Controversies and Future Directions in Management of Acute Appendicitis: An Updated Comprehensive Review

Globally, acute appendicitis has an estimated lifetime risk of 7-8%. However, there are numerous controversies surrounding the management of acute appendicitis, and the best treatment approach depends on patient characteristics. Non-operative management (NOM), which involves the utilization of antibiotics and aggressive intravenous hydration, and surgical appendectomy are valid treatment options for healthy adults. NOM is also ideal for poor surgical candidates. Another important consideration is the timing of surgery, i.e., the role of interval appendectomy (IA) and the possibility of delaying surgery for a few hours on index admission. IA refers to surgical removal of the appendix 8-12 weeks after the initial diagnosis of appendicitis. It is ideal in patients with a contained appendiceal perforation on initial presentation, wherein an initial nonoperative approach is preferred. Furthermore, IA can help distinguish malignant and non-malignant causes of acute appendicitis, while reducing the risk of recurrence. On the contrary, a decision to delay appendectomy for a few hours on index admission should be made based on the patients' baseline health status and severity of appendicitis. Post-operatively, surgical drain placement may help reduce postoperative complications; however, it carries an increased risk of drain occlusion, fistula formation, and paralytic ileus. Furthermore, one of the most critical aspects of appendectomy is the closure of the appendiceal stump, which can be achieved with the help of endoclips, sutures, staples, and endoloops. In this review, we discuss different aspects of management of acute appendicitis, current controversies in management, and the potential role of endoscopic appendectomy as a future treatment option.

Incidence and Management of Appendiceal Neuroendocrine Tumors in Pediatric Population: A Bicentric Experience with 6285 Appendectomies

BACKGROUND

Neuroendocrine tumors (NETs) are rare tumors that arise from neuroendocrine cells and are the most common tumors of the appendix. NETs of the appendix usually cause no symptoms and often go unnoticed until they cause acute appendicitis or are discovered during an accidental appendectomy. As the trend towards the conservative treatment of acute appendicitis increases in the pediatric population, the question arises as to whether the majority of NETs go undetected and are only discovered at an advanced stage. The purpose of the proposed study is to review the incidence and outcomes of treatment for NETs of the appendix in children and include the data presented in the data pool for further review.

METHODS

From 1 January 2009 to 1 November 2023, a total of 6285 appendectomies were performed in two large pediatric centers in Croatia. After a retrospective review of the case records and histopathologic findings, a total of 31 children (0.49%) were diagnosed with NET of the appendix and included in the further analysis. The primary outcome of this study was the incidence and treatment outcome of pediatric patients diagnosed with NET of the appendix. Secondary outcomes included the patients' demographic, clinical, and laboratory data and the histopathologic characteristics of tumor species.

RESULTS

The overall incidence of NETs of the appendix was stable over the study years, with minor fluctuations. The median age of patients was 14 (interquartile range-IQR: 12, 16) years, with a female predominance (64.5%). The majority of patients (96.8%) presented with acute abdominal pain and underwent appendectomy because acute appendicitis was suspected. Acute appendicitis was confirmed by histopathology in 18 (58%) cases. NETs of the appendix were not detected preoperatively in any of the patients. Among patients with confirmed acute appendicitis, most (n = 14; 77.8%) were found to have non-perforated acute appendicitis. In most children, the tumor was located at the tip of the appendix (n = 18; 58.1%), and the majority of tumors had a diameter of less than 1 cm (n = 21, 67.7%). The mitotic count (n = 25, 80.6%) and Ki-67 proliferation index (n = 23, 74.2%) were low in most patients, so most tumors were classified as NET G1 (n = 25, 80.6%), while NET G2 and NET G3 were found in four (12.9%) and two (6.5%) patients, respectively. All children were treated with appendectomy only. The median follow-up time was 54 (IQR: 24, 95) months.

CONCLUSIONS

The incidence of appendiceal NET among pediatric patients is very low. NET occurs most frequently in adolescents, with a female predominance. Most tumors are less than 1 cm in diameter, located at the tip, and associated with non-perforated appendicitis. Appendectomy is the treatment of choice, and major surgery was not necessary in our cohort.

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.

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.

Two-year outcomes of conservatively managed appendicitis during the COVID-19 pandemic-a multicentre cohort study

PURPOSE

During the COVID-19 pandemic, the new RCSEng guidelines resulted in appendicitis being more commonly managed conservatively to avoid aerosol-generating procedures. This resulted in shorter hospital stays without increased short-term complications. The 2-year outcomes of this change, specifically recurrence and re-admission rates remain unknown.

METHODS

We conducted a multicentre, prospective, observational study including all adult patients treated as appendicitis after the implementation of the new surgical guidelines during the COVID-19 pandemic. Outcomes included initial management failure, re-admission rate, appendicitis recurrence, and interval appendicectomy. A historical cohort prior to the COVID-19 pandemic was used for comparison. Patients were followed up for 2-years post index admission. Categorical and continuous variables were compared using Fisher's exact test and Student's T or Mann-Whitney U tests as appropriate.

RESULTS

Sixty-three and 79 patients with appendicitis were included from four NHS trusts, before (A) and after (B) the new intercollegiate guidelines respectively. Operative management was used less frequently in cohort B (28/79 vs 52/63; p<0.001). More patients re-presented in cohort B (14/79 vs 3/63; p=0.020), but not when comparing only those managed conservatively (2/11 vs 13/52; p=1.000). A similar trend was observed for appendicitis recurrence although without statistical significance (2/63 vs 9/79; p=0.112); with loss of trend when comparing those managed conservatively-only (2/11 vs 9/52; p=1.000). Among all patients, four (2.8%) were found to have underlying neoplasia of which three were initially managed conservatively (3/63; 4.8%).

CONCLUSION

Conservative management of appendicitis has previously been shown to have short-term benefits in expedited hospital discharge without early complications. The present study shows it has a higher readmission and appendicitis recurrence rates. The risks of this alongside missed/delayed management of neoplasia needs to be considered alongside the benefits including avoidance of aerosol-generating general anaesthesia and laparoscopy during the COVID-19 pandemic or similar future health crises. Small case numbers limit analysis.

Low grade appendiceal mucinous neoplasm metastatic to the ovary: A case report and intraoperative assessment guide

INTRODUCTION

Incidence of low grade appendiceal mucinous neoplasm is increasing. Preoperatively, it may present similarly to primary ovarian malignancy. This case report describes a case of presumed ovarian malignancy with final pathologic diagnosis of low grade appendiceal mucinous neoplasm. We also propose several surgical strategies to approach this conundrum.

PRESENTATION OF CASE

A postmenopausal woman with abdominal pain was found to have a 30 cm abdominopelvic mass with elevated CA-125 and CEA presumably a primary ovarian malignancy. During surgical staging, intraoperative findings were notable for an appendiceal mass. Intraoperative surgical oncology consultation recommended appendectomy for diagnostic purposes. Following primary surgery and final pathologic diagnosis, she underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

DISCUSSION

Low grade appendiceal mucinous neoplasm should be within the differential diagnosis of gynecologic surgeons when presented with a patient with large volume ascites and biopsy of acellular mucin. Intraoperatively, an abnormal appearing appendix with normal appearing gynecologic structures should trigger suspicion for appendiceal rather than ovarian origin. Preoperative symptoms, imaging studies, tumor markers, and frozen section pathology may not be able to differentiate between appendiceal and epithelial ovarian malignancies.

CONCLUSION

A recognition of mucinous material and abnormal appearing appendix should prompt the surgeon to consider performing an appendectomy to obtain primary pathologic diagnosis. A high level of suspicion could better optimize the patient for a joint case with the appropriate surgeons. Given the documented disguise of low grade appendiceal mucinous neoplasm as primary ovarian cancer and its increasing incidence, diagnosis and general understanding of treatment should be understood.

Analysis of appendiceal neoplasms in 1,423 appendectomy specimens: a 10-year retrospective cohort study from a single institution

OBJECTIVE

This study aimed to reveal the incidence, clinicopathological, and oncological outcomes of appendiceal neoplasms.

METHODS

This is a retrospective cohort study from a single institution. Patients with a pathological diagnosis of malignancy who underwent appendectomy between January 2011 and 2021 were included in the study, and groups were formed according to pathological type. Clinical, pathological, and oncological results were compared in these groups.

RESULTS

The incidence of neoplasia was 2.38% (n=34) in a cohort of 1,423 appendectomy cases. Of the cases, 56% (n=19) were female. The median age in the entire cohort was 55.5 (range: 13-106) years. In the cohort, the rate of neuroendocrine tumor mucinous cystadenoma adenocarcinoma, and low-grade appendiceal mucinous neoplasm, according to the American Joint Committee on Cancer classification of appendiceal neoplasms, was 32.3% (n=11), 26.4% (n=9), 26.4% (n=9), and 14.7% (n=5), respectively. Neuroendocrine tumor patients (median age: 35 years) were younger than the other groups (p=0.021). Secondary complementary surgery was performed in 66.7% (n=6) of adenocarcinoma patients and 27.3% (n=3) of neuroendocrine tumor patients. Right hemicolectomy was performed in all neuroendocrine tumor patients requiring secondary surgery, while right hemicolectomy was performed in three adenocarcinoma patients and cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in three adenocarcinoma patients. After a median follow-up of 44.4 months (95% confidence interval: 18.6-70.1), the mean survival rate was 55% in appendiceal adenocarcinoma patients compared to 100% in neuroendocrine tumor patients.

CONCLUSION

Appendiceal neoplasms are rare but remain an important cause of mortality. Appendiceal adenocarcinomas are associated with poorer oncological outcomes compared to other neoplasms.

Factors associated with recurrent appendicitis after nonoperative management

BACKGROUND

The objective of this study is to identify predictors for recurrent appendicitis in patients with appendicitis previously treated nonoperatively.

METHODS

This is a prospective cohort study of all adult patients with appendicitis treated at a tertiary care hospital. Patient demographics, radiographic information, management, and clinical outcomes were recorded. The primary outcome was recurrent appendicitis within 6 months after discharge from the index admission. Given the competing risk of interval appendectomy, a time-to-event competing-risk analysis was performed.

RESULTS

Of the 699 patients presenting with appendicitis, 74 were treated nonoperatively (35 [47%] were women; median [IQR] age, 48 [33,64] years), and 21 patients (29%) had recurrent appendicitis. On univariate and multivariate analysis, presence of an appendicolith on imaging was the only factor associated with a higher risk of recurrent appendicitis (p = 0.02).

CONCLUSIONS

The presence of appendicolith was associated with an increased risk of developing recurrent appendicitis within 6 months.

Metastatic gastric adenocarcinoma with appendiceal phlegmon: a case report

BACKGROUND

Gastric carcinoma is one of the most frequent malignancies worldwide. Gastric cancer metastasis to the appendix is uncommon in incidence, and has been rarely described in acute-appendicitis-related literature reviews. In this presented case, we have reported a rare case of appendiceal phlegmon, due to a diagnosis of metastatic gastric adenocarcinoma with uncommon symptoms.

CASE PRESENTATION

A 79-year-old Caucasian male presented to the emergency department with history of weakness, anorexia, lethargy, and mood changes for 2 months. Abdominopelvic computed tomography showed an abscess in right iliac muscle. After percutaneous drainage of the abscess and 6 weeks antibiotic therapy, an appendectomy was done for the patient. Histopathologic findings revealed the involvement of the appendiceal wall by adenocarcinoma, most probably with gastrointestinal origin. Gastric cancer was confirmed later by upper endoscopy and pathologic report.

CONCLUSIONS

Although the presence of tumor in appendectomy specimens is rare, and metastasis to appendix is even rarer, it should be considered as a cause of appendicitis, especially in elderly patients.

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.

[S073]-The impact of interval appendectomy timing on follow-up adverse outcomes

OBJECTIVE

This study aims to compare the timing of interval appendectomy (IA) and its impact on post-operative outcomes.

METHODS

A retrospective analysis was performed for adult patients diagnosed with appendicitis between 2006 and 2017. IA was defined as a follow-up appendectomy > 1 week and < 2 years after the initial presentation. Time intervals were divided into 4 groups based on patient quartiles: 1-6 weeks, 7-9 weeks, 10-15 weeks, and > 15 weeks. The primary outcome measure was length of stay (LOS). Secondary outcomes included 30-day readmission and IA post-operative complications. Tertiary outcomes included 30-day mortality and colonoscopy suggesting neoplasm or Inflammatory Bowel Disease.

RESULTS

A total of 5069 patients' records whose interval appendectomy fell > 1 week and < 2 years after initial presentation were analyzed. Among them, 1006 (19.85%) underwent an initial percutaneous abscess drainage at diagnosis. The median timing for IA was 9.2 weeks. Patients with IA at 1-6 weeks were more likely to have longer LOS when compared to 7-9 weeks (ratio 1.33, 95% CI 1.2-1.48) and 10-15 weeks (ratio 1.38, 95% CI 1.25-1.52). IA between 7 and 9 weeks (ratio 0.81, 95% CI 0.73-0.89) and 10-15 weeks (ratio 0.78, 95% CI 0.71-0.86) was associated with significantly shorter LOS compared to those receiving the operation after 15 weeks. Further, patients requiring abscess drainage (ratio 1.2, 95% CI 1.13-1.34) or those with comorbidities (ratio 1.51, 95% CI 1.39-1.63) were more likely to have longer LOS at IA. Socioeconomic and demographic differences including Black, Hispanic, and those with Medicare and Medicaid insurance had a greater LOS after their IA.

CONCLUSION

LOS remains lowest among patients undergoing IA between 7-9 weeks and 10-15 weeks after initial appendicitis presentation. Patients with lower socioeconomic status or from racial minorities had a longer LOS after IA.

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.

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.

Progression to pseudomyxoma peritonei in patients with low grade appendiceal mucinous neoplasms discovered at time of appendectomy

BACKGROUND

The discovery of a low grade appendiceal mucinous neoplasm (LAMN) during appendectomy is a rare scenario. These neoplasms can progress to pseudomyxoma peritonei (PMP), however the incidence of progression is not well known.

METHODS

The records of all patients with a diagnosis of localized LAMN found during appendectomy were identified, and demographic, tumor, surveillance, and outcome variables were analyzed.

RESULTS

Progression to PMP occurred in 20% of patients in an average of 12.4 months after appendectomy with median follow-up of 18 months. Tumor variables such as margin positivity, appendiceal perforation, and presence of extra-appendiceal acellular mucin or mucinous epithelium on the serosal were not significantly associated with progression.

CONCLUSIONS

During an average follow-up period of 18 months after surgery, progression to PMP occurred in a fifth of patients. It is difficult to predict which patients will progress, therefore cross-sectional imaging surveillance is recommended for all patients.

Controversies in appendiceal pathology: Mucinous and goblet cell neoplasms

Appendiceal goblet cell adenocarcinomas and mucinous neoplasms are uncommon compared with other epithelial tumours of the gastrointestinal tract. Both tumour types have been subjected to terminology that belies their biological risk and leads to confusion. Goblet cell adenocarcinomas display patchy staining for endocrine markers and, thus, were previously classified as goblet cell carcinoids. Unlike well-differentiated endocrine neoplasms, however, they often contain high-grade glandular elements and pursue an aggressive course akin to that of conventional adenocarcinoma. Although several authors have recently proposed grading schemes to predict behaviour among goblet cell neoplasms, most that contain high-grade components have already spread beyond the appendix at the time of diagnosis, whereas those confined to the appendix almost always have low-grade features; the added value of grading these tumours is limited. Contradictions also surround the nomenclature of mucinous neoplasms. The World Health Organization and others promote non-malignant terminology to describe metastatic mucinous neoplasms of the peritoneum and eliminate a benign category entirely, even though virtually all neoplasms confined to the appendix pose no recurrence risk following appendectomy. 'Low-grade appendiceal mucinous neoplasm' now encompasses a spectrum of benign tumours and malignant neoplasms in the appendix and peritoneum. Although using an umbrella term in this fashion simplifies the roles of pathologists, it provides essentially no actionable information beyond that which is already clinically apparent. Broad strokes nomenclature also ensures that many patients with no risk of recurrence will receive unnecessary surveillance while others will undergo inappropriate surgical procedures due to lapses in communication. Moreover, a surprising number of non-neoplastic mucinous lesions are misclassified as low-grade appendiceal mucinous neoplasms, which can result in unwarranted patient concern or even mismanagement. The purpose of this review is to critically evaluate the literature and describe an approach to appendiceal neoplasms that more clearly denotes their biologic risk.

Modern Management of the Appendix: So Many Options

Nonoperative management (NOM) of acute appendicitis is becoming more popular, especially in resource-strapped locations, to minimize hospital system costs. In uncomplicated cases of appendicitis, NOM can effectively treat the patient. It does carry a 39.1% risk of recurrence in 5 years, and operative management (OM) does not increase morbidity or risk of complication, so the authors recommend laparoscopic OM for uncomplicated appendicitis. For complicated cases of appendicitis, the authors recommend initial NOM with interval appendectomy in all patients. All appendicitis patients should undergo surveillance endoscopy if older than 40 years to rule out a contributing neoplasm.

Appendiceal neoplasm incidence and mortality rates are on the rise in Australia

OBJECTIVES

The study aimed to examine the incidence and mortality rates of appendiceal neoplasms (ANs) in Australia.

METHODS

A retrospective analysis was performed on national data obtained from the Australian Institute of Health and Welfare (AIHW) from 1982 to 2013. Changes to the incidence, and the cancer-specific mortality following the diagnosis of ANs were analyzed over this time period, with stratification performed for histological subtype, gender, and age groups (<50y and ≥50y).

RESULTS

Incidence and mortality rates of ANs increased significantly across both genders and age groups. Incidence rates increased by 415%, from 0.40/100 000 population in 1982 to 2.06/100 000 in 2013. Overall mortality rates increased by 130%, from 0.057/100 000 during 1982-1985 to 0.131/100 000 during 2010-2013. Controlling for age group and gender, the incidence rates increased by 20% every four years (Incidence rate ratio (IRR) = 1.20, 95% confidence interval (CI): 1.17, 1.23, global P value<0.0001), and controlling for age, the mortality rates increased by 8% every four years (IRR = 1.08, 95% CI: 1.00, 1.17, global P-value = 0.0401).

CONCLUSION

The increasing use of CT scanning, improvements in pathological assessment of the appendix, and the growing aging population may have contributed in part to the apparent rise in the incidence of ANs.

The Frontiers of Appendiceal Controversies: Mucinous Neoplasms and Pseudomyxoma Peritonei

Appendiceal mucinous neoplasms show a range of morphologic features and biological risk. At one end of the spectrum, high-grade adenocarcinomas are cytologically malignant with infiltrative invasion, lymph node metastases, and behavior similar to that of extra-appendiceal mucinous adenocarcinomas. At the other end, mucinous neoplasms confined to the mucosa are uniformly benign. Some cases lying between these extremes have potential risk to metastasize within the abdomen despite a lack of malignant histologic features. They show "diverticulum-like," pushing invasion of mostly low-grade epithelium through the appendix with, or without, concomitant organizing intra-abdominal mucin. The latter condition, widely termed "pseudomyxoma peritonei," tends to pursue a relentless course punctuated by multiple recurrences despite cytoreductive therapy, culminating in death for many patients. The combination of bland histologic features and protracted behavior of peritoneal disease has led some authors to question whether these metastatic tumors even represent malignancies. The World Health Organization and its cadre of experts widely promote usage of "low-grade appendiceal mucinous neoplasm" as an umbrella term to encompass benign and malignant conditions, as well as those that have uncertain biological potential. Although this practice greatly simplifies tumor classification, it causes confusion and consternation among pathologists, clinical colleagues, and patients. It also increases the likelihood that at least some patients will undergo unnecessary surveillance for, and treatment of, benign neoplasms and non-neoplastic conditions. The purpose of this review is to critically evaluate the relevant literature and discuss a practical approach to classifying appendiceal mucinous neoplasms that more closely approximates their biological risk.

Risk Factors for Appendiceal Cancer After Appendectomy

BACKGROUND

Appendiceal cancer (AC) is a rare malignancy usually diagnosed incidentally after appendectomy. Risk factors for AC are poorly understood. We sought to provide a descriptive analysis for patients with AC discovered after appendectomy for acute appendicitis (AA).

METHODS

The 2016-2017 American College of Surgeons-National Surgical Quality Improvement Program Procedure-Targeted Appendectomy database was queried for adult patients who underwent appendectomy for image-suspected AA. Patients with pathology consistent with AA were compared to patients found to have AC. A multivariable logistic regression model was used for analysis.

RESULTS

From 21 058 patients, 203 (1.0%) were found to have AC on pathology. Compared to patients with AA, patients with AC were older (median, 48 vs. 40 years old, P < .001). The AA group had a similar rate of perforated appendix compared to the AC group (16.3% vs. 13.4% P = .32). After adjusting for covariates, associated risk factors for AC were: age ≥65 years old (odds ratio (OR) 2.25, 1.5-3.38, P < .001), absence of leukocytosis (OR 1.58, 1.16-2.17, P = .004), and operative time ≥1 hour (OR 1.57, 1.14-2.16, P = .006). Gender, race, and history of smoking were not independent associated risk factors for AC.

CONCLUSION

The incidence of AC after appendectomy for suspected AA is approximately 1% in a large national analysis. These factors may be used to help identify patients at higher risk for AC after appendectomy.

Preoperative computed tomography is poor in detecting tumors of the appendix among patients with acute appendicitis: A cohort study of 5,224 appendectomies

BACKGROUND

Neoplastic processes are among the known etiologies for acute appendicitis. While conservative treatment with antibiotics alone has been proposed as a treatment for uncomplicated appendicitis, the presence of tumors should be excluded when offering patients this option. The aim of this study was to assess the accuracy of computed tomography (CT) in detecting appendiceal tumors.

METHOD

Consecutive patients operated on for acute appendicitis between January 2007 and October 3, 2018, in our university hospital were included. Whenever appendiceal tumor was histopathologically confirmed, CT interpretations and surgical reports were carefully reviewed. All CT scans were reanalyzed by consultant body radiologists. Discrepancies between the preliminary and final radiological interpretations were noted.

RESULTS

A total of 5,224 patients underwent appendectomy, of whom 4,766 had histopathologically confirmed acute appendicitis. Eighty-four patients (median, 61 (13-89) years; 54% female) were diagnosed with appendiceal tumor. Fifty-two patients (62%) had uncomplicated appendicitis. Although incidence of tumors was associated with older age, tumors were found in all ages. The share of tumors increased from 1.7% to 3.0%/year during the study. The most common tumors were neuroendocrine tumors (n = 33), low-grade appendiceal mucinous neoplasms (n = 14), and adenocarcinomas (n = 11). Sixty-one patients (73%) underwent preoperative CT. Computed tomography interpretation during on-call hours suspected tumor in only one case (3.4%) with invasive tumor, and in five cases (16%) with noninvasive tumor.

CONCLUSION

Appendiceal tumors are possible findings in appendix specimens, and most patients had uncomplicated acute appendicitis. In light of findings we conclude that CT cannot be used to exclude neoplastic etiology underlying acute appendicitis.

LEVEL OF EVIDENCE

Diagnostic, level IV.

Increased risk of malignancy for patients older than 40 years with appendicitis and an appendix wider than 10 mm on computed tomography scan: A post hoc analysis of an EAST multicenter study

BACKGROUND

The incidence of underlying malignancy in appendicitis ranges between 0.5% and 1.7%. We sought to identify the subset of patients with appendicitis who are at increased risk of appendiceal malignancy.

METHODS

Using the Eastern Association for the Surgery of Trauma Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous database, we included all patients from 28 centers undergoing immediate, delayed, or interval appendectomy between 2017 and 2018. Univariate then multivariable analyses were performed to compare patients with and without malignancy and to identify independent demographic, clinical, laboratory, and/or radiological predictors of malignancy. Akaike information criteria for regression models were used to evaluate goodness of fit.

RESULTS

A total of 3,293 patients were included. The median age was 38 (27-53) years, and 46.5% were female patients. On pathology, 48 (1.5%) had an underlying malignancy (adenocarcinoma [60.4%], neuroendocrine [37.5%], and lymphoma [2.1%]). Patients with malignancy were older (56 [34.5-67] vs 37 [27-52] years, P < .001), had longer duration of symptoms before presentation (36-41 vs 18-23 hours, P = .03), and were more likely to have a phlegmon on imaging (6.3% vs 1.3%, P = .03). Multivariable analyses showed that an enlarged appendiceal diameter was independently associated with malignancy (odds ratio = 1.06, 95% confidence interval = 1.01-1.12; P = .01). The incidence of malignancy in patients >40 years with an appendiceal diameter >10 mm on computed tomography was 2.95% compared with 0.97% in patients ≤40 years old with appendiceal diameter ≤10 mm. The corresponding risk ratio for that population was 3.03 (95% confidence interval: 1.24-7.42; P = .02).

CONCLUSION

The combination of age >40 and an appendiceal diameter >10 mm is associated with a greater than 3-fold increased risk of malignancy in patients presenting with appendicitis.

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.

Interval laparoscopic appendectomy after antibiotic therapy for appendiceal abscess in elderly patients

INTRODUCTION

The aim of this study was to evaluate the safety and efficacy of interval laparoscopic appendectomy after antibiotic therapy in elderly patients with appendiceal abscess.

METHODS

We retrospectively analyzed data for 50 patients with appendiceal abscess aged ≥18 years who had initially planned to undergo interval laparoscopic appendectomy after antibiotic therapy and 50 patients with appendicitis aged ≥70 years who had undergone early laparoscopic appendectomy. All patients were treated at the National Hospital Organization Kumamoto Medical Center between 2012 and 2018. We compared perioperative outcomes after interval appendectomy between patients aged <70 years and ≥70 years.

RESULTS

Clinical progression of appendicitis during antibiotic therapy developed in one patient (2.0%), and recurrent appendicitis after antibiotic therapy for appendiceal abscess occurred in two patients (4.0%). Pathological findings confirmed appendiceal neoplasms in four patients (8.0%). Postoperative infectious complications occurred in 1 of 47 patients (2.1%) who had undergone successful interval laparoscopic appendectomy, and the median length of postoperative hospital stay was 4 days (interquartile range, 3-5 days). There were no significant differences in outcomes after interval appendectomy between patients aged <70 years and ≥70 years. In the secondary analysis, the median length of postoperative hospital stay after interval laparoscopic appendectomy for appendiceal abscess (4 days) was significantly shorter than that after early laparoscopic appendectomy for uncomplicated appendicitis (7 days; P < .001).

CONCLUSIONS

Interval laparoscopic appendectomy for appendiceal abscess may be safe and effective in elderly patients without severe comorbidities. Interval appendectomy may be necessary for determining the underlying cause of appendiceal abscess in adults.

Post-inflammatory mucosal hyperplasia and appendiceal diverticula simulate features of low-grade appendiceal mucinous neoplasms

Post-inflammatory mucosal hyperplasia and appendiceal diverticulosis simulate mucinous neoplasms, causing diagnostic confusion. Distinction between neoplasia and its mimics is particularly important since many authorities now consider all appendiceal mucinous neoplasms to be potentially malignant. The purpose of this study was to identify clinicopathologic and molecular features that may distinguish appendiceal mucinous neoplasms from non-neoplastic mimics. We retrospectively identified 92 mucinous lesions confined to the right lower quadrant, including 55 non-neoplastic examples of mucosal hyperplasia and/or diverticulosis and 37 low-grade neoplasms. Presenting symptoms, radiographic findings, appendiceal diameter, appearances of the lamina propria, non-neoplastic crypts, and epithelium, as well as mural changes were recorded. Twenty non-neoplastic lesions were subjected to KRAS mutational testing. Non-neoplastic appendices were smaller (p < 0.05) and more likely to present with symptoms of appendicitis (p < 0.05) than neoplasms. While post-inflammatory mucosal hyperplasia and diverticula often showed goblet cell-rich epithelium, extruded mucin pools, and patchy mural alterations with fibrosis, they always contained non-neoplastic crypts lined by mixed epithelial cell types and separated by lamina propria with predominantly preserved wall architecture. On the other hand, mucinous neoplasms lacked normal crypts (p < 0.05) and showed decreased lamina propria (p < 0.05) with diffusely thickened muscularis mucosae and lymphoid atrophy. Six (30%) non-neoplastic lesions contained KRAS mutations, particularly those containing goblet cell-rich hyperplastic epithelium. We conclude that distinction between neoplastic and non-neoplastic mucinous appendiceal lesions requires recognition of key morphologic features; KRAS mutational testing is an unreliable biomarker that cannot be used to assess biologic risk or confirm a diagnosis of neoplasia.

Consensus Statement of the Italian Polispecialistic Society of Young Surgeons (SPIGC): Diagnosis and Treatment of Acute Appendicitis

Background: Acute appendicitis (AA) is one of the most common causes of abdominal pain requiring surgical intervention. Approximately 20% of AA cases are characterized by complications such as gangrene, abscesses, perforation, or diffuse peritonitis, which increase patients' morbidity and mortality. Diagnosis of AA can be difficult, and evaluation of clinical signs, laboratory index and imaging should be part of the management of patients with suspicion of AA.Methods: This consensus statement was written in relation to the most recent evidence for diagnosis and treatment of AA, performing a literature review on the most largely adopted scientific sources. The members of the SPIGC (Italian Polispecialistic Society of Young Surgeons) worked jointly to draft it. The recommendations were defined and graded based on the current levels of evidence and in accordance with the criteria adopted by the American College of Chest Physicians (CHEST) for the strength of the recommendations.Results: Fever and migratory pain tend to be present in patients with suspicion of AA. Laboratory and radiological examinations are commonly employed in the clinical practice, but today also scoring systems based on clinical signs and laboratory data have slowly been adopted for diagnostic purpose. The clinical presentation of AA in children, pregnant and elderly patients can be unusual, leading to more difficult and delayed diagnosis. Surgery is the best option in case of complicated AA, whereas it is not mandatory in case of uncomplicated AA. Laparoscopic surgical treatment is feasible and recommended. Postoperative antibiotic treatment is recommended only in patients with complicated AA.

Increased Risk of Neoplasms in Adult Patients Undergoing Interval Appendectomy

PURPOSE

The low rate of recurrent appendicitis after initial nonsurgical management of complicated appendicitis supports the recently implemented strategy of omitting routine interval appendectomy. However, several reports have suggested an increased incidence rate of neoplasms in these patients. We aimed to identify the risk of neoplasms in the population undergoing interval appendectomy.

METHODS

This study retrospectively analyzed consecutive cases of appendicitis that were treated surgically between January 2014 and December 2018 at a single tertiary referral center. Patients were divided into 2 groups depending on whether they underwent immediate or interval appendectomy. Demographics and perioperative clinical and pathologic parameters were analyzed.

RESULTS

All 2,013 adults included in the study underwent surgical treatment because of an initial diagnosis of acute appendicitis. Of these, 5.5% (111 of 2,013) underwent interval appendectomy. Appendiceal neoplasm was identified on pathologic analysis in 36 cases (1.8%). The incidence of neoplasm in the interval group was 12.6% (14 of 111), which was significantly higher than that of the immediate group (1.2% [22 of 1,902], P < 0.001).

CONCLUSION

The incidence rate of neoplasms was significantly higher in patients undergoing interval appendectomy. These findings should be considered when choosing treatment options after successful nonsurgical management of complicated appendicitis.

Risk factors for appendiceal neoplasm and malignancy among patients with acute appendicitis

PURPOSE

Non-operative management of acute uncomplicated appendicitis has shown promising results but might carry the risk of delayed diagnosis of premalignant or malignant appendiceal tumors found by chance in 0.7-2.5% of appendiceal specimen after appendectomy. Purpose of this study was to analyze whether appendiceal tumors are associated with a complicated appendicitis and to determine risk factors for appendiceal neoplasm and malignancy in patients with acute appendicitis.

METHODS

We performed a retrospective analysis of 1033 adult patients, who underwent appendectomy for acute appendicitis from 2010 to 2016 at the University hospital Erlangen. Data included patients' demographics; comorbidities; pre-, intra- and postoperative findings; and histopathological results. Complicated appendicitis was defined in the presence of perforation or abscess.

RESULTS

Appendiceal neoplasm respectively malignancy rate was 2.8% respectively 1.5%. Using univariate analysis, we identified seven risk factors at least for appendiceal neoplasm or malignancy: age, ASA, C-reactive protein, appendiceal diameter, perforation, intraoperative perithyphilitic abscess, and complicated appendicitis. Risk for appendiceal neoplasm or malignancy was 4.4% respectively 2.7% in complicated acute appendicitis compared to 2.0% respectively 1.0% in uncomplicated appendicitis (p = 0.043 respectively p = 0.060). In multivariate analysis, age ≥ 50 years and a diameter of the appendix in the sonography ≥ 13 mm were independent risk factors predicting the presence of appendiceal neoplasm and malignancy.

CONCLUSION

Among patients with appendicitis, there are relevant risk factors predicting appendiceal tumors, especially age and appendiceal diameter in sonography. But the identified risk factors have a low sensitivity and specificity, so obtaining a confident preoperative diagnosis is challenging.

Risk of Appendiceal Neoplasm in Periappendicular Abscess in Patients Treated With Interval Appendectomy vs Follow-up With Magnetic Resonance Imaging: 1-Year Outcomes of the Peri-Appendicitis Acuta Randomized Clinical Trial

Importance

The step after conservative treatment of periappendicular abscess arouses controversy, ranging from recommendations to abandon interval appendectomy based on low recurrence rates of the precipitating diagnosis to performing routine interval appendectomy owing to novel findings of increased neoplasm risk at interval appendectomy. To our knowledge, there are no randomized clinical trials with sufficient patient numbers comparing these treatments.

Objective

To compare interval appendectomy and follow-up with magnetic resonance imaging after initial successful nonoperative treatment of periappendicular abscess.

Design, Setting, and Participants

The Peri-Appendicitis Acuta randomized clinical trial was a multicenter, noninferiority trial conducted in 5 hospitals in Finland. All patients between age 18 and 60 years with periappendicular abscess diagnosed by computed tomography and successful initial nonoperative treatment from January 2013 to April 2016 were included. Data analysis occurred from April 2016 to September 2017.

Interventions

Patients were randomized either to interval appendectomy or follow-up with magnetic resonance imaging; all patients underwent colonoscopy.

Main Outcomes and Measures

The primary end point was treatment success, defined as an absence of postoperative morbidity in the appendectomy group and appendicitis recurrence in the follow-up group. Secondary predefined end points included neoplasm incidence, inflammatory bowel disease, length of hospital stay, and days of sick leave.

Results

A total of 60 patients were included (36 men [60%]; median [interquartile range] age: interval appendectomy group, 49 [18-60] years; follow-up group, 47 [22-61] years). An interim analysis in April 2016 showed a high rate of neoplasm (10 of 60 [17%]), with all neoplasms in patients older than 40 years. The trial was prematurely terminated owing to ethical concerns. Two more neoplasms were diagnosed after study termination, resulting in an overall neoplasm incidence of 20% (12 of 60). On study termination, the overall morbidity rate of interval appendectomy was 10% (3 of 30), and 10 of the patients in the follow-up group (33%) had undergone appendectomy.

Conclusions and Relevance

The neoplasm rate after periappendicular abscess in this small study population was high, especially in patients older than 40 years. If this considerable rate of neoplasms after periappendicular abscess is validated by future studies, it would argue for routine interval appendectomy in this setting.

Trial Registration

ClinicalTrials.gov identifier: NCT03013686.

Comparison of treatment methods of appendiceal mass and abscess: A prospective Cohort Study

Background

The aim of our prospective study is to compare and analyze the results of two treatment methods of appendiceal mass and abscess: emergency surgery and conservative treatment with and without interval surgery.

Materials and methods

74 Patients with the diagnosis of appendiceal mass or abscess were enrolled in this study. The patients were assigned into two groups: the emergency surgery group and the conservative management group. The conservative management group was subdivided into two groups: interval surgery group and the ambulatory follow-up observation group without interval surgery. Several clinical characteristics were determined and compared between the groups. Among patients who underwent surgery, the surgical methods, operation time, postoperative hospitalization period, and post-surgical complications were analyzed. In the ambulatory follow-up observation group, recurrence of appendicitis was assessed.

Results

Comparison of the emergency surgery group and interval surgery group revealed that the interval surgery group was characterized by shorter operation time (P = 0.008), a smallernumber of postoperative complications (P = 0.02) and also shorter postoperative hospital stay (P = 0.009). In the ambulatory follow-up observation group, recurrence of appendicitis developed in 3 (13%) patients. US or CT-guided PCD was performed in all 3 patients on the conservative treatment stage. Comparing the interval surgery and recurrent appendicitis groups revealed statistically significant difference: operation time (P = 0.04) as well as postoperative hospital stay (P = 0.04) were shorter in recurrent appendicitis group. In 3 (4.1%) patients, the cause of the appendiceal mass was caecal cancer (2 cases) and Crohn's disease.

Conclusion

Conservative treatment without interval surgery seems to be the preferred method for treatment of appendiceal mass and abscess. Patients can be operated on only in case of recurrence of appendicitis. US or CT PCD of appendiceal abscess presents the risk-factor for the development of recurrence of appendicitis. CT and colonoscopy within 4–6 weeks after completing the conservative treatment is recommended to be performed in all patients.

•

Conservative treatment without interval surgery should be the method of choice for treatment of appendiceal mass and abscess.

•

Patients should be operated only in case of recurrence of appendicitis.

•

US or CT PCD of appendiceal abscess present the risk-factor for the development of recurrence of appendicitis.

•

All patients should be performed CT and colonoscopy in 4–6 weeks after completing the conservative treatment.

Appendiceal cancer masked as inflammatory appendicitis in the elderly, not an uncommon presentation (Surveillance Epidemiology and End Results (SEER)-Medicare Analysis)

BACKGROUND

The misdiagnosis of appendiceal cancer as inflammatory appendicitis is becoming of greater clinical concern because of the rise of nonoperative management especially in the elder population. To quantify this rate of misdiagnosis, we retrospectively reviewed SEER-Medicare data.

METHODS

The SEER-Medicare database was reviewed from 2000 to 2014. We identified patients older than 65 years old who were diagnosed with appendiceal cancer and then cross-referenced them for a diagnosis of inflammatory appendicitis. Demographic data and oncologic stage were collected.

RESULTS

Our results showed that 28.6% of appendiceal cancer patients received an incorrect initial diagnosis of inflammatory appendicitis. Patients older than 75 years of age were more likely to be misdiagnosed than those between ages 65 and 75 (risk ratio [RR]: 0.81; 95% confidence interval: 0.70-0.93; P = .003). We found that 42% of patients within the misdiagnosis group presented with an earlier stage of disease (stage 1 or 2) compared to 26% of those primarily diagnosed with appendiceal cancer (P < .001).

CONCLUSION

A significant proportion of patients older than 65 years old with appendiceal cancer were initially misdiagnosed with acute appendicitis. We suggest caution when considering a nonoperative approach for appendicitis in the elderly and follow-up imaging or an interval appendectomy should be part of the treatment plan.

Predictors for interval appendectomy in non-operatively treated complicated appendicitis

PURPOSE

To determine the incidence rate and identify predictive factors for interval appendectomy after non-operatively treated complicated appendicitis.

METHODS

Single-center retrospective cohort study conducted between January 2008 and June 2017. Adult patients with acute appendicitis were identified. Patients with complicated appendicitis initially treated non-operatively were included. Outcomes included abscess rate on imaging, results of additional imaging during follow-up, incidence rate of and surgical indications for interval appendectomy, and outcomes of histological reports.

RESULTS

Of all adult patients with acute appendicitis (n = 1839), 9% (170/1839) was initially treated non-operatively. Median age of these patients was 55 years (IQR 42-65) and 48.8% (83/170) were men. In 36.4% (62/170) of the patients, an appendicular abscess was diagnosed. 62.4% (106/170) did not require subsequent surgery (no interval appendectomy group) and in 37.6% (64/170), an interval appendectomy was performed (interval appendectomy group). Median follow-up was 80 weeks (17-192) and 113 weeks (34-246), respectively. Most frequent reason to perform subsequent surgery was recurrent appendicitis (45% (29/64)). Increasing age was significantly associated with a lower risk of undergoing interval appendectomy (OR 0.7; CI 0.6-0.89); p = 0.002). In the interval appendectomy group, appendicular neoplasm was found in 11% (7/64) of the patients, in contrast to 1.5% (25/1669) of the patients that had acute surgery (p < 0.001).

CONCLUSIONS

One out of three patients non-operatively treated for complicated appendicitis required an interval appendectomy. The incidence of appendicular neoplasms was high in these patients compared with those that had acute surgery. Therefore, additional radiological imaging following non-operatively treated complicated appendicitis is recommended.

What is the Long-Term Follow-Up of Nonoperatively Treated Patients with Appendicitis?

In this study, we determine outcomes after nonoperative treatment of appendicitis. First, we abstracted data for patients discharged with a diagnosis of appendicitis from a tertiary care facility from August 1, 2007, through June 30, 2017. For patients treated nonoperatively, we collected additional medical treatment for appendicitis, future surgical treatment, and date of last follow-up. In our study, we identified 487 patients treated for appendicitis. From this group, 66 patients were successfully treated nonoperatively. Eight patients (12%) had an interval appendectomy at a mean follow-up time of two months. Of the 58 remaining patients, 20 (34%) did not have any further appendicitis-related issues over a mean follow-up period of 25 months. A total of 38 (66%) had recurring or additional concerns requiring further treatment or emergent surgery within a mean time of four months. A large proportion, 76 per cent (n = 29), required unscheduled or emergent appendectomy. There were more patients diagnosed with an abscess (55%) in the group that had further appendicitis issues. In conclusion, nonoperative treatment of appendicitis is associated with significant likelihood of future appendicitis-related treatment or emergency surgery (66%). In addition, patients diagnosed with an abscess are at particularly high risk of future appendicitis-related issues.

Appendiceal neoplasm risk associated with complicated acute appendicitis-a population based study

PURPOSE

Appendiceal tumors are rare, but high neoplasm rates have been reported at interval appendectomy after periappendicular abscess. Non-operative management of uncomplicated acute appendicitis has shown promising results. The data on appendiceal tumor incidence and presentation among acute appendicitis patients is limited, especially in patient cohorts differentiating between uncomplicated and complicated acute appendicitis. Objective was to assess appendiceal tumor incidence and tumor association to appendicitis in patients with uncomplicated and complicated acute appendicitis.

METHODS

This nationwide population-based registry study was conducted from 2007 to 2013. The Finnish Cancer Registry and the National Institute for Health Registry were used to combine data on all appendiceal tumors and acute appendicitis diagnosis with medical reports evaluated at eight study hospitals.

RESULTS

Altogether, 840 appendiceal tumors were identified, and out of these, 504 patient reports were reviewed, including 472 patients in this study. Tumor was diagnosed at appendectomy for suspected acute appendicitis in 276 patients (58%). In the whole study, histologically acute appendicitis and tumor were both present in 53% (n = 250), and out of these, 41% (n = 102) were complicated and 59% (n = 148) uncomplicated acute appendicitis. The associated tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated cases (3.24% vs. 0.87%, p < 0.001). Overall tumor prevalence among acute appendicitis patients was 1.24%.

CONCLUSIONS

Appendiceal tumor prevalence in acute appendicitis was low. Tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated acute appendicitis. The risk of missed appendiceal tumors related to antibiotic therapy of uncomplicated acute appendicitis is very low.

Complicated appendicitis and considerations for interval appendectomy

Acute appendicitis is one of the most common surgical emergencies. Of the 300,000 appendectomies performed each year, 25% are due to complicated appendicitis. This article reviews the incidence and pathophysiology of acute appendicitis, the nonoperative management of complicated appendicitis, and the rationales for and against interval appendectomy.

Comprehensive review of typical and atypical pathology of the appendix on CT: cases with clinical implications

Acute appendicitis is the most common abdominal surgical emergency in the United States with approximately 250,000 cases annually. Computed Tomography (CT) has emerged as the most accurate diagnostic test to triage these patients for emergent surgery. Although the radiology search pattern is prioritized to detect an inflamed appendix, not all appearances equate to a typical surgical appendicitis. There are a select set of atypical pathologies involving the appendix that have subtle differences on CT, but can have catastrophic complications if treated with emergent appendectomy. This paper will review the spectrum of CT appearances and clinical management for typical and atypical appendiceal pathologies.

Minimally Invasive Treatment for Appendiceal Mass Formed After Acute Perforated Appendicitis

The optimal treatment for appendiceal mass formed after appendiceal rupture due to acute appendicitis is surrounded with controversy. The treatment strategy ranges from open surgery (emergency or interval appendectomy), laparoscopic appendectomy, and image-guided drainage, to conservative treatment with or without antibiotics. Nonsurgical treatment (including conservative and drainage treatment), followed by interval appendectomy to prevent recurrence, is the traditional management of these patients. The need for interval appendectomy after a successful conservative or/and image-guided drainage treatment, has recently been questioned as the risk of recurrence is relatively small. Several authors consider that even in cases involving only ambulatory follow-up observation, without interval surgery after conservative management, the recurrence rate and risks of missing underlying pathologies were not high. This article evaluates the minimally invasive treatment modalities in the management of appendiceal mass, risk of undetected serious disease, and the need for interval appendectomy to prevent recurrence.

Occult Appendiceal Neoplasms in Acute and Chronic Appendicitis: A Single-Institution Experience of 1793 Appendectomies

The incidence of appendiceal neoplasms may have been underreported in the past. Patients undergoing incidental appendectomies or appendectomies for chronic appendicitis may be at higher risk for an incidental appendiceal neoplasm. To determine the incidence of occult appendiceal neoplasms and identify risk factors associated with this pathology, a retrospective review of a pathology specimen database was conducted from November 2007 to December 2011, in a single tertiary care hospital center. All patients with appendectomies were included for analysis (n = 1793). Pathology specimens were grouped based on the indication for appendectomy, and the incidence of appendiceal neoplasms, and patient variables among the groups were compared using χ2 test and Student's t test. A total of 1793 appendectomy specimens met criteria for evaluation. The total number of appendiceal neoplasms was 31 (1.7%). There were 14 neoplasms in 1337 (1.0%) cases of acute appendicitis with 2 in 41 (4.9%) cases of chronic and 15 in 415 (3.6%) cases, where an incidental appendectomy was performed (P < 0.001). Patients with carcinoid tumors were significantly younger than patients with noncarcinoid tumors (P = 0.0001). Indication for operation was the only significant factor for predicting an appendiceal tumor on final pathology. Patients who undergo interval or incidental appendectomies may be at higher risk of appendiceal neoplasm compared with those performed for other indications. Younger patients may be at a higher risk of occult appendiceal carcinoid neoplasms than other age groups. Pathologic diagnosis in specific high-risk patient groups may be the only way to effectively capture these tumors for optimal treatment.

Predicting appendiceal tumors among patients with appendicitis

BACKGROUND

As nonoperative management of appendicitis gains popularity, vigilance for appendiceal tumors becomes increasingly important. We hypothesized that, among patients presenting with acute appendicitis, those with advanced age, multiple comorbidities, atypical presentation, and complicated appendicitis would be more likely to have underlying appendiceal tumors.

METHODS

We performed a 4-year retrospective cohort analysis of 677 consecutive adult patients who underwent appendectomy for appendicitis at our tertiary care center. Patients with an appendiceal tumor on their final pathology report were compared to patients with no tumor. Conditions present on admission were used to create a multivariate logistic regression model to predict appendiceal tumor. Risk factors were reported as odds ratio (OR) [95% CI]. Model strength was assessed by area under the receiver operating characteristic curve.

RESULTS

Seventeen patients (2.5%) had an appendiceal tumor. Within this group. 14 underwent immediate appendectomy, two initially had nonoperative management but failed to improve on antibiotics and underwent appendectomy during the initial admission, and one had successful nonoperative management and elective appendectomy 19 days after discharge. Four variables contributed to the multivariate model to predict the presence appendiceal tumor: age ≥ 50 (OR 3.6 [1.1-11.4]), outpatient steroid/immunosuppressant use (OR 12.1 [2.0-72.5]), the absence of migratory right lower quadrant pain (OR 4.7 [1.2-18.1]), and the appearance of a phlegmon on CT scan (OR 7.0 [1.6-30.2]); model area under the receiver operating characteristic curve: 0.860 [0.705-0.969].

CONCLUSION

For patients presenting with acute appendicitis, conditions present on admission may predict underlying appendiceal tumor. Patients with advanced age, multiple comorbidities, atypical presentation, and complicated appendicitis should be considered for appendectomy during the index admission or at earliest convenience if nonoperative management is necessary.

LEVEL OF EVIDENCE

Prognostic study, level III.

Acute appendicitis, inflammatory appendiceal mass and the risk of a hidden malignant tumor: a systematic review of the literature

Introduction

Acute appendicitis is significantly common. Despite the increased use of computed tomography, the number of perforated cases has been stable in the past three decades. Between 2% and 6% of patients with acute appendicitis present appendiceal mass, often described as inflammatory phlegmon or abscess. Malignant tumors are confirmed by pathological analysis in 0.9–1.4% of all appendectomies performed to treat acute appendicitis. However, recent series demonstrate an elevated incidence of malignancies, ranging from 5.9 to 12%, in patients with inflammatory appendiceal mass.

Methods

The analysis was based on a systematic review of the literature. The articles were searched in PubMed for the period from 1987 to 2016. Articles presenting the incidence of the hidden malignancy among patients with appendiceal inflammatory mass were selected. Variables as age, interval appendectomy rate, the incidence of neoplasm, time to surgery, minimally invasive assessment, histology, right colectomy rate and morbidity were analyzed.

Results

A total of 13.244 patients were described as presenting acute appendicitis. Appendiceal tumor is present in approximately 1% of the appendectomies, while the rate of neoplasm varies from 10 to 29% in patients presenting appendiceal inflammatory mass. Interval appendectomies, despite been the minority of the procedures, disregard the higher morbidity associated with right sided colectomies. The review of literature also describes oncologic, histologic and clinical aspects of patients presenting appendiceal neoplasm, describing the most frequent histologic subtypes of this illness.

Conclusion

Hidden appendiceal neoplasm in acute appendicitis are rare, fortunately. However, its incidence is much higher in patients presenting appendiceal inflammatory mass. Hence, interval appendectomy should be considered in this subgroup of patients.

Management of Appendiceal Mass and Abscess. An 11-Year Experience

The aim of our study is to compare the results of emergency surgery versus conservative treatment with interval surgery in patients diagnosed with appendiceal mass and abscess. A retrospective review of 48 patients with appendiceal mass and abscess treated from January 2002 to January 2013 at General Surgery Department of Kipshidze Central University Hospital was performed. Patients with emergency surgery were compared to patients treated by nonoperative management with interval surgery. Demographics, clinical profile, and operative outcomes were studied. The emergency surgery group included 25 patients, and the interval surgery group included 23 patients. The clinical characteristics of the emergency surgery and interval surgery groups were not statistically different. In the emergency surgery group, an open appendectomy was performed on 17 patients, and colonic resections (ileocecectomy or right hemicolectomy) were performed on 8 patients. In the interval surgery group, an open appendectomy was performed on 21 patients, and colonic resections were performed on 2 patients. There were no statistical differences in types of surgery, postoperative complications, operation time without colonic resections, and postoperative hospitalization period among these 2 groups. Operation time with colonic resections was of greater duration in the emergency surgery group than in the interval surgery group (P = 0.04). Both treatment methods for appendiceal mass and abscess have the same results. The surgeon must consider clinical symptoms and results of investigations in each particular case when choosing an appropriate treatment method. Prospective randomized controlled trials are required for comparing the results of all 3 treatment methods of appendiceal mass.

Appendicitis in Cancer Patients is often Observed and Can Represent Appendiceal Malignancy

Appendectomy is standard of care for uncomplicated appendicitis, but cancer patients may not be optimal surgical candidates. Interval appendectomy is controversial, and appendiceal malignancy is rare. Study objectives were to review the role of surgery, observation, and interventional radiology (IR)-guided drainage in patients with appendicitis and advanced malignancy. Retrospective review was performed on cancer patients presenting to a tertiary academic cancer center from January 1, 2001 to December 31, 2014. Patients diagnosed with appendicitis were assigned to observation, surgery, and IR drainage after surgical evaluation. Success rates of initial treatment strategies were calculated. Rates of interval appendectomies and pathology were reviewed. Of 72 consults, 32 patients were included. Median age was 53 years, 50 per cent (16/32) were male, 50 per cent (16/32) had chemotherapy less than six weeks to presentation, and 63 per cent (20/32) had advanced stage malignancy. Of the 62.5 per cent (20/32) observed, 25 per cent (8/32) received immediate surgery, 12.5 per cent (4/32) required IR drainage, and 69 per cent (22/32) of patients were initially managed without surgery. Interval appendectomy rate was 19 per cent (6/32). Pathology confirmed appendiceal malignancies in 9.3 per cent (3/32). Cancer patients with acute appendicitis are frequently observed. High incidence of appendiceal malignancy may be due to the older median age. Interval appendectomy should be considered in this population.