A retrospective analysis and literature review of neoplastic appendiceal mucinous lesions

Neoplastic appendiceal mucinous lesions: a narrative review of the literature from an oncologist's perspective

Appendiceal mucinous lesions' classification and nomenclature has been modified several times along the last decades, reflecting their great heterogeneity and making difficult to compare results and draw conclusions. Despite its nearby origin, appendiceal mucinous lesions have a distinctive behaviour compared to colorectal cancer, including their molecular and genetic markers. Due to their low frequency, their management is not well standardised. However, surgery is considered the cornerstone of treatment. Their indolent behaviour has encouraged surgeons to apply more aggressive treatments, such as cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC), that may extend overall survival. Chemotherapy is reserved for unresectable and/or disseminated disease and could play a role in the adjuvant and neoadjuvant setting. Pressurised intraperitoneal aerosol chemotherapy (PIPAC) is recently emerging as a possible alternative for treatment in advanced disease although its results in long-term survival are lacking Hereby, we review the available evidence in the management of appendiceal mucinous lesions, including localised and disseminated disease, with a special emphasis on the oncological perspective, focusing on the lights and shadows of the systemic treatments.

Beyond boundaries: Feasibility of curved linear array echoendoscope in appendiceal neoplasm detection

We recently read with great interest a study by Zhang et al in the World Journal of Gastroenterology. In our practice, we focus specifically on examining appendiceal mucinous neoplasms (AMNs) with endoscopic ultrasound (EUS) using different scopes. AMNs are rare neoplastic lesions characterized by an accumulation of mucin inside a cystic dilatation of the appendix. Clinically, they can present as nonspecific acute appendicitis. AMNs can turn into a life-threatening condition, termed pseudomyxoma peritonei, in which the ruptured appendix causes accumulation of mucin in the abdomen. Therefore, accurate and rapid diagnosis of AMN is essential. EUS is able to confirm and stage AMNs; although, EUS examination was once limited to the rectal and anal regions due to the conventional oblique-view scopes. With the emergence of new forward-view linear echoendoscopes and instruments like EUS miniprobes and overtubes, the scope of examination is changing. Herein, we discuss the feasibility of using the curved linear array echoendoscopes to examine cecal and appendiceal orifice lesions.

Superiority of 18F-FAPI-42 PET/CT in the detection of primary tumor and management of appendiceal neoplasm to 18F-FDG PET/CT and CE-CT

BACKGROUND

In the present study, we investigated the value of 18F-fibroblast-activation protein inhibitor (FAPI) positron emission tomography/computed tomography (18F-FAPI-42 PET/CT) to preoperative evaluations of appendiceal neoplasms and management for patients.

METHODS

This single-center retrospective clinical study, including 16 untreated and 6 treated patients, was performed from January 2022 to May 2023 at Southern Medical University Nanfang Hospital. Histopathologic examination and imaging follow-up served as the reference standard. 18F-FAPI-42 PET/CT was compared to 18F-fluorodeoxyglucose (18F-FDG) PET/CT and contrast-enhanced CT (CE-CT) in terms of maximal standardized uptake value (SUVmax), diagnostic efficacy and impact on treatment decisions.

RESULTS

The accurate detection of primary tumors and peritoneal metastases were improved from 28.6% (4/14) and 50% (8/16) for CE-CT, and 43.8% (7/16) and 85.0% (17/20) for 18F-FDG PET/CT, to 87.5% (14/16) and 100% (20/20) for 18F-FAPI-42 PET/CT. Compared to 18F-FDG PET/CT, 18F-FAPI-42 PET/CT detected more regions infiltrated by peritoneal metastases (108 vs. 43), thus produced a higher peritoneal cancer index (PCI) score (median PCI: 12 vs. 5, P < 0.01). 18F-FAPI-42 PET/CT changed the intended treatment plans in 35.7% (5/14) of patients compared to CE-CT and 25% (4/16) of patients compared to 18F-FDG PET/CT but did not improve the management of patients with recurrent tumors.

CONCLUSIONS

The present study revealed that 18F-FAPI-42 PET/CT can supplement CE-CT and 18F-FDG PET/CT to provide a more accurate detection of appendiceal neoplasms and improved treatment decision making for patients.

Lower Gastrointestinal Bleeding Secondary to Appendiceal Mucinous Neoplasm: A Report of Two Cases and a Review of the Literature

Appendicular mucinous neoplasms, constituting less than 1% of gastrointestinal tract neoplasms, are heterogeneous entities. They may be asymptomatic, discovered incidentally, or present as large tumors due to mucin accumulation. The lack of standardized treatment complicates management. Imaging studies, particularly CT scans, are crucial for diagnosis and follow-up. This case report presents two clinical cases of women in their sixth and seventh decades of life with a history of lower gastrointestinal bleeding, mild anemia in laboratory studies, and incomplete colonoscopies. The diagnosis, confirmed through CT scans, led to the decision for surgical intervention in both cases, involving laparoscopic right hemicolectomy with ileotransverse anastomosis. Subsequently, histopathological reports confirmed the diagnosis of high-grade appendicular mucinous neoplasms, and a follow-up plan was established with imaging studies every six months with no recurrence at two years. Over 50% of appendicular tumors are mucinous neoplasms originating from low-grade mucinous neoplasms. Given the low lymph node invasion (2%), appendectomy may suffice if the entire tumor is excised. Extensive resections or right hemicolectomy are reserved for larger tumors or high-grade neoplasms to minimize local recurrence risk. Mucinous neoplasms with acellular mucin and peritoneal invasion may require cytoreduction or right hemicolectomy, while those with mucinous epithelium may need hyperthermic intraperitoneal chemotherapy (HIPEC) due to the risk of local recurrence, worsened by the presence of extra appendiceal epithelial cells. Disease-free and overall survival depend on treatment and initial lesion characterization. A five-year survival rate of 86% is reported for low-grade mucinous neoplasms. Follow-up approaches lack an ideal standard, generally involving physical examinations and imaging studies every six months to one year during the first six years.

Incidental Appendiceal Tumors During Appendectomy: A Nineteen-Year Retrospective Review at a Municipal Hospital

Non-operative management of appendicitis (NOMA) has recently gained popularity, but a concern is that NOMA might miss appendiceal neoplasms. We conducted a retrospective review of 1694 appendectomies done for acute appendicitis at our institution between January 2001 and December 2019 to study the incidence and distribution of appendiceal tumors. We identified 24 appendiceal neoplasms (1.43%), including 9 Low Grade Appendiceal Mucinous Neoplasms (LAMNs), 6 neuroendocrine tumors (NETs), 6 mucoceles, and one each of adenocarcinoma, endometrioma, and neurofibroma. Tumor occurrence had two age peaks, with LAMNs prominent in the 5th and 6th decades of life and NETs in the 2nd and 3rd decades. All patients under age 40 had benign disease. Presence of appendicoliths was independent of the presence of neoplasms. All cases were managed per National Comprehensive Cancer Network (NCCN) guidelines, with twenty cases cured by appendectomy alone. Given these, we conclude that NOMA is safe for patients under 40.

Does a Positive Appendiceal Resection Margin in Low-Grade Appendiceal Mucinous Neoplasms, Warrant Additional Surgery? Our Institution Experience and Literature Review

BACKGROUND

Management of low-grade appendiceal mucinous neoplasm (LAMN) with positive resection margin is controversial. Some guidelines recommend surgical reexcision, whereas others recommend a conservative approach. The purpose of our study was to determine whether involvement of the resection margin by LAMN is a risk factor for local recurrence requiring additional surgery.

DESIGN

This is a retrospective study (January 2000-December 2020) of uncomplicated LAMNs with neoplastic epithelium or dissecting mucin at the resection margin. For cases treated with additional surgery, the presence of residual tumor was evaluated. Clinical follow-up was attained in all cases. We also conducted a literature review.

RESULTS

The study investigated 98 patients. Eight with median age of 67 (range: 45-91) years had a LAMN involving the resection margin (8.2%). Five of eight LAMNs (62.5%) with neoplastic epithelium at the margin underwent surgery, and no residual neoplasm was identified. The other three cases were followed conservatively, and no patient developed recurrence (follow-up: 18-69 months with a mean of 45 months). In a review of the literature, we identified 52 LAMNs with positive margin. Although three cases had acellular mucin and one residual LAMN in the reexcision specimen (7.7%), neither of these four cases or any of the other 46 followed conservatively had recurrence of disease.

CONCLUSIONS

These data suggest that for patients with uncomplicated LAMN confined to the appendix, the involvement of the appendiceal margin does not necessary lead to recurrence of LAMN, and a conservative management is a reasonable alternative.

Appendectomy in endometriosis: an update on surgical indications and management of uncommon diseases

PURPOSE OF REVIEW

Abnormal appendiceal disease is commonly encountered following an appendectomy when performed in patients with endometriosis. Appendiceal endometriosis is the most notable finding and can affect up to 39% of patients with endometriosis. Despite this knowledge, guidelines for performing an appendectomy have not been formally established. In this article, we review the surgical indications for an appendectomy at the time of endometriosis surgery and discuss the management of other diseases that may be encountered following the histopathologic evaluation of an excised appendix.

RECENT FINDINGS

Removal of the appendix in patients with endometriosis contributes to optimal surgical management. Relying on abnormal appendiceal appearance for removal may leave endometriosis-affected appendices. For this reason, utilizing risk factors to guide surgical management is essential. Common appendiceal diseases are sufficiently managed with appendectomy. Uncommon diseases may require further surveillance.

SUMMARY

Emerging data in our field support the performance of an appendectomy at the time of endometriosis surgery. Guidelines for performing a concurrent appendectomy should be formalized to encourage preoperative counselling and management for patients with risk factors for appendiceal endometriosis. Abnormal diseases is frequently encountered after appendectomy in the setting of endometriosis surgery and further management is based on the histopathology of the specimen.

Appendiceal collision tumors: case reports, management and literature review

Appendiceal tumors are incidentally detected in 0.5% cases of appendectomy for acute appendicitis and occur in approximately 1% of all appendectomies. Here, we report two cases of appendiceal collision tumors in two asymptomatic women. In both cases, imaging revealed right-lower-quadrant abdominal masses, which were laparoscopically resected. In both cases, histological examinations revealed an appendiceal collision tumor comprising a low-grade appendiceal mucinous neoplasm and well-differentiated neuroendocrine neoplasm (NEN). For complete oncological control, right hemicolectomy was performed in one patient for the aggressive behavior of NEN; however, histology revealed no metastasis. The other patient only underwent appendectomy. No further treatment was recommended. According to the latest guidelines, exact pathology needs to be defined. Proper management indicated by a multidisciplinary team is fundamental.

Appendiceal mucocele presenting as a leading point in ileocolic intussusceptions: "Case report"

INTRODUCTION AND IMPORTANCE

Appendiceal mucocele is a rare clinical scenario, which is found in 0.2-0.7 % of appendectomies. Ileocecal/ileocolic intusception caused by appendiceal mucocele is an extremely rare condition with few case reports in literatures. The treatment is surgery with the extent determined by intra-operative findings. Ultrasound and CECT scan can suggest the diagnosis, but definitive diagnosis is by histopathology. The aim of this presentation is to discuss appendiceal mucocele in terms of clinical features, diagnostic imaging and treatment. This case report can create awareness to primary care physicians, radiologists, surgeons and pathologists aiding in accurate diagnosis and early surgical intervention to prevent rupture.

PRESENTATION OF THE CASE

A fifty years old woman presented with intermittent colicky peri umbilical abdominal pain of one-week duration. She had nausea, vomiting, mild abdominal distension, and failure to pass feces and flatus. Physical examination was normal. Imaging suggested ileocolic intussusceptions with cystic leading point on ultrasound, but on CECT scan, no leading point reported. Appendiceal mucocele diagnosed intra operatively and confirmed by pathology.

CONCLUSION

Appendiceal mucocele is rare and can be benign or malignant. Preoperative diagnosis is often difficult. Definitive diagnosis is by histopathology. Appendiceal mucocele can rarely present with ileocolic intussusceptions. Radiologists, pathologists, primary care physicians and surgeons must be aware of this condition. Accurate preoperative diagnosis and early surgical treatment of appendiceal mucocele is important to prevent complications like pseudo myxoma peritonei(PMP), which has poor prognosis.

OUP accepted manuscript

Primary neoplasm of the appendix is often diagnosed incidentally after an appendectomy. Low-grade appendiceal mucinous neoplasms (LAMNs) make up a small portion of these neoplasms. We present a rare case of a patient with a slow-growing LAMN causing urinary retention and constipation. The mass was initially found incidentally 25 years prior, but the patient declined further workup since he was asymptomatic at that time. The patient experienced progressively worsening abdominal discomfort related to urinary retention and difficulty in evacuating his bowels. Imaging identified a large abdominal mass (19.3 × 8.7 × 13.5 cm). The mass was surgically resected. Pathology was consistent with a LAMN. In general, an incidental finding of an abdominal mass should be further investigated regardless of symptomology. Patients should be educated about the potential of malignancy and the need for a major abdominal surgery in the future if they choose not to have a mass further evaluated.