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

INTRODUCTION: 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. MATERIAL AND METHODS: 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). RESULTS: 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 89 years 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. CONCLUSION: 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.

Retrospective analysis of the incidence of appendiceal neoplasm and malignancy in patients treated for suspected acute appendicitis.

BACKGROUND: Nonoperative management of uncomplicated appendicitis is currently being promoted as treatment option, albeit 0.7-2.5% of appendectomies performed due to suspected acute appendicitis show histologically malignant findings. The purpose of this study was to investigate the incidence of neoplasm and malignancy of the appendix in patients presenting with suspected acute appendicitis in real world setting. METHODS: This is a retrospective single-centre investigation of 457 patients undergoing appendectomy between the years 2017-2020. The patients' demographics, symptoms and diagnosis, intraoperative findings, and histopathological results were analysed. RESULTS: In 3.7% (n = 17) histological analysis revealed neoplasms or malignancies. Median age was 48 years (20-90 years), without sex predominance. Leukocytes (11.3 ± 3.7 G/l) and C-reactive protein (54.2 ± 69.0 mg/l) were elevated. Histological analysis revealed low-grade mucinous appendiceal neoplasia (n = 3), sessile serrated adenoma of the appendix (n = 3), neuroendocrine tumours (n = 7), appendiceal adenocarcinoma of intestinal type (n = 3), and goblet cell carcinoma (n = 1). Additional treatment varied between no treatment or follow-up due to early tumour stage (n = 4), follow-up care (n = 3), additional surgical treatment (n = 8), or best supportive care (n = 2). CONCLUSIONS: Preoperative diagnosis of appendiceal tumours is difficult. Nonoperative management of patients with acute, uncomplicated appendicitis potentially prevents the correct diagnosis of malignant appendiceal pathologies. Therefore, close follow-up or surgical removal of the appendix is mandatory.

Multi-institutional assessment of the prevalence of neuroendocrine tumors in children undergoing laparoscopic appendectomy for acute appendicitis in the United States.

As non-operative management of acute appendicitis in children has become more common, missed incidental appendiceal pathology can be an unintended consequence. We assessed the prevalence of neuroendocrine tumors in appendectomy specimens from eight US children's hospitals from 2012 to 2021. The prevalence of neuroendocrine tumors (NET) was found to be 1:271, with a median age of 14 years and 62% female. Most tumors were small (median 6 mm; interquartile range [IQR]: 3-10), and no recurrence was noted during the follow-up period (median 22.5 months; IQR: 3-53). The possibility of delayed diagnosis of these tumors should be part of the discussion for non-operative management of pediatric acute appendicitis.

Well-Differentiated Neuroendocrine Tumors of the Appendix in Children and Adolescents: A Clinicopathologic Study.

BACKGROUND AND AIMS: Pediatric neuroendocrine tumors (NET) of the GI tract are rare and appendiceal NET are typically incidental. Few studies have been done in the pediatric population and practice guidelines are mainly based on adult data. There are currently no diagnostic studies specific for NET. Our study aimed to identify clinical, radiological, and pathological findings in pediatric appendiceal NET, test criteria for follow up surgical treatment, review potential prognostic pathological findings, and possible pre-operative diagnostic radiological studies. MATERIALS AND METHODS: A retrospective data search was conducted for well-differentiated NET of the appendix in patients ≤21 years between 1/1/2003 and 7/1/2022. Available clinical, radiologic, pathological, and follow-up information was recorded. RESULTS: Thirty-seven patients with appendiceal NET were identified. No masses were reported in the patients who underwent presurgical imaging. Appendectomy samples showed NET (0.2->4 cm), most located in the tip. Most cases were WHO G1 (34/37), with negative margins (n = 25). Sixteen cases extended to the subserosa/mesoappendix (pT3). Lymphovascular (6), perineural (2), and both lymphovascular and perineural invasion were also noted (2). The specified tumor stages were pT1 (10/37), pT3 (16/37), and pT4 (4/37). Patients who underwent laboratory testing for chromogranin A (20) and urine 5HIAA (11) had normal limits. Subsequent surgical resection was recommended in 13 cases and performed in 11. To date, all patients have no recurrent or additional metastatic disease. CONCLUSIONS: Our study showed that all pediatric well-differentiated appendiceal NET were incidentally found as part of acute appendicitis management. Most NET were localized with low-grade histology. Our small cohort support the previously suggested management guidelines with follow up resection in certain cases. Our radiologic review didn't identify a best modality for NET. Comparing cases with and without metastatic disease, no tumors under 1 cm had metastasis, but serosal and perineural invasion along with G2 status were associated with metastasis in our limited study.

Incidence rate and histology of appendiceal neoplasms in complicated versus uncomplicated appendicitis: A meta-analysis and systematic review.

INTRODUCTION: Studies evaluating the rate and histology of appendiceal neoplasms between complicated and uncomplicated appendicitis include a small number of patients. Therefore, we sought a meta-analysis and systematic review comparing the rates and types of appendiceal neoplasm between complicated and uncomplicated appendicitis. METHODS: We included articles published from the time of inception of the datasets to September 30, 2022. The electronic databases included English publications in Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, and Scopus. RESULTS: A total of 4962 patients with appendicitis enrolled in 4 comparative studies were included. The mean age was 43.55 years (16- 94), and half were male (51%). Based on intra-operative findings, 1394 (38%) had complicated appendicitis, and 3558 (62%) had uncomplicated appendicitis. The overall incidence rate of neoplasm was 1.98%. No significant difference was found in the incidence rate of appendiceal neoplasm between complicated (3.29%) and uncomplicated (1.49%) appendicitis (OR 0.44, 95% CI 0.16- 1.23; p < 0.087; I2 = 54.9%). The most common appendiceal neoplasms were Neuroendocrine Tumors (NET) (49.21%), Nonmucinous Adenocarcinoma (24.24%), Mixed Adeno-Neuroendocrine Tumor (MANEC) (11.40%), Mucinous Adenocarcinoma (4.44%). There was a significant difference between complicated and uncomplicated appendicitis in rates of adenocarcinoma (50% vs. 13%), NET (31% vs. 74%), MANEC (19% vs. 13%) (P < 0.001). CONCLUSION: While there was no significant difference in the overall neoplasm rate between complicated and uncomplicated appendicitis, the NET rate was significantly higher in uncomplicated appendicitis. In comparison, the Adenocarcinoma rate was considerably higher in Complicated appendicitis. These findings emphasize the importance of evaluating risk factors for neoplasm when considering appendectomy in patients with appendicitis.

Incidence of appendiceal neoplasms in appendectomy patients.

BACKGROUND: Non-operative management has been suggested as a therapy for uncomplicated appendicitis. Notwithstanding, the risk of missing an appendiceal tumor must be considered, being the surgical piece crucial to rule out neoplasms. Therefore, we aim to determine the incidence of appendiceal neoplasms in patients with acute appendicitis, tumor types and the importance of the anatomopathological study of the surgical piece. STUDY DESIGN: Retrospective study in which we described patients who underwent emergent appendectomy with histopathological findings of appendiceal neoplasms from January 2012 to September 2018. Descriptive analysis included demographic variables, diagnostic methods, and surgical techniques. RESULTS: 2993 patients diagnosed with acute appendicitis who underwent an emergency appendectomy. 64 neoplasms of the appendix were found with an incidence of 2,14%. 67.2% were women, the mean age was 46,4 years (± 19.5). The most frequent appendiceal neoplasms were neuroendocrine tumors (42,2%), followed by appendiceal mucinous neoplasms (35,9%), sessile serrated adenomas (18,8%), and adenocarcinomas (3,1%). In 89,1% of the cases, acute appendicitis was determined by imaging, and 14% of cases were suspected intraoperatively. Appendectomy was performed in 78,1% without additional procedures. CONCLUSIONS: Appendiceal tumors are rare and must be ruled out in patients with suspected acute appendicitis. The incidence of incidental neoplasms is higher in this study than in the previously reported series. This information must be included in decision-making when considering treatment options for acute appendicitis.

High Incidence of Appendiceal Neoplasms in the Elderly: A Critical Concern for Non-Surgical Treatment.

OBJECTIVE: Appendiceal neoplasms (ANs) are rare tumors that are often discovered incidentally during histopathological examinations. The increasing incidence of ANs is a critical issue in the non-operative management of acute appendicitis. This study aimed to document the temporal trends over a 12-year period by analyzing the clinical presentation, imaging findings, and histopathological features of ANs. SUBJECTS AND METHODS: Health records of patients who underwent appendectomy from 2011 to 2022 were examined. Demographic and clinical data, laboratory results, imaging findings, and histopathological features were documented. The characteristics of both ANs and non-neoplastic cases were evaluated. RESULTS: A total of 22,304 cases were identified, of which 330 (1.5%) were diagnosed with ANs. The odds ratio for ANs increased with age, with the highest odds ratio observed in patients aged 70 or older. Receiver Operating Characteristic analysis showed that age and appendiceal diameter were significant predictors of ANs. An optimal age cut-off point of 28.5 years was determined, yielding a sensitivity of 72% and a specificity of 64%. For appendiceal diameter, the optimal cut-off was found to be 9.5 mm, exhibiting a sensitivity of 77% and a specificity of 56%. CONCLUSION: Although the incidence of ANs remains relatively low, a steady increase has been observed over the past decade. The increasing rate of ANs raises concerns regarding non-surgical management options. The results of this study highlight the importance of considering ANs as a potential diagnosis in older patients and in patients with an appendix diameter greater than 9.5 mm. These findings may have implications for treatment and management.

Incidence of occult appendiceal neoplasm in patients over 40 years with acute appendicitis: A single-institution review.

OBJECTIVE: To investigate the incidence of occult appendiceal neoplasm in patients aged 40 years and over who underwent appendicectomy for appendicitis. METHODS: The clinical coding electronic database was used to identify patients aged 40 years and over who were diagnosed with appendicitis from September 2010 to September 2022. Patients were included if they were managed operatively. DESIGN: Retrospective cohort study. SETTING: Modified Monash category 3 (large rural town). PARTICIPANTS: Patients aged 40 years and over undergoing appendicectomy for appendicitis. MAIN OUTCOME MEASURES: Incidence of appendiceal neoplasm within appendicectomy specimen. RESULTS: A total of 279 patients aged 40 years and over underwent appendicectomy, with a median age of 53 years (range 40-95). Nineteen patients (7%) were found to have a primary neoplastic lesion within the appendix: seven neuroendocrine neoplasms (37%), six sessile serrated lesions (32%), two colonic-type adenocarcinoma (11%), two goblet cell adenocarcinoma (11%) and two appendiceal mucinous neoplasms (11%). Additionally, one patient had a metastatic adenocarcinoma of pancreaticobiliary aetiology. CONCLUSIONS: Occult appendiceal neoplasm was higher than reported in the literature in our cohort. This would support appendicectomy as the treatment of choice for patients aged 40 years and over with acute appendicitis and caution against nonoperative management in this demographic.

Appendiceal Incidentalomas: Prevalence, Radiographic Characteristics, Management, and Outcomes.

BACKGROUND: Radiographically detected incidental appendiceal abnormalities, in this report termed "appendiceal incidentalomas" (AIs), are an ill-defined entity with an unknown prevalence of neoplasm. This study aimed to describe the prevalence, radiographic characteristics, and outcomes of patients with a diagnosis of AI. METHODS: The study reviewed the electronic health records for patients at a single institution undergoing abdominopelvic computed tomography and magnetic resonance imaging (MRI) from 2000 to 2020 for non-appendix-related complaints with mention of appendix abnormality in the radiology report. The suggested diagnosis at the index imaging was recorded. Outcomes were compared between the operative and non-operative patients. RESULTS: Of 5197 records, 484 were identified as reports of AIs (9 % of screened patients). Neoplasms were suggested radiographically in 16 % (n = 79) of the records, 59 % (47/79) of which were resected. Pathologically, 32 of the abnormalities were confirmed as neoplasms, yielding a diagnostic accuracy of 68 %. Compared with the non-operative patients, the operative patients had AIs with a larger mean diameter (22.7 ± 13.0 vs. 17.8 ±7.7 mm; p = 0.04), a higher colonoscopy rate (51 % vs. 22 %; p = 0.01), and diagnosis at a younger age (55.8 ± 15.6 vs. 67.2 ± 16.0 years; p = 0.003). The postoperative complications were minor (Clavien-Dindo grade 1 or 2) in 26 % and major (grades 3-5) in 4 % of the cases. During a median follow-up period of 28.3 months, 94 % of the patients were alive without disease, and 6 % died of other causes. The 32 non-operative suggested neoplastic AIs had a median follow-up period of 20.9 months. At this writing, 59 % of the operative patients are alive with a stable abnormal appendix, 13 % had no appendix abnormality at last follow-up visit, and 28 % have died of other causes. CONCLUSION: Neoplastic AIs are an uncommon finding and radiographically diagnosed with relatively high accuracy. Larger appendiceal diameter and younger age predict operative intervention. Although surgery is associated with favorable outcomes and minimal risk of postoperative complications, observation of suspected neoplastic AIs may be a safe alternative for select patients undergoing follow-up longitudinal imaging.

The association between appendicitis severity and patient age with appendiceal neoplasm histology-a population-based study.

PURPOSE: Recent studies have reported alarming appendiceal tumor rates associated with complicated acute appendicitis, especially in patients presenting with a periappendicular abscess. However, the data on histology of appendiceal tumors among acute appendicitis patients is limited, especially in patient cohorts differentiating between uncomplicated and complicated acute appendicitis. We have previously reported the association of increased appendiceal tumor prevalence with complicated acute appendicitis in this population-based study. The objective of this secondary analysis was to evaluate the association of both appendicitis severity and patient age with appendiceal tumor histology. METHODS: This nationwide population-based registry study (The Finnish Cancer Registry) was conducted from 2007 to 2013. All appendiceal tumors (n = 840) and available medical reports (n = 504) of these patients at eight study hospitals were previously evaluated, identifying altogether 250 patients with both acute appendicitis and appendiceal tumor. RESULTS: The severity of acute appendicitis was significantly associated with more malignant tumor histology. The risk of adenocarcinoma or pseudomyxoma was significantly higher among patients with periappendicular abscess (OR 15.05, CI 95% 6.98-32.49, p < 0.001) and patients presenting with perforated acute appendicitis (OR 4.09, CI 95% 1.69-9.90, p = 0.0018) compared to patients with uncomplicated acute appendicitis. Similarly, patient age over 40 years was significantly associated with the risk of adenocarcinoma and pseudomyxoma (OR 26.46, Cl 95% 7.95-88.09, p < 0.001). Patient sex was not associated with a more malignant appendiceal tumor histology (p = 0.67). CONCLUSION: More malignant appendiceal tumor histology of adenocarcinoma or pseudomyxoma was significantly associated with patient age over 40 years and complicated acute appendicitis, especially periappendicular abscess.

Comparison of the risk of appendiceal tumors in uncomplicated and complicated appendicitis.

BACKGROUND: Interval appendectomy or non-operative management is commonly performed for complicated appendicitis in adult patients. However, these treatments are still controversial because the incidence rate of appendiceal tumors recognized after interval appendectomy is reportedly higher than that after emergency appendectomy. Thus, this study aimed to compare the appendiceal tumor rates between uncomplicated and complicated appendicitis. METHODS: This study was a retrospective review of patients with appendicitis who underwent surgical removal at a single institution over 7.5 years. The primary objective was the comparison of the incidence rate of appendiceal tumors using propensity score matching, and the secondary objective was the same comparison among older patients, defined as patients aged ≥ 60 years. RESULTS: A total of 1277 patients were included. Of these patients, 297 (23.3%) were preoperatively diagnosed with complicated appendicitis. Moreover, 22 (1.7%) patients, including 14 cases of complicated appendicitis and 8 cases of uncomplicated appendicitis, were diagnosed with appendiceal tumors based on pathological examination. No significant difference was found in the incidence rate of appendiceal tumors between the two groups after matching for patients' background, including age, sex, and history of appendicitis by propensity score matching (P = 0.073). However, among patients aged ≥ 60 years, the incidence of appendiceal tumors was significantly higher in complicated than in uncomplicated appendicitis (P = 0.006). CONCLUSIONS: Although the overall risk of appendiceal tumors did not differ between complicated and uncomplicated appendicitis when analyzed by the propensity score matching, in older patients aged ≥ 60 years, the risk increased among those with complicated appendicitis. Therefore, although the incidence is low, complicated appendicitis, particularly, among older patients, should be examined carefully and be performed IA when unusual findings exist.

Low-grade mucinous neoplasms (LAMN) of the appendix in Germany between 2011 and 2018: a nationwide analysis based on data provided by the German Center for Cancer Registry Data (ZfKD) at the Robert Koch Institute (RKI).

INTRODUCTION: Low-grade appendiceal mucinous neoplasms (LAMN) are semi-malignant tumors of the appendix which are incidentally found in up to 1% of appendectomy specimen. To this day, no valid descriptive analysis on LAMN is available for the German population. METHODS: Data of LAMN (ICD-10: D37.3) were collected from the population-based cancer registries in Germany, provided by the German Center for Cancer Registry Data (Zentrum für Krebsregisterdaten-ZfKD). Data was anonymized and included gender, age at diagnosis, tumor staging according to the TNM-classification, state of residence, information on the performed therapy, and survival data. RESULTS: A total of 612 cases were reported to the ZfKD between 2011 and 2018. A total of 63.07% were female and 36.93% were male. Great inhomogeneity in reporting cases was seen in the federal states of Germany including the fact that some federal states did not report any cases at all. Age distribution showed a mean age of 62.03 years (SD 16.15) at diagnosis. However, data on tumor stage was only available in 24.86% of cases (n = 152). A total of 49.34% of these patients presented with a T4-stage. Likewise, information regarding performed therapy was available in the minority of patients: 269 patients received surgery, 22 did not and for 312 cases no information was available. Twenty-four patients received chemotherapy, 188 did not, and for 400 cases, no information was available. Overall 5-year survival was estimated at 79.52%. Patients below the age of 55 years at time of diagnosis had a significantly higher 5-year survival rate compared to patients above the age of 55 years (85.77% vs. 73.27%). DISCUSSION: In this study, we observed an incidence of LAMN in 0.13% of all appendectomy specimen in 2018. It seems likely that not all cases were reported to the ZfKD; therefore, case numbers may be considered underestimated. Age and gender distribution goes in line with international studies with females being predominantly affected. Especially regarding tumor stage and therapy in depth information cannot be provided through the ZfKD-database. This data analysis emphasizes the need for further studies and the need for setting up a specialized registry for this unique tumor entity to develop guidelines for the appropriate treatment and follow-up.

Appendiceal Carcinoids in Children-Prevalence, Treatment and Outcome in a Large Nationwide Pediatric Cohort.

Background and Objectives: Appendiceal carcinoids are rare neuroendocrine tumors and mainly found incidentally during histopathological examination following appendectomy. This observational cohort study was performed to determine the prevalence, treatment modalities and outcomes in children diagnosed with an appendiceal carcinoid tumor. Materials and Methods: Data from the largest German statutory health insurance "Techniker Krankenkasse" were analyzed within an 8-year period: January 2010 to December 2012 and January 2016 to December 2020. Patient characteristics, surgical technique, type of surgical department, diagnostic management, and postoperative morbidity were analyzed. Results: Out of 40.499 patients following appendectomy, appendiceal carcinoids were found in 44 children, resulting in a prevalence of 0.11%. Mean age at appendectomy was 14.7 (±2.6) years. Laparoscopic approach was performed in 40 (91%) cases. Right-sided hemicolectomy was performed in 8 (18%) patients. Additional diagnostic work-up (CT and MRI) was recorded in 5 (11%) children. Conclusions: This large nationwide pediatric study shows that 1 in 1000 patients was found to have a neuroendocrine tumor of the appendix (prevalence 0.11%), emphasizing its low prevalence in the pediatric age group. The majority of patients were treated with appendectomy only. However, treatment modalities are still variable. Longer follow-up analyses are needed to evaluate published guidelines and recommendations to aim for a limited surgical approach.

Is interval appendectomy really needed? A closer look at neoplasm rates in adult patients undergoing interval appendectomy after complicated appendicitis.

BACKGROUND: The treatment algorithm for appendicitis is evolving, with recent interest in non-operative management. However, the safety of non-operative management for patients with complicated appendicitis has been questioned due to concern for increased risk of occult appendiceal neoplasm in this patient population. Our study aims to determine the rate of neoplasms discovered during interval appendectomy for patients with complicated appendicitis and determine the necessity of interval appendectomy. METHODS: A retrospective chart review was conducted on interval appendectomies performed in adult patients for complicated appendicitis at our institution over a 9-year period. Interval appendectomy was defined as appendectomy delayed from initial presentation with appendicitis. Complicated appendicitis was defined as perforation, phlegmon, and/or abscess as seen on computed tomography at time of presentation. RESULTS: We identified 402 patients who underwent interval appendectomy for complicated appendicitis. A total of 36 appendiceal neoplasms were discovered on final pathology with an overall neoplasm rate of 9%. Patients with an appendiceal neoplasm were significantly older (56.6 years vs 45.1 years, p < 0.01). No patients under the age of 30 had a neoplasm. The rate of appendiceal neoplasms in patients 30 years and older was 11%. The rate for patients 50 years and older was 16%. For patients 80 years and older, the rate of appendiceal neoplasm was 43%. CONCLUSION: The risk of occult appendiceal neoplasm is low in patients under the age of 30; however, there was an 11% rate of appendiceal neoplasm in patients 30 years and older. The risk increases with increased age, with a 16% risk in patients 50 years and older. Given these findings, we recommend consideration of interval appendectomy in all patients 30 years and older with complicated appendicitis.

Rising incidence of appendiceal neoplasms over time: Does pathological handling of appendectomy specimens play a role?

BACKGROUND: Appendectomy is the most common emergent surgical procedure. Primary appendiceal neoplasms are rare entities that are usually detected incidentally in less than 2% of all appendectomies. The increase in the incidence rates of appendiceal neoplasms over time raises the question whether there is an actual change in the disease occurrence or is it a matter of increased recognition and reporting of what would have been previously missed and undiagnosed. OBJECTIVES: In our study, we aimed to review the archived tissue specimens of patients who were diagnosed with appendiceal neoplasms during the past decade at our institution and compare our clinical experience with published data to identify possible reasons that contribute to the increase in incidence rates of such neoplasms over the past few years. METHODS: Using a pathological database of surgical specimens from patients who underwent appendectomies between January 01, 2010 and September 30, 2020 at a large academic medical center, a single-center retrospective cohort analysis was performed, and medical charts of patients were reviewed. RESULTS: Of the total 1568 patients included, 102 (6.5%) had appendiceal neoplasms divided between primary (79.4%) and secondary/metastatic (20.6%) neoplasms. Annual incidence of appendiceal neoplasms over the past 10 years in our institution demonstrated an increasing trend from 5.6% in 2010 to 12.7% in 2020, which we hypothesize might be attributed to submitting more representative sections of the appendix for pathological examination than we had previously. Our results also showed that 2.8% of patients initially presenting with a typical clinical picture of acute appendicitis had appendiceal neoplasms as a truly incidental finding, while 20.3% of patients who underwent elective appendectomies for a suspicious appendiceal mass were found to be neoplastic. Interestingly, among the 80 cases of epithelial neoplasms, more non-carcinoid neoplasms were detected than carcinoid tumors. CONCLUSION: Based on our results and what has been published recently, we confirm an additional increase in incidental appendiceal neoplasms found in appendectomies performed for a clinical picture of acute appendicitis, which may be related to more thorough specimen assessment. Whether this is clinically impactful remains to be determined. However, these data support a modification in the way appendectomy specimens are handled in pathology labs post-operatively.

A retrospective analysis and literature review of neoplastic appendiceal mucinous lesions.

BACKGROUND: At present, the term mucocele is outdated, and mucinous appendiceal neoplasm is preferred. Mucinous appendiceal neoplasm is an uncommon pathology that occurs predominantly in middle-aged women. Its classification and management have been the subject of debate in recent decades. The aim of this study was to analyse the incidence, clinical management and survival of these tumours diagnosed in our centre in the last 10 years. METHODS: This was a retrospective observational study of patients with a diagnosis of appendiceal neoplasms between 2009 and 2018 in our centre. Variables such as sex, age, tumour type, clinical status, diagnosis, treatment and survival were collected. All data were analysed using the statistical program IBM SPSS Statistic® version 25. RESULTS: Twenty-nine patients with a diagnosis of appendiceal neoplasm were identified, and 24 corresponded to neoplastic appendiceal mucinous lesions (85.7%). The average age was 59.7 ± 17.6 years. Most patients were women (15 cases; 62.5%). Most of them presented with chronic abdominal pain (37.5%), and the diagnosis was performed by computed tomography (CT) (50%). The treatment was surgical in all cases. The surgical technique depended on the findings and histology of the tumour. CONCLUSION: Mucinous appendiceal neoplasms are an uncommon entity, and their pathological classification and management have recently changed.

Appendiceal adenocarcinoma found by surgery for acute appendicitis is associated with older age.

BACKGROUND: Appendectomy for acute appendicitis is the most common procedure performed emergently by general surgeons in the United States. The current management of acute appendicitis is increasingly controversial as non-operative management gains favor. Although rare, appendiceal neoplasms are often found as an incidental finding in the setting of appendectomy. Criteria and screening for appendiceal neoplasms are not standardized among surgical societies. METHODS: The National Surgical Quality Improvement Program (NSQIP) database was queried for all patients who underwent appendectomy over a 9-year period (2010-2018). Over the same time period, patients who underwent appendectomy in two municipal hospitals in The Bronx, New York City, USA were reviewed. RESULTS: We found a 1.7% incidence of appendiceal neoplasms locally and a 0.53% incidence of appendiceal tumors in a national population sample. Both groups demonstrated an increased incidence of appendiceal carcinoma by age. This finding was most pronounced after the age of 40 in both local and national populations. In our study, the incidence of appendiceal tumors increased with each decade interval up to the age of 80 and peaked at 2.1% in patients between 70 and 79 years. CONCLUSIONS: Appendiceal adenocarcinomas were identified in patients with acute appendicitis that seem to be associated with increasing age. The presence of an appendiceal malignancy should be considered in the management of older patients with acute appendicitis before a decision to embark on non-operative therapy.

Risk of appendiceal neoplasm after interval appendectomy for complicated appendicitis: A systematic review and meta-analysis.

BACKGROUND: Non-operative management is often the treatment of choice in cases of complicated appendicitis and routine interval appendectomy is not usually recommended. Actually, recent studies show an alarming number of appendiceal neoplasms following interval appendectomy. The aim of this study is to evaluate the prevalence of appendiceal neoplasms and their histological types after interval appendectomy for complicated appendicitis in adults. METHODS: A comprehensive literature search of the PubMed, Scopus and Web of Science databases was conducted according to the PRISMA statement. Studies reporting appendiceal neoplasm rates after interval appendectomy and histopathological characteristics were included. The most recent World Health Organization (WHO) classification of malignant tumours was considered. A pooled prevalence analysis for both prevalence and pathology was performed. RESULTS: A total of eight studies was included: seven retrospective series and one randomized controlled trial. The pooled prevalence of neoplasms after interval appendectomy was 11% (95% CI 7-15; I2 = 37.5%, p = 0.13). Appendiceal mucinous neoplasms occurred in 43% (95% CI 19-68), adenocarcinoma in 29% (95% CI 6-51), appendiceal neuroendocrine neoplasm in 21% (95% CI 6-36), globet cell carcinoma in 13% (95% CI -2-28), adenoma or serrated lesions in 20% (95% CI -0-41) of cases. CONCLUSION: The risk of appendiceal neoplasm in patients treated with interval appendectomy for complicated appendicitis is 11%; mucinous neoplasm is the most common histopathological type. Further studies should investigate this association in order to clarify the biological pathway and clinical implications.

[Analysis of correlation factors and risk prediction for acute appendicitis associated with appendiceal neoplasms].

Objective: To examine the correlation factors of acute appendicitis associated with appendiceal neoplasms. Methods: Consecutive 712 patients with acute appendicitis who treated at Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University from January 2002 to December 2016 were analyzed retrospectively. There were 314 females and 398 males, aging (42.5±16.2) years (range: 14 to 94 years). Among the 712 cases, 36 patients were diagnosed with acute appendicitis associated with appendiceal neoplasms, the other 676 patients had no appendiceal neoplasm. The patients' clinical baseline characteristics and clinical parameters were compared between the two groups. The correlation factors of acute appendicitis associated with appendiceal neoplasms were evaluated by using the univariate (χ2 test or t test) and multivariate Logistic regression analysis. The area under curve of receiver operating characteristic curves was utilized to evaluate the discriminatory power of the predictive models. Results: According to the univariate analysis, gender, age, body mass index, the duration of chronic right low abdominal pains≥3 months, the frequency of recurrently acute right lower abdominal pain≥2, the frequency of acute right lower abdominal pain, past history of diabetes, hypertension or coronary heart disease, the level of neutrophils and leukocytes preoperatively, stercolith and periappendiceal effusion, and modified Alvarado score were positively correlated with appendiceal neoplasms (all P<0.05). Then four variables were incorporated into the model eventually by multivariate Logistic regression analysis, which were as follows: age (increased per decade) (OR=2.23, 95%CI: 1.68 to 2.95, P<0.01), gender (female) (OR=4.21, 95%CI: 1.74 to 10.19, P=0.001), the duration of chronic right low abdominal pains (more than 3 months) (OR=2.53, 95%CI: 1.01 to 3.37, P=0.048), and modified Alvarado score (decreased per 1 score) (OR=2.54, 95%CI: 1.87 to 3.34, P<0.01). The area of curve was 0.93 (95%CI: 0.88 to 0.97), which indicated that the model exhibits an excellent ability to discriminate between appendiceal neoplasms and acute appendicitis. Conclusions: The older age, female, the duration of chronic right low abdominal pains, and lower modified Alvarado score are independent correlation factors for acute appendicitis associated with appendiceal neoplasms. Clinicians should be alert for the above clinical characteristics and choose optimal treatment for acute appendicitis associated with appendiceal neoplasms.

Continued increasing incidence of malignant appendiceal tumors in Canada and the United States: A population-based study.

BACKGROUND: To the authors' knowledge, there are limited data regarding the epidemiology of malignant appendiceal tumors. It remains unknown whether the previously reported trends are occurring in different countries and/or continuing in recent years and/or whether they are possibly due to increasing rates of appendectomies. In the current study, the authors investigated the patterns and time trends of malignant appendiceal tumor diagnosis by age group, sex, stage of disease, and histology in Canada and the United States and concomitant rates of appendectomies in Canada. METHODS: The Canadian Cancer Registry and the US Surveillance, Epidemiology, and End Results incidence databases were used to identify incident patients of malignant appendiceal tumors in the 2 countries between 1992 and 2016. The Canadian national hospitals Discharge Abstract Database was used to identify appendectomies performed between 2004 and 2015. Joinpoint regression analyses were performed to determine time trends. RESULTS: There was an overall increase in the incidence of malignant appendiceal tumors of 232% in the United States and 292% in Canada between 2000 and 2016. The increase was noted for malignant adenocarcinomas and neuroendocrine appendiceal tumors in both countries. The increase occurred across all age groups, sexes, and stages of disease. The highest rate of increase was noted for appendiceal neuroendocrine malignant tumors diagnosed among the youngest age groups. The rate of appendectomies was stable in the recent time periods, resulting in a decreasing rate of appendectomies per malignant appendiceal tumor diagnosis. CONCLUSIONS: The incidence of malignant appendiceal tumor is continuing to increase, which is not likely due to the increasing diagnosis of asymptomatic tumors at the time of appendectomies.