Appendiceal neoplasms in Saudi Arabia: prevalence and clinicopathological profile.

BACKGROUND: 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. OBJECTIVES: 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. DESIGN: Retrospective cohort. SETTING: Tertiary care center in Riyadh. PATIENTS AND METHODS: 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. MAIN OUTCOME MEASURES: Demographics, clinical presentations, surgical interventions, histopathological findings, complications, and recurrence rates. SAMPLE SIZE: 25 AN patients. RESULTS: 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. CONCLUSIONS: 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. LIMITATIONS: Data collected retrospectively, a single institution, and a small population.

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.

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.

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.

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.

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.

Risk of appendiceal malignancy in conservatively treated acute appendicitis.

BACKGROUND AND AIMS: Appendectomy has historically been the standard treatment of acute appendicitis, but lately, conservative treatment of uncomplicated acute appendicitis with antibiotics has successfully been used in selected patients. Complicated acute appendicitis is often treated conservatively initially, but may benefit from interval appendectomy due to the higher risk of appendiceal malignancy and recurrence. Recommendations for follow-up after conservatively treated appendicitis vary. Furthermore, the risk of underlying malignancy and the necessity of routine interval appendectomy are unclear. This study aims to evaluate follow-up status, recurrence, and underlying appendiceal malignancy in conservatively treated uncomplicated and complicated acute appendicitis. METHODS: This study included patients with conservatively treated acute appendicitis at Skåne University Hospital, Sweden during 2012-2019. Information on patient demographics at index admission and data on follow-up, recurrence, number of appendectomies after initial conservative treatment, and underlying malignancy were retrieved from medical charts. RESULTS: The study cohort included 391 patients, 152 with uncomplicated and 239 with complicated acute appendicitis. Median time of study follow-up was 52 months. The recurrence risk was 23 (15.1%) after uncomplicated and 58 (24.3%) after complicated acute appendicitis (p = 0.030). During follow-up, 55 (23%) patients with complicated acute appendicitis underwent appendectomy. Appendiceal malignancies were found in 12 (5%) patients with previous complicated acute appendicitis versus no appendiceal malignancies after uncomplicated acute appendicitis (p = 0.002). CONCLUSION: The risk of appendiceal malignancy and recurrent appendicitis was significantly higher in patients with complicated acute appendicitis compared with uncomplicated acute appendicitis.

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.

Oncological aspect of incidental appendectomy with regard to histopathological findings: A retrospective cohort study.

INTRODUCTION: The aim of this retrospective cohort study was to describe the findings on histopathological examination of removed, macroscopically non-diseased, vermicular appendix during another primary surgical procedure (incidental appendectomy (IA)). Previous studies disapproved IA but were based on the possibility of complicated appendicitis. We observed the prevalence of neoplasms of the appendix in IA versus the appendectomy performed due to acute appendicitis (AA). METHODS: The database of histopathology reports of the Surgery Department, University Hospital of Split was reviewed in the period from January 1, 2017, to December 31, 2021. A total of 2832 histopathology reports were reviewed. RESULTS: There was no difference in gender distribution between these two groups, but AA had a statistically significantly lower median patient age compared to the group IA (40 vs. 68 years; P < 0.001). In the AA group, there were 84.5% acute appendicitis, 11.1% normal appendiceal reports, 3.2% appendiceal neoplasms, and 1.2% other pathologies. The group IA had 89.5% normal findings of the appendix, 7.2% appendiceal neoplasms, and 0.5% other pathology. The difference in neoplasm prevalence between IA and AA groups was 4.0% (95%CI: 2.2 to 5.8), P < 0.001. The number of incidental appendectomies needed to detect one neoplasm of the appendix is 25. CONCLUSION: Incidental appendectomies in patients undergoing abdominal surgery revealed a relatively high prevalence of appendiceal neoplasms above the age of 60 years. Prospective studies about incidental appendectomies, their clinical consequences, and impact on prognosis should be performed to define the value of incidental appendectomy in those patients.

Cancer-specific survival in non-mucinous appendiceal adenocarcinomas after local resection versus right hemicolectomy: A Surveillance, Epidemiology, and End Results database study.

BACKGROUND: Adenocarcinomas of the appendix are rare cancers for which no National Comprehensive Cancer Network guidelines exist, and for patients who undergo resection with curative intent, there is a paucity of data on prognostic factors affecting long-term cancer-specific survival. We aimed to compare the cancer-specific survival outcomes in adult patients with appendiceal non-mucinous adenocarcinoma undergoing either local resection versus right hemicolectomy. METHODS: This was a retrospective study from the National Cancer Institute Surveillance, Epidemiology, and End Results of patients who underwent curative resection over a 15-year period (2004-2019) for primary appendiceal adenocarcinoma. Out of 16,699 patients, 14,945 were excluded (exclusion criteria were non-adenocarcinoma histological types and patients with regional or distant metastasis as per National Cancer Institute Surveillance, Epidemiology, and End Results stage). Effects of factors (age, race, tumor biology [mucinous versus non-mucinous tumors], the extent of resection of the primary lesion, and lymph nodes) on cancer-specific long-term survival were studied. Survival analysis was performed using the Kaplan-Meier method. Survival outcomes were reported as mean survival (months). RESULTS: Of 1,754 patients, 827 (47.1%) were women, and 927 (52.1%) were men. The mean age in years (± standard deviation) was 62.43 ± 14.3. The racial distribution was as follows: Black 237 (13.5%), White 1,398 (79.7%), and Other 119 (6.8%). A total of 771 (44.6%) underwent local resection (appendectomy or segmental resection of colon without lymph node resection), and 983 (55.4%) underwent hemicolectomy with lymph node resection. Favorable survival prognosticators were age <50 years, White race, and well-differentiated histology. Patients with mucinous tumors experienced better survival. Patients who underwent right hemicolectomy with lymph node resection experienced better survival compared with those who had an appendectomy or segmental colonic resection for non-mucinous tumors rather than mucinous tumors. CONCLUSION: We report novel demographic, tumor-related, and operative prognostic factors impacting long-term cancer-specific survival in patients who undergo resection for appendiceal adenocarcinoma. The extent of resection of the primary lesion with draining lymph nodes determines long-term cancer-specific survival in non-mucinous appendiceal adenocarcinomas.

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.

Appendiceal neoplasms: Suspected findings and reports of 14 cases.

Background: Neoplastic lesions of the vermiform appendix are still considered to be rare, some studies suggest that appendix cancer may be on the rise, with an estimated incidence of 0.08-0.1% of all appendiceal specimens. The lifetime incidence of malignant appendiceal tumors ranges from 0.2 to 0.5%. Patients and Methods: Our study is applied at the Department of General Surgery at tertiary training and research hospital; 14 patients who had appendectomy or right hemicolectomy between December 2015 and April 2020 were evaluated. Results: The mean age of the patients was 52.3 ± 15.1 (range, 26-79) years. Gender of the patients were: five (35.7%) men and nine (64.3%) women. The clinical diagnosis was appendicitis without suspected findings in 11 (78.6%), appendicitis with suspected findings (appendiceal mass, etc.) in three (21.4%) of the patients, and there is no patient with asymptomatic or other rare findings. Surgeries applied for the patients were: nine (64.3%) underwent open appendectomy, four (28.6%) underwent laparoscopic appendectomy, and one (7.1%) underwent open right hemicolectomy. Histopathologic results were as follows: five (35.7%) neuroendocrine neoplasm, eight (57.1%), noninvasive mucinous neoplasm, and one (7.1%) adenocarcinoma. Conclusion: While diagnosis and management of appendiceal pathology, surgeons should be familiar with suspected findings of appendiceal tumors and discuss them with patients to the possibility of histopathologic results.

Appendiceal adenocarcinoma is associated with better prognosis than cecal adenocarcinoma: a population-based comparative survival study.

OBJECTIVE: Although appendiceal cancer remains a rare gastrointestinal malignancy compared with colorectal cancer, incidence rates of appendiceal cancer have increased in the last two decades. Appendiceal and cecal adenocarcinomas have distinct genomic profiles, but chemotherapy protocols for these malignancies are the same and survival outcomes between them have not been compared extensively. To this end, we conducted a comparative survival analysis of appendiceal and cecal adenocarcinomas. DESIGN: Using the Surveillance, Epidemiology and End Results (SEER) database, we identified individuals ≥30 years of age with appendiceal or cecal adenocarcinoma from 1975 to 2016. Demographic, clinical and county-level socioeconomic data were extracted using SEER*Stat software. Survival was compared by Mantel-Haenszel log-rank test, and survival curves were generated using the Kaplan-Meier method. Relative HRs for death in the 5-year period following diagnosis were calculated using multivariable Cox regression analysis, adjusted for all other covariates. The significance level was set at p<0.05 for two-tailed tests. Data were analysed using SAS V.9.4 and R software. RESULTS: We identified 6491 patients with appendiceal adenocarcinoma and 99 387 patients with cecal adenocarcinoma. Multivariable Cox regression analysis demonstrated significantly higher cancer-specific and overall survival in appendiceal adenocarcinoma compared with cecal adenocarcinoma. Male sex, older age, earlier year of diagnosis, black race, single marital status, non-Hispanic ethnicity, and non-mucinous histology were associated with increased mortality rates. In addition, counties with lower percentage of individuals below the poverty line and higher colorectal cancer screening rates had better survival. CONCLUSION: This is the first study to show greater survival in appendiceal adenocarcinoma compared with cecal adenocarcinoma. We also highlighted novel associations of county-level socioeconomic factors with increased mortality in appendiceal adenocarcinoma. Future efforts to develop targeted molecular therapies and reduce socioeconomic barriers to diagnosis and treatment are warranted to improve survival.

Clinical and pathologic characteristics of appendiceal neuroendocrine neoplasms diagnosed during pregnancy.

Introduction: Although appendicitis occurs in approximately 1:1000 pregnancies, appendiceal neuroendocrine neoplasm (ANEN) diagnosis during pregnancy is very rare. Data on presentation, treatment and prognosis is scarce. Aim: To describe ANEN cases diagnosed during pregnancy. Materials and methods: A retrospective appraisal of 7 consecutive ANEN patients diagnosed during pregnancy from four Israeli tertiary medical centers and comparison with 17 cases described in the literature from 1965-2021. Results: Age at ANEN diagnosis was 26.4 ± 3.5 years (range 21-33). Patients were diagnosed between gestational weeks 6-40, most frequently in the third trimester (53%). The most common presenting symptom was abdominal pain. Tumor size was 14.3 ± 8.9mm (range 3-45mm). In patients from our series appendiceal base involvement was reported in 2/7; mesoappendiceal invasion in 5/7; lympho-vascular invasion in 2/7. Ki67 staining was reported in 6/7 cases and ranged from 1-10%. Pathology details were lacking in most of the previously published cases. All 7 pregnancies in our series resulted in term delivery with no complications, whereas in historical cases there were one first trimester abortion, one ectopic pregnancy, and one stillbirth. Right hemicolectomy was performed in 5/7 patients in our series and reported in 2/17 historical cases. All hemicolectomies were performed after delivery, 3-16 months after appendectomy. Local metastases were reported in two cases. Follow-up duration was 7-98 months for our patients and 3-48 months in 5 historical cases. No disease recurrence, distant metastases or mortality were noted. Conclusions: To the best of our knowledge, this is the largest series describing the extremely rare diagnosis of ANEN during pregnancy. Although pathologic characteristics varied, pregnancy outcomes were usually favorable and long-term prognosis was excellent. This data may suggest that a conservative approach to patients with ANEN diagnosis during pregnancy can be considered.

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.

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 tumors in patients undergoing primary surgery for mucinous ovarian tumors in a tertiary hospital, in Southern Thailand.

OBJECTIVE: To evaluate the prevalence of appendiceal tumors in patients diagnosed with mucinous ovarian tumors and to determine factors associated with coexisting appendiceal tumors. MATERIALS AND METHODS: Retrospective review of all patients who were diagnosed with mucinous ovarian tumors and underwent an appendectomy during surgery between January 2002 and June 2017 was performed. Univariate and multivariate logistic regression analyses were used to identify risk factors for coexisting appendiceal tumors. RESULTS: A total of 303 patients with mucinous ovarian tumors who underwent appendectomy were identified, including 77 (25.4%) mucinous cystadenoma and 226 (74.6%) mucinous borderline tumor or carcinoma. Twenty-one (6.9%) had coexisting appendiceal tumors including 8 that were primary appendiceal mucinous adenocarcinomas, 6 low-grade appendiceal mucinous neoplasms, 6 secondary appendiceal metastasis from the ovary, and one hyperplastic polyp. None of mucinous cystadenoma had coexisting appendiceal tumors. Multivariate analysis revealed advanced age ≥50 years, previous rupture of ovarian tumors, abdominal extension of tumors, and grossly abnormal appendix were independent factors for coexisting appendiceal tumors. CONCLUSION: Prevalence of coexisting appendiceal tumors in mucinous ovarian tumors was not uncommon. The risk factors were grossly abnormal appendix, abdominal extension of tumor, previous rupture of ovarian tumors, and advanced age.

Appendiceal Cancer in the National Cancer Database: Increasing Frequency, Decreasing Age, and Shifting Histology.

BACKGROUND: Nonoperative management of acute appendicitis is increasingly common. However, small studies have demonstrated high rates of appendiceal cancer in interval appendectomy specimens. Therefore, we sought to identify national trends in appendiceal cancer incidence and histology. STUDY DESIGN: The National Cancer Database was queried for patients 18 years or older, diagnosed with a right-sided colon cancer (including appendiceal) from 2004 to 2017 who had undergone surgery. Outcomes included trends in appendiceal cancer compared with right-sided colon cancers and trends in appendiceal cancer histology. Logistic regression was used to assess trends over time while adjusting for patient age, insurance, income, area of residence, and comorbidity. Predicted probabilities of the outcomes were derived from the logistic regression models. RESULTS: Of 387,867 patients with right-sided colon cancer, 19,570 had appendiceal cancer and of those 5,628 had a carcinoid tumor. Odds of appendiceal cancer, relative to other right-sided colon cancers, increased from 2004 to 2017 (odds ratio [OR] 2.56, 95% CI 2.35-2.79). The increase occurred in all age groups; however, it was more markedly increased in patients 40-49 years old (2004: 10%, 95% CI 9-12 to 2017: 18%, 95% CI 16-20; pairwise comparisons p < 0.001). Odds of appendiceal carcinoid, relative to other appendiceal histologies, increased from 2004 to 2017 (OR 1.70, 95% CI 1.40-2.07) with the greatest increase in probability of a carcinoid in patients younger than 40 years old (2004: 24%, 95% CI 15-34 to 2017: 45%, 95% CI 37-53; pairwise comparisons p < 0.001). CONCLUSION: Appendiceal cancer has increased over time, and the increase appears to be driven by a rise in carcinoids, most prevalent in patients 49 years of age or younger. When nonoperative management of acute appendicitis is undertaken, close follow-up may be appropriate given these findings.