Appendiceal mucinous neoplasm in an inverted appendix found on prior colonoscopy.
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ABSTRACT:
SUBMITTER: Pokhrel B
PROVIDER: S-EPMC6945229 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionMucinous neoplasms of appendix account for 0.2-0.4% of all the appendix specimens. The occurrence of this neoplasm in pregnancy is extremely rare. We describe a case of a pregnant lady who was diagnosed as acute appendicitis and found to have Low-Grade Mucinous neoplasm on histopathology. In the existent literature, there are only a few such cases reported and none from our Middle East region.Case presentation42-year-old pregnant lady at 24 weeks of gestation presented with classical symptoms of acute appendicitis. She had leukocytosis but the Ultrasound was equivocal. She underwent laparoscopic appendectomy and found to have an inflamed appendix. Postoperative recovery was satisfactory and was discharged home. The histopathology report showed low-grade mucinous neoplasm of the appendix and she was detailed about it on follow up.DiscussionThe incidence of appendiceal neoplasm is rare in routine appendectomy and carcinoid is the most common tumor of the appendix. Low-Grade mucinous neoplasm is a rare entity and its presence in pregnancy is further rarer.ConclusionSince this neoplasm does not manifest with a characteristic clinical profile it is difficult to diagnose, even with extensive preoperative evaluation. Although surgical treatment is straight forward, the management of the appendiceal neoplasm during pregnancy necessitates full knowledge of the natural history of the disease to attain equilibrium of concern for maternal survival and fetal health.
| S-EPMC7647936 | biostudies-literature
Project description:OBJECTIVES:It is challenging to distinguish between primary ovarian mucinous tumors and metastatic mucinous neoplasms from the lower gastrointestinal tract, including appendiceal tumors. A combination of PAX8 and SATB2 immunohistochemical stains can be used as a diagnostic tool to distinguish between these cases. RESULTS:Immunostaining for SATB2, PAX8, CK7, CK20 and CDX2 was performed on 50 ovarian mucinous neoplasms (OMN) (39 cystadenomas, 4 borderline and 7 adenocarcinomas), 63 mucinous colorectal carcinoma (CRC), and 9 appendiceal mucinous neoplasms (AMN) [8 low grade appendiceal mucinous neoplasms (LAMN) and 1 adenocarcinoma]. PAX8 was positive in 32% of OMN and negative in all CRC and AMN cases. SATB2 was expressed in 2.0% of OMN, 77.8% of AMN, and 49.2% of CRC cases. CK7 was positive in 78.0% of OMN, 33.3% of AMN, and 9.5% of CRC cases. CK20 was expressed in 24.0% of OMN, 88.9% of OMN, and 87.3% of CRC cases. CDX2 was positive in 14.0% of OMN, 100% of AMN, and 90.5% of CRC cases. PAX8 can differentiate between OMN and AMN with high specificity but low sensitivity. CDX2 is the most sensitive marker for CRC and AMN, whereas SATB2 has better specificity.
| S-EPMC6880435 | biostudies-literature
Project description:The molecular basis for the development of appendiceal mucinous tumours, which can be a cause of pseudomyxoma peritonei, remains largely unknown.Thirty-five appendiceal mucinous neoplasms were analysed for GNAS and KRAS mutations. A functional analysis of mutant GNAS was performed using a colorectal cancer cell line.A mutational analysis identified activating GNAS mutations in 16 of 32 low-grade appendiceal mucinous neoplasms (LAMNs) but in none of three mucinous adenocarcinomas (MACs). KRAS mutations were found in 30 LAMNs and in all MACs. We additionally analysed a total of 186 extra-appendiceal mucinous tumours and found that GNAS mutations were highly prevalent in intraductal papillary mucinous tumours of the pancreas (88%) but were rare or absent in mucinous tumours of the colorectum, ovary, lung and breast (0-9%). The prevalence of KRAS mutations was quite variable among the tumours. The introduction of the mutant GNAS into a colorectal cancer cell line markedly induced MUC2 and MUC5AC expression, but did not promote cell growth either in vitro or in vivo.Activating GNAS mutations are a frequent and characteristic genetic abnormality of LAMN. Mutant GNAS might play a direct role in the prominent mucin production that is a hallmark of LAMN.
| S-EPMC3590682 | biostudies-other
Project description:BACKGROUND:Occasionally, low-grade appendiceal mucinous neoplasms (LAMN) present with mucinous peritoneal deposits (MPD) localized to periappendiceal tissue or diffused throughout the peritoneum. OBJECTIVE:This study was aimed at evaluating the relevance of mucin cellularity for predicting outcomes of LAMN with remote MPD. METHODS:The records of patients with LAMN and remote MPD who underwent initial assessment at a comprehensive cancer center from 1990 to 2015 were reviewed, and diagnostic procedures, treatments, and outcomes were analyzed. RESULTS:Of 48 patients included in the analysis, 19 had cellular MPD (CMPD) and 29 had acellular MPD. Of 33 patients who underwent cytoreductive surgery, 30 had a complete cytoreduction; the 3 patients with an incomplete cytoreduction had CMPD. In the follow-up period (median, 4 years), 6 patients died of the disease, all of whom had CMPD. Of 11 patients who had progression of disease, 10 had CMPD. CONCLUSION:Cellularity of remote MPD is an important determinant of disease outcome in LAMN. Approaches such as active surveillance may have a role in selected patients with LAMN and AMPD.
| S-EPMC6339600 | biostudies-literature
Project description:Although the understanding of appendiceal mucinous neoplasms (AMNs) and their relationship with disseminated peritoneal mucinous disease have advanced, the diagnosis, classification, and treatment of AMNs are still confusing for pathologists and clinicians. The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists (GPSG-KSP) proposed a multicenter study and held a workshop for the "Standardization of the Pathologic Diagnosis of the Appendiceal Mucinous Neoplasm" to overcome the controversy and potential conflicts. The present article is focused on the diagnostic criteria, terminologies, tumor grading, pathologic staging, biologic behavior, treatment, and prognosis of AMNs and disseminated peritoneal mucinous disease. In addition, GPSG-KSP proposes a checklist of standard data elements of appendiceal epithelial neoplasms to standardize pathologic diagnosis. We hope the present article will provide pathologists with updated knowledge on how to handle and diagnose AMNs and disseminated peritoneal mucinous disease.
| S-EPMC8353140 | biostudies-literature
Project description:Mucinous neoplasms of the appendix (MNA) are rare tumors which may progress from benign to malignant disease with an aggressive biological behavior. MNA is often diagnosed after metastasis to the peritoneal surfaces resulting in mucinous carcinomatosis peritonei (MCP). Genetic alterations in MNA are poorly characterized due to its low incidence, the hypo-cellularity of MCPs, and a lack of relevant pre-clinical models. As such, application of targeted therapies to this disease is limited to those developed for colorectal cancer and not based on molecular rationale.We sequenced the whole exomes of 10 MCPs of appendiceal origin to identify genome-wide somatic mutations and copy number aberrations and validated significant findings in 19 additional cases.Our study demonstrates that MNA has a different molecular makeup than colorectal cancer. Most tumors have co-existing oncogenic mutations in KRAS (26/29) and GNAS (20/29) and are characterized by downstream PKA activation. High-grade tumors are GNAS wild-type (5/6), suggesting they do not progress from low-grade tumors. MNAs do share some genetic alterations with colorectal cancer including gain of 1q (5/10), Wnt, and TGF? pathway alterations. In contrast, mutations in TP53 (1/10) and APC (0/10), common in colorectal cancer, are rare in MNA. Concurrent activation of the KRAS and GNAS mediated signaling pathways appears to be shared with pancreatic intraductal papillary mucinous neoplasm.MNA genome-wide mutational analysis reveals genetic alterations distinct from colorectal cancer, in support of its unique pathophysiology and suggests new targeted therapeutic opportunities.
| S-EPMC4062050 | biostudies-literature
Project description:Primary adenocarcinoma of the vermiform appendix is a rare entity and is frequently discovered by the pathologist following appendectomy for suspected appendicitis.We present a 42-year-old male with primary mucinous adenocarcinoma of the appendix initially presenting symptoms of acute appendicitis. Histological investigation of the appendectomy specimen showed a mucinous adenocarcinoma and the patient was treated by secondary right hemicolectomy giving the final histopathological classification of an UICC IIIC tumor. Since the patient fulfills the revised Bethesda criteria analysis of immunoreactivity of DNA mismatch repair proteins was performed showing loss of MLH1 and MSH2 expression associated with high microsatellite instability (MSI-H), not yet reported for primary mucinous appendiceal carcinoma. Further genetic analysis for DNA mismatch repair gene mutations were negative. The patient received intensified adjuvant chemotherapy according to the FOLFOX-4-scheme, since MSI-H colorectal carcinomas might show lower response rates following standard 5-FU-based adjuvant chemotherapy.
| S-EPMC3119391 | biostudies-literature
Project description:Data describing appendiceal tumor incidence and epidemiology is limited. We collated data from appendectomy pathology reports between 2005 and 2018 in our institution and examined patient epidemiological and appendectomy pathological features [1]. Overall, 8,328 appendectomies were performed at our institution over the pre-specified time period and 8,162 patients had sufficient epidemiological data to be included in the analysis. A total of 153 patients (1.9%) were diagnosed with appendiceal tumors, of which 57 (37.3%) were Appendiceal Neuroendocrine Neoplasm (ANEN), 35 (22.9%) were mucinous cystadenoma and 34 (22.2%) ovarian cancer metastases. We further examined the ANEN cases in order to characterize initial patient and tumor characteristics, to evaluate the performance of further investigations and interventions, and ultimately to study the behavior of these tumors over time.
| S-EPMC7666302 | biostudies-literature
Project description:Molecular-targeted therapies have demonstrated disappointing results against most advanced solid cancers. This may largey be attributed to irrational drug use against unselected cancers. We investigated the efficacy of dual MEK-PI3K drug therapy against KRAS mutated mucin 2 (MUC2)-secreting LS174T cells and patient-derived ex vivo and in vivo models of KRAS mutated mucinous colon/appendix cancers. These tumors demonstrate unique phenotypic and genotypic features that likely predict sensitivity to this targeted co-therapy. Co-treatment with MEK inhibitor (trametinib) and PI3K inhibitor (pictilisib)-induced synergistic cytotoxicity and intrinsic mitochondrial-mediated apoptosis in LS174T cells and tumor explants in vitro. Dual drug therapy also induced endoplasmic reticulum stress (ERS)-associated proteins (GRP78/BiP, ATF4, and CHOP). However, CHOP knock-down assays demonstrated that mitochondrial-mediated apoptosis in LS174T cells was not ERS-dependent. Dual drug therapy also significantly decreased MUC2 expression, MUC2 post-translational modification (palmitoylation) and secretion in LS174T cells, suggesting a simultaneous cytotoxic and mucin suppressive mechanism of action. We also demonstrated effective mucinous tumor growth suppression in ex vivo epithelial organoid (colonoid) cultures and in in vivo intraperitoneal patient-derived xenograft models derived from mucinous colon/appendix cancer. These promising preclinical data support a role for dual MEK-PI3K inhibitor therapy in mucinous colon/appendix cancers. We postulate that mucinous KRAS mutated cancers are especially vulnerable to this co-treatment based on their unique phenotypic and genotypic characteristics.
| S-EPMC7050077 | biostudies-literature
Project description:Intraductal papillary mucinous neoplasms are classified into gastric, intestinal, pancreatobiliary, and oncocytic subtypes where morphology portends disease prognosis. The study aim was to demonstrate EUS-guided needle-based confocal laser endomicroscopy imaging features of intraductal papillary mucinous neoplasm subtypes. Four subjects, each with a specific intraductal papillary mucinous neoplasm subtype were enrolled. An EUS-guided needle-based confocal laser endomicroscopy miniprobe was utilized for image acquisition. The mean cyst size from the 4 subjects (2 females; mean age = 65.3±12 years) was 36.8±12 mm. All lesions demonstrated mural nodules and focal dilation of the main pancreatic duct. EUS-nCLE demonstrated characteristic finger-like papillae with inner vascular core for all subtypes. The image patterns of the papillae for the gastric, intestinal, and pancreatobiliary subtypes were similar. However, the papillae in the oncocytic subtype were thick and demonstrated a fine scale-like or honeycomb pattern with intraepithelial lumina correlating with histopathology. There was significant overlap in the needle-based confocal laser endomicroscopy findings for the different intraductal papillary mucinous neoplasm subtypes; however, the oncocytic subtype demonstrated distinct patterns. These findings need to be replicated in larger multicenter studies.
| S-EPMC5558896 | biostudies-literature