The American Society of Colon and Rectal Surgeons, Clinical Practice Guidelines for the Management of Appendiceal Neoplasms

Retrospective Review of Outcomes in Non-Invasive Mucinous Appendiceal Neoplasms with and without Peritoneal Spread: A Cohort Study

Patients treated surgically for local non-invasive mucinous appendiceal neoplasm (NI-MAN) may recur with the development of peritoneal dissemination (PD). The risk of recurrence and predictive factors are not well studied. Patients with NI-MAN, with or without peritoneal dissemination at presentation, were included. Patients with limited disease underwent surgical resection only. Patients with peritoneal dissemination underwent cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC). Patients without PD (nPD) were compared to those who presented with PD. Thirty-nine patients were included, 25 in nPD and 14 in PD. LAMN was diagnosed in 96% and 93% of patients in nPD and PD, respectively. Acellular mucin on the peritoneal surface was seen in 16% of nPD patients vs. 50% of PD patients (p = 0.019). Two (8%) patients in the nPD group who had LAMN without wall rupture recurred, at 57 and 68 months, with a PCI of 9 and 22. The recurrence rate in the PD group was 36%. All recurred patients underwent CRS+HIPEC. A peritoneal recurrence is possible in NI-MANs confined to the appendix even with an intact wall at initial diagnosis. The peritoneal disease may occur with significant delay, which is longer than a conventional follow-up.

Incidental Finding of Appendiceal Mucinous Neoplasm After Trauma: A Case Report

Appendiceal neoplasms are uncommon; most are identified by pathologic examination after appendectomy for presumed appendicitis or as an incidental finding. When found incidentally, patients are typically asymptomatic. If the neoplasm has perforated, patients may present with symptoms that mimic acute appendicitis. In advanced disease, patients may have systemic symptoms associated with peritoneal disease, including abdominal distension, weight loss, and diffuse abdominal pain. Because of their rarity, as well as rapidly evolving research on the subject, the nomenclature of appendiceal mucinous neoplasms has proven challenging. This lesion was identified as a low-grade appendiceal mucinous neoplasm (LAMN), previously termed mucoceles or mucinous cystadenomas. LAMNs are non-invasive neoplasms that have the potential to proliferate outside the appendix in a malignant fashion. All mucinous appendiceal neoplasms can perforate and spread mucin production throughout the abdominal cavity, known as pseudomyxoma peritonei (PMP). The presence of PMP designates LAMNs as malignant, though the neoplasm itself is non-invasive. When appendiceal neoplasms have peritoneal involvement, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the standard of care. Complete cytoreduction has been shown to be an independent predictor of survival. Here we describe a case of a 30-year-old male involved in a motor vehicle collision with a grade IV splenic laceration, who is also found to have a large appendiceal mass. His traumatic injuries required emergent intervention, which delayed treatment of his malignancy.

Inverted Appendix in a Patient With Weakness and Occult Bleeding

BACKGROUND

Appendiceal mucinous neoplasms (AMNs) are rare adenomatous primary tumors of the appendix. Although of low malignant potential, these neoplasms can cause serious potentially fatal complications such as bowel obstruction and pseudomyxoma peritonei, making prompt identification and removal of utmost importance. AMNs often present with nonspecific gastrointestinal symptoms or are asymptomatic and found incidentally.

CASE PRESENTATION

A patient aged 72 years presented with generalized weakness and appeared on imaging to have acute appendicitis complicated by rupture. On colonoscopy, the patient was found to have an inverted appendix that after appendectomy was revealed to harbor a perforated low-grade AMN.

CONCLUSIONS

Although AMNs are rare, physicians should still consider it when imaging suggests appendicitis. Having AMNs as part of the differential diagnosis is especially necessary in cases, such as this one, in which the patient has appendiceal inversion, is aged > 50 years, and has concurrent colorectal neoplasms.

Pathologic Factors Associated with Low Risk of Lymph Node Metastasis in Nonmucinous Adenocarcinoma of the Appendix

BACKGROUND

Right hemicolectomy (RHC) for nodal staging is recommended for nonmucinous adenocarcinoma of the appendix (NMACA), but it is unclear whether a subgroup of patients at low risk for lymph node (LN) metastasis exists who may be managed with a less extensive resection.

PATIENTS AND METHODS

Patients with NMACA without distant metastases who underwent margin negative resection via either RHC or appendectomy/partial colectomy (A/PC) were evaluated from the National Cancer Database (2004-2016). Patients at low risk for LN metastasis were identified. Multivariable survival analysis was performed, and 5-year overall survival (OS) was estimated.

RESULTS

Of the 2487 patients included, 652 [26.2%; 95% confidence interval (CI) 24.5-28.0%] had LN metastases. T4 T stage [odds ratio (OR) 4.2, p = 0.032], poorly/undifferentiated histology (OR 2.2, p = 0.004), and lymphovascular invasion (LVI) (OR 4.4, p < 0.001) were associated with LN positivity. One hundred and thirteen patients (4.5%) had tumors at low risk for LN metastasis (T1 T stage, well/moderately differentiated tumors without LVI), and the rate of LN metastasis for this group was 1.8% (95% CI 0.5-6.2%). Conversely, the LN metastasis rate among the 2374 non-low-risk patients was 27.4% (95% CI 25.6-29.2%). Performance of A/PC instead of RHC was associated with a survival disadvantage among all patients (hazards ratio 1.5, p = 0.049), but among the low-risk cohort, 5-year OS did not differ based on resection type (88.3% A/PC versus 92.7% RHC, p = 0.305).

CONCLUSIONS

Although relatively uncommon, early, pathologically favorable NMACA is associated with a very low risk of LN metastasis. These select patients may be managed with a less extensive resection without compromising oncologic outcomes.

Prognostic Impact of Pathology, Cytoreduction, and Tumor Markers in Pseudomyxoma Peritonei

INTRODUCTION

The pathologic classification of pseudomyxoma peritonei is controversial. This study aimed to standardize the histopathological evaluation of pseudomyxoma peritonei and identify the clinicopathological factors associated with survival.

METHODS

A pathologic review was performed to systematize the pathology report and verify the relationship between clinical features and survival. Terminology was based on the World Health Organization and Peritoneal Surface Oncology Group International definitions. Preoperative serum levels of carcinoembryonic antigen, CA19-9, and CA-125 were evaluated to determine their association with overall survival (OS) and ability to predict CC0-1 cytoreduction.

RESULTS

Among 109 patients with carcinomas resulting from primary appendiceal neoplasms, 72 had pseudomyxoma peritonei of appendiceal origin and underwent debulking surgery. CC0-1 cytoreduction and CC2-3 cytoreduction were achieved in 61% and 39% of patients, respectively. Patients in the CC0-1 and CC2-3 groups had an OS of 122.80 and 32.92 mo, respectively. The histologic grade was associated with CC0-1 cytoreduction; however, it did not influence OS. Patients with CC0-1 cytoreduction, acellular mucin, and low-grade lesions had better disease-free survival. Higher preoperative CA19-9 levels were associated with poor OS. Normal carcinoembryonic antigen values were associated with 100% sensitivity for predicting CC0-1. CA19-9 levels of 625 U/mL were associated with a low possibility of predicting CC0-1.

CONCLUSIONS

Histologic grades are associated with disease-free survival when CC0-1 cytoreduction is achieved. Normal preoperative CA19-9 levels were associated with a better OS. CC0-1 cytoreduction is the main determinant of longer survival.

Locally advanced perforated appendiceal cancer: Case report and review

Appendiceal cancers may be difficult to diagnose even after comprehensive investigation. This report of locally advanced perforated appendiceal adenocarcinoma attached to the terminal ileum, cecum, and rectosigmoid illustrates the management challenges that require comprehensive knowledge of pathologic variations and range from simple appendectomy to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

The Role of Adjuvant Chemotherapy Following Right Hemicolectomy for Non-metastatic Mucinous and Nonmucinous Appendiceal Adenocarcinoma

BACKGROUND

Appendiceal adenocarcinoma (AA) represents a heterogenous group of neoplasms with distinct histologic features. The role and efficacy of adjuvant chemotherapy (AC) in non-metastatic disease remain controversial. The aim of this study was to ascertain the role of AC in non-metastatic AA in a national cohort of patients.

METHODS

The National Cancer Database (NCDB) was queried to identify patients diagnosed with stage I-III mucinous and nonmucinous AA who underwent right hemicolectomy between 2006 and 2016. Kaplan-Meier and Cox regression analyses were used to evaluate the impact of AC on overall survival (OS) stratified by each pathologic stage.

RESULTS

A total of 1433 mucinous and 1954 nonmucinous AA were identified; 578 (40%) and 722 (40%) received AC respectively. In both AC groups, there was a higher proportion of T4 disease, lymph node metastasis, pathologic stage III, and poorly/undifferentiated grade (all P<0.05). On unadjusted analysis, there was no significant association between AC and OS for stage I-III mucinous AA. For nonmucinous AA, AC significantly improved OS only for stage II and III disease. On adjusted analysis, AC was independently associated with an improved OS for stage III nonmucinous AA (HR: 0.61, 95%CI 0.45-0.84, P=0.002), while for mucinous AA, AC was associated with worse outcomes for stage I/II disease (HR: 1.4, 95%CI 1.02-1.91, P=0.038) and had no significant association with OS for stage III disease.

CONCLUSION

This current analysis of a national cohort of patients suggests a beneficial role for AC in stage III nonmucinous AA and demonstrates no identifiable benefit for stage I-III mucinous AA.

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.

Necessity of posttreatment surveillance for low-grade appendiceal mucinous neoplasms

BACKGROUND AND OBJECTIVES

Low-grade appendiceal mucinous neoplasms (LAMNs) are generally treated by surgical resection, but posttreatment surveillance protocols are not well-established. The objectives of this study were to characterize posttreatment surveillance and determine the risk of recurrence following surgical resection of LAMN.

METHODS

Patients who underwent surgical resection of localized LAMNs in an 11-hospital regional healthcare system from 2000 to 2019 were identified. Posttreatment surveillance regimens were characterized, and rates of disease recurrence were evaluated.

RESULTS

A total of 114 patients with LAMNs were identified. T-category was pTis for 92 patients (80.7%), pT3 for 7 (6.1%), pT4a for 14 (12.3%), and pT4b for 1 (0.9%). Two patients (1.8%) had a positive resection margin. Posttreatment surveillance was performed for 39 (34.2%) patients and consisted of office visits for 32 (82%) patients, computerized tomography imaging for 30 (77%), magnetic resonance imaging for 5 (13%), colonoscopy for 15 (38%), and serum tumor marker measurement for 12 (31%). After a mean follow-up duration of 4.7 years, no patients experienced tumor recurrence.

CONCLUSIONS

Posttreatment surveillance is common among patients with LAMNs. However, no patients experienced tumor recurrence, regardless of T-category or margin status, suggesting that routine surveillance following surgical resection of LAMN may be unnecessary.

A rare case of synchronous appendiceal and cecal cancer

Primary appendiceal cancer is rare, and difficult to diagnose pre-operatively because lack of specific symptoms. This report presents a rare case of synchronous colon and appendiceal cancer. A 50-year-old man was referred to our hospital due to endoscopic submucosal resection (ESD) for early cecal cancer. ESD was performed, and the pathological examination revealed tubular adenocarcinoma with deep submucosal invasion. Laparoscopic ileocecal resection was performed as additional resection after ESD of cecal cancer. There were no obvious abnormalities around the ileocecal region in the preoperative examination. Postoperative pathological examination incidentally revealed a mucosal papillary adenocarcinoma of the appendix, with no residual lesion in the ESD scar. The patient was discharged on the seventh postoperative day. Synchronous appendiceal and colon cancer is extremely rare in past reports. Here, we report the case details and review previous case reports.

Surveillance Colonoscopy Revealing Asymptomatic Low-Grade Appendiceal Mucinous Neoplasm

Appendicular mucinous neoplasms are a collection of rare tumors with diverse clinical presentations and pathologic potential, which can cause diagnostic and therapeutic challenges. Traditionally, they are diagnosed by radiologic imaging or identified intraoperatively; however, rarely, they may be diagnosed during an endoscopic procedure. In this unusual case, we present the case of a 62-year-old Caucasian male undergoing routine surveillance colonoscopy due to a history of colonic neoplasia. During the colonoscopy, a submucosal, non-bleeding 1cm mass of benign appearance was found in the appendix. Further workup determined the mass was likely a mucocele, and surgical consultation was recommended. The patient denied any symptoms suggestive of a mucinous neoplasm prior to and during evaluation. A laparoscopic appendectomy was subsequently performed, and the histopathology report confirmed the diagnosis of a low-grade appendiceal mucinous neoplasm. The patient recovered without complications and continued to deny any symptoms during his postoperative course and follow-up care. Given their rare incidence and unpredictable nature, appendiceal mucinous neoplasms remain difficult to identify. Discovering a low-grade mucinous neoplasm in an asymptomatic patient via colonoscopy illustrates the spectrum of unique presentations and modalities for diagnosis.

Endoscopic diagnosis and treatment of an appendiceal mucocele: A case report

BACKGROUND

Appendiceal mucocele is a rare disease that causes obstructive dilatation of the appendix due to the intraluminal accumulation of mucin. We report a case of endoscopic diagnosis and treatment of an appendiceal mucocele.

CASE SUMMARY

A 47-year-old man presented with a protrusion around the orifice of the appendix discovered by colonoscopy incidentally. He was admitted to our hospital for a routine checkup without any symptoms. Abdominal computed tomography showed a cystic mass approximately 3 cm in diameter with fat stranding. The preoperative diagnosis was non-neoplastic appendiceal mucocele, and endoscopic treatment was performed. The endoscopic findings and pathological results supported our preoperative diagnosis. The endoscopic treatment of appendiceal mucocele was feasible and effective, which was confirmed by repeated endoscopy and post-operative computed tomography after 7 mo.

CONCLUSION

Endoscopic therapy provides a new method for the treatment of appendiceal mucocele.

Surgical Outcomes of Single-Port Laparoscopic Surgery Compared With Conventional Laparoscopic Surgery for Appendiceal Mucinous Neoplasm

PURPOSE

This study aimed to evaluate the safety and feasibility of single-port laparoscopic surgery (SLS) for appendiceal mucinous neoplasm (AMN) when compared with conventional laparoscopic surgery (CLS).

METHODS

This retrospective study enrolled patients who underwent surgery for AMN between July 2014 and June 2020 at Seoul National University Bundang Hospital. Patient demographics, surgical data, pathology, hospital stay, postoperative morbidity, and follow-up data were extracted from electronic records for analysis.

RESULTS

We enrolled 18 patients who underwent SLS and 22 who underwent CLS. The SLS group included patients who underwent partial cecectomy (14 patients), ileocecectomy (3 patients), and right hemicolectomy (1 patient). The CLS group included patients who underwent appendectomy (4 patients), partial cecectomy (11 patients), ileocecectomy (5 patients), and right hemicolectomy (2 patients). Operation type was not significantly different between groups (P = 0.213). No patient required open surgery in the SLS group in contrast to the CLS group (13.6%; P = 0.238). The operative time tended to be shorter in the SLS group than the CLS group (median [interquartile range]: 52.5 minutes [40-65.2 minutes] and 60 minutes [40-120 minutes], respectively; P = 0.251). Morbidity was 5.5% in the SLS group and 9.0% in the CLS group (P = 0.692). Surgical margins were clear in all cases. The median duration of postoperative hospital stay was 2.0 and 4.0 days in the SLS and CLS groups, respectively (P = 0.013). No recurrence occurred in either group during follow-up.

CONCLUSION

This study indicates that SLS is a safe and feasible surgical approach for AMN.

Diagnosis and Treatment of Primary Tumors of the Appendix: a Critical Review

INTRODUCTION

The aim of the current paper was to critically collect, select and summarize the evidence regarding diagnosis, treatment and follow up of primary tumors of the appendix.

METHODS

A literature review was performed by search and review of the scientific studies pertaining to the subject of our inquiry.

RESULTS

Recommendations regarding pimary tumors of the appendix were formulated on the basis of the collected evidence. CONCLUSION : Primary tumors of the appendix are rare and a high index of suspicion is required not to miss a potentially life threatening medical condition.

Low-grade mucinous appendiceal neoplasm mimicking an ovarian lesion: A case report and review of literature

BACKGROUND

Appendiceal tumors are rare lesions that may not be easily differentiated from primary ovarian lesions preoperatively, despite the use of advanced diagnostic methods by experienced clinicians.

CASE SUMMARY

A 59-year-old G2P2 woman, with chronic pelvic pain, underwent a pelvic ultrasound that revealed an adnexal mass measuring 58 mm × 34 mm × 36 mm, with irregular borders, heterogeneous echogenicity, no color Doppler vascularization and without acoustic shadowing. Normal ovarian tissue was visualized in contact with the lesion, and it was impossible to separate the lesion from the ovary by applying pressure with the ultrasound probe. Ascites, peritoneal metastases or other alterations were not observed. With the international ovarian tumor analysis ADNEX model, the lesion was classified as a malignant tumor (the risk of malignancy was 27.1%, corresponding to Ovarian-Adnexal Reporting Data System category 4). Magnetic resonance imaging confirmed the presence of a right adnexal mass, apparently an ovarian tumor measuring 65 mm × 35 mm, without signs of invasive or metastatic disease. During explorative laparotomy, normal morphology of the internal reproductive organs was noted. A solid mobile lesion involved the entire appendix. Appendectomy was performed. Inspection of the abdominal cavity revealed no signs of malignant dissemination. Histopathologically, the appendiceal lesion corresponded to a completely resected low-grade mucinous appendiceal neoplasm (LAMN).

CONCLUSION

The appropriate treatment and team of specialists who should provide health care to patients with seemingly adnexal lesions depend on the nature (benign vs malignant) and origin (gynecological vs nongynecological) of the lesion. Radiologists, gynecologists and other pelvic surgeons should be familiar with the imaging signs of LAMN whose clinical presentation is silent or nonspecific. The assistance of a consultant specializing in intestinal tumors is important support that gynecological surgeons can receive during the operation to offer the patient with intestinal pathology an optimal intervention.

Epidemiology, histopathology, clinical outcomes and survival of 50 cases of appendiceal mucinous neoplasms: Retrospective cross-sectional single academic tertiary care hospital experience

Background

Appendicular neoplasms are rare, most commonly as carcinoids followed by appendicular mucinous neoplasms (AMN). To date, there remains controversy regarding the best treatment of AMN and factors affecting its prognosis.

Method

Retrospective chart review of patients operated for appendicular pathology (January 2011–December 2018, follow up to December 2020) at our institution. For all AMN patients, data included pre-operative clinical presentation, and operative/post-operative findings.

Results

12454 patients underwent appendectomy, of whom 50 (0.4%) had AMN histopathologically (mean age = 47.2). Most patients had laparoscopic appendectomy as primary surgery. Low grade AMN was the most common subtype (n = 41, 82%), and pseudomyxoma peritonei (PMP) was found in 8 (16%) patients. Based on histopathology and margin involvement, the 50 patients were categorized into 3 prognostic categories of recurrence risk (no risk, 24 patients; low risk, 8; high recurrence risk, 18 patients). Disease-free survival (DFS) was lowest for high recurrence risk group (P < 0.001). Eleven (22%) patients had AMN involving resection margin, of whom 3 had no completion surgery and had no recurrence. Higher tumor markers were associated with lower DFS, however it was not statistically significant.

Conclusion

AMNs are rare but serious due to the risk of PMP. Laparoscopic approach for AMN may be feasible. Prognostic categories were significantly inversely correlated with recurrence risk; hence useful in predicting prognosis. Contrary to previous proposals, AMNs with acellular mucin at margin or local acellular mucin spillage may not require secondary surgery, especially if the patient is in low recurrence risk group. Tumor markers may predict risk of recurrence.

•

Laparoscopic approach may be feasible for appendiceal mucinous neoplasms (AMN).

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AMN can be categorized into 3 risk recurrence groups (No risk, low, and high).

•

AMN with acellular mucin at the margin may not require secondary surgery.

•

Higher tumor markers may indicate high risk of AMN recurrence.

Case Report: The importance of examining colon and rectum in patients with appendiceal cancer

Appendiceal cancer is rare and is often diagnosed incidentally in patients undergoing appendectomy for acute appendicitis. However, patients with appendiceal cancer are at increased risk of synchronous malignancy. In this case report, we present a 58-year-old man initially diagnosed with acute appendicitis after presenting to the emergency department with abdominal pain. He had an appendectomy and was discharged the following day. Unexpectedly, the postoperative histopathologic examination showed a primary adenocarcinoma in the appendix. A computed tomography scan showed rectal wall thickening and the patient was referred to colonoscopy where an experienced endoscopist found a rectal tumor during the digital rectal examination prior to the colonoscopy. The tumor was initially missed by the newly qualified doctor who examined the patient during his first admittance to hospital. The patient's two primary cancers were treated with a laparoscopic right hemicolectomy for the appendiceal cancer and a low anterior resection for the rectal cancer. This case supports the importance of a full colorectal workup in patients with appendiceal cancer. It also emphasizes the value of a thorough digital rectal examination and the need for improved focus on teaching and practice of the procedure.

Case Report: The importance of examining colon and rectum in patients with appendiceal cancer

Appendiceal cancer is rare and is often diagnosed incidentally in patients undergoing appendectomy for acute appendicitis. However, patients with appendiceal cancer are at increased risk of synchronous malignancy. In this case report, we present a 58-year-old man initially diagnosed with acute appendicitis after presenting to the emergency department with abdominal pain. He had an appendectomy and was discharged the following day. Unexpectedly, the postoperative histopathologic examination showed a primary adenocarcinoma in the appendix. A computed tomography scan showed rectal wall thickening and the patient was referred to colonoscopy where an experienced endoscopist found a rectal tumor during the digital rectal examination prior to the colonoscopy. The tumor was initially missed by the newly qualified doctor who examined the patient during his first admittance to hospital. The patient's two primary cancers were treated with a laparoscopic right hemicolectomy for the appendiceal cancer and a low anterior resection for the rectal cancer. This case supports the importance of a full colorectal workup in patients with appendiceal cancer. It also emphasizes the value of a thorough digital rectal examination and the need for improved focus on teaching and practice of the procedure.

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

BACKGROUND

Appendectomy is the most common emergent surgical procedure. Primary appendiceal neoplasms are rare entities that are usually detected incidentally in less than 2% of all appendectomies. The increase in the incidence rates of appendiceal neoplasms over time raises the question whether there is an actual change in the disease occurrence or is it a matter of increased recognition and reporting of what would have been previously missed and undiagnosed.

OBJECTIVES

In our study, we aimed to review the archived tissue specimens of patients who were diagnosed with appendiceal neoplasms during the past decade at our institution and compare our clinical experience with published data to identify possible reasons that contribute to the increase in incidence rates of such neoplasms over the past few years.

METHODS

Using a pathological database of surgical specimens from patients who underwent appendectomies between January 01, 2010 and September 30, 2020 at a large academic medical center, a single-center retrospective cohort analysis was performed, and medical charts of patients were reviewed.

RESULTS

Of the total 1568 patients included, 102 (6.5%) had appendiceal neoplasms divided between primary (79.4%) and secondary/metastatic (20.6%) neoplasms. Annual incidence of appendiceal neoplasms over the past 10 years in our institution demonstrated an increasing trend from 5.6% in 2010 to 12.7% in 2020, which we hypothesize might be attributed to submitting more representative sections of the appendix for pathological examination than we had previously. Our results also showed that 2.8% of patients initially presenting with a typical clinical picture of acute appendicitis had appendiceal neoplasms as a truly incidental finding, while 20.3% of patients who underwent elective appendectomies for a suspicious appendiceal mass were found to be neoplastic. Interestingly, among the 80 cases of epithelial neoplasms, more non-carcinoid neoplasms were detected than carcinoid tumors.

CONCLUSION

Based on our results and what has been published recently, we confirm an additional increase in incidental appendiceal neoplasms found in appendectomies performed for a clinical picture of acute appendicitis, which may be related to more thorough specimen assessment. Whether this is clinically impactful remains to be determined. However, these data support a modification in the way appendectomy specimens are handled in pathology labs post-operatively.

Impact of high-risk features for stage II adenocarcinoma of the appendix

BACKGROUND

Clinico-pathological high-risk features are frequently utilized in adjuvant chemotherapy (AC) decisions in stage II colorectal cancer and their utility in stage II appendiceal adenocarcinoma (AA) is not established. The aim of this study is to determine the impact of high-risk features in clinical outcomes and whether high risk features are predictive of AC benefit in stage II AA.

METHODS

Patients with pathological stage II AA between 2010 and 2015 were identified from the National Cancer Database (NCDB) using ICD-O-3 morphology and topography codes: 8140, 8480 and C18.1. High risk stage II AA was defined as having at least one of the following clinicopathological features: T4 tumor, <12 lymph nodes examined, poorly differentiated histology, positive margins, or lymphovascular invasion. Patients with none of these features were defined as low-risk.

RESULTS

A total of 1040 patients with pathological stage II AA were identified. 51.0% males, 84.5% Caucasian; median age 61 (range, 19-90). 46.4% were determined to have high-risk stage II AA. High-risk status was associated with worse OS compared to low-risk in univariate (HR 1.55; 95% CI 1.18-2.02; p = 0.001) and multivariable analyses (HR 1.36; 95% CI 1.03-1.79; p = 0.028). High-risk stage II AA patients had significantly worse 5-year OS compared to low-risk patients (67.1% vs. 74.5%, p = 0.0013). AC was administered in 34.4% (n = 166) of high-risk patients and in 36.5% (n = 203) of low-risk patients. Among high-risk patients, AC was not associated with better OS in univariate (HR 0.86; 95% CI 0.59-1.26; p = 0.448) and multivariable analyses (HR 1.35; 95% CI 0.90-2.04; p = 0.151) compared to no AC. Similarly, among low-risk patients, AC was not associated with better OS in univariate (HR 0.92; 95% CI 0.60-1.39; p = 0.679) and multivariable analyses (HR 1.27; 95% CI 0.81-2.02; p = 0.299) compared to no AC. For high-risk patients, 5-year OS was 68.3% in patients that received AC vs. 66.5% in patients that did not (p = 0.722). For low-risk patients, 5-year OS was 74.0% in patients that received AC vs. 76.3% in patients that did not (p = 0.813).

CONCLUSION

High-risk stage II AA patients had significantly worse 5-year OS compared to low-risk patients. AC did not improve survival regardless of high-risk features in stage II AA in this retrospective study. A prospective randomized clinical trial would be required to determine the impact of high-risk features on AC in stage II AA.

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.

Invasive Mucinous Neoplasm of the Appendix Masquerading as Recurrent Urinary Tract Infections: a Case Report

We report on a case of a healthy male patient who was referred to Urology for recurrent persistent urinary tract infections. Investigation revealed a large intraabdominal inflammatory collection abutting the cecum and bladder suspicious for ruptured appendicitis and colovesical fistula. He was taken to the operating room for exploratory laparotomy with General Surgery and Urology and found to have a ruptured appendix secondary to mucinous appendiceal neoplasm with invasion into the cecum and the bladder wall. He then underwent systemic chemotherapy followed by hyperthermic intraperitoneal chemotherapy. He is well with stable right lower quadrant inflammatory collection and without evidence of metastatic disease 22 months following initial surgery. This case presents a rare presentation of a rare disease process that is easy to misdiagnose or be delayed in diagnosis because of its vague and often varied presentation.

Integrated clinico-molecular profiling of appendiceal adenocarcinoma reveals a unique grade-driven entity distinct from colorectal cancer

BACKGROUND

Appendiceal adenocarcinoma (AA) is an orphan disease with unique clinical attributes but often treated as colorectal cancer (CRC). Understanding key molecular differences between AA and CRC is critical.

METHODS

We performed retrospective analyses of AA patients (N = 266) with tumour and/or blood next-generation sequencing (NGS) (2013-2018) with in-depth clinicopathological annotation. Overall survival (OS) was examined. For comparison, CRC cohorts annotated for sidedness, consensus molecular subtypes (CMS) and mutations (N = 3283) were used.

RESULTS

Blood-NGS identified less RAS/GNAS mutations compared to tissue-NGS (4.2% vs. 60.9%, P < 0.0001) and showed poor concordance with tissue for well-/moderately differentiated tumours. RAS (56.2%), GNAS (28.1%) and TP53 (26.9%) were most frequent mutations. Well/moderately differentiated tumours harboured more RAS (69.2%/64.0% vs. 40.5%) and GNAS (48.7%/32.0% vs. 10.1%) while moderate/poorly differentiated tumours had more TP53 (26.0%/27.8% vs. 7.7%) mutations. Appendiceal adenocarcinoma (compared to CRC) harboured significantly fewer APC (9.1% vs. 55.4%) and TP53 (26.9% vs. 67.5%) and more GNAS mutations (28.1% vs. 2.0%) (P < 0.0001). Appendiceal adenocarcinoma mutation profile did not resemble either right-sided CRC or any of the four CMS in CRC. High grade, but no mutation, was independently predictive of survival.

CONCLUSION

Integrated clinico-molecular profiling of AA identified key molecular drivers distinct from CRC. Appendiceal adenocarcinoma has a predominantly grade-driven biology that trumps mutations.

Appendiceal mucocele: three cases with different clinical presentation and review of literature

Mucinous lesions of appendix are a rare clinical entity and may be neoplastic or non-neoplastic. The diagnosis is usual incidental during computed tomography scan or colonoscopy performed for general abdominal symptoms or occasional finding during operation for acute appendicitis. For this reason, initial treatment should be tailored to the situation, aiming at complete resection of the appendix with disease-free margins: this can be achieved by simple appendectomy or more extensive resection. The pathological examination of the specimen is the key to offer the patient a correct and complete treatment, and, if a neoplastic pathology is found, the case should be discussed in multidisciplinary group. We describe three cases with different clinical presentation leading to different surgical treatment: one elective case, in which the diagnosis was suspected preoperatively; and two urgent cases, one mimicking an intussusception and another one presenting as an acute appendicitis.

Nomenclature of appendiceal mucinous lesions according to the 2019 WHO Classification of Tumors of the Digestive System

BACKGROUND/AIMS

To analysis the appendiceal mucinous lesions according to the World Health Organization (WHO) 2019 classification of tumors of the digestive system (non-neuroendocrine tumors of the appendix vermiformis)

MATERIALS AND METHODS

Clinical and histopathological data of 37 patients with histopathologically proven appendiceal mucinous lesion from January 2010 to May 2019 were evaluated retrospectively. Pathology slides were re-evaluated by two pathologists according to the WHO 2019 classification of tumors of the digestive system.

RESULTS

Totally 37 patients (male:19 female: 18) aged 23 to 93 years were analyzed. Majority of the patients (75.7 %) had underwent appendectomy due to preliminary diagnosis of acute appendicitis (n=22) or periappendiceal tumoral lesions (n=9), the others (n=9) underwent incidental appendectomy. Whereas acute appendicitis was histopathologically diagnosed in 16 (43.2%) patients, perforation was diagnosed in 12 (32.4%) patients (perforation without appendicitis=3, perforation with appendicitis=6). According to the initial, pathology reports were prepared as follows: mucocele (n=10), mucinous cystadenoma (n=9), low-grade mucinous neoplasm (n=6), mucinous adenocarcinoma (n=5), mucosal hyperplasia (n=5), hyperplastic polyp (n=1), adenomatous polyp (n=1). On the basis of the WHO 2019 classification, pathology reports were prepared as follows: low-grade mucinous neoplasm (n=17), simple retention cysts (n=6), hyperplastic polyp (n=6), mucinous adenocarcinoma (n=5), ruptured appendiceal diverticula (n=2), sessile serrated lesion (n=1).

CONCLUSION

The term of appendiceal mucinous lesion, which is recently introduced into medical literature is suitable to distinguish between lesions with and without malignancy potential. The WHO 2019 classification system has been an important step in simplifying the classification of non- neuroendocrine tumors of the appendix vermiformis.

Local Protocol for Management of Low-Grade Appendiceal Mucinous Neoplasm (LAMN)

The management and surveillance of low-grade appendiceal mucinous neoplasm (LAMN) is a confusing topic in the colorectal MDM. This study was aiming to provide a local protocol for our trust for such cases. From prospectively maintained database, patients who underwent appendicectomy between 2011 and 2017 were identified. Those with histological confirmation of LAMN were included. Retrospective analysis of operative notes, investigations and follow-up, return to theatres or development of pseudomyxoma peritonei (PMP) was performed. Four thousand six hundred twenty-eight patients had appendicectomy; 36 were diagnosed with LAMN. Age range was 30-88 (20 females). Fifteen had their operation as emergency and 13 elective, either for abnormal-looking appendix on CT scan or as part of elective right hemicolectomy. In 8 patients, LAMNs were diagnosed incidentally during other surgery either intraoperatively or on histology. Two patients had mucus in the peritoneal cavity (not sampled). The remaining 34 had either contained mucocele or inflamed appendix. Regarding follow-up, 28 patients had CT scans only, and 2 had ultrasound scan (USS). Two had both CT and USS. Three had CT and MRI scans. One patient did not have radiological investigations. Eighteen patients had colonoscopies (50%). Three patients had no follow-up, while 33 had 5-year follow-up. Ten patients are still currently under follow-up. None of the 36 patients required further surgeries related to LAMN, and none has developed PMP to date of the study. We have developed a local protocol based on our findings and literature review for management and surveillance of LAMN in line with national centres.

The challenge of creating evidence-based clinical practice guidelines for the use of hyperthermic intraperitoneal chemotherapy in the management of peritoneal malignancies

The management of primary and secondary malignancies of the peritoneum continues to pose a challenge to modern, multidisciplinary cancer care.[...]