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. .

Colonoscopy in the diagnosis and management of appendiceal disease

In this editorial,we comment on the article published in the recent issue of the World Journal of Gastrointestinal Endoscopy.We focused on the understanding of appendiceal disease,and the various options for diagnosis and treatment via endoscopy.Some factors affecting the diagnosis and management of appendiceal diseases are also discussed.The existence of any organ has its natural rationality,and the appendix is such a magical organ.A growing number of experts and scholars have gradually come to a consensus that the appendix is not a useless evolutionary relic.There are many lymphocytes and lymph nodes in the appendix wall,which has a strong immune function,and this function is particularly important for children and adolescents.Many intestinal probiotics in the appendix are very helpful for maintaining the balance of the intestinal flora.With the continuous progress of endoscopic technology,endoscopic treatment involving preservation of the appendix has shown great advantages over surgery.In the diagnosis of appendiceal inflammation and neoplasms,colonoscopy,endoscopic retrograde appendicography and choledochoscopy help assess conditions of the appendix.Endoscopic retrograde appendicitis therapy,abscess drainage under colonoscopy,fenestration of abscess under colonoscopy,and endoscopic or natural orifice transluminal endoscopic surgery resection of appendiceal neoplasms are safe and effective endoscopic treatments for appendiceal disease.New breakthroughs in the application of endoscopy in the appendix are expected to occur in the near future.

Evaluation of appendiceal mucinous neoplasms by curved lineararray echoendoscope:A preliminary study

BACKGROUND Preoperative diagnosis of appendiceal mucinous neoplasms is challenging,and there are few reports regarding the endosonographic characteristics of these neoplasms.AIM To provide a retrospective assessment of the imaging features of appendiceal mucinous neoplasms using endoscopic ultrasound(EUS)by curved linear-array echoendoscope.METHODS A database of all patients with appendiceal mucinous neoplasms who had received EUS examination at our hospital between January 2018 and July 2023 was retrospectively analyzed.The EUS characteristics and patients’clinical data were reviewed.RESULTS Twenty-two patients were included in the study.The linear-array echoendoscope successfully reached the ileocecal region in every patient.In the endoscopic view,we could observe the protrusion in the appendiceal orifice in all patients.A volcano sign was observed in two patients,and an atypical volcano sign was seen in two patients.EUS showed that all 22 lesions were submucosal cystic hypoechoic lesions with clear boundaries.No wall nodules were observed,but an onion-peeling sign was observed in 17 cases.CONCLUSION Linear-array echoendoscope is safe to reach the ileocecal region under the guidance of EUS.Image features on endoscopic and echoendosonograhic views could be used to diagnose appendiceal mucinous neoplasms.

Risk of appendiceal neoplasm in patients with appendix disorders

The most common appendicular disease is acute appendicitis,with a lifetime risk of 7%–8%.Complicated cases,which can occur in 2%–7%of patients,can signi-ficantly impact the severity of the condition and may require different manage-ment approaches.Nonoperative management with possible delayed appende-ctomy has been suggested for selected patients,however,there is a non-negligible risk of missing an underlying malignancy,which is reported to be as high as 11%.Diagnostic work-up is paramount to achieve optimal treatment with good results.

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.

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.

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.

Management of incidentally discovered appendiceal neuroendocrine tumors after an appendicectomy

Appendiceal neuroendocrine tumors(aNETs)are an uncommon neoplasm that is relatively indolent in most cases.They are typically diagnosed in younger patients than other neuroendocrine tumors and are often an incidental finding after an appendectomy.Although there are numerous clinical practice guidelines on management of a NETs,there is continues to be a dearth of evidence on optimal treatment.Management of these tumors is stratified according to risk of locoregional and distant metastasis.However,there is a lack of consensus regarding tumors that measure 1-2 cm.In these cases,some histopathological features such as size,tumor grade,presence of lymphovascular invasion,or mesoappendix infiltration must also be considered.Computed tomography or magnetic resonance imaging scans are recommended for evaluating the presence of additional disease,except in the case of tumors smaller than 1 cm without additional risk factors.Somatostatin receptor scintigraphy or positron emission tomography with computed tomography should be considered in cases with suspected residual or distant disease.The main point of controversy is the indication for performing a completion right hemicolectomy after an initial appendectomy,based on the risk of lymph node metastases.The main factor considered is tumor size and 2 cm is the most common threshold for indicating a colectomy.Other factors such as mesoappendix infiltration,lymphovascular invasion,or tumor grade may also be considered.On the other hand,potential complications,and decreased quality of life after a hemicolectomy as well as the lack of evidence on benefits in terms of survival must be taken into consideration.In this review,we present data regarding the current indications,outcomes,and benefits of a colectomy.

Actinomycosis of the appendix mimicking appendiceal tumor:A case report

Actinomycosis is an uncommon chronic infectious disease. Common sites of involvement include the cervicofacial, thoracic and abdominopelvic regions. In abdominopelvic actinomycosis, the ileocecal region, including the appendix, is the most commonly involved site. In some reports, limited appendiceal actinomycosis has revealed a thickened appendiceal wall with peri-appendiceal inflammation as acute appendicitis or perforated appendicitis. We experienced pathologically confirmed intraluminal limited appendiceal actinomycosis without peri-appendiceal infiltration. Here, we report the computed tomography and ultrasound findings.

Mucinous appendiceal neoplasm:A case report

BACKGROUND Primary appendiceal tumors are histologically diverse and have an insidious onset and few specific clinical manifestations.In the majority of cases,these tumors are discovered after appendectomy during pathological exam of the resected tissue.Treatment may include appendectomy(simple or radical)and right hemicolectomy depending on factors such as histological type,tumor size and lymph node/organ involvement.The aim of this case study is to describe a rare case of a giant appendicular mucocele and raise awareness of this condition and its management options and follow-up protocol.CASE SUMMARY We present the case of a 43-year-old patient who presented to our emergency department with mild right lower quadrant pain.After the initial check-up and imaging exams,he underwent surgery,where a giant 20 cm×13 cm appendicular tumor was found and resected.Appendicular mucocele was suspected due to the macroscopic appearance and was later confirmed by the pathological exam.The patient’s postoperative evolution was uneventful,and after discharge,he was included in our follow-up program.CONCLUSION In conclusion,mucinous appendiceal neoplasms embody a rare pathology;they are asymptomatic or have few,unspecific clinical signs and in many cases are discovered after appendectomy.

Treatment of a giant low-grade appendiceal mucinous neoplasm:A case report

BACKGROUND Low-grade appendiceal mucinous neoplasm(LAMN)is extremely rare and easily misdiagnosed before surgery.CASE SUMMARY We report the treatment of an asymptomatic case of LAMN diagnosed by magnetic resonance imaging(MRI)and surgical findings.A 70-year-old woman presented with an adnexal mass found by physical examination in July 2020.Gynecologic ultrasonography revealed a cystic mass in the right adnexa,and computed tomography showed a cystic mass in the pelvic cavity.All tumor markers were normal.A further MRI examination suggested mucinous neoplasm in the right pelvic cavity,excluding the possibility of adnexal cyst.Laparoscopic exploration found a huge cystic mass of about 10 cm×7 cm that originated from the apex of the appendix,with spontaneous rupture.LAMN was confirmed by pathological examination.As of May 2021,no disease recurrence occurred after an open appendectomy.CONCLUSION This case indicates that we should pay more attention to female patients who are clinically diagnosed with an adnexal mass at admission,.The physical examination should be done carefully,and the laboratory and imaging examination results should be comprehensively analyzed to avoid misdiagnosis and to ensure prompt diagnosis and treatment,and to improve prognosis.MRI may be a better option for the diagnosis of appendiceal mucinous neoplasm.

Low-grade mucinous appendiceal neoplasm mimicking an ovarian lesion: A case report and review of literature

BACKGROUND Appendiceal tumors are rare lesions that may not be easily differentiated from primary ovarian lesions preoperatively,despite the use of advanced diagnostic methods by experienced clinicians.CASE SUMMARY A 59-year-old G2P2 woman,with chronic pelvic pain,underwent a pelvic ultrasound that revealed an adnexal mass measuring 58 mm×34 mm×36 mm,with irregular borders,heterogeneous echogenicity,no color Doppler vascularization and without acoustic shadowing.Normal ovarian tissue was visualized in contact with the lesion,and it was impossible to separate the lesion from the ovary by applying pressure with the ultrasound probe.Ascites,peritoneal metastases or other alterations were not observed.With the international ovarian tumor analysis ADNEX model,the lesion was classified as a malignant tumor(the risk of malignancy was 27.1%,corresponding to Ovarian-Adnexal Reporting Data System category 4).Magnetic resonance imaging confirmed the presence of a right adnexal mass,apparently an ovarian tumor measuring 65 mm×35 mm,without signs of invasive or metastatic disease.During explorative laparotomy,normal morphology of the internal reproductive organs was noted.A solid mobile lesion involved the entire appendix.Appendectomy was performed.Inspection of the abdominal cavity revealed no signs of malignant dissemination.Histopathologically,the appendiceal lesion corresponded to a completely resected low-grade mucinous appendiceal neoplasm(LAMN).CONCLUSION The appropriate treatment and team of specialists who should provide health care to patients with seemingly adnexal lesions depend on the nature(benign vs malignant)and origin(gynecological vs nongynecological)of the lesion.Radiologists,gynecologists and other pelvic surgeons should be familiar with the imaging signs of LAMN whose clinical presentation is silent or nonspecific.The assistance of a consultant specializing in intestinal tumors is important support that gynecological surgeons can receive during the operation to offer the patient with intestinal pathology an optimal intervention.

Synchronous Mucinous Borderline Tumor of the Ovary and Low-Grade Appendiceal Mucinous Neoplasm

We present a rare case of synchronous mucinous borderline tumor of the ovary and low-grade appendiceal mucinous neoplasm (LAMN). We performed a left adnexectomy to diagnose the left ovarian borderline malignancy and an ileostomy because of the swollen appendix during the operation. It was diagnosed as left ovarian mucinous borderline malignancy and LAMN. LAMN causes peritoneal dissemination, ovarian metastasis, and peritoneal pseudomyxoma. The appendix and ovary are close to each other anatomically and can metastasize if there is a tumor in either. For ovarian mucinous tumors, it is necessary to search the gastrointestinal tract, especially the appendix, as the primary lesion. For appendix tumors, it is necessary to search for the ovary. Since LAMN may be associated with borderline ovarian malignancies, as in this case, there is a possibility of the duplication of tumors when searching for ovarian mucinous tumors as the primary tumor and if ovarian tumors are found. Since LAMN and mucinous ovarian tumors have similar histological features, immunohistochemical staining is useful for their differentiation because they show different immunostaining patterns.

Prognostic impact of number of examined lymph nodes on survival of patients with appendiceal neuroendocrine tumors

BACKGROUND The prognosis of patients with appendiceal neuroendocrine tumors(ANETs) is related to lymph node(LN) metastasis and other factors.However,it is unclear how the number of examined LNs(ELNs) impact on survival.AIM To determine the factors affecting the cancer-specific survival(CSS) of patients with ANET and to evaluate the impact of the number of ELNs on survival.METHODS A total of 4583 ANET patients were analyzed in the Surveillance,Epidemiology,and End Results database.Univariate survival analysis was used to identify factors related to survival and the optimal number of ELNs and lymph node ratio(LNR) were determined by the Kaplan–Meier method.The survival difference was determined by CSS.RESULTS Except for sex,the other factors,such as age,year,race,grade,histological type,stage,tumor size,ELNs,LNR,and surgery type,were associated with prognosis.The 3-,5-,and 10-year CSS rates of ANET patients were 91.2%,87.5,and 81.7%,respectively(median follow-up period of 31 mo and range of 0-499 mo).There was no survival difference between the two surgery types,namely,local resection and colectomy or greater,in both stratifications of tumor size ≥ 2 cm(P = 0.523)and < 2 cm(P = 0.068).In contrast to patients with a tumor size < 2 cm,those with a tumor size ≥ 2 cm were more likely to have LN metastasis(χ~2 = 378.16,P < 0.001).The optimal number of ELNs was more than 11,7,and 18 for all patients,nodenegative patients,and node-positive patients,respectively.CSS rates of patients with a larger number of ELNs were significantly improved(≤ 10 vs ≥ 11,χ~2 =20.303,P < 0.001;≤ 6 vs ≥ 7,χ~2 = 11.569,P < 0.001;≤ 17 vs ≥ 18,χ~2 = 21.990,P < 0.001;respectively).ANET patients with an LNR value ≤ 0.16 were more likely to have better survival than those with values of 0.17-0.48(χ~2 = 48.243,P < 0.001) and 0.49-1(χ~2 = 168.485,P < 0.001).CONCLUSION ANET ≥ 2 cm are more likely to develop LN metastasis.At least 11 ELNs are required to better evaluate the prognosis.For patients with positive LN metastasis,18 or more LNs need to be detected and lower LNR values(LNR ≤ 0.16) indicate a better survival prognosis.

A Case of Low-Grade Appendiceal Mucinous Neoplasm of Its Difficultly to Distinguish from a Right Ovarian Tumor Due to Postmenopause

We here present a rare case of appendiceal tumor mimicking ovarian tumor in menopause woman. The patient was a 56-year-old woman, G1P1, who presented to our hospital with a right adnexal cyst diagnosed at another hospital. Transvaginal echocardiography showed a cyst in the right adnexal region, and pelvic contrast-enhanced MRI revealed a small cyst in the same region. The left ovary was atrophic and identifiable. It was unclear whether the cyst was contiguous with the gastrointestinal tract. Blood tests showed no elevation of tumor markers. We considered its possibility of a gastrointestinal origin, but since right normal ovary was not found, we thought the tumor was of ovarian origin and decided on a laparoscopic resection of the right adnexa. Intraoperatively, we observed atrophied bilateral normal ovaries, and the pelvic tumor was contiguous to the appendix. Surgeons performed a laparoscopic appendectomy after consultation with us. After resection we searched the abdominal and pelvic cavities, but found no obvious disseminated lesions. The histological diagnosis was low-grade appendiceal mucinous neoplasm (LAMN), a rare benign tumor of the appendix. Appendiceal tumors can be difficult to differentiate from right ovarian tumors due to their close anatomic location in the pelvis. It is possible to determine whether the tumor is of ovarian or appendiceal origin by identifying normal ovaries and the location of the feeding vessels into the tumors. In our case, there were no lesions other than the appendix, but LAMN can metastasize to the ovary, cause pseudomyoxoma peritonei, or be an overlapping tumor with an ovarian tumor. If an appendiceal tumor is diagnosed after surgery for ovarian tumor, the intra-abdominal cavity should be searched for metastasis or dissemination, and a thorough search for ovarian lesions should be performed with the possibility of an overlapping tumor in mind.

Low Grade Appendiceal Mucinous Neoplasm Presenting as a Mucocoele of the Appendix

Low grade appendiceal mucinous neoplasm (LAMN) is a rare malignancy with incidence of 0.7% to 1.7% of all appendicectomies [1]. LAMN has the worst complication of mucin seeding into adjacent peritoneum leading to pseudomyxoma peritonei. LAMN lacks standardised treatment approach where only appendicectomy is preferred for resection of non metastatic disease. Case Presentation A 38 yr old female presented with right lower quadrant where CT Abdomen revealed Mucocele of Appendix. Patient underwent Laparoscopic Appendicectomy and Histopathological examination revealed Low grade appendiceal mucinous neoplasm. Patient is on regular follow up and is disease free. Conclusion low grade appendiceal mucinous neoplasm is usually an incidental finding where treatment depends on staging and histology of the tumour.

Bowel mesentery(meso-appendix) microcystic/reticular schwannoma: Case report and literature review

Microcystic/reticular schwannoma is a recently described variant of schwannoma with a predilection for the gastrointestinal tract. Due to overlapping features with other tumors, unawareness of this tumor type may lead to diagnostic and therapeutic pitfalls. We here report a case of microcystic/reticular schwannoma arising in the meso-appendix of a 43-year-old woman. The tumor was incidentally discovered by computed tomography scan for unrelated reasons. A laparoscopic operation was performed shortly after admission. Histological examination revealed a circumscribed tumor with a striking microcystic and cribriform architecture. Immunohistochemically, the tumor cells were diffusely positive for S100 protein, glial fibrillary acid protein and protein gene product 9.5, which were consistent with a peripheral nerve sheath tumor. The patient remains well with no signs of recurrence at a 10-mo follow-up. To our knowledge, this is the first case of microcystic/reticular schwannoma arising in the meso-appendix. Albeit very rare, microcystic/reticular schwannoma should be included in the differential diagnosis of appendiceal tumors.

Primary signet ring cell carcinoma of the appendix:A rare case report and our 18-year experience

Primary adenocarcinoma of the appendix is a rare malignancy that constitutes 〈 0.5% of all gastrointestinal neoplasms. Moreover, primary signet ring cell carc noma of the appendix is an exceedingly rare entity. We have encountered 15 cases of primary appendiceal cancer among 3389 patients who underwent appen- dectomy over the past 18 years. In the present report, we describe a rare case of primary signet ring cell carcinoma of the appendix with ovarian metastases and unresectable peritoneal dissemination occurring in a 67-year-old female patient. She underwent ap- pendectomy and bilateral salpingo-oophorectomy with a laparoscopy procedure. She then received palliative systemic chemotherapy with 12 cycles of oxaliplatin, 5-flurorouracil, and leucovorin （FOIFOX-4）. The patient currently is well without progression of disease 12 mo after beginning chemotherapy.

Late recurrence and metastasis of an appendiceal goblet cell carcinoid 24 years after appendectomy

A 36-year-old woman presented with right iliac fossa pain in March 1988.Abdominal ultrasound showed nothing unusual and an appendectomy was performed for acute appendicitis.The resected appendix appeared inflamed without perforation.No enlarged lymph nodes were seen during surgery.Microscopic examination of the resected specimen showed acute appendicitis and a tumor in the lamina propria and submucosal layer,infiltrating to the deep muscular layer.Groups of four to ten tumor cells were arranged in small clusters which lacked central lumens and were widely separated by stroma.The tumor cells,which were distended with mucin and had crescentic nuclei,resembled signet ring cells （Figure 1A）.Keywords：recurrence; metastasis; appendiceal neoplasm; appendectomy; carcinoid tumor

Clinical and pathological features of follicular dendritic cell sarcoma of appendix： a case report

Follicular dendritic cell sarcoma （FDCS） is a rare spindle cell neoplasm usually identified as lymph node-based neoplasm that occasionally occurs in extranodal regions. It was first characterized by Monda et al in 1986. In the present report, we describe the first case of FDCS arising from the appendix.