated Hemolytic Anemia in a Maltese Dog

An 8-month-old, intact male Maltese dog was referred to us because of anorexia, diarrhea, and jaundice. Hematologic examination revealed immune-mediated hemolytic anemia, and abdominal ultrasonography revealed heterogeneous changes in mesenteric fat and coarse echotexture in the splenic parenchyma. Septic peritonitis was diagnosed on the basis of a bacterial culture test of the peritoneal fluid. Exploratory laparotomy and subsequent omental biopsy and splenectomy were performed. On histopathological examination, the omental mass and splenic lesions were diagnosed as grain foreign body granulomas. This report describes a rare case in which a grain foreign body was embedded in the spleen of a dog.

CT Findings of Benign Omental Lesions Following Abdominal Cancer Surgery

The greater omentum is frequently involved in the intra-abdominal dissemination of gastrointestinal and ovarian malignancies, either during primary seeding or as a site of recurrent cancer after surgical treatment (1-4). Therefore, the greater omentum, historically, was totally resected during surgery for abdominal cancer. However, several studies of omentum-preserving operations show a lower rate of postoperative complications and no statistically significant difference in patient survival, as compared with total omentectomy (5-7). Therefore, the use of omentum-preserving operations has recently been increasing, especially for gastric cancer surgery. However, a variety of benign lesions of traumatic, inflammatory, vascular, or systemic origin can occur in the remnant omentum. Various findings are visible on computed tomography (CT), including hazy stranding, nodules, mass formation, and diffuse infiltration. In this article, we review the CT findings of a variety of benign omental lesions after abdominal cancer surgery. The appearances of benign omental lesions on CT are classified into four categories, according to the etiopathogenic mechanism: 1) traumatic omental lesions; 2) inflammatory omental lesions; 3) vascular omental lesions; and 4) omental lesion from systemic causes.