Grade Appendiceal Mucinous Neoplasm Research Articles

The risk of developing pseudomyxoma peritonei from a non-perforated low grade appendiceal mucinous neoplasm found at appendicectomy

IntroductionLow-grade appendiceal mucinous neoplasms (LAMNs) are classified as non-perforated (pTis, pT3) or perforated (pT4), and considered precursors of pseudomyxoma peritonei (PMP). This study aims to quantify the risk of developing PMP from pTis and pT3 LAMNs. Materials and methodsRetrospective analysis of a prospectively collected database identified LAMN patients referred to a specialist centre from 2004 to 2019. pT4 LAMNs and other appendix tumours were excluded. All patients had specialist review of their pathology, operation note, and a CT scan (at least 6 weeks post-operatively). Surveillance CTs were then performed at 6, 12, 24, 36, 48, & 60 months, with tumour markers (CEA, CA19-9, CA125). Results193 pT3/pTis LAMN patients were included (pTis = 153, pT3 = 40). Median follow-up = 6.45 (3.91–22.13) years, M:F ratio = 1:1.57, and median age = 57 (23–83) years. Initial surgery included: appendicectomy (67 %), appendicectomy + visceral resection (6 %), and right hemicolectomy (27 %). R1 resections were identified in 5/193 patients (2.5 %). 3 R1 patients underwent re-operation (2 caecal pole excision and 1 ileocecectomy), none of which had residual tumour. 8/193 patients (4 %) were lost to follow up. None of the remaining 185 developed PMP. ConclusionThis is the largest reported series of pTis/pT3 LAMNs with standardised follow-up in the literature. LAMNs correctly classified as pT3/pTis (after careful specialist review of pathology, operation note, and a baseline post-operative CT) have negligible risk of developing PMP and should have low intensity surveillance. If completely excised, further surgery is not indicated. R1 resections should be considered on an individual basis at a specialist centre.

Survival among 148 patients with an incidentally detected appendiceal tumours at surgery for acute appendicitis: a population-based cohort follow-up study.

To investigate the long-term prognosis of appendiceal tumours incidentally detected at appendicectomy for suspicion of benign appendicitis. A retrospective register-based single centre cohort study was carried out, using data from the local acute appendicectomy quality register of cases operated on at the Department of Surgery, South General Hospital, Stockholm, Sweden. The local colorectal cancer register was also used to identify appendix tumours. The study period was between January 2004 and January 2023. Survival was calculated according to the Kaplan-Meier method. A total of 11,888 patients were registered in the acute acute appendicectomy register, 54% males and 46% females, median age 32 (Q1 = 21, Q3 = 47) (with 33.7% were 41 years or older). From the appendicectomy and colorectal registers 148 (1.2% of the total cohort) appendiceal tumours were found; 60% in females and 40% in males, median age 56 (Q1 = 43, Q3 = 70) (with 78.4% being 41 years or older). Tumours found were: Low grade Appendiceal Mucinous Neoplasms (LAMN, N = 64); Neuroendocrine Tumours (NET N = 24); adenocarcinomas or other form of carcinomas (N = 57); and adenomas (N = 3). The overall 5-year survival in patients operated for LAMN was 96.8%, for NET 93.3% and for adenocarcinoma 69.7%. The overall 5-year survival for all tumour patients was 85.7%. For the younger patients (< 51 years) with LAMN and NET, almost all survived to the end of follow-up. Survival of patients in the carcinoma group was statistically significantly lower than for the LAMN and NET groups, especially in females 51 years or older. In the group of tumour patients undergoing surgery (n = 146), primary surgery was laparoscopic in 47% and open in 52%. Two patients did not undergo surgery due to widespread disease. In 64% of cases operation was acute, whereas it was delayed and/or planned in 34%. Most procedures were laparoscopic appendicectomy 36%, followed by open appendicectomy 30%, right-sided hemicolectomy 14.6% (open 11.6% and laparoscopic 3%, acute operation 5.5%), ileocaecal resection 5% (acute operation 3.4%), and staging laparoscopy 7%. In 38% of the operated patients the tumour was discovered incidentally at histopathology examination. Two patients had CRS and HIPEC as the initial operation. Forthy-three per cent of the 146 tumour patients operated underwent a second procedure: CRS and HIPEC in 23.3% and right-sided hemicolectomy in 13.6% (laparoscopic 8.2% open 5.4%). Survival was high for patients with incidentally detected appendiceal LAMN or NET, but not so for carcinoma. Survival was lower in the carcinoma group older than 50 years, especially those sick and females.

Mucinous carcinoma of the appendix: a case report

Mucinous carcinoma of the appendix is ​​​​a rare malignant tumor of the appendix. Incidence ranges about 0.01-0.2% in cases of malignancy in the gastrointestinal tract. Clinically, the symptoms appear to resemble acute appendicitis. The diagnosis was established at intraoperative time. Studies on this case are still few. A 69-year-old man complained of lower right abdominal pain since 6 days before going to Sanjiwani hospital. The patient also complained of fever, nausea, decreased appetite and constipation. Examination results temperature 37.6 0C, McBurney sign (+), rebound tenderness (+), localized defense on lower right abdomen. Ultrasound examination of the abdomen with an impression of the end tubular structure, a peristaltic diameter of 0.87 cm accompanied by a fluid collection, suspicious of appendicitis with perforation. Inflamed appendix and localized mucin were found at ileocaecal junction intraoperatively. The patient underwent a right hemicolectomy. Histopathological examination revealed a morphological picture suitable for mucinous carcinoma of the appendix. Mucinous carcinoma of the appendix is ​​​​a rare malignant tumor of appendix. Patients can have the same symptoms as appendicitis. Ultrasound investigations can find a picture like appendicitis. Mucinous carcinoma of the appendix is ​​more frequently found intraoperatively. Histopathological examination is necessary to determine a definitive diagnosis of mucinous carcinoma of the appendix. In high grade appendiceal mucinous neoplasm (HAMN) a right hemicolectomy can be performed and continued with adjuvant chemotherapy.

Non-inflamed appendix with LAMN causing closed-loop small bowel obstruction

Introduction: Low grade appendiceal mucinous neoplasms are generally encountered incidentally in appendicectomies for suspected appendicitis. This case is a documentation of a rare occurrence of LAMN presenting with small bowel obstruction. Case Report: An 83-year-old male presented to the Emergency Department with a three day history of nausea, vomiting, and obstipation and profoundly dehydrated. Computed tomography revealed a high grade small bowel obstruction with 2 transition points in the right iliac fossa, concerning for closed loop obstruction, necessitating an urgent laparotomy. Conclusion: While acute appendicitis is a common cause of emergency abdominal pathology, when coupled with small bowel obstruction, a neoplastic cause should be considered as part of the differential diagnosis.

Mucocele of the Anorectal Pouch: Mucinous Cystic Neoplasm with Low-Grade Dysplasia Simulating Low- Grade Appendiceal Mucinous Neoplasm (LAMN)

Abstract Introduction/Objective We present the second case of colonic mucocele with dysplasia. To date, only five cases of colonic mucocele have been reported, all in the setting of a pouch or bypass, with only one of them showing dysplasia. The exceptional rarity of the lesion provides unique insight into etiology of mucocele. Methods/Case Report A 44-year-old male with complex surgical history including pull-through procedure for imperforate anus at birth, and later proctectomy with end colostomy due to poor anorectal function, presented with worsening low back pain radiating down to his left leg. An abdominal CT scan revealed a large pelvic cyst, causing compressive neuropathy. Multilocular cystic mass (17.5 cm) was resected, which was partially filled with mucinous material. Mucin was not seen on the cyst surface. On microscopic examination, the cyst was largely denuded however was partially lined by markedly attenuated ano-rectal type mucosa and focally by dysplastic glandular epithelium. Similar to LAMN, pools of acellular mucin dissecting stromal tissues were noted, associated with degenerative changes, calcifications and fibrosis. No invasive carcinoma or high-grade dysplasia was seen. Given the lack of extra- cystic mucin or evidence of overt malignancy, it was reported as mucinous cystic neoplasm with uncertain malignant potential. The patient has been followed for 16 months without evidence of recurrence or peritoneal disease. Results (if a Case Study enter NA) NA Conclusion Extended stasis within a bowel segment appear to contribute to the development of mucoceles. The blind-ended anatomy of the appendix renders it highly susceptible to this phenomenon, explaining the relatively high incidence of LAMN. Conversely, such prolonged stasis rarely occurs elsewhere in colon unless a pouch or bypassed segment is surgically created, particularly placing patients with a complex surgical history at the highest risk. Therefore, close follow-up is indicated in this patient group to screen for mucocele that may progress to develop dysplasia and mucinous neoplasm.

Subtotal and Total Colectomy as a One-Stage Surgical Treatment for Malignant Left-Sided Colonic Obstruction

Abstract Aim: We conducted this retrospective study in order to evaluate the short- and long-term results of Subtotal/Total Colectomy (STC/TC) and primary anastomosis for the treatment of occlusive left colon cancer. Methods: Data were retrospectively collected from the medical records from general surgery clinic in January 2016 to June 2022 period. The study included patients diagnosed with acute colonic occlusion produced by tumor located from the splenic flexure to the rectosigmoid junction. Results: During the study period, 40 patients who underwent STC/TC and primary anastomosis were included in the study. According to the Clavien-Dindo grades, major complication rate was 17.5%. Seven patients (17.5%) had synchronous adenocarcinoma. Adenoma was detected in 11 of 40 patients, and 18.1% of them were reported as high-grade dysplasia. Besides, incidental low grade appendiceal mucinous neoplasm was reported in one patient. Ischemia and perforation of proximal colon was found in 28 cases (70%). No patient had anastomotic leak. After one year of surgery, the average defecation was two stools per day. Three-year OS was 92.3% in stage II and 68.7% in stage III. There was no survival more than three years in stage IV patients. The three-year overall disease- free survival was 90.6%. Conclusion: Treatment of obstructive left colon cancer using STC/TC and primary anastomosis is a confident method resulting in a good bowel function. The method allows the resection of synchronous tumors. Besides, it removes the proximal colon with ischemic lesions, serosal tears and filled with stool.

Diagnostic pitfalls in low grade appendiceal mucinous neoplasms

Primary neoplasms of the appendix are present in less than 2% of appendicectomy specimens. Appendiceal mucinous neoplasm is a rare malignancy which is found in less than 0.3% of appendicectomy specimens and accounts for around 1% of gastrointestinal neoplasms. These have varying malignant potential and include a heterogeneous group of diseases. According to the WHO 5th edition (2019), the neoplastic spectrum of appendiceal mucinous neoplasms comprise of low-grade appendiceal mucinous neoplasms (LAMNs), high grade appendiceal mucinous neoplasms (HAMNs), and mucinous adenocarcinoma of the appendix. The patients with mucinous appendiceal lesions are frequently operated for symptoms resembling acute appendicitis as they lack specific clinical and imaging presentation. Categorisation of these neoplasms with attention to extent of mucin and neoplastic cells is crucial to stage the disease as well as to assess the risk of pseudomyxoma peritonei (PMP), a life threatening complication with poor prognosis. We present 8 LAMNs including a rare case of synchronous mucinous cystadenoma of ovary and LAMNs. We discuss the different clinical presentations and the challenges faced in diagnosis.

Laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: Long term oncologic outcomes from the international PSOGI registry

The laparoscopic approach for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (L-CRS + HIPEC) in highly selected patients was previously reported from the PSOGI registry with a demonstrable reduction in length of stay and post-operative morbidity. This study aims to update this international PSOGI registry with a larger cohort of patients and a longer follow-up period. MethodsAn international registry was designed through a networking database (REDCAP®). All centers performing L-CRS + HIPEC were invited through PSOGI to submit data on their cases. Variables such as demographics, clinical outcomes, and survival were analyzed. ResultsA total of 315 L-CRS + HIPEC cases were provided by 14 worldwide centers. A total of 215 patients were included in the L-CRS + HIPEC group. The median peritoneal cancer index (PCI) was 3 (3–5). The median length of stay was 7 days (5-10) and the major morbidity (Clavien-Dindo ≥3) was 6.1% after 30 days. The 5-year disease-free survival (DFS) per tumor origin was: 94% for PMP-LG, 85% for PMP-HG, 100% for benign multicyst peritoneal mesothelioma (MPM), 37.4% for colonic origin, and 54%(at 3 years) for ovarian origin. The 5 years overall survival (OS) per tumor origin was: 100% for PMP-LG, PMP-HG and MPM; 61% for colonic origin, and 74% (at 3 years) for ovarian origin.In addition, a total of 85 patients were analyzed in the laparoscopic risk-reducing HIPEC (L-RR + HIPEC). The median length of stay was 5 days (4–6) and the major morbidity was 6% after 30 days. The 5-year DFS per tumor origin was: 96% for perforated low grade appendiceal mucinous neoplasm (LAMN II) and 68.1% for colon origin. The 5 years OS per tumor origin was: 98% for LAMN II and 83.5% for colonic origin. ConclusionsMinimally invasive CRS + HIPEC is a safe procedure for selected patients with peritoneal carcinomatosis in specialized centers. It improves perioperative results while providing satisfactory oncologic outcomes. L-RR + HIPEC represents a promising strategy that could be evaluated in patients with high risk of developing peritoneal carcinomatosis into prospective randomized trials.

Combined appendiceal goblet cell adenocarcinoma and low grade appendiceal mucinous neoplasm: a case report

Appendiceal goblet cell adenocarcinomas (GCA) are rare entities with a distinctive composition of goblet, paneth and neuroendocrine cells. Cases of combined or collision GCAs and other appendiceal tumours exist in the literature, with only a few publications describing combined GCA and low-grade mucinous neoplasm (LAMN). A 73-year-old female underwent a right hemicolectomy following an appendiceal orifice polypectomy showing adenocarcinoma. Histological examination revealed combined GCA and LAMN at the orifice, and LAMN in the remaining appendiceal mucosa. By immunohistochemistry, the GCA showed CK20, synaptophysin and chromogranin reactivity. Grading was performed using the WHO-recommended three-tiered system based on the proportion of low and high-grade morphological features. Current views of GCA and appendiceal neoplasm biology revolve around the unitary hypothesis of neoplasia arising from a pluripotent progenitor cell. This is supported by the observation of varied morphological components at primary and metastatic disease sites, and shared expression of several differentiation markers among appendiceal neoplasms. Genomic studies have shown that appendiceal neoplasms acquire different mutations during tumourigenesis culminating in entities with distinct mutational profiles. Prospective studies into GCA-specific optimal treatment regimens are lacking, and current treatment strategies have been extrapolated from those of appendiceal and colon adenocarcinomas, despite having different pathological molecular signatures.

Mucinous neoplasms of the appendix - A clinicopathologic study of 21 cases with special insight into current classification &amp; controversies.

Background : Appendiceal mucinous neoplasms are rare and heterogenous disease which often clinically present as appendicitis. There are many controversies regarding the classification of mucinous neoplasms of the appendix.&#x0D; Aims and Objectives: Our aim of this study was to study different types of mucinous neoplasms of appendix based on current ( WHO 2019) classification, their clinical and radiological presentations and controversies regarding their diagnosis.&#x0D; Materials and Methods: This was a retrospective study done in a tertiary care hospital. We studied clinical presentations of 21 cases along with the histopathological study of respective appendectomy specimens .&#x0D; Results: Out of 21 cases, 3 (14.28%) cases were serrated polyp, 9 cases (42.85%) were Low grade appendiceal mucinous neoplasm (LAMN), 3 cases (14.28%) were high grade appendiceal neoplasm (HAMN) and 6 (28.57%) cases were mucinous adenocarcinoma. In this study we have discussed in brief about regarding the current classification and controversies of appendiceal mucinous neoplasms.&#x0D; Conclusion: Mucinous neoplasms of the appendix are complex lesions with many controversies. Oversimplification in the recent classification may add to more complexity. Reintroduction of the old terminology of Mucinous Tumour of Uncertain Malignant Potential might save histopathologists from potential litigation.

High Grade Appendiceal Mucinous Neoplasm Presenting as Intussusception In an Elderly Female-A Case Report

Introduction: Appendiceal mucinous neoplasms (AMNs) are rare and account for 1% of gastrointestinal neoplasms and the diagnosis is mostly incidental. In spite of advances in the understanding of AMNs and their association with peritoneal disease, AMNs are still confusing entities in respect to their diagnosis and treatment alike.&#x0D; Case Report: We report a case of a 51year old female who presented with abdominal pain and vomiting and was diagnosed as ileo-colic intussusception on ultrasonography and CECT abdomen. Histopathological examination of right hemicolectomy specimen revealed a high grade appendicular mucinous neoplasm with low grade areas. The peri-appendiceal mucin deposition forming a mass in the cecum at the base of appendix was the lead point for intussusception in this case. No features of pseudomyxoma peritonei was seen in this case. This patient is well after 18 months of follow up period.&#x0D; Conclusion: Appendiceal mucinous neoplasms are rare and diagnosis is often difficult as presentation is mostly non-specific. Hence, awareness and further classification of these tumours is essential for diagnosis, determining the risk of recurrence and malignancy and also prognostication.

Incidental Appendiceal Tumors During Appendectomy: A Nineteen-Year Retrospective Review at a Municipal Hospital.

Non-operative management of appendicitis (NOMA) has recently gained popularity, but a concern is that NOMA might miss appendiceal neoplasms. We conducted a retrospective review of 1694 appendectomies done for acute appendicitis at our institution between January 2001 and December 2019 to study the incidence and distribution of appendiceal tumors. We identified 24 appendiceal neoplasms (1.43%), including 9 Low Grade Appendiceal Mucinous Neoplasms (LAMNs), 6 neuroendocrine tumors (NETs), 6 mucoceles, and one each of adenocarcinoma, endometrioma, and neurofibroma. Tumor occurrence had two age peaks, with LAMNs prominent in the 5th and 6th decades of life and NETs in the 2nd and 3rd decades. All patients under age 40 had benign disease. Presence of appendicoliths was independent of the presence of neoplasms. All cases were managed per National Comprehensive Cancer Network (NCCN) guidelines, with twenty cases cured by appendectomy alone. Given these, we conclude that NOMA is safe for patients under 40.

A rare case of a Low Grade Appendiceal Mucinous Neoplasm in a 46-year-old Middle Eastern female - A case report.

Introduction and importanceMucinous cell neoplasia are rare and conceivably fatal causes of surgical abdomen. Adult manifestations can be obscure and ill-defined, yielding misdiagnoses and wasting precious time and effort to reach the correct one. Clinical awareness ought to be present once presented with a surgical abdomen in such a patient because this neoplasm may present with misleading presentations which mask the actual diagnosis and masquerade as a different one, and in turn, may result in performing a dissimilar treatment intervention. Rapid learnt surgical judgments must be taken and put into action to diminish the morbidity and mortality consequential to this pathology.Case presentationOur case is of a 46-year-old female, who was admitted into our hospital with a 2-month-history of general fatigue. Colicky abdominal pain and discomfort developed shortly prior to admission. Multi-Slice Computed Tomography (MSCT) scan exposed cystic formation in the terminal ileum. Exploratory laparotomy was warranted, in addition to performing a right hemicolectomy.Clinical discussionWe treated our patient via open surgery and performing an appendectomy with right hemicolectomy in addition to the excision of several surrounding lymph nodes. Diagnosis is traditionally reached intraoperatively relying on gross morphology and postoperatively through histopathological analysis of the excised specimens.ConclusionLow Grade Appendiceal Mucinous Neoplasm is a scarce entity and varies critically in its manifestations, hence, it is existential to thoroughly study this kind of neoplasia, document it, and consider it, so that we can construct precise decisions to reach ideal results for patients who suffer from this neoplasm.

STUDY ON INCIDENCE AND MANAGEMENT OF APPENDICULAR MALIGNANCY IN PATIENTS UNDERGOING APPENDICECTOMY IN A TERTIARY CARE HOSPITAL

AIMS: To study the incidence and management of appendicular malignancy in patients undergoing appendicectomy in a tertiary care hospital METHODS: A retrospective study including 1,275 patients who were admitted in JSS hospital, under surgery department, between September 2016 to September 2021. Patients were ≥ 16 years, any gender who presented with pain abdomen, abdominal distension, fever, vomiting, or mass per abdomen, diagnosed as appendicitis or appendicular mass. Patients underwent laparoscopic/open appendicectomy or right hemicolectomy, based on intraoperative ndings. The specimen was sent for histopathological examination and followed up for further management if required. RESULTS: Among 1275 patients who underwent appendicectomy either open or laparoscopy, following histopathological examination of all the appendicectomy specimens, appendicular malignancy was reported in 7 patients (0.53). All 7 patients had complaints of pain in the right iliac fossa. On examination, 71.4% had tenderness in the right iliac fossa. Most common preoperative provisional diagnosis was acute appendicitis (57.1%). 3 patients underwent laparoscopic appendicectomy, 1 open appendicectomy, and based on intraoperative ndings, 2 underwent right hemicolectomy, 1 resection and anastomosis with ileostomy as metastasis was present. Histopathologically, 2 patients were diagnosed with adenocarcinoma appendix, 2 with low grade appendiceal mucinous neoplasm, 2 with metastatic mucinous adenocarcinoma and 1 patient with neuroendocrine tumour of appendix CONCLUSION: Appendiceal tumors are uncommon, majority are comprised of epithelial neoplasms. Present with abdominal pain, manifest as acute appendicitis, or incidentally discovered in appendectomy specimens during histopathological evaluation. Imaging ndings are suggestive of acute appendicitis mostly. CT is used for staging of appendiceal tumors and subsequent follow up. In majority, appendicectomy will be sufcient, and some require right hemicolectomy. Cytoreductive surgery and intraperitoneal chemotherapy have improved the prognosis of patients with peritoneal disease.

Low grade appendiceal mucinous neoplasm

Low grade appendiceal mucinous neoplasm (LAMN) is a rare tumour which lacks usual form of destructive invasion but has ability to spread to peritoneum and ovaries which frequently progresses to pseudomyxoma peritonei and often result in death of patient despite the bland histology of the mucinous epithelium. There are lot of controversies about its classification, clinical significance of pseudomyxoma peritonei, whether ovarian mucinous tumours in this setting are separate primaries or are the metastasis from the appendiceal tumours which are to be solved. We reported two cases of LAMN in which first case was with pseudomyxoma peritonei with secondary involvement of left ovary while other was simple LAMN without any involvement. Whenever we diagnosed LAMN it is necessary to look for ovarian involvement and pseudomyxoma peritonei.It is necessary to rule out ovarian involvement and pseudomyxoma peritonie whenever we diagnosed LAMN. The unified approach of grading pseudomyxoma peritonei is required for more standardized and prognostically valuable diagnostic reporting.

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.

Clinicopathological analysis and surgical strategy of primary appendiceal neoplasms

Objective: To investigate the clinicopathological features, surgical methods and prognosis of primary appendiceal neoplasms. Methods: A descriptive case series study was performed. Clinical data of patients diagnosed with primary appendiceal neoplasms in Peking University First Hospital from 2006 to 2017 were retrospectively analyzed. Patients who underwent surgery and were confirmed as appendiceal neoplasms by postoperative pathology were included. Cases of cecal tumor invading the appendix and other organ tumors implanting in the appendix and cases of recurrent appendix tumors were excluded Pathological classification was based on the 4th edition of the WHO classification of digestive tract tumors (2010 edition), and the efficacy of operation methods of low grade appendiceal mucinous neoplasm (LAMN) were analyzed. Results: A total of 115 patients were enrolled, including 52 males and 63 females with a median age of 59 (51, 71) years. Clinical symptoms usually manifested as dormant pain in the right lower quadrant, migrating right lower abdominal pain, fever and bloating. Twenty-four cases were accidentally discovered during surgery, and 21 cases were found by physical examination. The preoperative diagnosis rate of CT and ultrasound was 40.2% (43/107) and 25.5% (24/94) respectively. The postoperative pathological types contained 83 cases of LAMN, 12 cases of mucinous adenocarcinoma, 9 cases of appendiceal neuroendocrine neoplasms (aNEN), 2 cases of mucinous adenocarcinoma with signet ring cells, 3 cases of serrated adenoma, 2 cases of goblet cell carcinoid, 2 cases of lymphoma, 1 case of leiomyoma and 1 case of schwannomas. All the patients underwent surgical resection, including 41 cases of appendectomy, 21 cases of partial cecectomy, 48 cases of right hemicolectomy, and 5 cases of combined organ resection due to appendiceal tumor infiltration or dissemination. Eighteen cases were diagnosed with pseudomyxoma peritonei (PMP) during operation. A total of 98 patients were enrolled for follow-up. The median follow-up time was 58 (5-172) months. The 5-year disease-free survival (DFS) rate was 84.5% and 5-year overall survival (OS) was 88.2%. Multivariate analysis revealed that high-grade malignancy tumors (HR=25.881, 95% CI: 2.827-236.935, P=0.004) and PMP formation (HR=42.166, 95% CI: 3.470-512.439,P=0.003) were independent risk factors for prognosis. Patients undergoing right hemicolectomy presented longer operation time, more blood loss and higher morbidity of complication as compared to those undergoing appendectomy and partial cecectomy (all P<0.05), while no significant differences in 5-year DFS (P=0.627) and 5-year OS (P=0.718) were found. Conclusions: Primary appendiceal neoplasms usually have no typical features, accompanied with low preoperative diagnosis rate. The common pathological types are LAMN, mucinous adenocarcinoma and aNEN. Appendectomy or partial cecectomy for LAMN may achieve satisfactory prognosis. High-grade malignancy tumors and PMP formation are independent risk factors for prognosis.

Progression to pseudomyxoma peritonei in patients with low grade appendiceal mucinous neoplasms discovered at time of appendectomy

BackgroundThe discovery of a low grade appendiceal mucinous neoplasm (LAMN) during appendectomy is a rare scenario. These neoplasms can progress to pseudomyxoma peritonei (PMP), however the incidence of progression is not well known. MethodsThe records of all patients with a diagnosis of localized LAMN found during appendectomy were identified, and demographic, tumor, surveillance, and outcome variables were analyzed. ResultsProgression to PMP occurred in 20% of patients in an average of 12.4 months after appendectomy with median follow-up of 18 months. Tumor variables such as margin positivity, appendiceal perforation, and presence of extra-appendiceal acellular mucin or mucinous epithelium on the serosal were not significantly associated with progression. ConclusionsDuring an average follow-up period of 18 months after surgery, progression to PMP occurred in a fifth of patients. It is difficult to predict which patients will progress, therefore cross-sectional imaging surveillance is recommended for all patients.

A case of Pseudomyxoma Peritonei of an unexpected origin

BackgroundPseudomyxoma peritonei (PMP) is a complex and partially understood disease defined by mucin deposits in the peritoneal cavity, mostly of appendiceal origin caused by the rupture of a mucocele often containing Low or High grade Appendiceal Mucinous Neoplasm (LAMN/HAMN). Other origins include primitive ovarian mucinous cystadenoma or cystadenocarcinoma almost always with an associated teratoma, but to our knowledge no case of ovarian teratomatous appendiceal-like mucocele with LAMN has been reported as a cause of PMP.Case presentationA 25-year old female with infertility was diagnosed with an isolated left ovarian tumor in a context of PMP. Histological examination revealed an ovarian teratoma containing an appendiceal-like structure with mucocele and LAMN, without any associated lesion of the appendix on full histological analysis. Molecular characterization of the ovarian lesion showed co-KRAS and GNAS mutations, as described in PMP of appendiceal origin, while only KRAS mutations are reported in primitive ovarian mucinous tumor.ConclusionsDetection of co-KRAS and GNAS mutations in our case of ovarian teratomatous appendiceal-like mucocele with LAMN shows that when PMP derives from a mucinous ovarian lesion (with histological proof of none-appendiceal involvement), it is probably of a digestive teratomatous origin, emphasizing the need to actively search for tetatomatous signs in a context of ovarian PMP.

EP.FRI.247 Incidence and diversity of the primary appendiceal tumours in patients presenting with acute appendicitis: Our Experience

Abstract Background Primary appendiceal tumours are rare. Our experience with the incidental primary appendiceal tumours and their histological diversity. Patients and Method Operative and pathological databases of appendicectomies for presumed diagnosis of acute appendicitis between January 2015 and December 2020 were interrogated. Clinicopathological data were collected and analysed to present the incidence of primary appendiceal tumours, histopathological diversity and outcomes. Results 1908 appendicectomies were performed over the study period. 22 patients with primary appendiceal tumours (incidence rate 1.2%) had a mean age of 45.6(15-97) years and M:F ratio of 1:1.2. Only six patients (27.3%) had appendiceal tumour suspected either before or during surgery. 91% of the patients underwent laparoscopic appendicectomy. Right hemicolectomy was performed as the first intervention and further surgical procedure in 1 and 5 patients respectively. Histological tumour types included carcinoid(10), adenocarcinoma(4), low grade appendiceal mucinous neoplasm(4) mucinous adenocarcinoma &amp; carcinoid(1), goblet cell carcinoid(2) and dysplastic serrated polyp(1). Tumours were located at the tip(10), body(10) and base(2). Median tumour size was 13(2.0-55.0) mm. Median hospital stay was 1.5(0-25) days. The mean survival was 30.9(2.80-73.70) months. Disease related death was a 97-year-old lady with a T4 adenocarcinoma and peritoneal disease who stayed for 25 days and offered palliative supports post appendicectomy. Conclusion Primary appendiceal tumours are diverse in histological types and are of varying prognosis. Appendicectomy alone seemed to be adequate in most cases with early-stage disease. Further surgery such as right hemicolectomy was required for adenocarcinoma and other high-grade tumours.