Staging of appendiceal mucinous neoplasms: challenges and recent updates

Mucocele of the appendix: case report of a rare disease with changing diagnostic-therapeutic behavior

Mucinous appendicular neoplasms are a rare and heterogeneous group of tumors, whose treatment may vary based on histologic features and extent. We present a case of low-grade appendiceal mucinous neoplasm mimicking an acute appendicitis scenario. The patient underwent appendectomy along with resection of the caecal fundus. Choosing the correct treatment according to the case by following current guidelines is crucial to avoid under- or overtreatment.

Current Status of Treatment among Patients with Appendiceal Tumors-Old Challenges and New Solutions?

The 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system distinguishes four categories of appendiceal tumors (ATs): serrated lesions and polyps, mucinous neoplasms, adenocarcinomas, and neuroendocrine neoplasms (NENs). The differential diagnosis of ATs can be challenging in medical practice, due to their rarity and lack of data from randomized controlled trials on a large, diverse group of patients. ATs are usually noted in specimens obtained during appendectomies due to clinical acute appendicitis. In the European population, most ATs (65%) occur over the age of 50 and among women (56.8%). According to histological type, 54.6% are neuroendocrine tumors (NETs); 26.8% cystic, mucinous, and serous neoplasms; and 18.6% adenocarcinoma not otherwise specified (NOS). On pathologic analysis, most AT findings are benign lesions or small NENs that do not require further therapeutic measures. The presence of appendiceal mucinous neoplasm (AMN) can lead to pseudomyxoma peritonei (PMP). While the multimodal treatment for abdominal malignancies has evolved over the past several decades, the clinical workup and treatment of ATs remain a challenge. Therefore, this review aims to describe the diagnostic possibilities, molecular-based diagnosis, staging, differences in the treatment process, and prognostic factors associated with ATs.

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.

Survival outcomes used to validate version 9 of the American Joint Committee on Cancer staging system for appendiceal cancer

The standard for cancer staging in the United States for all cancer sites, including primary carcinomas of the appendix, is the American Joint Committee on Cancer (AJCC) staging system. AJCC staging criteria undergo periodic revisions, led by a panel of site-specific experts, to maintain contemporary staging definitions through the evaluation of new evidence. Since its last revision, the AJCC has restructured its processes to include prospectively collected data because large data sets have become increasingly robust and available over time. Thus survival analyses using AJCC eighth edition staging criteria were used to inform stage group revisions in the version 9 AJCC staging system, including appendiceal cancer. Although the current AJCC staging definitions were maintained for appendiceal cancer, incorporating survival analysis into the version 9 staging system provided unique insight into the clinical challenges in staging rare malignancies. This article highlights the critical clinical components of the now published version 9 AJCC staging system for appendix cancer, which (1) justified the separation of three different histologies (non-mucinous, mucinous, signet-ring cell) in terms of prognostic variance, (2) demonstrated the clinical implications and challenges in staging heterogeneous and rare tumors, and (3) emphasized the influence of data limitations on survival analysis for low-grade appendiceal mucinous neoplasms.

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

BACKGROUND

Adenocarcinomas of the appendix are rare cancers for which no National Comprehensive Cancer Network guidelines exist, and for patients who undergo resection with curative intent, there is a paucity of data on prognostic factors affecting long-term cancer-specific survival. We aimed to compare the cancer-specific survival outcomes in adult patients with appendiceal non-mucinous adenocarcinoma undergoing either local resection versus right hemicolectomy.

METHODS

This was a retrospective study from the National Cancer Institute Surveillance, Epidemiology, and End Results of patients who underwent curative resection over a 15-year period (2004-2019) for primary appendiceal adenocarcinoma. Out of 16,699 patients, 14,945 were excluded (exclusion criteria were non-adenocarcinoma histological types and patients with regional or distant metastasis as per National Cancer Institute Surveillance, Epidemiology, and End Results stage). Effects of factors (age, race, tumor biology [mucinous versus non-mucinous tumors], the extent of resection of the primary lesion, and lymph nodes) on cancer-specific long-term survival were studied. Survival analysis was performed using the Kaplan-Meier method. Survival outcomes were reported as mean survival (months).

RESULTS

Of 1,754 patients, 827 (47.1%) were women, and 927 (52.1%) were men. The mean age in years (± standard deviation) was 62.43 ± 14.3. The racial distribution was as follows: Black 237 (13.5%), White 1,398 (79.7%), and Other 119 (6.8%). A total of 771 (44.6%) underwent local resection (appendectomy or segmental resection of colon without lymph node resection), and 983 (55.4%) underwent hemicolectomy with lymph node resection. Favorable survival prognosticators were age <50 years, White race, and well-differentiated histology. Patients with mucinous tumors experienced better survival. Patients who underwent right hemicolectomy with lymph node resection experienced better survival compared with those who had an appendectomy or segmental colonic resection for non-mucinous tumors rather than mucinous tumors.

CONCLUSION

We report novel demographic, tumor-related, and operative prognostic factors impacting long-term cancer-specific survival in patients who undergo resection for appendiceal adenocarcinoma. The extent of resection of the primary lesion with draining lymph nodes determines long-term cancer-specific survival in non-mucinous appendiceal adenocarcinomas.

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 perforation secondary to endometriosis with intestinal metaplasia: A case report

Appendiceal endometriosis with intestinal metaplasia is particularly challenging to diagnose preoperatively based on clinical features. Microscopically, it can mimic malignant transformation into mucinous neoplasms of the appendix. The present study reports a case of a 47-year-old woman who presented with abdominal pain that was not related to her menstruation. The preoperative diagnosis and laparoscopic evaluation were chronic appendicitis. No mucinous or haemorrhagic secretions were present within the abdominal cavity. Pathological evaluation revealed conventional endometriosis with intestinal-type metaplasia of the epithelium. An inverse pattern of cytokeratin (CK)7, paired-box 8, estrogen receptor, CK20, caudal type homeobox transcription factor 2 and mucin 2 immunoreactivity between intestinal-type and endometrial-type endothelium was observed. Infiltration and replacement of the appendiceal wall by marked levels of acellular mucin, a lack of stromal components and a DNA mismatch repair protein profile were vital in diagnosing appendiceal endometriosis without appendiceal mucinous neoplasms (AMNs). The lesion of appendiceal endometriosis are usually superficial and small in previously reported cases but was deeply invasive in our case. A careful histopathological examination is necessary for diagnosing and distinguishing the histologic imitators of AMN.