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

Abstract

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.

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

“…Patients who had stage IIIA disease, defined as T1–T2N1M0, had better survival compared with those who had stage IIB (T4aN0M0) and stage IIC (T4bN0M0) disease. However, these patterns did not persist for patients who had mucinous or signet‐ring cell appendiceal cancers 12,13 . Although the analysis of prospectively collected data for the explicit purpose of optimizing stage groupings for each disease site is now being uniformly used across version 9 AJCC staging protocol revisions, it is important to acknowledge that this must be performed under the deliberate direction of the expert panel.…”

“…However, these patterns did not persist for patients who had mucinous or signet-ring cell appendiceal cancers. 12,13 Although the analysis of prospectively collected data for the explicit purpose of optimizing stage groupings for each disease site is now being uniformly used across version 9 AJCC staging protocol revisions, it is important to acknowledge that this must be performed under the deliberate direction of the expert panel. In an ideal situation, hierarchical prognostication would be exhibited across all appendiceal histologies to be congruent with the restructured staging revision process of the AJCC, but the diverse biology and behavior of these cancers rendered this challenging.…”

A giant low-grade appendiceal mucinous neoplasm (LAMN) presenting as ileocecal intussusception: a case report

“…Generally, small LAMNs can be treated with open or laparoscopic appendectomy, but for larger LAMNs, laparotomy may be necessary because of possible cecal involvement [ 15 ]. If LAMN is suspected, careful removal is indicated to avoid cystic wall rupture and spillage of any potentially malignant cells or mucus that may result to PMP [ 13 ].…”

Discrepancies between preoperative diagnosis of tumors and the right uterine appendage and intraoperative data. Appendiculare mucocele, which manifests itself in the form of an appendage formation. Clinical case

“…AM belongs to the category of rare types of tumors of the gastrointestinal tract, more common among postmenopausal women [4,22]. However, in recent years, there have been more and more publications on the detection of appendix tumors in women of reproductive age [5,11].…”