Low-grade Appendiceal Mucinous Neoplasm Research Articles

A Rare Case of Low-Grade Appendiceal Mucinous Neoplasm Presenting As Mucinous Vaginal Discharge

A Rare Case of Low-Grade Appendiceal Mucinous Neoplasm Presenting As Mucinous Vaginal Discharge

S4825 A Challenging Diagnosis of Low-Grade Appendiceal Mucinous Neoplasm Mimicking Ovarian Cancer and Primary Biliary Cholangitis

S4825 A Challenging Diagnosis of Low-Grade Appendiceal Mucinous Neoplasm Mimicking Ovarian Cancer and Primary Biliary Cholangitis

Ileocolic Intussusception Due to Low-Grade Appendiceal Mucinous Neoplasm.

We report a rare case of low-grade appendiceal mucinous neoplasm (LAMN) causing ileocolic intussusception. The case underscores the importance of considering ileocolic intussusception in differential diagnoses for nonspecific gastrointestinal symptoms. Early diagnosis via contrast-enhanced CT and scrupulous surgical intervention are crucial for favorable outcomes.

Risk stratification of surveillance for low-grade appendiceal mucinous neoplasms

BackgroundLow-grade appendiceal mucinous neoplasms (LAMNs) can progress to pseudomyxoma peritonei (PMP). The incidence and risk factors for recurrence are unclear, and there is a lack of consensus on the need and duration of surveillance imaging. MethodsPatients at the Mayo Clinic in Rochester, Minnesota, with a histologic diagnosis of LAMNs confined to the appendix and limited involvement of the right lower quadrant from 1992 to 2023 were included. Associations between recurrence and risk factors were assessed using Kaplan-Meier curves and Cox proportional hazards regression. ResultsA total of 125 patients with LAMNs underwent abdominal imaging surveillance for a median of 51.2 months (IQR, 26–92). Of note, 5 patients (4%) recurred, all of which were PMP. Overall, the 5- and 10-year cumulative recurrence incidence rates were 3% and 6%, respectively. The median time to recurrence was 24 months (IQR, 23–87). Only LAMNs limited to the right lower quadrant and LAMN tumor size of <2 cm were associated with recurrence (P < .05). The 5- and 10-year cumulative recurrence risks were 12% and 30%, respectively, for the 21 patients with either risk factor. Only 1% of patients without these 2 risk factors developed a recurrence at 10 years. ConclusionThe overall recurrence risk of LAMN after resection is low. Appendectomy is sufficient for LAMN. Select patients with acellular mucin confined to the right lower quadrant and a tumor size of <2 cm are at higher risk of recurrence. Thus, long-term surveillance is recommended for high-risk individuals. Conversely, LAMNs without risk factors can be safely observed expectantly.

Low-Grade Appendiceal Mucinous Neoplasm Adhered to the Posterior Cecum: A Case Report

Low-Grade Appendiceal Mucinous Neoplasm Adhered to the Posterior Cecum: A Case Report

The risk of developing pseudomyxoma peritonei from a non-perforated low grade appendiceal mucinous neoplasm found at appendicectomy

IntroductionLow-grade appendiceal mucinous neoplasms (LAMNs) are classified as non-perforated (pTis, pT3) or perforated (pT4), and considered precursors of pseudomyxoma peritonei (PMP). This study aims to quantify the risk of developing PMP from pTis and pT3 LAMNs. Materials and methodsRetrospective analysis of a prospectively collected database identified LAMN patients referred to a specialist centre from 2004 to 2019. pT4 LAMNs and other appendix tumours were excluded. All patients had specialist review of their pathology, operation note, and a CT scan (at least 6 weeks post-operatively). Surveillance CTs were then performed at 6, 12, 24, 36, 48, & 60 months, with tumour markers (CEA, CA19-9, CA125). Results193 pT3/pTis LAMN patients were included (pTis = 153, pT3 = 40). Median follow-up = 6.45 (3.91–22.13) years, M:F ratio = 1:1.57, and median age = 57 (23–83) years. Initial surgery included: appendicectomy (67 %), appendicectomy + visceral resection (6 %), and right hemicolectomy (27 %). R1 resections were identified in 5/193 patients (2.5 %). 3 R1 patients underwent re-operation (2 caecal pole excision and 1 ileocecectomy), none of which had residual tumour. 8/193 patients (4 %) were lost to follow up. None of the remaining 185 developed PMP. ConclusionThis is the largest reported series of pTis/pT3 LAMNs with standardised follow-up in the literature. LAMNs correctly classified as pT3/pTis (after careful specialist review of pathology, operation note, and a baseline post-operative CT) have negligible risk of developing PMP and should have low intensity surveillance. If completely excised, further surgery is not indicated. R1 resections should be considered on an individual basis at a specialist centre.

Ultrasound and clinical features for differential diagnosis of low-grade appendiceal mucinous neoplasm and acute suppurative appendicitis.

To investigate the application of ultrasound along with clinical features for the differential diagnosis of low-grade appendiceal mucinous neoplasm (LAMN) and acute suppurative appendicitis (ASA). The ultrasound and clinical data of 76 patients with histopathologically confirmed LAMN (31 patients) and ASA (45 patients) were retrospectively analyzed. Univariate analysis and binary logistic regression analysis of the influencing factors were conducted to identify LAMN and ASA. The AUROC was calculated to analyze the diagnostic efficacy of these independent factors. A four-grid table was established to determine the diagnostic efficacy of the ultrasound marks for diagnosing LAMN. Patient age and appendix short diameter in the LAMN group were found to be significantly higher than those in the ASA group. The neutrophil ratio and thickness of the appendix wall in the LAMN group were significantly lower than they were in the ASA group. Patient age (OR=1.112, p=0.015) and appendix short diameter (OR=1.476, p=0.008) were independent risk factors for LAMN. The AUROCs for age and short diameter were 0.898 [95% CI: 0.807, 0.956] and 0.953 [95% CI: 0.879, 0.988], respectively. The LAMN group tumors were characterized by the appearance of an "onion skin" sign or a purely cystic mark on sonograms, with specificities of 100% for both. Neutrophil ratio (OR<0.001, p=0.064) and thickness of the appendix wall (OR=0.776, p=0.414) were not independent risk factors for ASA. Employing ultrasonography with clinical features is useful for distinguishing LAMN from ASA. Patient age, short diameter of the appendix, and sonographic appearance of "onion skin" or purely cystic mark could be key factors in diagnosing LAMN.

High-Grade Appendiceal Mucinous Neoplasm Mimicking Appendiceal Tubulovillous Adenoma: A Case Report and Literature Review.

High-grade appendiceal mucinous neoplasm (HAMN) has been separated from appendiceal adenocarcinoma recently as an independent entity and categorized into appendiceal mucinous neoplasms. These neoplasms demonstrate distinct histological characteristics, including architectures and appendiceal mural changes similar to low-grade appendiceal mucinous neoplasm but with high-grade cytology, and no infiltrative invasion. Overt mucinous feature are not evident in some cases as the high-grade neoplastic epithelium may show intracytoplasmic mucin reduction. Occasionally, the neoplastic epithelial cells show florid proliferation and tubulovillous configuration and may be misdiagnosed as appendiceal tubulovillous adenoma. We report the case of a 67-year-old woman with appendicular dilatation and luminal mucin. She underwent an ileocecoectomy. The appendiceal lesion was found histologically to be a HAMN, which closely resembled appendiceal tubulovillous adenoma. The tumor cells demonstrated wild-type p53 expression and mismatch repair proficiency by immunochemistry. Molecular testing showed 1 KRAS mutation, 2 PIK3CA mutations, and 1 BRCA2, EP300, TGFBR2, CHD4, CREBBP, FANCC, PKHD1 mutation each in the tumor. The patient was followed up for 1 year with no evidence of disease.

Survival among 148 patients with an incidentally detected appendiceal tumours at surgery for acute appendicitis: a population-based cohort follow-up study.

To investigate the long-term prognosis of appendiceal tumours incidentally detected at appendicectomy for suspicion of benign appendicitis. A retrospective register-based single centre cohort study was carried out, using data from the local acute appendicectomy quality register of cases operated on at the Department of Surgery, South General Hospital, Stockholm, Sweden. The local colorectal cancer register was also used to identify appendix tumours. The study period was between January 2004 and January 2023. Survival was calculated according to the Kaplan-Meier method. A total of 11,888 patients were registered in the acute acute appendicectomy register, 54% males and 46% females, median age 32 (Q1 = 21, Q3 = 47) (with 33.7% were 41 years or older). From the appendicectomy and colorectal registers 148 (1.2% of the total cohort) appendiceal tumours were found; 60% in females and 40% in males, median age 56 (Q1 = 43, Q3 = 70) (with 78.4% being 41 years or older). Tumours found were: Low grade Appendiceal Mucinous Neoplasms (LAMN, N = 64); Neuroendocrine Tumours (NET N = 24); adenocarcinomas or other form of carcinomas (N = 57); and adenomas (N = 3). The overall 5-year survival in patients operated for LAMN was 96.8%, for NET 93.3% and for adenocarcinoma 69.7%. The overall 5-year survival for all tumour patients was 85.7%. For the younger patients (< 51 years) with LAMN and NET, almost all survived to the end of follow-up. Survival of patients in the carcinoma group was statistically significantly lower than for the LAMN and NET groups, especially in females 51 years or older. In the group of tumour patients undergoing surgery (n = 146), primary surgery was laparoscopic in 47% and open in 52%. Two patients did not undergo surgery due to widespread disease. In 64% of cases operation was acute, whereas it was delayed and/or planned in 34%. Most procedures were laparoscopic appendicectomy 36%, followed by open appendicectomy 30%, right-sided hemicolectomy 14.6% (open 11.6% and laparoscopic 3%, acute operation 5.5%), ileocaecal resection 5% (acute operation 3.4%), and staging laparoscopy 7%. In 38% of the operated patients the tumour was discovered incidentally at histopathology examination. Two patients had CRS and HIPEC as the initial operation. Forthy-three per cent of the 146 tumour patients operated underwent a second procedure: CRS and HIPEC in 23.3% and right-sided hemicolectomy in 13.6% (laparoscopic 8.2% open 5.4%). Survival was high for patients with incidentally detected appendiceal LAMN or NET, but not so for carcinoma. Survival was lower in the carcinoma group older than 50 years, especially those sick and females.

Mucin Secretion From Appendiceal Lumen Detected by Colonoscopy: A Very Rare Presentation of a Low-Grade Appendiceal Mucinous Neoplasm

Mucin Secretion From Appendiceal Lumen Detected by Colonoscopy: A Very Rare Presentation of a Low-Grade Appendiceal Mucinous Neoplasm

Appendiceal neoplasms derived from appendiceal tip remnants following appendectomy: a report of two cases

BackgroundNeoplasms derived from remnant appendix are rarely described, with most cases arising from the appendiceal “stump”. Here, we present two surgical cases of appendiceal neoplasms derived from appendiceal “tip” remnants.Case presentationThe first patient was a 71-year-old man who had undergone laparoscopic appendectomy for acute appendicitis 12 years prior. During appendectomy, the appendiceal root was ligated, but the appendix was not completely removed due to severe inflammation. At the most recent presentation, computed tomography (CT) was performed to examine choledocholithiasis, which incidentally revealed a cystic lesion of approximately 90 mm adjacent to the cecum. A retrospective review revealed that the cystic lesion had increased in size over time, and laparoscopic ileocecal resection was performed. Pathology revealed no continuity from the appendiceal orifice to the cyst, and a diagnosis of low-grade appendiceal mucinous neoplasm (LAMN) was made from the appendiceal tip remnant. The patient was discharged without complications. The second patient was a 65-year-old man who had undergone surgery for peritonitis due to severe appendicitis 21 years prior. During this operation, the appendix could not be clearly identified due to severe inflammation; consequently, cecal resection was performed. He was referred to our department with a chief complaint of general fatigue and loss of appetite and a cystic lesion of approximately 85 mm close to the cecum that had increased over time. CT showed irregular wall thickening, and malignancy could not be ruled out; therefore, laparoscopic ileocecal resection with D3 lymph node dissection was performed. The pathological diagnosis revealed mucinous adenocarcinoma (TXN0M0) arising from the remnant appendiceal tip. The patient is undergoing follow-up without postoperative adjuvant chemotherapy, with no evidence of pseudomyxoma peritonei or cancer recurrence for 32 months postoperatively.ConclusionsIf appendicitis-associated inflammation is sufficiently severe that accurate identification of the appendix is difficult, it may remain on the apical side of the appendix, even if the root of the appendix is ligated and removed. If the appendectomy is terminated incompletely, it is necessary to check for the presence of a residual appendix postoperatively and provide appropriate follow-up.

KRAS mutations and their prognostic implications in appendiceal cancers.

4177 Background: Despite shared embryonic origin, appendiceal cancers (AC) have distinct clinical and molecular features compared to colorectal cancers (CRC). Detection of mutant KRAS has been associated with worse survival in CRC, whereas in AC the prognostic significance of mutant KRAS (55-65% prevalence) has yet to be characterized. Methods: AC tissues from 852 individual patients that underwent DNA (592, NextSeq, or whole exome sequencing) and whole transcriptome sequencing (NovaSeq) at Caris Life Sciences (Phoenix, AZ) were analyzed. Low-grade appendiceal mucinous neoplasms were excluded. Chi-square, Fishers-exact, and Mann Whitney U tests were used to determine statistical significance and were adjusted for multiple hypothesis testing (p&lt; 0.05). Real-world overall survival (OS) was calculated using insurance claims of AC patients from time of sample collection to last contact. Hazard ratios (HRs) were calculated using the Cox proportional hazards model (log-rank test). Multivariate regression analysis was performed on age, sex, histology, site, comutations and KRASmut vs. KRASwt. Results: AC histological subtypes comprised mucinous adenocarcinoma (37.9%), goblet cell carcinoma (19.6%), signet ring cell carcinoma (12.1%), and adenocarcinoma- not otherwise specified (NOS, 30.4%). Among all AC specimens, KRAS was the most common mutation (49%). KRASmut vs. KRASwt tumors were more frequently associated with TP53mut (51.2% vs. 36.8%, respectively; p&lt; 0.01) and GNASmut (41.1% vs. 5.7%, respectively; p &lt; 0.00001). Most frequent co-mutant gene with KRAS was TP53 (61.2%) in adenocarcinoma-NOS, and GNAS (46.9%) in mucinous adenocarcinomas.Median OS among KRASmut vs. KRASwt was 33.3 vs. 25.1 months, respectively (HR 0.68, 95% CI: 0.58-0.80, p &lt; 0.00001). KRASmut was associated with improved survival in mucinous adenocarcinomas (HR 0.71; 95% CI: 0.52-0.96, p = 0.028) and adenocarcinoma-NOS (HR 0.77; 95% CI: 0.62-0.97, p = 0.025), but not with signet ring cell (HR 1.92; 95% CI: 0.90-4.10, p = 0.087) or goblet cell carcinoma (HR 1.39; 95% CI: 0.50-3.91, p = 0.536). Multivariate analysis showed KRASmut was an independent prognostic factor for improved survival among all AC (HR 0.77, 95% CI: 0.64-0.93, p = 0.007) and mucinous adenocarcinoma (HR 0.60, 95% CI: 0.42-0.84, p&lt;0.0001).Notably, GNASmut was associated with improved survival (HR 0.57, 95% CI: 0.47-0.70, p &lt; 0.00001), while TP53mut was associated with poorer survival (HR 1.58, 95% CI: 1.35-1.86, p &lt; 0.00001) among all AC. Conclusions: KRAS was one of most frequently mutated genes in ACs. In contrast to CRC, KRASmut was associated with significantly improved survival. This observed survival advantage remained consistent in the histologic subgroup of mucinous adenocarcinoma, but not in goblet and signet ring cell cancers. Further studies with population level data understanding the molecular profiles and their survival implications in histologically distinct AC are needed.

Critical reappraisal of prognostic indicators for 949 mucinous appendiceal neoplasm patients.

The standard of care for treatment of an appendiceal mucinous neoplasm with peritoneal dissemination is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). These two treatments are combined in the operating room. A crucial requirement for benefit long-term is proper patient selection. Clinical and histopathologic prognostic indicators are used, along with the patient's fitness for surgery, to select patients to receive CRS and HIPEC. This study seeks to identify the reliable prognostic indicators for four different groups of patients. They are (1) the low-grade appendiceal mucinous neoplasms (LAMN) with a complete CRS, (2) the mucinous appendiceal adenocarcinomas (MACA) with complete CRS, (3) MACA with lymph node metastases (MACA-LN) with complete CRS, and (4) all histologic subtypes with incomplete cytoreduction. The prognostic indicators were evaluated for their impact on overall survival in these four groups of patients. The completeness of cytoreduction (CC) score statistically significantly showed survival differences in all three histologic subtypes. The peritoneal cancer index (PCI) showed significance with LAMN and MACA-LN but not with MACA and not with incomplete CRS. The prior surgical score (PSS) was a prognostic indicator that predicted the outcome with LAMN, MACA-LN, and incomplete CRS patients but not with the MACA group. Patients who were symptomatic or who had extensive systemic chemotherapy before CRS had a significantly reduced survival. The utility of prognostic indicators varied greatly within our four different groups of appendiceal mucinous neoplasms. CC score was always a reliable prognosticator. Surprisingly, PCI was not.

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.

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

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

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.

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.