Defining stage in mucinous tumours of the appendix with peritoneal dissemination: the importance of grading terminology: systematic review

Abstract

Background Mucinous appendiceal neoplasms with peritoneal dissemination (PD) show a wide spectrum of clinical behaviour. Histological grade has been correlated with prognosis, but no universally accepted histological grading has been established. The aim of this systematic review was to provide historical insight to understand current grading classifications, basic histopathological features of each category, and to define which classification correlates best with prognosis. Methods MEDLINE and the Cochrane Library were searched for studies that reported survival across different pathological grades in patients with mucinous neoplasm of the appendix with PD treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. PRISMA guidelines were followed. Results Thirty-eight studies were included. Ronnett’s classification was the most common (9 studies). Classifications proposed by the Peritoneal Surface Oncology Group International (PSOGI) (6 studies) and the seventh or eighth edition of the AJCC (7 studies) are gaining in popularity. Nine studies supported a two-tier, 12 a three-tier, and two a four-tier classification system. Three studies demonstrated that acellular mucin had a better prognosis than low-grade pseudomyxoma peritonei in the PSOGI classification or M1bG1 in the eighth edition of the AJCC classification. Four studies demonstrated that the presence of signet ring cells was associated with a worse outcome than high-grade pseudomyxoma peritonei in the PSOGI classification and M1bG2 in the eighth edition of the AJCC. Conclusion There is a great need for a common language in describing mucinous neoplasms of the appendix with PD. Evolution in terminology as a result of pathological insight turns the four-tiered PSOGI classification system into a coherent classification option.

Misdiagnosed appendiceal mucinous neoplasms and primary ovarian mucinous tumors present with different pre- and intraoperative characteristics

“…We reviewed and collected data from 70 cases of AMN that were misdiagnosed as ovarian tumors, which were then categorized into 50 patients with LAMNs and 20 patients with mucinous carcinomas, including three with signet ring cell carcinomas and one with a goblet cell carcinoid carcinoma. These patients were staged according to American Joint Committee on Cancer(AJCC) ( 22 ), four (8.0%), nine (18.0%), six (12.0%), three (6.0%) and 28 (56.0%) of the LAMNs cases were classified as confined disease, Tis, pT3, pT4aM1a and pT4bM1bG2 disease, respectively, and one (5.0%), two (10.0%), 12 (60.0%), and five (25.0%) patients with carcinomas were diagnosed with stage pT4aM1a, pT4bM1bG1, pT4aM1bG2 and pT4bM1bG3 disease, respectively.…”

Appendiceal Mucinous Neoplasms Involving the Testis: A Case Report

“…Appendiceal mucinous neoplasms are usually implanted in the peritoneal cavity after rupture [3,6]. Due to its rarity, mucinous neoplasms implanted in the scrotum are inexperienced with imaging and are easily misdiagnosed.…”

“…A ppendiceal mucinous neoplasms are relatively rare [1][2]. It has been reported in the literature that the rupture of appendiceal mucinous neoplasms generally causes peritoneal dissemination and invasion of the bladder [3][4][5][6]. Ultrasonographic manifestations of appendiceal neoplasms tumor invading the testis have not been reported in the literature.…”

Appendiceal Mucinous Neoplasms: From Clinic to Pathology and Prognosis

“…Table 1. Main histologic classification systems [93]. SRC-signet ring cells; DPAM-disseminated peritoneal adenomucinosis; PMCA-peritoneal mucinous carcinomatosis; PMCA-I/D-peritoneal mucinous carcinomatosis with intermediate/disconcordant features; LAMN-low-grade appendiceal mucinous neoplasm; MACA-mucinous adenocarcinoma of the appendix, HAMN-high-grade appendiceal mucinous neoplasms; LG-MCP-low-grade mucinous carcinomatosis peritonei; HG-MCP-high-grade mucinous carcinomatosis peritonei.…”