Progress on immuno-microenvironment and immune-related therapies in patients with pseudomyxoma peritonei

Pseudomyxoma peritonei(PMP) is an indolent malignant syndrome. The standard treatment for PMP is cytoreductive surgery combined with intraperitoneal hyperthermic chemotherapy(CRS + HIPEC). However, the high recurrence rate and latent clinical symptoms and signs are major obstacles to further improving clinical outcomes. Moreover, patients in advanced stages receive little benefit from CRS + HIPEC due to widespread intraperitoneal metastases. Another challenge in PMP treatment involves the progressive sclerosis of PMP cell-secreted mucus, which is often increased due to activating mutations in the gene coding for guanine nucleotide-binding protein alpha subunit(GNAS). Consequently, the development of other PMP therapies is urgently needed. Several immune-related therapies have shown promise, including the use of bacterium-derived non-specific immunogenic agents, radioimmunotherapeutic agents, and tumor cell-derived neoantigens, but a well-recognized immunotherapy has not been established. In this review the roles of GNAS mutations in the promotion of mucin secretion and disease development are discussed. In addition, the immunologic features of the PMP microenvironment and immune-associated treatments are discussed to summarize the current understanding of key features of the disease and to facilitate the development of immunotherapies.

A Case of Diagnosis of Pseudomyxoma Peritonei

Objective: To report a case of pseudomyxoma peritonei accidentally discovered during preoperative examination and review relevant literature to improve the early diagnosis of the origin of pseudomyxoma peritonei. Methods: To analyze a case accidentally discovered due to abdominal distension in our hospital in October 2023. Combined with domestic and foreign literature, the etiology, clinical manifestations, diagnosis, differential diagnosis and treatment of PMP were discussed. Results: The patient was admitted due to abdominal distension with no other specific discomfort. Mucinous tumors were found during imaging examinations. Conclusion: PMP is a rare disease, and clinical manifestations often include abdominal distension. It is usually first discovered through imaging examinations such as ultrasound, CT or MRI. CRS and HIPEC are still recommended as the standard treatment for PMP.

Treatment outcome analysis of bevacizumab combined with cyclophosphamide and oxaliplatin in advanced pseudomyxoma peritonei

BACKGROUND Pseudomyxoma peritonei(PMP)is a rare peritoneal malignant tumor syndrome.Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is its standard treatment.However,there are few studies and insufficient evidence regarding systemic chemotherapy of advanced PMP.Regimens for colorectal cancer are often used clinically,but there is no uniform standard for late-stage treatment.AIM To determine if bevacizumab combined with cyclophosphamide and oxaliplatin(Bev+CTX+OXA)is effective for treatment of advanced PMP.The primary study endpoint was progression-free survival(PFS).METHODS Retrospective analysis was conducted on the clinical data of patients with advanced PMP who received Bev+CTX+OXA regimen(bevacizumab 7.5 mg/kg ivgtt d1,oxaliplatin 130 mg/m2 ivgtt d1 and cyclophosphamide 500 mg/m2 ivgtt d1,q3w)in our center from December 2015 to December 2020.Objective response rate(ORR),disease control rate(DCR)and incidence of adverse events were evaluated.PFS was followed up.Kaplan-Meier method was used to draw survival curve,and log-rank test was used for comparison between groups.Multivariate Cox proportional hazards regression model was used to analyze the independent influencing factors of PFS.RESULTS A total of 32 patients were enrolled.After 2 cycles,the ORR and DCR were 3.1%and 93.7%,respectively.The median follow-up time was 7.5 mo.During the follow-up period,14 patients(43.8%)had disease progression,and the median PFS was 8.9 mo.Stratified analysis showed that the PFS of patients with a preoperative increase in CA125(8.9 vs 2.1,P=0.022)and a completeness of cytoreduction score of 2-3(8.9 vs 5.0,P=0.043)was significantly longer than that of the control group.Multivariate analysis showed that a preoperative increase in CA125 was an independent prognostic factor for PFS(HR=0.245,95%CI:0.066-0.904,P=0.035).CONCLUSION Our retrospective assessment confirmed that the Bev+CTX+OXA regimen is effective in second-or posterior-line treatment of advanced PMP and that adverse reactions can be tolerated.A preoperative increase in CA125 is an independent prognostic factor of PFS.

Approach to pseudomyxoma peritonei

Pseudomyxoma peritonei(PMP) is a mucinous tumour of the appendix that spreads into the peritoneal cavity in the form of gelatinous deposits. The incidence of PMP is believed to be approximately 1-3 out of a million per year. Nonetheless, due to its indolent nature, it is usually discovered at an advanced stage and severely impacts quality of life. Curative treatment for PMP is complete cytoreductive surgery(CRS) with hyperthermic intraperitoneal chemotherapy(HIPEC). An extensive literature review was conducted searching EMBASE, MEDLINE, Pub Med, and Google Scholar databases for PMP in aims to delineate a clinical approach to diagnosis and treatment. Literature was limited to the years 2007-2018. We found the 5-year overall survival with CRS and HIPEC estimated to be between 23%-82% and rates of major complications as high as 24%. Therefore, it is important to appropriately stage and select patients that should undergo CRS with HIPEC. Modalities like MDCT radiological scores have been shown to have sensitivity and specificity of 94% and 81%, respectively, in being able to predict resectability and survival. Despite treatment, the disease often recurs. Tumor markers have significant potential for establishing prognosis preoperatively, and this paper will review the most recent evidence in support of them.

Histological origin of pseudomyxoma peritonei in Chinese women:Clinicopathology and

AIM： To investigate the myxoma peritonei （PMP） histological origin of pseudo- n Chinese women. METHODS： The clinical and pathological data were reviewed for 35 women with PMP, and specimens of the peritoneal, appendiceal and ovarian lesions of each patient were examined using the PV-6000 immunohistochemistry method. Antibodies included cytokeratin （CK）7, CK20, mucin （MUC）-1, MUC-2, carbohydrate antigen （CA）-125, estrogen receptor （ER）, and progesterone receptor （PR）. RESULTS： Abundant colloidal mucinous tumors were observed in the peritoneum in all 35 cases. Thirty-one patients had a history of appendectomy, 28 of whom had mucinous lesions. There was one patient with appendicitis, one whose appendix showed no apparent pathological changes, and one with unknown surgical pathology. Ovarian mucinous tumors were found in 24 patients. The tumors were bilateral in 13 patients, on the right-side in nine, and on the left side in two. Twenty patients had combined appendiceal and ovarian lesions; 16 of whom had undergone initial surgery for appendiceal lesions. Four patients had undergone initial surgery for ovarian lesions, and relapse occurred in these patients at 1, 11, 32 and 85 mo after initial surgery. Appendi-ceal mucinous tumors were found in each of these four patients. Thirty-three of the 35 patients showed peritoneal lesions that were positive for CK20 and MUC-2, but negative for CK7, MUC-1, CA125, ER and PR. The expression patterns in the appendix and the ovary were similar to those of the peritoneal lesions. In one of the remaining two cases, CK20, CK7 and MUC-2 were positive, and MUC-1, CA125, ER and PR were negative. The ovaries were not resected. The appendix of one patient was removed at another hospital, and no specimen was evaluated. In the other case, the appendix appeared to be normal during surgery, and was not resected. Peritoneal and ovarian lesions were negative for CK20, MUC-2, CK7, MUC-1, CA125, ER and PR. CONCLUSION： Most PMP originated from the appendix. Among women with PMP, the ovarian tumors were implanted rather than primary. For patients with PMP, appendectomy should be performed routinely. The ovaries, especially the right ovaries should be explored.

Appendiceal mucocoeles and pseudomyxoma peritonei

Mucocoele of the appendix occurs when obstruction of the appendiceal lumen results in mucus accumulation and consequent abnormal dilatation. The most impor- tant aetiology, from a surgical perspective, is either mucinous cystadenoma or cystadenocarcinoma. In the latter, a spontaneous or iatrogenic rupture of the mucocoele can lead to mucinous intraperitoneal ascites, a syndrome known as pseudomyxoma peritonei. Optimal management of mucoceles is achieved through accurate preoperative identification and subsequent careful resection. We report two cases and subsequently discuss the clinical presentation of mucocoeles, their association with pseudomyxoma peritonei and an optimal management of both conditions.

Pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is an uncommon "bor-derline malignancy" generally arising from a perforated appendiceal epithelial tumour. Optimal treatment involves a combination of cytoreductive surgery (CRS) with heated intraperitoneal chemotherapy (HIPEC). Controversy persists regarding the pathological classification and its prognostic value. Computed tomography scanning is the optimal preoperative staging technique. Tumour marker elevations correlate with worse prognosis and increased recurrence rates. Following CRS with HIPEC, 5-year survival ranges from 62.5% to 100% for low grade, and 0%-65% for high grade disease. Treat-ment related morbidity and mortality ranges from 12 to 67.6%, and 0 to 9%, respectively. Surgery and HIPEC are the optimal treatment for PMP which is at best a "borderline" peritoneal malignancy.

Management of pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a rare disease. It refers to a progressive disease process within the peritoneum which originates from the appendix or ovaries and is characterised by the production of copious amounts of mucinous fluid resulting in a “jelly belly”. If untreated the condition is fatal. The traditional approach to PMP is based on repeated surgical debulking procedures, often associated with intraperitoneal or systemic chemotherapy. The natural history of this disease has been drastically modified since the introduction of a new surgical approach defined as a peritonectomy procedure. This paper is to review the literature on this treatment strategy.

History of pseudomyxoma peritonei from its origin to the first decades of the twenty-first century

Pseudomyxoma peritonei(PMP)is a disease surrounded by misunderstanding and controversies.Knowledge about the etymology of pseudomyxoma is useful to remove the ambiguity around that term.The word pseudomyxoma derives from pseudomucin,a type of mucin.PMP was first described in a case of a woman alleged to have a ruptured pseudomucinous cystadenoma of the ovary,a term that has disappeared from today’s classifications of cystic ovarian neoplasms.It is known today that in the majority of cases,the origin for PMP is an appendiceal neoplasm,often of low histological grade.Currently,ovarian tumors are wrongly being considered a significant recognized etiology of PMP.PMP classification continues to be under discussion,and experts’panels strive for consensus.Malignancy is also under discussion,and it is shown in this review that there is a long-standing historical reason for that.Surgery is the main tool in the treatment armamentarium for PMP,and the only therapy with potential curative option.

Pseudomyxoma peritonei of 92 Chinese patients:Clinical characteristics,pathological classification and prognostic factors

AIM:To assess the clinicopathologic features and its relationship with prognosis of pseudomyxoma peritonei(PMP) in Chinese patients.METHODS:The clinicopathologic features and followup data of 92 patients with PMP were reviewed and retrospectively analyzed.The cases were categorized into three groups:disseminated peritoneal adenomucinosis(DPAM),peritoneal mucinous carcinomatosis(PMCA),and peritoneal mucinous carcinomatosis with intermediate or discordant features(PMCA-I/D).The log-rank test was used to analyze survival for each group and various clinicopathological parameters.Multivariate Cox proportional-hazard models were constructed to determine the important factors associated with survival.RESULTS:The median age at diagnosis was 51.9 years(range:22-76 years).The median follow up was 124 mo.The 3-,5-and 10-year survival rates were 74.0%,67.4% and 49.1%,respectively.There were 49(53.2%)patients with DPAM,26(28.3%) with PMCA-I and 17(18.5%) with PMCA.Patients with DPAM,PMCA-I/D and PMCA exhibited statistically significant difference in survival(P = 0.001).The 3 year survival for DPAM,PMCAI/D and PMCA was 97.0%,80.0% and 67.0%,respectively;the 5 year survival was 80.0%,67.0% and 50.0%,respectively;and the 10 year survival was 65.0%,28.0% and 14.0%,respectively.Survival rate was significantly lowest in patients < 40 age years of age(P = 0.011).Appendiceal tumor and extra-ovarian parenchymal organ involvement were significantly related to overall survival.Patients with appendiceal mucinous adenocarcinoma(MACA) showed the significantly poorer prognosis(P = 0.011).Multivariate analysis showed that pathological classification,age,appendiceal tumor were significant related to overall survival.CONCLUSION:The clinical process "PMP" should be pathologically classified into DPAM,PMCA and PMCA-I/D.Pathological classification,age,appendiceal MACA are survival independent predictors in Chinese patients with PMP.

Pseudomyxoma peritonei originating from intestinal duplication:A case report and review of the literature

BACKGROUND Pseudomyxoma peritonei(PMP)is a rare mucinous neoplasm with a relatively low incidence of 1 to 2 per million individuals.It is typically characterized by a type of gelatinous ascites named“jelly belly”.Most cases of PMP occur in association with ruptured primary mucinous tumors of the appendix(90%).Periodically,PMP can originate from mucinous carcinomas at other sites,including the colorectum,gallbladder,and pancreas.However,unusual origin can occur,as noted in this case report.CASE SUMMARY A 52-year-old woman had an unusual derivation of PMP from intestinal duplication.The patient complained of abdominal distension and increasing abdominal girth.Abdominal contrast-enhanced computed tomography showed a mass in the greater omentum located on the left side of the abdomen,likely to be a cystic mass of peritoneal origin.A PMP diagnosis was presumed based on the specific signs of the mass with flocculent and stripe-like echoes in ultrasound images.Ultrasound-guided percutaneous aspiration suggested a high likelihood of PMP.Once the PMP diagnosis was recognized,identification of the origin of the primary tumor was indicated.Thus,an exploratory laparoscopy was performed.In the absence of a primary tumor of appendix origin,the diagnosis of a low-grade mucinous neoplasm of intestinal duplication origin was finally confirmed by histopathology.CONCLUSION PMP is secondary to mucinous carcinomas of the appendix mostly.This case resulted from an unusual derivation from intestinal duplication.

Incidence of leukopenia after intraperitoneal vs combined intravenous/intraperitoneal chemotherapy in pseudomyxoma peritonei

AIM: To investigate the clinical impact of post-hyperthermic intraperitoneal chemotherapy(HIPEC) leukopenia, intraperitoneal and combined intravenous/intraperitoneal drug administrations were compared.METHODS: Two patient cohorts were retrospectively analyzed regarding the incidence of postoperative leukopenia. The first cohort(n = 32) received Mitomycin C(MMC)-based HIPEC intraperitoneally(35 mg/m2 for 90 min) and the second cohort(n = 10) received a bidirectional therapy consisting of oxaliplatin(OX)(300 mg/m2 for 30 min) intraperitoneally and 5-fluorouracil(5-FU) 400 mg/m2 plus folinic acid 20 mg/m2 intravenously. The following data were collected retrospectively: Age, sex, length of operation, length of hospital stay, amount of resection including extent of peritonectomy, peritoneal cancer index, CC(completeness of cytoreduction)-status and leukocyte-count before cytoreductive surgery(CRS) and HIPEC, on days 3, 7 and 14 after CRS and HIPEC. HIPEC leukopenia was defined as < 4000 cells/m3. RESULTS: Leukopenia occurred statistically more often in the MMC than in the OX/5-FU-group(10/32 vs 0/10; P = 0.042). Leukopenia set-on was on day 7 after CRS and MMC-HIPEC and lasted for two to three days. Three patients(33%) required medical treatment. Patients affected by leukopenia were predominantly female(7/10 patients) and older than 50 years(8/10 patients). Thelength of hospital stay tended to be higher in the MMCgroup without reaching statistical significance(22.5± 11 vs 16.5 ± 3.5 d). Length of operation(08:54 ± 01:44 vs 09:48 ± 02:28 h) were comparable between patients with and without postoperative leukopenia. Prior history of systemic chemotherapy did not trigger postHIPEC leukopenia. Occurrence of leucopenia did not trigger surgical site infections, intraabdominal abscess formations, hospital-acquired pneumonia or anastomotic insufficiencies. CONCLUSION: Surgeons must be aware that there is a higher incidence of postoperative leukopenia in MMCbased HIPEC protocols primarily affecting females and older patients.

Apatinib for treatment of a pseudomyxoma peritonei patient after surgical treatment and hyperthermic intraperitoneal chemotherapy:A case report

BACKGROUND Pseudomyxoma peritonei(PMP)is a rare benign,but progressive,disease according to myxoma histopathology.Surgical resection is the preferred and most effective treatment,but the outcomes are often unsatisfactory.CASE SUMMARY A 63-year-old Chinese woman with PMP received apatinib at a daily dose of 0.5 mg for 15 d per cycle and at a daily dose of 0.4 mg to date for recurrent abdominal distension after surgical treatment and hyperthermic intraperitoneal chemotherapy.During the follow-up period,apatinib was the maintenance treatment with a progression-free period of 10 mo and the toxicity of apatinib was controllable and tolerable.Unfortunately,recurrence occurred 10 mo after administration.After two operations,the patient gave up treatment at the 18th mo and eventually died of intestinal obstruction and multiple organ failure.CONCLUSION Apatinib may be an option for recurrent PMP after surgical treatment,but this conclusion remains to be confirmed.

SEPTIN9与HOXA9基因甲基化在鉴别阑尾和卵巢来源腹膜假黏液瘤中的诊断价值

目的:腹膜假黏液瘤(pseudomyxoma peritonei,PMP)是一种罕见的腹膜恶性肿瘤综合征,其来源鉴别较困难。本研究旨在探讨SEPTIN9与HOXA9基因在阑尾黏液性肿瘤来源的PMP(appendiceal mucinous neoplasms-PMP,AMNs-PMP)与卵巢黏液性肿瘤来源的PMP(ovarian mucinous tumors-PMP,OMTs-PMP)中的甲基化水平及其对PMP鉴别的意义。方法:采用甲基化特异度聚合酶链反应(methylation-specific polymerase chain reaction,MS-PCR)检测SEPTIN9与HOXA9基因在正常阑尾(appendix control,APD control)组(n=10)、正常卵巢(ovary control,OV control)组(n=17)、AMNs-PMP组(n=40)及OMTs-PMP组(n=19)中的甲基化水平,同时对AMNs-PMP组及OMTs-PMP组的组织样本进行细胞角蛋白(cytokeratin,CK)7、CK20免疫组织化学检测。通过t检验分析SEPTIN9及HOXA9基因甲基化在AMNs-PMP组及OMTs-PMP组中表达差异并分析其与免疫组织化学联合检测的作用及价值。结果:AMNs-PMP组中SEPTIN9基因甲基化的阳性率明显高于OMTs-PMP组(92.5%vs 63.2%,P<0.01);OMTs-PMP组中HOXA9基因甲基化的阳性率显著高于AMNs-PMP组(94.7%vs 12.5%,P<0.001)。OMTs-PMP组中HOXA9基因甲基化的ΔCt值显著低于AMNs-PMP组(3.20±0.47 vs 8.63±0.61,P<0.001)。OMTs-PMP组中CK7的阳性率显著高于AMNs-PMP组(94.7%vs17.5%,P<0.001),AMNs-PMP组中CK20的阳性率显著高于OMTs-PMP组(97.5%vs 63.2%,P<0.001)。CK7(-)CK20(+)与SEPTIN9(+)HOXA9(-)基因甲基化在AMNs-PMP中诊断均有较高的敏感度(82.5%vs 87.5%)和特异度(均为94.7%);CK7(+)CK20(-)与SEPTIN9(-)HOXA9(+)基因甲基化在OMTs-PMP诊断中均有较低的敏感度(均为36.8%)、较高的特异度(97.5%vs 92.5%),而CK7(+)HOXA9(+)在与前2种组合特异度相似的情况下,其敏感度为89.5%,显著高于前二者。结论:SEPTIN9(+)HOXA9(-)可用于AMNs-PMP诊断,CK7(+)HOXA9(+)可用于OMTs-PMP诊断。SEPTIN9与HOXA9基因甲基化可成为AMNs-PMP及OMTs-PMP的潜在生物学标志物。

不同病理分级腹膜假黏液瘤:^(18)F-FDG PET/CT双时相显像表现及血清肿瘤标志物水平

目的对比不同病理分级腹膜假黏液瘤(PMP)^(18)F-FDG PET/CT双时相显像表现及血清肿瘤标志物水平。方法回顾性分析31例经病理确诊阑尾来源PMP患者,根据病理结果分为低级别、高级别及高级别伴印戒细胞PMP。对比不同级别PMP^(18)F-FDG PET/CT常规和延迟显像表现,以及PET/CT检查前1个月内血清癌胚抗原(CEA)、糖类抗原(CA)125及CA 19-9水平。结果31例PMP包括14例低级别、12例高级别及5例高级别伴印戒细胞PMP。^(18)F-FDG PET/CT延迟显像中,低、高级别PMP病灶最大标准摄取值(SUV_(max))、病灶SUV_(max)与肝脏平均标准摄取值之比(SUV_(max)/SUV_(livermean))及PET-腹膜癌指数(PCI)均高于常规^(18)F-FDG PET/CT显像(P均<0.05);延迟显像中,高级别伴印戒细胞PMP病灶SUV_(max)、SUV_(max)/SUV_(livermean)和PET-PCI均与常规显像差异均无统计学意义(P均>0.05)。不同病理分级PMP患者之间,CEA、CA 125及CA 19-9水平差异均无统计学意义(P均>0.05)。结论不同病理分级PMP的^(18)F-FDG PET/CT双时相显像表现具有一定特征性,血清肿瘤标志物水平与PMP病理分级无明显相关。

Asymptomatic low-grade appendiceal mucinous neoplasm:A case report

BACKGROUND Low-grade appendiceal neoplasms(LAMN)are characterized by low incidence and atypical clinical presentations,often leading to misdiagnosis as acute or chronic appendicitis before surgery.The primary diagnostic tool for LAMN is abdominal computed tomography(CT)imaging.Surgical resection remains the cornerstone of LAMN management,necessitating en bloc tumor excision to minimize the risk of iatrogenic rupture.Laparoscopy,known for its minimal invasiveness,reduced postoperative discomfort,and expedited recovery,is a safe and reliable approach for LAMN treatment.Despite the possibility of pseudomyxoma peritonei development,appendectomy and partial appendectomy generally result in negative tumor margins and favorable outcomes,which can be attributed to the disease’s slow growth and lower malignancy.CASE SUMMARY A 71-year-old male patient was admitted to our hospital with a pelvic spaceoccupying lesion detected 1 mo prior.Physical examination showed a soft abdomen without tenderness or rebound and no palpable masses.No shifting dullness was noted,and digital rectal examination revealed no palpable mass.Enteroscopy revealed a raised,smooth-surfaced mass measuring 3.0 cm in the cecum.Abdominal contrast-enhanced CT showed a markedly thickened and dilated appendix with visible cystic shadows.Laparoscopic surgery was performed and revealed a significantly dilated appendix,leading to laparoscopic resection of the appendix and part of the cecum.Post-surgical pathologic analysis confirmed LAMN.The patient received symptomatic and supportive post-operative care and was discharged on postoperative day 4 without complications such as abdominal bleeding,intestinal obstruction,or incision infection.No tumor recurrence was observed during a 7-mo follow-up period.CONCLUSION LAMN is a rare disease that lacks specific clinical manifestations.Abdominal CT plays a crucial role in diagnosing LAMN,and laparoscopic surgery is a safe and effective diagnostic and therapeutic approach.

Visualizing the landscape of appendiceal tumor research after 2010: A bibliometric study

BACKGROUND Despite the rarity of appendiceal tumors,research in this field has intensified,resulting in a growing number of studies and published papers.Surprisingly,no comprehensive bibliometric analysis has specifically addressed appendiceal tumors.AIM To offer a thorough analysis of the current landscape and future trends in appendiceal tumor research.METHODS In our bibliometric analysis studies,we explored the Web of Science Core Collection database.The bibliographic details of the chosen publications were automatically converted and analyzed using the bibliometric package in the R environment.Additionally,we employed VoSviewer to create cooperation network maps for countries,institutions,and authors,as well as clustering maps for keywords.Furthermore,CiteSpace,another software tool,was utilized to build dual-map overlays of journals and analyze references with citation bursts.RESULTS Our study included 780 English-language articles published after 2010.The number of related publications and citations has increased in the past decade.The United States leads in this area,but there is a need to improve cooperation and communication among countries and institutions.Co-occurrence analysis also revealed close collaboration among different authors.Annals of Surgical Oncology was the most influential journal in this field.Analysis of references with high cocitations and references with citation bursts,consistent with analysis of keywords and hotspots,indicated that current research primarily centers on the classification and management of appendiceal mucinous neoplasms and consequent pseudomyxoma peritonei.Despite the abundance of clinical studies,a greater number of in-depth basic research studies should be conducted.CONCLUSION Current research on appendiceal tumors focuses on classification and management of appendiceal mucinous neoplasms and pseudomyxoma peritonei.Enhanced collaboration and basic research are vital for further advancement.

Mucinous neoplasm of the appendix:A case report and review of literature

BACKGROUND Appendiceal mucinous neoplasms(AMNs),although not classified as rare,are relatively uncommon tumors most often discovered incidentally during colorectal surgery.Accurate identification of AMNs is difficult due to non-specific sym-ptoms,overlapping tumor markers with other conditions,and the potential for misdiagnosis.This underscores the urgent need for precision in diagnosis to pre-vent severe complications.CASE SUMMARY This case report describes the unexpected discovery and treatment of a low-grade AMN(LAMN)in a 74-year-old man undergoing laparoscopic hemicolectomy for transverse colon adenocarcinoma(AC).Preoperatively,non-specific gastroin-testinal symptoms and elevated tumor markers masked the presence of AMN.The tumor,presumed to be an AMN peritoneal cyst intraoperatively,was con-firmed as LAMN through histopathological examination.The neoplasm exhibited mucin accumulation and a distinct immunohistochemical profile:Positive for Ho-meobox protein CDX-2,Cytokeratin 20,special AT-rich sequence-binding protein 2,and Mucin 2 but negative for cytokeratin 7 and Paired box gene 8.This profile aids in distinguishing appendiceal and ovarian mucinous tumors.Postoperative recovery was uncomplicated,and the patient initiated adjuvant chemotherapy for the colon AC.CONCLUSION This case highlights the diagnostic complexity of AMNs,emphasizing the need for vigilant identification to avert potential complications,such as pseudomyxoma peritonei.

Advances in the Diagnosis and Treatment of Appendiceal Mucinous Neoplasms

Primary appendiceal neoplasms represent a relatively low percentage of all gastrointestinal cancers. A subset of these neoplasms, those of epithelial origin, are characterised by the production of a considerable amount of mucus, which is referred to as appendiceal mucinous neoplasms (AMN). Appendiceal mucinous neoplasms (AMN) have a low incidence, are easily misdiagnosed, depend on postoperative examination for confirmation of the diagnosis, are prone to form a “diagnosis”, and have a high incidence of the disease. Furthermore, they are prone to form peritoneal pseudomyxoma peritonei (PMP), are controversial in surgical decision-making, are prone to recurring after surgery alone, and are tricky to manage clinically. In this paper, we review the pathological characteristics, diagnosis and treatment of appendiceal mucinous tumours in the light of recent literature reports, with a view to providing certain references for the clinical diagnosis and treatment of this disease. .

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 conven-tional 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.