Increased risk of mucinous neoplasm of the appendix in adults undergoing interval appendectomy

Massive appendiceal mucinous neoplasm diagnosed after abdominal trauma: Pitfalls in imaging and diagnosis

Low grade appendiceal mucinous neoplasm (LAMN) is a rare tumor presenting typically with symptoms of acute appendicitis. A 33-year-old gentleman presented with abdominal fullness and discomfort secondary to abdominal trauma obtained during boxing training. Investigations with magnetic resonance imaging (MRI), ultrasound, and colonoscopy revealed a large cystic lesion in the ascending colon mesentery with unclear continuation with the appendix. There were no obvious features of malignancy. Laparoscopy revealed a large, firm mass connected to the appendix with enlarged lymph nodes, and the patient underwent radical resection with a right hemicolectomy. Histopathology revealed complete excision of LAMN with no lymphatic involvement. Post traumatic intra-abdominal cystic lesions pose a diagnostic challenge, and neoplastic lesions cannot be ruled out with imaging alone, even with benign appearances. Careful surgical excision and histopathological diagnosis is the only definitive method of ruling-out malignancy.

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 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.

Comparison of the efficacy and safety of antibiotic treatment and appendectomy for acute uncomplicated appendicitis: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis aimed to compare the efficacy and safety of antibiotic treatment and appendectomy for acute uncomplicated appendicitis.

METHODS

We searched the randomized controlled studies (RCTs) comparing appendectomy with antibiotic treatment for uncomplicated acute appendicitis in the electronic database including Pubmed, Embase, Cochrane, Web of Science, CNKI, VIP, and WanFang. The primary outcomes included complication-free treatment success at 1 year, complications, surgical complications, and the complicated appendicitis rates. Secondary outcomes included negative appendicitis, length of hospital stay, the quality of life at 1 month, and the impact of an appendicolith on antibiotic therapy.

RESULTS

Twelve randomized controlled studies were included. Compared with surgery group, the antibiotic group decreased the complication-free treatment success at 1 year (RR 0.81; 95% CI 0.73-0.91; z = 3.65; p = 0.000). Statistically significance was existed between antibiotic group and surgical group with both surgical types(open and laparoscopic) (RR 0.43; 95% CI 0.31-0.58; z = 5.36; p = 0.000), while no between the antibiotic treatment and laparoscopic surgery (RR 0.72; 95% CI 0.41-1.24; z = 1.19; p = 0.236). There was no statistically significant differences between two groups of surgical complications (RR 1.38; 95% CI 0.70-2.73; z = 0.93; p = 0.353), the complicated appendicitis rate (RR 0.71; 95% CI 0.36-1.42; z = 0.96; p = 0.338), negative appendectomy rate (RR 1.11; 95% CI 0.69-1.79; z = 0.43; p = 0.670), duration of hospital stay (SMD 0.08; 95%CI -0.11-0.27; z = 0.80; p = 0.422), and quality of life at 1 month (SMD 0.09; 95%CI -0.03-0.20; z = 1.53; p = 0.127). However, in the antibiotic treatment group, appendicolith rates were statistically higher in those whose symptoms did not improve (RR 2.94; 95% CI 1.28-6.74; z = 2.55; p = 0.011).

CONCLUSIONS

Although the cure rate of antibiotics is lower than surgery, antibiotic treatment is still a reasonable option for patients with uncomplicated acute appendicitis who do not want surgery without having to worry about complications or complicating the original illness.

Appendiceal Mucinous Neoplasms: From Clinic to Pathology and Prognosis

Appendiceal mucinous neoplasms have been classified differently over time causing confusion when comparing results between working groups in this field and establishing a prognosis of the disease. A historical perspective of the different classification systems of these tumors is essential for the understanding of the evolution of concepts and histopathological definitions that have led up to the present moment. We carried out a systematic review of the pathological classifications of appendiceal mucinous tumors and how they have included the new criteria resulting from clinical and pathological research. The latest classifications by PSOGI and AJCC 8th edition Cancer Staging have made a great effort to incorporate the new pathological descriptions and develop prognostic groups. The introduction of these new classification systems has posed the challenge of verifying how they adapt to our casuistry and which one defines best the prognosis of our patients. We reclassified our series of patients treated for mucinous appendiceal tumors with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy following the PSOGI and the AJCC 8th edition criteria and concluded that both classifications correspond well with the OS and DFS of these patients, with some advantage relative to the PSOGI classification due to a better histopathological description of the different groups.

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.

The other colon cancer: a population-based cohort study of appendix tumour trends and prognosis

AIM

Appendiceal neoplasms are rare subtypes of colorectal tumours that mainly affect younger patients some 20 years earlier than other colon tumours. The aim of this study was to gain more insight into the histological subtypes of this rare disease and include cases previously excluded, such as mucinous neoplasia.

METHOD

The cohort study included 1097 patients from the Munich Cancer Registry (MCR) diagnosed between 1998 and 2020. Joinpoint analysis was used to determine trend in incidence. Baseline demographic comparisons and survival analyses using competing risk and univariate/multivariate methods were conducted according to tumour histology: adenocarcinoma (ADENO), neuroendocrine neoplasia (NEN), mixed adeno-neuroendocrine carcinoma (MANEC), and low- (LAMN) and high-grade mucinous neoplasia (HAMN).

RESULTS

Up to 2016 the number of cases increased significantly [annual per cent change (APC) = 6.86, p < 0.001] followed by a decline in the following years (APC = -14.82, p = 0.014; average APC = 2.5, p = 0.046). Comparison of all patients showed that NEN (48.4%) and mucinous neoplasms (11.6%) had a considerably better prognosis than ADENO (36.0%) and MANEC (3.0%, p < 0.0001). A multivariate analysis within the NEN and ADENO subgroups revealed that further histological classification was not prognostically relevant, while older age and regional tumour spread at diagnosis were associated with a poor prognosis. ADENO histology with high tumour grade and appendectomy only was also associated with poorer survival.

CONCLUSION

Appendiceal neoplasms are histologically heterogeneous; however, this diversity becomes less relevant compared with the marked difference from cancers of the remaining colon. The previously observed increase in cases appears to be abating; fewer cases of appendicitis and/or appendectomies or changes in histopathological assessment may be behind this trend.

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.

Laparoscopic Right Hemicolectomy of a Low-Grade Appendiceal Mucinous Neoplasm Causing an Ileocolic Intussusception: A Case Report

Introduction

Intussusception, although common in the pediatric population, rarely occurs in adults. Furthermore, patients often show nonspecific symptoms. Most adult patients with intussusception have a surgical lead point, a well-defined pathological abnormality, often accurately diagnosed after surgery. A low-grade appendiceal mucinous neoplasm (LAMN), often misdiagnosed as acute appendicitis, is rarely associated with the development of intussusception. Here we report a case of LAMN-related ileocolic intussusception that was histologically diagnosed after laparoscopic right hemicolectomy.

Case presentation

A 58-year-old woman visited our emergency department because of intermittent episodes of epigastric pain with periumbilical tenderness. These symptoms persisted intermittently for 2 weeks. The pain was moderate in severity, colicky in nature, and sometimes shifted to the lower abdominal region. Abdominal computed tomography indicated intussusception with ileocecal and mesenteric telescoping into the transverse colon. Complete colonoscopy with reduction of intussusception was performed, revealing a ball-like mass protruding and occupying the entire cecum lumen. Laparoscopic right hemicolectomy was then performed. Macroscopically, a dilated appendix was revealed with mucin content, along with hyalinization and fibrosis of the appendiceal wall. Microscopically, a tumor exhibiting villous and flat proliferation of mucinous epithelial cells with low-grade nuclear atypia was seen. However, there was no infiltration growth of the tumor cells, thereby demonstrating LAMN. Postoperative recovery was uneventful, and the patient was discharged on the 8th postoperative day without surgical complications.

Conclusion

The differential diagnoses of chronic and colicky abdominal pain should be expanded to include intussusceptions as they can be severe, although cases in adults are rare.

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.

Novel Perspectives in Pseudomyxoma Peritonei Treatment

Simple Summary

Pseudomyxoma Peritonei (PMP) represents a rare entity which greatly benefits from Cytoreductive Surgery (CRS) associated with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). In fact, CRS-HIPEC represents the treatment with potential chances of cure and long-term disease control of patients affected by PMP. This therapeutic strategy should be performed in referral centers, where a consolidated know-how of this locoregional treatment and a multidisciplinary approach are available. CRS-HIPEC provides excellent results for PMP patients in terms of postoperative outcome, overall and disease-free survival, and quality of life. However, in patients with an extensive or recurrent disease, few therapeutic opportunities are available. This review is focused on the most recent clinical evidence and provides a better understanding of the molecular prognostic factors and potential therapeutic targets in this rare malignancy.

Abstract

Pseudomyxoma Peritonei (PMP) is an anatomo-clinical condition characterized by the implantation of neoplastic cells on peritoneal surfaces with the production of a large amount of mucin. The rarity of the disease precludes the evaluation of treatment strategies within randomized controlled trials. Cytoreductive Surgery (CRS) combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) has proven to be the only therapeutic option with potential chances of cure and long-term disease control. The present review discusses the epidemiology, pathogenesis, clinical presentation and treatment of PMP, focusing on the molecular factors involved in tumor progression and mucin production that could be used, in the upcoming future, to improve patient selection for surgery and to expand the therapeutic armamentarium.

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.

Benefits and Reduced Hospital Costs of Direct Surgery in Perforated Appendicitis With Abscess Cost-effectiveness Analysis of Treatment Complicated Appendicitis

PURPOSE

Elective interval appendectomy (IA) after percutaneous catheter drainage (PCD) is traditionally advocated for perforated appendicitis with an abscess. However, this is not the only way to manage these patients when we consider the cost-effectiveness of treatment. This study compared the outcomes and cost-effectiveness of patients who underwent IA and those who underwent direct surgery.

MATERIALS AND METHODS

A retrospective analysis of 79 patients who were diagnosed with perforated appendicitis with abscess was conducted. We compared the hospital course, outcomes, and total medical costs between the 2 groups.

RESULTS

Forty-three patients underwent PCD insertion for the management of appendiceal abscess (IA group), and 36 underwent appendectomy (DS group). There was no significant difference in abscess size (5.67 vs. 5.35 cm, P=0.15), appendectomy method (laparoscopic/open 39/4 vs. 37/5, P=0.523), or complications (7 vs. 6 cases, P=0.963) between the 2 groups. The operation time was longer in the DS group (83.8 vs. 112.7 min, P<0.001). However, length of hospitalization (15.4 vs. 7.7 d, P<0.001) and total hospital cost (US$2090.47 vs. US$3402.22, P<0.001) was greater in the IA group.

CONCLUSION

Direct surgery without PCD insertion in perforated appendicitis accompanied by abscess is more cost-effective and reduces the total length of hospitalization compared with the traditional IA.

Long-term effects of appendectomy in humans: is it the optimal management of appendicitis?

INTRODUCTION

Appendectomy remains the gold standard for treating uncomplicated and complicated appendicitis. However, the vermiform appendix may play a significant role in the immune system (secondary immune function) and maintain a reservoir of the normal microbiome for the human body. The aim of this study was to summarize the long-term effects after appendectomy and discuss whether appendectomy is suitable for all appendicitis patients.

AREAS COVERED

A comprehensive and unbiased literature search was performed in PubMed. The terms 'appendix,' 'appendicitis,' 'appendectomy,' and 'endoscopic retrograde appendicitis therapy' were searched in the title and/or abstract. This review summarizes the long-term effects of appendectomy on some diseases in humans and describes three methods including appendectomy, medical treatment, and an 'organ-sparing' technique, named endoscopic retrograde appendicitis therapy (ERAT) to treat appendicitis.

EXPERT OPINION

Appendectomy remains the first-line therapy for appendicitis. The patient's problem is appendix, not appendicitis. If we treat appendicitis, the problem should be resolved. During COVID-19, an initial antibiotic treatment of mild appendicitis represents a promising strategy. For patients who are worried about the long-term adverse effect after appendectomy and have a strong desire to preserve the appendix and are aware of the risk of appendicitis recurrence, medical treatment, or ERAT could be proposed.

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

BACKGROUND

Non-operative management is often the treatment of choice in cases of complicated appendicitis and routine interval appendectomy is not usually recommended. Actually, recent studies show an alarming number of appendiceal neoplasms following interval appendectomy. The aim of this study is to evaluate the prevalence of appendiceal neoplasms and their histological types after interval appendectomy for complicated appendicitis in adults.

METHODS

A comprehensive literature search of the PubMed, Scopus and Web of Science databases was conducted according to the PRISMA statement. Studies reporting appendiceal neoplasm rates after interval appendectomy and histopathological characteristics were included. The most recent World Health Organization (WHO) classification of malignant tumours was considered. A pooled prevalence analysis for both prevalence and pathology was performed.

RESULTS

A total of eight studies was included: seven retrospective series and one randomized controlled trial. The pooled prevalence of neoplasms after interval appendectomy was 11% (95% CI 7-15; I² = 37.5%, p = 0.13). Appendiceal mucinous neoplasms occurred in 43% (95% CI 19-68), adenocarcinoma in 29% (95% CI 6-51), appendiceal neuroendocrine neoplasm in 21% (95% CI 6-36), globet cell carcinoma in 13% (95% CI -2-28), adenoma or serrated lesions in 20% (95% CI -0-41) of cases.

CONCLUSION

The risk of appendiceal neoplasm in patients treated with interval appendectomy for complicated appendicitis is 11%; mucinous neoplasm is the most common histopathological type. Further studies should investigate this association in order to clarify the biological pathway and clinical implications.

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.

A general overview of mucocele of appendix

Mucocele of the appendix is a very rare disease entity that often discovered incidentally during surgery. It can result from both non-neoplastic and neoplastic lesions and histopathological examination is needed for confirmation. Failure to make an early preoperative diagnosis may results in its rapture and spillage of mucin contents into the peritoneal cavity leading to a disastrous complication of pseudomyxoma peritonei (PMP) that has a very bad prognosis. A clear pathological terminology and management strategies of appendiceal mucocele (AM) is lacking. This literature review aims to derive detailed information related to clinical significance of AM to avoid complication of PMP and plan appropriately during surgery according to the current evidence. The relevant articles from scientific databases such as Medline, PubMed, Google Scholar were searched and extracted using the keywords “mucocele appendix” “cystadenoma%”. Data based on epidemiology, clinical manifestations, complications, pathology, diagnostic work up and management were analyzed and summarized. A meticulous surgical excision is the mainstay of treatment and open surgical approach is still preferred over laparoscopy. Preoperative diagnosis of AM is very imperative as it may harbour neoplasm and can be made utilising the imaging tools like computed tomography and ultrasonography. Primary care physicians can have a crucial role in making early detection and timely referral for appropriate management in order to avoid complications. After appendectomy, 5-year survival rate for the simple AM is 91%-100% but it reduces to 25% for the malignant AM.

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.

Cost-effectiveness analysis of initial nonoperative management versus emergency laparoscopic appendectomy for acute complicated appendicitis

Background

The evidence regarding the safety and efficacy of nonoperative management is growing. However, the best treatment strategy for acute complicated appendicitis remains controversial. We aimed to evaluate the cost-effectiveness of treatment strategies for complicated appendicitis patients. This study sought to determine the most cost-effective strategy from the health care-payer’s perspective.

Methods

The primary outcome was an incremental cost effectiveness ratio (ICER) using nonoperative management with or without interval laparoscopic appendectomy (ILA) as the intervention compared with operative management with emergency laparoscopic appendectomy (ELA) alone as the control. Model variables were abstracted from a literature review, and from data obtained from the hospital records of Tochigi Medical Center. Cost-effectiveness was evaluated using an ICER. We constructed a Markov model to compare treatment strategies for complicated appendicitis in otherwise-healthy adults, over a time horizon of a single year. Uncertainty surrounding model parameters was assessed via one-way- and probabilistic-sensitivity analyses. Threshold analysis was performed using the willingness-to-pay threshold set at the World Health Organization’s criterion of $107,690.

Results

Three meta-analysis were included in our analysis. Operative management cost $6075 per patient. Nonoperative management with interval laparoscopic appendectomy (ILA) cost $984 more than operative management and produced only 0.005 more QALYs, resulting in an ICER of $182,587. Nonoperative management without ILA cost $235 more than operative management, and also yielded only 0.005 additional QALYs resulting in an ICER of $45,123 per QALY. Probabilistic sensitivity analysis with 1000 draws resulted in average ICER of $172,992 in nonoperative management with ILA and $462,843 in Nonoperative management without ILA. The threshold analysis demonstrated that regardless of willingness-to-pay, nonoperative management without ILA would not be most cost-effective strategy.

Conclusions

Nonoperative management with ILA and Nonoperative management without ILA were not cost-effective strategies compared with operative management to treat complicated appendicitis. Based on our findings, operative management remains the standard of care and nonoperative management would be reconsidered as a treatment option in complicated appendicitis from economic perspective.

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.

Adenocarcinoma of Stump Appendicitis: An Extremely Rare Pathology - A Literature Review

Emergency appendectomy for acute appendicitis is the most common emergency surgical procedure performed all over the world. While amputating the appendix from the cecum, a small (usually less than 5 mm) stump is left behind. Below this, the suture or stapler is applied to secure the base of the appendix, which is now known as a stump. Stump appendicitis, the inflammation of appendiceal remnant after an appendectomy, is a rare phenomenon. Additionally, the incidence of adenocarcinoma in the stump of the appendix is also extremely rare and can present with the symptoms of appendicitis. Adenocarcinoma in stump appendectomy patients can present from 5-43 years after the index appendectomy surgery. The majority of patients present with symptoms similar to that of appendicitis, with right lower quadrant abdominal pain, usually diagnosed via CT scans, after which they undergo stump appendectomy. The diagnosis of adenocarcinoma is only made on the histopathology report. We engaged in a review of the relevant literature published in the English language for the last 100 years. This was conducted by reviewing Google Scholar, PubMed, and MEDLINE® databases, as well as references to all related articles. There are only six cases reported in the literature, which shows the rarity of this condition. Regarding the appropriate treatment for this rare entity, multi-disciplinary team discussions should be carried out for optimum management of the individual patients. Right hemicolectomy is the recommended procedure for all patients, and prognosis depends on the staging of the disease.

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.

Preoperative Factors Associated with Appendiceal Tumors in Nonelective Appendectomy

Background: The rates of incidental appendiceal neoplasms after appendectomy performed for acute appendicitis is <2%. To date, no large studies have investigated the preoperative risk factors or imaging findings associated with incidental appendiceal tumors that present as appendicitis. Our study aims to identify preoperative factors that are associated with an increased risk of appendiceal tumors in patients who present with signs and symptoms of acute appendicitis. Materials and Methods: Using the targeted appendectomy American College of Surgeons National Surgical Quality Improvement Program database, we identified patients who underwent nonelective appendectomy for acute appendicitis in 2016. Patients with final pathology consistent with a tumor were compared with those with only appendicitis. A nonmatched case/control method was used to pull a random sample from the appendicitis cohort using a 1:4 ratio (tumor: acute appendicitis) to obtain adequate power for comparison. Preoperative patient variables and imaging findings were investigated using stepwise logistic regression to identify variables associated with appendiceal tumor. Results: Following multivariate analysis, preoperative imaging read of "indeterminate" and "not consistent with appendicitis," female gender, increased age, and lower preoperative white blood cell (WBC) count were significant predictors of tumor causing symptoms of appendicitis. The odds of having tumor pathology were significantly increased in patients with preoperative imaging of "indeterminate" and "not consistent with appendicitis." The odds of having tumor pathology were 82% higher for females than for males, increased by 2% for every 1-year increase in age, and increased by 3% for every one-unit decrease in WBC count. Conclusion: While incidental appendiceal tumors can present as acute appendicitis, 3 patient variables and one imaging finding were identified that may increase suspicion for appendiceal tumors. Consideration should be given to patients with these associated risk factors for additional preoperative consultation in addition to the potential for intraoperative pathology consultation.

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.

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.

Management of acute appendicitis in adults: A practice management guideline from the Eastern Association for the Surgery of Trauma

BACKGROUND

Acute appendicitis (AA) has been considered one of the most common acute surgical conditions in the world. Recent studies, however, have suggested that nonoperative management (NOM) with a course of antibiotics (ABX) may be as effective as surgery in treating appendicitis. As there are evolving perspectives regarding the optimal therapy for appendicitis, we sought to provide recommendations regarding the role of NOM with the administration of antibiotics (antibiotics-first approach) in uncomplicated AA as well as the need for routine interval appendectomy (RIA) in those presenting with appendiceal abscess or phlegmon (AAP) initially managed without appendectomy.

METHODS

A writing group from the Guidelines Committee of the Eastern Association for the Surgery of Trauma (EAST) performed a systematic review and meta-analysis of the current literature regarding appendicitis in adult populations. The Grading of Recommendations Assessment, Development and Evaluation methodology was applied and meta-analyses and evidence profiles generated.

RESULTS

When comparing antibiotics-first therapy to surgery for uncomplicated AA in adult populations, we found that perforation and recurrence of disease were the only outcomes consistently represented in the literature. For perforation, we were unable to make a definitive conclusion based on the degree of heterogeneity among the six randomized controlled trials reviewed. The risk of recurrence at 1 year with antibiotics-first treatment was 15.8% (95% confidence interval, 12.05-118.63). Critical outcomes could not be evaluated with the current literature. In NOM patients for AAP, the risk of recurrence was 24.3% if RIA was not performed (95% confidence interval, 2.74-73.11).

CONCLUSION

Based on the completed meta-analysis and Grading of Recommendations Assessment, Development and Evaluation profiles, we were unable to make a recommendation for or against the antibiotics-first approach as primary treatment for uncomplicated AA. For NOM with AAP, we conditionally recommend against RIA in an otherwise asymptomatic patient. This review reveals multiple limitations of the published literature, leaving ample opportunities for additional research on this topic.

LEVEL OF EVIDENCE

Systematic review, level II.

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.

Low-grade Appendiceal Mucinous Neoplasm and Endometriosis: Incidental Coincident Pathologies at Cesarean Section

Incidental pathologic findings at the time of Cesarean section are exceedingly uncommon. Similarly, occult low-grade appendiceal mucinous neoplasms and other noninflammatory, non-neoplastic appendiceal pathologies are rare, although appendiceal neoplasia, most commonly well-differentiated neuroendocrine tumors, may be found during evaluation of acute appendicitis. Here we report the first case of incidental coincident low-grade appendiceal mucinous tumor and endometriosis involving the appendix at the time of Cesarean section. We highlight pitfalls in the histopathologic evaluation of these processes, particularly given the setting of decidualization of ectopic endometrial stroma, as well as the prognostic implications of low-grade appendiceal mucinous tumors to emphasize the importance of clinicopathologic correlation and careful intraoperative examination of the appendix and other visible structures during Cesarean section.

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.

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.