Appendiceal Mucinous Neoplasm Research Articles

What is the optimum post treatment surveillance imaging protocol for low-grade appendiceal mucinous neoplasms and pseudomyxoma peritoneii?

Appendiceal mucinous neoplasms are rare and can be associated with the development of disseminated peritoneal disease known as pseudomyxoma peritonei (PMP). Mucinous tumours identified on appendicectomy are therefore followed up to assess for recurrence and the development of PMP. In addition, individuals who initially present with PMP and are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) are followed up to assess for recurrence. However, despite the concerted efforts of multiple expert groups, the optimal imaging follow-up protocol is yet to be established. The purpose of this article is to review the available evidence for imaging surveillance in these populations to identify the optimum post-resection imaging follow-up protocol.

Appendiceal mucinous neoplasm, a rare diagnosis within gastrointestinal tumors. Case report

Appendiceal mucinous neoplasm, a rare diagnosis within gastrointestinal tumors. Case report

Ovarian Causes of Pseudomyxoma Peritonei (PMP)-A Literature Review.

Pseudomyxoma peritonei (PMP) is a rare, progressive, slowly growing, inadequately understood neoplasm with a 5-year progression-free survival rate of as low as 48%. It is characterized by varying degrees of malignancy and the production of mucinous and gelatinous structures. Typically, the development of pseudomyxoma peritonei is associated with the rupture of appendiceal mucinous tumors and other gastrointestinal or ovarian mucinous tumors. The goal of our literature review was to identify various aspects that characterize the ovarian causes of pseudomyxoma peritonei. The authors performed an extensive literature search between 1 February 2024 and 2 March 2024 on the following databases: Pubmed, Scopus, Oxford Journals, and Reaxys, and the findings were summarized into seven main clinical and paraclinical situations. According to our research, the main instances in which pseudomyxoma peritonei can be triggered by an ovarian cause are the following: (1) mucinous cystadenoma; (2) mucinous ovarian cancer; (3) colon cancer with ovarian metastasis; (4) malignant transformation of an ovarian primary mature cystic teratoma; (5) appendiceal mucocele with peritoneal dissemination mimicking an ovarian tumor with peritoneal carcinomatosis; (6) mucinous borderline tumor developing inside an ovarian teratoma; and (7) the association between a mucinous bilateral ovarian cancer and a colonic tumor. In our study, we aimed to provide a comprehensive overview of the ovarian causes of pseudomyxoma peritonei, including its epidemiology, imagery characteristics, symptoms, current treatment, and promising future therapies, in the hopes of finding feasible solutions, as a lack of understanding of this mucus-secreting malignant disease increases the risk of delayed diagnosis or uncontrolled deterioration.

Abstract CT079: The Pseudovax trial: A novel peptide vaccine targeting mutated GNAS for pseudomyxoma peritonei

Abstract Background: Pseudomyxoma peritonei (PMP) is a rare cancer originating from appendiceal mucinous tumors, which may spread to encompass the entire peritoneal cavity. Complete surgical removal and hyperthermic intraperitoneal chemotherapy cures approximately half of the patients, but patients with recurrent or non-resectable disease have no efficacious treatment options. These patients have a high unmet need for novel treatment options, and in the Pseudovax trial we will explore a novel therapeutic concept. A main molecular driver of PMP (in up to 90% of cases) is otherwise rare mutations in the GNAS oncogene, coding for the Gsα protein. We hypothesized that mutated Gsα would be a tumor neoantigen, and in T cells isolated from peripheral blood of PMP patients, a strong T cell proliferative response was observed. In the corresponding tumors, T cells with up-regulated immune checkpoint molecules PD-1 and TIGIT were detected. Study hypotheses: Patients with GNAS-mutated PMP has a preexisting, attenuated immune response directed against mutated Gsα protein. Vaccination with mutated Gsα peptides can be combined with immune checkpoint inhibition (ICI) with acceptable toxicity. The vaccine will reactivate the immune response and ICI will restore measurable anticancer immunity in patients. Study design: The Pseudovax trial is a small (10 patients) first-in-human, proof-of-concept, prospective, open label, phase I trial. Patients with recurrent or non-resectable PMP are eligible for inclusion. During a treatment period of 12 months, a mutated Gsα peptide vaccine + adjuvant (GM-CSF) will be administered as intradermal injections. After 12 weeks, treatment with ICI will be initiated. The primary endpoints are toxicity and circulating immune response against the vaccine, measured as increase in interferon-gamma production or proliferation of circulating vaccine-specific T cells compared to pre-vaccination baseline. Secondary endpoints are progression-free survival (abdominopelvic CT scans, blood levels of carcinoembryonic antigen (CEA) and/or detection of GNAS mutation by ctDNA analysis). Citation Format: Kjersti Flatmark, Annette Torgunrud, Fleten G. Karianne, Ben Davidson, Hedvig V. Juel, Nadia Mensali, Christin Lund Andersen, Else Marit Inderberg. The Pseudovax trial: A novel peptide vaccine targeting mutated GNAS for pseudomyxoma peritonei [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT079.

Low-grade appendiceal mucinous neoplasm; a subtle presentation during colonoscopy.

Low-grade appendiceal mucinous neoplasm; a subtle presentation during colonoscopy.

Abstract 2449: Case report: DETECT-A participants with pre-malignant conditions

Abstract Background: Blood based tests for multi-cancer early detection (MCED) are being developed to facilitate the earlier detection of various cancer types. The Detecting cancers Earlier Through Elective mutation-based blood Collection and Testing (DETECT-A) study evaluated the CancerSEEK MCED test, an early version of the Exact Sciences MCED test in development, in 9,911 women, age 65-75, without previous history of cancer (Lennon et al., Science 2020). The degree to which MCED testing will facilitate detection of precancerous conditions or incidental findings is unclear. Here we focus on DETECT-A participants who had pre-cancerous conditions diagnosed during a diagnostic work-up for a positive CancerSEEK MCED test. Methods: In a post-hoc analysis, we report on the detection of precancerous conditions consequent to CancerSEEK MCED testing and follow-up. Electronic health records were reviewed for diagnostic procedures performed, details of premalignant and cancer diagnoses, and vital status. Results: In three individuals, mutations in PIK3CA, TP53, or KRAS genes led to a positive CancerSEEK MCED test result. The prescribed imaging protocol using 2-deoxy-2[fluorine-18] fluoro-D-glucose positron emission tomography-computed tomography (18-FDG PET-CT), revealed a 10.3 × 9.8 × 7.8(cm) ovarian mucinous cystadenoma, a 0.8 cm appendiceal mucinous neoplasm, and 3 colonic polyps displaying high-grade dysplasia. All three participants were diagnosed with clinically significant pre-cancerous lesions, subsequently underwent surgical treatment, and remain alive and cancer-free as of February 2023 (Table 1). Conclusion: The diagnostic evaluation of a positive MCED test may occasionally reveal clinically significant pre-cancerous conditions amenable to interventions. The frequency of such findings and their clinical impact warrants further study. Citation Format: Omair A. Choudhry, Angana Kharge, Seema P. Rego, Paul Z. Elias, Adam H. Buchanan, Anne Marie Lennon, Nickolas Papadopoulos, Frank Diehl, Tomasz M. Beer. Case report: DETECT-A participants with pre-malignant conditions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2449.

A CT-based radiomics nomogram involving the cystic fluid area for differentiating appendiceal mucinous neoplasms from appendicitis with intraluminal fluid

ObjectiveTo develop and validate a radiomics nomogram based on computed tomography (CT) to distinguish appendiceal mucinous neoplasms (AMNs) from appendicitis with intraluminal fluid (AWIF).MethodA total of 211 patients from two medical institutions were retrospectively analysed, of which 109 were pathologically confirmed as having appendicitis with concomitant CT signs of intraluminal fluid and 102 as having AMN. All patients were randomly assigned to a training (147 patients) or validation cohort (64 patients) at a 7:3 ratio. Radiomics features of the cystic fluid area of the appendiceal lesions were extracted from nonenhanced CT images using 3D Slicer software. Minimum redundancy maximum relevance and least absolute shrinkage and selection operator regression methods were employed to screen the radiomics features and develop a radiomics model. Combined radiomics nomogram and clinical-CT models were further developed based on the corresponding features selected after multivariate analysis. Lastly, receiver operating characteristic curves, and decision curve analysis (DCA) were used to assess the models’ performances in the training and validation cohorts.ResultsA total of 851 radiomics features were acquired from the nonenhanced CT images. Subsequently, a radiomics model consisting of eight selected features was developed. The combined radiomics nomogram model comprised rad-score, age, and mural calcification, while the clinical-CT model contained age and mural calcification. The combined model achieved area under the curves (AUCs) of 0.945 (95% confidence interval [CI]: 0.895, 0.976) and 0.933 (95% CI: 0.841, 0.980) in the training and validation cohorts, respectively, which were larger than those obtained by the radiomics (training cohort: AUC, 0.915 [95% CI: 0.865, 0.964]; validation cohort: AUC, 0.912 [95% CI: 0.843, 0.981]) and clinical-CT models (training cohort: AUC, 0.884 [95% CI: 0.820, 0.931]; validation cohort: AUC, 0.767 [95% CI: 0.644, 0.863]). Finally, DCA showed that the clinical utility of the combined model was superior to that of the clinical CT and radiomics models.ConclusionOur combined radiomics nomogram model constituting radiomics, clinical, and CT features exhibited good performance for differentiating AMN from AWIF, indicating its potential application in clinical decision-making.

Beyond acute appendicitis: a single-institution experience of unexpected pathology findings after 989 consecutive emergency appendectomy.

Appendiceal neoplasms (ANs) are rare, with an estimated incidence of around 1%: neuroendocrine tumours (NETs) and low-grade appendiceal mucinous neoplasms (LAMNs) comprise most cases. Most tumours are cured by appendectomy alone, although some require right hemicolectomy and intra-operative chemotherapy. The aim of the present study is to evaluate our institution's experience in terms of the prevalence of AN, their histological types, treatment and outcomes in adult patients undergoing emergency appendectomy. Single-centre retrospective cohort analysis of patients treated for acute appendicitis at a large academic medical centre. Patients with a diagnosis of acute appendicitis (AA) where further compared with patients with acute appendicitis and a histologically confirmed diagnosis of appendiceal neoplasm (AN). A diagnosis of acute appendicitis was made in 1200 patients. Of these, 989 patients underwent emergency appendectomy. The overall incidence of appendiceal neoplasm was 9.3% (92 patients). AN rate increased with increasing age. Patients under the age of 30 had a 3.8% (14/367 patients) rate of occult neoplasm, whereas patients between 40 and 89years and older had a 13.0% rate of neoplasm. No difference was found in clinical presentations and type of approach while we found a lower complicated appendicitis rate in the AN group. ANs are less rare with respect to the literature; however, clinically, there are no specific signs of suspicious and simple appendicectomy appears to be curative in most cases. However, age plays an important role; older patients are at higher risk for AN. ANs still challenge the non-operative management concept introduced into the surgical literature.

Current Status of Treatment among Patients with Appendiceal Tumors-Old Challenges and New Solutions?

The 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system distinguishes four categories of appendiceal tumors (ATs): serrated lesions and polyps, mucinous neoplasms, adenocarcinomas, and neuroendocrine neoplasms (NENs). The differential diagnosis of ATs can be challenging in medical practice, due to their rarity and lack of data from randomized controlled trials on a large, diverse group of patients. ATs are usually noted in specimens obtained during appendectomies due to clinical acute appendicitis. In the European population, most ATs (65%) occur over the age of 50 and among women (56.8%). According to histological type, 54.6% are neuroendocrine tumors (NETs); 26.8% cystic, mucinous, and serous neoplasms; and 18.6% adenocarcinoma not otherwise specified (NOS). On pathologic analysis, most AT findings are benign lesions or small NENs that do not require further therapeutic measures. The presence of appendiceal mucinous neoplasm (AMN) can lead to pseudomyxoma peritonei (PMP). While the multimodal treatment for abdominal malignancies has evolved over the past several decades, the clinical workup and treatment of ATs remain a challenge. Therefore, this review aims to describe the diagnostic possibilities, molecular-based diagnosis, staging, differences in the treatment process, and prognostic factors associated with ATs.

CK7+/CK20+/CDX2+ mucinous carcinoma, arising in a mature cystic teratoma of ovary, presenting with disseminated metastasis and pseudomyxoma peritonei.

Mucinous carcinomas arising within an ovarian dermoid tumor are rare. Most of the cases reported in the literature show morphological features resembling an appendiceal mucinous neoplasm. They exhibit CK7-/CK20+ immunophenotype similar to carcinomas of the lower gastrointestinal tract. In this report, we have described a case of a well-differentiated mucinous carcinoma arising within a mature cystic teratoma. The mucinous carcinoma showed a spectrum of morphological patterns, including cystadenoma-like areas, proliferative/borderline areas, villous adenoma-like areas, and areas of invasive carcinoma. In addition, our case showed some unusual findings, namely, diffuse CK7 positivity, associated pseudomyxoma peritonei, and metastasis to lungs. These features were not demonstrated in any of the previously reported cases. Our case shows that the teratomatous mucinous neoplasm of the ovary may show CK7+/CK20+/CDX2 + immunoprofile making it immunohistochemically indistinguishable from a primary ovarian mucinous neoplasm or a metastatic mucinous carcinoma of the lower gastrointestinal tract.

Appendiceal neoplasms in Saudi Arabia: prevalence and clinicopathological profile.

The appendix is a small organ with no particular known function. Primary appendiceal neoplasms (ANs) are rare. While the prevalence is increasing worldwide over the past two decades, no apparent increase in the prevalence of ANs has been reported in the Arabian Gulf States. Recently, a significant decline in the age at diagnosis of some types of ANs has been reported worldwide, with a female predominance. Evaluate the prevalence and clinicopathological characteristics of ANs within our institution in Saudi Arabia and compare them to limited existing studies from different regions as well as the Arabian Gulf States. Retrospective cohort. Tertiary care center in Riyadh. All patients who underwent appendectomy and had the appendix submitted for histopathological evaluation between May 2015 and June 2020 were included to allow for a follow-up of 5 years or more at the time of data collection. Demographics, clinical presentations, surgical interventions, histopathological findings, complications, and recurrence rates. 25 AN patients. Of 1110 patients, 25 had ANs (13 female and 12 male participants) with a mean (standard deviation) age of 54.6 (14.1) years. Only 40% presented with acute appendicitis, 64% had comorbidities, and less than 50% underwent laparoscopic appendectomy. Histopathologically, 72% were low-grade appendiceal mucinous neoplasms (LAMNs). Complications were minimal grades (Clavien-Dindo classification), with 80% experiencing none. The mean hospital stay was 9.96 days. Local recurrence occurred in 8% of cases, and distant metastasis was documented in one adenocarcinoma case. However, the 5-year overall and disease-free survival rates were 88% and 80%, respectively. The incidence of ANs is increasing in Saudi Arabia with the higher prevalence of LAMNs. The pathological examination of the resected appendix played a pivotal role in the diagnosis of ANs. Data collected retrospectively, a single institution, and a small population.

Low-grade Appendiceal Mucinous Neoplasms: A Case Report

Low-grade Appendiceal Mucinous Neoplasms: A Case Report

Appendicular Mucocele Complicated by Peritoneal Pseudomyxoma

Appendiceal mucocele (AM) or Appendiceal mucinous neoplasms is a rare but potentially dangerous condition. In the latter, a spontaneous or iatrogenic rupture of the mucocele can lead to mucinous intraperitoneal ascites, a syndrome known as pseudomyxoma peritonei. We present the case of a 76-year-old female patient who reported right iliac fossa pain with RIF tenderness on clinical examination, and underwent an abdominal CT scan showing an appendiceal mucocele associated with a small peritoneal effusion suspecting a ruptured mucocele, related to peritoneal pseudomyxoma. The patient underwent appendectomy with peritoneal lavage and aspiration of all mucin found. Anatomopathological analysis confirmed the diagnosis of appendiceal mucocele (a low-grade appendiceal mucinous neoplasm).

Incidental findings during donor liver assessment: Single center experience

Intraoperative consultation of donor liver is an important part of transplant evaluation and determination of liver eligibility. In this study, we describe incidental pathologic findings discovered during the pretransplant evaluation of liver donors in our Institution from 1/2010 to 12/2022. During this 13-year period 369 intraoperative consultations from 262 liver donors were performed. Of those cases, incidental findings were identified in 22 cases (5.9 %) from 19 donors (7.3 %); two donors had more than one lesion. The median age of this subset of patients was 53 years (range: 18–70) and females predominated (63 %). Sixteen of the donors had abnormal findings in the liver: 6 bile duct hamartoma (BDH), 5 hyalinized nodule with Histoplasma capsulatum, 5 focal nodular hyperplasia (FNH), 2 bile duct adenomas (BDA), 1 biliary cyst and 1 hemangioma. One donor had both FNH and a BDH. One BDH and 1 BDA case was misdiagnosed as malignancy during the frozen section evaluation. Three donors had extrahepatic pathologies: a pancreatic tail schwannoma, a low-grade appendiceal mucinous neoplasm, and a lymph node with metastatic endometrial endometrioid adenocarcinoma. Of the 19 livers, the final organ disposition was available for 9: 6 were transplanted (67 %) and 3 were discarded (33 %). Two of the 3 discarded organs were misdiagnosed BDH and BDA cases, and one was incorrectly reported as having 90 % microvesicular steatosis during the frozen assessment. We present the clinicopathologic characteristics of liver donors with incidental findings during the pre-transplant evaluation which could lead to unwarranted graft dismissal if misdiagnosed. Additionally, incidental fungal infections can have implications for immunosuppressive therapy and the decision to use or reject the graft.

The volcano sign and mucus outflow by colonoscopy - Low grade appendiceal mucinous neoplasm.

An 82-year-old woman presented with painless hematochezia. Colonoscopy revealed a submucosal tumor-like mass in the cecum. The appendiceal orifice was identified in the center of the prominence, showing the volcano sign. The yellowish mucus was discharged from the orifice like a lava flow, the so-called mucus outflow. She underwent laparoscopic appendectomy based on the diagnosis of appendiceal mucinous neoplasm. The pathological diagnosis was low grade appendiceal mucinous neoplasm, that is a clinical entity characterized by absence of infiltrative growth or destructive invasion. The differential diagnosis includes appendiceal polyps, lipomas, neuroendocrine neoplasms, and endometriosis. Our case underscores the importance of the volcano sign and the mucus outflow for the preoperative diagnosis of appendiceal mucinous neoplasm.

Low-grade Appendiceal Mucinous Neoplasm Masquerading as Acute Appendicitis: A Case Report

Appendiceal mucinous neoplasms, particularly Low-grade Appendiceal Mucinous Neoplasms (LAMN), are rare but important diagnostic entities as they are potential causes of a surgical abdomen. The clinical manifestations of this lesion are obscure and ill-defined, and these lesions are commonly misdiagnosed as acute appendicitis, adnexal masses, or retroperitoneal tumours. This lesion can rupture and seed mucin and neoplastic epithelium into the peritoneum, leading to Pseudomyxoma Peritonei (PMP), a serious complication with a high morbidity and mortality rate. Therefore, timely identification and treatment of LAMN are crucial for reducing the risk of PMP and improving prognosis and outcomes. Ultrasonography (USG) and Computed Tomography (CT) scans are useful methods for diagnosis; however, the diagnosis is often incidental or found intraoperatively during resection for suspected acute appendicitis. Clinical awareness of the misleading presentations of LAMN should be present in cases of a surgical acute abdomen to prevent performing a dissimilar treatment intervention. Considering the rarity of this lesion and its varied presentation, it is important to study and document this type of neoplasia in the literature. Hereby, authors report a rare case of LAMN in a 33-year-old male patient with a primary diagnosis of acute appendicitis. This case highlights the importance of having a high index of clinical suspicion of appendiceal malignancy and mucocele rupture in patients planned for appendectomy. This also emphasises the fact that all excised appendicectomy tissues should be sent for histopathological examination as they can harbor pathological changes like LAMN.

Low-grade Appendiceal Mucinous Neoplasm in a Middle-aged Female: A Case Report

Mucinous Appendiceal Neoplasms (MANs) are rare tumours where more than 50% of the tumour volume is composed of extracellular mucin. Low-grade Appendiceal Mucinous Neoplasm (LAMN) is a rare condition with symptoms that vary depending on clinical manifestations. It can manifest as an unruptured mucin-filled appendix, transmural invasion of the primary tumour, or present with peritoneal metastases post-rupture. The prognosis of LAMN depends on the presence or absence of neoplastic epithelium outside the appendix. Here, the authors describe a case of 35-year-old female who visited the OPD of Emergency Medicine with only complain of pain in abdomen for three days. She exhibited right iliac fossa tenderness with no guarding during the abdominal examination. She underwent an open appendectomy and was diagnosed with LAMN upon histopathological examination. She was advised to follow up after six months post-discharge to monitor for any metastatic spread. Due to its malignant potential, mucinous lesions of the appendix are uncommon yet significant entities. They are more prevalent in women and can range from mucinous adenocarcinomas to straightforward retention cysts. This case illustrates the need for extreme caution when dealing with appendiceal tumours and the importance of selecting the appropriate course of action, be it surgical or medical.

Long-term Postoperative Follow-up for 60 Months in Three Patients with Low-grade Appendiceal Mucinous Neoplasm

Long-term Postoperative Follow-up for 60 Months in Three Patients with Low-grade Appendiceal Mucinous Neoplasm

Complete debulking of the porta hepatis in low-grade appendiceal mucinous neoplasms: a case series

Complete debulking of the porta hepatis in low-grade appendiceal mucinous neoplasms: a case series

Unraveling the Unusual Pathological Findings of Appendiceal Lesions: A Cross-sectional Study from Tertiary Care Centre in Chengalpattu, Tamil Nadu, India

Introduction: The appendix, once considered a vestigial structure, is now recognised as a site of diverse pathologies beyond simple appendicitis through a systematic analysis of published literature and case studies. The diagnosis of appendiceal lesions is still a clinical phenomenon and a constant struggle. The gold standard for diagnosing appendiceal lesions, however, is meticulous histopathological examination. Aim: To determine the histopathological distribution of all the appendiceal lesions and to identify the rare and unusual histopathological findings in appendectomy specimens received at a tertiary care Centre. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at Karpaga Vinayaga Institute of Medical Sciences and Research Centre, Chengalpattu, Tamil Nadu, India for a duration of 10 years, from August 2013 to August 2023. From the histopathological records of 832 appendectomies, 40 specimens with unusual histopathological findings were identified and analysed in this study. Relevant recorded data from all the appendiceal specimens reported during the study period, with special reference to age, sex, and histopathological findings, were retrieved and evaluated retrospectively. Corresponding slides and specimens were reviewed. The data were presented in the form of frequency tables and percentages. The analysis was done using Statistical Package for Social Sciences (SPSS) software version 20.0. Results: Out of 832 appendectomy specimens, there were 485 (58.29%) cases of acute appendicitis, 244 (29.33%) cases of chronic appendicitis, 59 (7.09%) cases of subacute appendicitis, and 4 (0.48%) cases of gangrenous appendicitis. Unusual histopathology findings were noted in 40 cases (4.81%). These include 17 cases of appendiceal neuroma, eight cases of Xanthogranulomatous appendicitis, seven cases of Enterobius vermicularis, three cases of Low-grade Appendiceal Mucinous Neoplasm (LAMN), one case of appendiceal Neuroendocrine Tumour (NET), one case of Goblet Cell Adenocarcinoma (GCA), one case of metastatic squamous cell carcinomatous deposit in the appendix, one case of urothelial rests in the appendix, and one case of appendiceal lipoma. Conclusion: In this study, 4.81% of patients had atypical appendiceal lesions. A complete histopathological examination of appendectomy specimens increases the chances of discovering unusual lesions of the appendix. Ultimately, this comprehensive analysis will contribute to future improvements in clinical management and prognostication, fostering better patient outcomes.