Case Of Pseudomyxoma Peritonei Research Articles

Pseudomyxoma Peritonei: A Challenging Clinical Diagnosis. Case Report and Review of the Literature.

Pseudomyxoma peritonei (PMP) is a clinical entity of subtle onset abdominal pain, ascites, and distention associated with characteristic imaging. In most cases, laparoscopic exploration will give the definitive diagnosis and histopathologic verification. However, usually there are difficulties in the diagnosis of this disease. Herein, we present a case of a 51-year-old female who developed ascites over 5 months. An investigational laparotomy established the diagnosis of PMP, after the discovery of a mucinous, grey-brown tumor that was CK20 positive and CK7 negative. Subsequently, chemotherapy with oxaliplatin combined with 5-FU (FOLFOX4 regimen), was initiated and the patient survived for 30 months. We also present a comprehensive review of the English literature concerning the different symptoms and radiological findings of this rare entity. According to the literature review, 35 cases of PMP with different clinical and radiological findings have been described. In the majority of the cases, ultrasound, computed tomography or magnetic resonance imaging was orientating towards a proper diagnosis before a diagnostic laparotomy. The combination of a clinical picture with the characteristic imaging findings enables a prompt diagnosis of PMP, making prognosis more favorable.

Origin and survival outcomes of Pseudomyxoma peritonei-A retrospective study.

Pseudomyxoma peritonei (PMP) is an unusual clinical condition typically presenting with widespread mucinous neoplastic lesions within the peritoneum resulting in gelatin material-rich ascites. It was first described by Werth in 1884. Ever since, its clinical presentation, definition, site of origin, and prognosis have been a subject of debate. However, many histopathologic, immunohistochemical, and genetic studies have attempted to locate the primary lesion in the appendix in both genders. To analyze the histological origin and survival outcomes of pseudomyxoma peritonei in patients treated at a regional cancer center. Fifteen cases of PMP were diagnosed during the five-year study period. The demographic and clinicopathological details were retrieved; the slides were reviewed and histological parameters reassessed. Descriptive statistics were used to express proportions. Continuous variables were recorded as mean (SD) or median (IQR). Kaplan-Meier (KM) curve was used to estimate overall survival. Mean age for PMP was found to be 47.5 years for low grade Mucinous Carcinoma Peritonei (MCP), 54.2 years for high grade MCP, and 58 years for high grade MCP with signet ring cells. Most common overall presentation was abdominal distension in 53.3% (8/15) of cases, followed by acute appendicitis in 20% (3/15) cases. PMP was detected synchronous with the primary tumor in 9/15 cases (60%). Primary lesion in the appendix was grossly identified in 7/15 cases, while it was not explored in the remaining eight cases. Yet, by combined clinical, radiological, histopathological, and immunohistochemical analysis, we identified that most of the cases (14/15) had an appendiceal origin (93.3%). The overall survival for 12 months was 50% and for 18 months was 37%. The surgeon and radiologist may well bear in mind the most common possibility of an appendiceal origin for PMP and resect the appendix, irrespective of the presence of a grossly or radiologically detectable lesions. We emphasize that immunohistochemistry helped to detect the site of origin even when the primary was occult.

Patterns of presentation and delivery of care of appendiceal neoplasms in the largest municipal health care delivery system in the United States.

14 Background: Appendiceal neoplasms (AN) are rare tumors with a broad spectrum of referral and treatment patterns. NYC Health+Hospital (HHC) is the largest municipal health care system in the United States. Here, we study patterns of presentation and management of AN in this safety-net setting. Methods: We identified 92 patients in HHC with AN between 01/01/2017 to 07/01/2023. Statistical analyses were performed in Python. Results: There were 38 (41.3%) mucinous neoplasms, 24 (26.1%) adenocarcinomas, 23 (25.0%) neuroendocrine, and 7 (7.6%) ex-goblet cell adenocarcinomas. 16 cases of pseudomyxoma peritonei were identified. The median age at diagnosis was 55 (IQR: 45-65). 49% were Hispanic, and African Americans were the largest racial block (28%). 50% of cases presented as appendicitis. Appendectomy and a second surgical intervention were more common in this group (p<0.001 and p=0.044, respectively). Other surgical interventions included colon resections and cytoreduction ± Hyperthermic intraperitoneal chemotherapy. Among the patients with mucinous neoplasm or adenocarcinoma, 35 had multidisciplinary tumor board discussion (15 mucinous neoplasm and 20 adenocarcinomas). The median follow-up period was 22.0 months (95% CI: 11.5-30.7 months). Surveillance modalities included CT (75%), CEA (74%), and colonoscopy (35%). 85% remained within HHC during treatment. 16 patients were planned to have chemotherapy, including 9 pseudomyxoma peritonei cases. 5 patients did not follow through, and the other cases had a median of 10 cycles. The following adjuvant chemotherapy regimens were employed: 50% FOLFOX, 20% FOLFIRI, 20% XELODA, and 10% CapeOX and FOLFIRI. There were 2 cancer-related deaths (pseudomyxomas). Excluding pseudomyxomas, none had evidence of disease at the last follow-up. Conclusions: Minorities and immigrants constitute the majority of the population of HHC. 50% of AN presented as appendicitis emphasizing the need for a robust system to identify these cases. Despite challenges encountered in providing long-term oncological care, HHC has treated and provided vigorous follow-up for this underserved population. [Table: see text]

Oral administration of bromelain and acetylcysteine in pseudomyxoma peritonei (PMP) caused by low-grade appendiceal mucinous neoplasm (LAMN): a case report

BackgroundPseudomyxoma Peritonei (PMP) is a severe neoplastic clinical syndrome characterised by secretion of mucin from tumors often originating in the appendix. The standard treatment includes cytoreductive surgery (CRS) combined with heated intraperitoneal chemotherapy (HIPEC). A new perspective in PMP treatment aims at the mucins themselves as a therapeutic target.Case presentationHere we report the first case of PMP with peritoneal dissemination of mucinous implants caused by low-grade appendiceal mucinous neoplasm (LAMN) in a 58-year-old white male exclusively treated by appendectomy and oral administration of bromelain and acetylcysteine in the context of a medical self-experimentation (by co-author T.R.). Observation so far covers a period of 48 months including regular magnetic resonance imaging (MRI) with stable findings.ConclusionsOral administration of bromelain and acetylcysteine can be used in the treatment of PMP caused by LAMN without relevant clinical side effects.

Four cases of pseudomyxoma peritonei with ovarian tumors at our hospital.

We describe four cases of pseudomyxoma peritonei (PMP) that were diagnosed and treated at our hospital.Case 1: A 26-year-old woman with a large multicystic ovarian tumor and massive ascites was diagnosed with PMP originating from a borderline mucinous ovarian tumor. She underwent fertility-preserving staging laparotomy and was treated with three courses of intraperitoneal chemotherapy. There has been no recurrence in the 15 years since her first operation. Case 2: A 72-year-old woman with a giant ovarian tumor and massive ascites was diagnosed with PMP originating from low-grade appendiceal mucinous neoplasm (LAMN). After laparotomy, the patient was managed conservatively because she did not want aggressive treatment. She has remained asymptomatic with a small amount of ascites for 3 years. Case 3: A 82-year-old woman with ovarian tumors, massive ascites, and suspected PMP underwent emergency laparotomy due to appendiceal perforation and pan-peritonitis. She was diagnosed with PMP originating from LAMN. She has remained asymptomatic with a small amount of ascites for 2 years. Case 4: A 42-year-old woman with multicystic ovarian tumors and massive ascites underwent laparotomy. She was diagnosed with PMP originating from LAMN. Since multidisciplinary treatment was indicated and desired, the patient was referred to a specialized facility where cytoreductive surgery and hyperthermic intraperitoneal chemotherapy was performed. The patient has done well since the treatment.Although most cases of PMP originate from mucinous tumors of the appendix, female patients with PMP often present with ovarian tumors and are commonly referred to gynecology clinics. It is therefore important for gynecologists to be familiar with PMP and to be able to diagnose it accurately and select the most suitable management including multidisciplinary treatments.

Varied Histomorphological Presentations of Appendiceal Neoplasms: A Case Series of Eight Cases

During routine histopathological study of appendicular specimens, we identified eight cases of appendiceal tumours, including five cases of Low-grade Appendiceal Mucinous Neoplasms (LAMN) and three cases of adenocarcinoma. Among the adenocarcinoma cases, one was a rare colorectal type adenocarcinoma in an older male and two were mucinous adenocarcinoma which includes a case of signet ring cell rich type. These tumours were classified and staged according to the recent WHO classification (5th edition) and the eighth edition of the American Joint Committee of Cancer (AJCC) staging manual. The median age in our series was 60 years. Serum markers were evaluated in two cases of Pseudomyxoma Peritonei (PMP), which showed elevated levels of CA-125 and CA 19.9 in each case. In this case series, three patients were initially diagnosed with acute appendicitis, one case as mucocele, two cases underwent surgery for ovarian malignancy, one patient was operated for an incisional hernia, and one patient was diagnosed with acute intestinal obstruction after clinical and radiological investigations. Histopathological examination confirmed the diagnosis of appendicular neoplasms in these eight cases. Meticulous histopathological examination of all appendectomy specimens is important for the proper diagnosis of appendicular neoplasms and to predict their severity. This will help surgeons plan further treatment to increase the patient's survival rate.

Genetic diagnosis of pseudomyxoma peritonei originating from mucinous borderline tumor inside an ovarian teratoma

BackgroundPseudomyxoma peritonei is a rare disease condition mainly caused by primary mucinous tumors from the appendix and rarely from the ovary, such as when mucinous ovarian tumors arise from within a teratoma. Molecular analyses of pseudomyxoma from the appendix showed that KRAS and GNAS pathogenic variants are common genetic features of pseudomyxoma peritonei. However, the origin of the tumors is difficult to be identified via genetic variants alone. This study presents a case of pseudomyxoma peritonei of ovarian origin, which was diagnosed by comprehensive genomic profiling with ploidy analysis in a series of primary, recurrent, and autopsy tumor specimens.Case presentationA 40-year-old woman was diagnosed with Stage IC2 mucinous ovarian tumor of borderline malignancy with mature cystic teratoma, upon clinical pathology. Immunohistochemical analysis suggested that the mucinous tumor was derived from the intestinal component of an ovarian teratoma. Three years later, intraperitoneal recurrence was detected, which subsequently progressed to pseudomyxoma peritonei. Genomic analysis detected KRAS (G12D), GNAS (R201C), and FBXW7 (R367*) variants in the primary tumor. In addition, the tumor showed aneuploidy with loss of heterozygosity (LOH) in all its chromosomes, which suggested that the primary ovarian tumor was derived from germ cells. Existence of one Barr body suggested the existence of uniparental disomy of the tumors throughout the genome, instead of a haploid genotype. All three pathogenic variants remained positive in the initial recurrent tumor, as well as in the paired DNA from the whole blood in pseudomyxoma peritonei. The pathogenic variant of KRAS (G12D) was also identified in the autopsy specimen of the appendix by droplet digital polymerase chain reaction.ConclusionsThis study pathologically and genetically confirmed that the primary ovarian borderline tumor was derived from the intestinal component of an ovarian teratoma, and that the subsequent pseudomyxoma peritonei progressed from the primary ovarian tumor. Integrative genomic analysis was useful to identify cellular origin of tumors, as well as to precisely interpret the process of disease progression.

A proposal for modification of PSOGI classification according to Ki-67 proliferation index in pseudomyxoma peritonei.

Background: Pseudomyxoma peritonei (PMP) is a rare malignancy, classified according to PSOGI, whose response to treatment remains highly heterogeneous within the high-grade (HG) category. Molecular profiling of PMP cases might help to better categorize patients and predict treatment responses.v

A rare case of pseudomyxoma peritonei caused by borderline mucinous tumor arising from primary mature cystic ovarian teratoma

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by diffuse intraperitoneal mucinous spread originating from mucinous neoplasms. The most common cause of PMP is a mucinous epithelial tumor of the appendix, but may also develop from other abdominal organs such as the ovaries, colon, and pancreas. Here, we describe the case of a patient with a prior history of appendectomy, in whom the appendix was easily excluded as the primary site of PMP. Previous studies have reported that only 3–8% of ovarian mucinous tumors may arise from mature cystic teratoma. In addition, borderline ovarian malignancies from mature cystic teratoma are not common, and the occurrence of PMPs from these borderline ovarian mucinous tumors is very rare. We report a rare case of PMP with clinicopathological features between PMP and borderline mucinous tumors arising in a mature cystic teratoma of the ovary.

Pseudomyxoma Peritonei A Rare Abdominal Tumor

Pseudomyxoma peritonei is a rare abdominal tumor with a reported incidence of approximately I per million per year. It is invariably fatal as the space within the abdomen is eventually replaced by mucinous tumor. We report one case of Pseudomyxoma peritonei.

A Proposal for Modification of the PSOGI Classification According to the Ki-67 Proliferation Index in Pseudomyxoma Peritonei.

Pseudomyxoma peritonei (PMP) is a rare malignancy, classified according to the Peritoneal Surface Oncology Group International (PSOGI) classification, whose response to treatment remains highly heterogeneous within the high-grade (HG) category. Molecular profiling of PMP cases might help to better categorize patients and predict treatment responses. We studied the Ki-67 proliferation rate and P53 overexpression in tissue samples from our historical cohort of HG-PMP patients. We established as cut-off levels the third quartile of each marker to perform univariate and multivariate Cox regression survival analyses. According to these results, the HG-PMP category was divided into subcategories and a new survival analysis was performed. A total of 90/117 patients with PMP undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) were selected for secondary analysis. The survival analysis of the HG-PMP category for preoperative variables showed that a proliferation index defined by Ki-67 >15% is a bad prognostic factor, with a hazard ratio (HR) of 3.20 (95% confidence interval [CI] 1.24-8.25). Accordingly, the HG-PMP group was divided using the Ki-67 15% cut-off. The new PSOGI/Ki-67 variable was an independent prognostic factor for overall survival (OS), with an HR of 3.74 (95% CI 1.88-7.47), and disease-free survival (DFS), with an HR of 4.184 (95% CI 1.79-9.75). The estimated 5-year OS rate was 100%, 70% and 24% for the LG-PMP, HG-PMP ≤15% and HG-PMP >15% groups, respectively (p=0.0001), while the 5-year DFS rate was 90%, 44% and 0%, respectively (p=0.0001). Division of the HG-PMP category of the PSOGI classification, according to the Ki-67 proliferation index, provides two well-defined subcategories, with significant differences in terms of OS and DFS, and hence high prognostic value.

Omics analyses in peritoneal metastasis-utility in the management of peritoneal metastases from colorectal cancer and pseudomyxoma peritonei: a narrative review.

High-throughput "-omics" analysis may provide a broader and deeper understanding of cancer biology to define prognostic and predictive biomarkers and identify novel therapy targets. In this review we provide an overview of studies where the peritoneal tumor component of peritoneal metastases from colorectal cancer (PM-CRC) and pseudomyxoma peritonei (PMP) were analyzed. Most of the available data was derived from DNA mutation analysis, but a brief review of findings from transcriptomic and protein expression analysis was also performed. Studies reporting genomic analysis of peritoneal tumor samples from 1,779 PM-CRC and 623 PMP cases were identified. The most frequently mutated genes in PM-CRC were KRAS, APC, SMAD4, BRAF, and PIK3CA, while in PMP KRAS, GNAS, FAT4, TGFBR1, TP53 and SMAD3/4 mutations were most commonly identified. Analyses were performed by single-gene analyses and to some extent targeted next-generation sequencing, and a very limited amount of broad explorative data exists. The investigated cohorts were typically small and heterogeneous with respect to the methods used and to the reporting of clinical data. This was even more apparent regarding transcriptomic and protein data, as the low number of cases examined and quality of clinical data would not support firm conclusions. Even for the most frequently mutated genes, the results varied greatly; for instance, KRAS mutations were reported at frequencies between 20-57% in PM-CRC and 38-100% in PMP. Such variation could be caused by random effects in small cohorts, heterogeneity in patient selection, or sensitivity of applied technology. Although a large number of samples have been subjected to analysis, cross-study comparisons are difficult to perform, and combined with small cohorts and varying quality and detail of clinical information, the observed variation precludes useful interpretation in a clinical context. Although omics data in theory could answer questions to aid management decisions in PM-CRC and PMP, the existing data does not presently support clinical implementation. With the necessary technologies being generally available, the main challenge will be to obtain sufficiently large, representative cohorts with adequate clinical data and standardized reporting of results. Importantly, studies where the focus is specifically on peritoneal disease are needed, where the study designs are aligned with clearly defined research questions to allow robust conclusions. Such studies are highly warranted if patients with PM-CRC and PMP are to derive benefit from recent advances in precision cancer medicine.

Evaluation of the significance of pseudomyxoma peritonei patients based on the Peritoneal Surface Oncology Group International (PSOGI) classification

Pseudomyxoma peritonei (PMP) is a rare disease characterized by mucinous ascites and deposits on the peritoneal surfaces. The study aimed to assess PMP patients according to the Peritoneal Surface Oncology Group International (PSOGI) classification, as a part of standardization of this rare disease. This retrospective study analyzed PMP patients who underwent surgery between January 2007 and December 2017. All histologic slides were re-evaluated and the clinical data were collected. According to the PSOGI, PMP was retrospectively classified into three categories: low-grade (LG-PMP), high-grade (HG-PMP), and signet-ring cells (SRC-PMP). The extent of peritoneal involvement was quantified by the peritoneal cancer index (PCI). The completeness of cytoreduction (CCR) was dichotomized as complete or incomplete. Fifty-seven patients were included in this study, consisted of 39 patients with LG-PMP (74.0%), 14 with HG-PMP (20.8%), and 4 with SRC-PMP (5.2%). There was no operative mortality and major complications occurred in 24 patients (31.2%). The 5-year overall survival was 56.2%±8.1% for LG-PMP, 37.5%±12.1% for HG-PMP, and 25.0%±21.7% for SRC-PMP. Concerning CCR, the 5-year overall (complete: 59.5%±8.4% vs. incomplete: 12.7%±8.1%, p=0.001) and disease-free survival (complete: 38.6%±8.9% vs. incomplete: 7.7%±6.8%, p=0.001) were significantly different. In a multivariable analysis, PSOGI classification and CCR independently correlated with survival (p=0.011 and 0.018, respectively). The PSOGI classification provides prognostic stratification, hopefully requiring further validation including every single case of PMP established as a standard criteria.

The mutational landscape and prognostic indicators of pseudomyxoma peritonei originating from the ovary.

Pseudomyxoma peritonei (PMP) is a rare disorder with unique pathological and genetic changes. Although several studies have reported the clinical features and mutational changes of PMP that originates from the appendix, few studies on PMP originating from the ovary have been reported due to its extreme rarity. In order to characterize the somatic mutational landscape and to investigate the prognosis predicting factors of ovary-originating PMP, we examined 830 cases of PMP and identified 16 patients with PMP that originated from the ovary. Whole-exome sequencing (WES) was performed on 12 cases using formalin-fixed, paraffin-embedded (FFPE) tissue samples. We found that 25% (3/12) of the patients carried mutations in cancer driver genes, including TP53, ATM and SETD2, and 16.7% (2/12) of the patients carried mutations in cancer driver genes, including ATRX, EP300, FGFR2, KRAS, NOCR1 and RB1. The MUC16 (58.33%), BSN (41.67%), PCNT (41.67%), PPP2R5A (41.67%), PRSS36 (41.67%), PTPRK (41.67%) and SBF1 (41.67%) genes presented the highest mutational frequencies. The PI3K-Akt signaling pathway, human papillomavirus infection pathway, cell skeleton, cell adhesion, and extracellular matrix and membrane proteins were the major pathways or functions that were affected. Patients were followed up to 174 months (median: 48.26 months). The 5-year OS rate for all patients was 71.2% and the median OS was not reached. PTPRK mutations, presurgical CA199 level, completeness of cytoreduction (CCR) and peritoneal cancer index (PCI) were identified as potential predictive factors for patient survival. In conclusion, the mutational landscape for ovary-originating PMP was revealed and exhibited unique features distinct from appendix-originating PMP. PTPRK, CA199, CCR and PCI may predict patient survival.

S2097 Pseudomyxoma Peritonei Presenting with Extrinsic Compression on Esophagogastroduodenoscopy and Colonoscopy

INTRODUCTION: Pseudomyxoma peritonei (PMP) is a rare disease characterized by mucinous ascites, classically originating from a ruptured low-grade appendiceal mucocele. We present a case of PMP identified because of signs of extrinsic compression on esophagogastroduodenoscopy (EGD) and colonoscopy. CASE DESCRIPTION/METHODS: A 66-year-old male presented for screening colonoscopy and EGD. His medical history was significant for renal calculi and recurrent acid reflux resistant to medical therapy. He denied weight gain or abdominal distension. A colonoscopy performed six years prior identified a single 3 mm tubular adenoma, diverticulosis, and internal hemorrhoids. Colonoscopy revealed sigmoid diverticulosis, a benign stricture in the recto-sigmoid colon, and a large, extrinsic-appearing mass in the descending colon (Figure 1). EGD revealed LA Grade C reflux esophagitis, a hiatal hernia, gastritis, one large non-bleeding duodenal ulcer with a clean ulcer base, and possible extrinsic compression in the gastric body (Figure 2). A CT Abdomen/Pelvis with contrast was obtained to further characterize this apparent extrinsic compression, which revealed diffuse low-density masses and ascites distending the peritoneal cavity with scalloped appearance of the liver and spleen. He was referred to surgical oncology and underwent a diagnostic laparoscopy with peritoneal biopsies that revealed extensive mucin and fibrin deposits, consistent with PMP. He underwent cytoreduction, right hemicolectomy, and hyperthermic intraperitoneal chemotherapy (HIPEC). Surgical pathology showed low grade mucinous carcinoma peritonei and the appendix showed a low-grade mucinous neoplasm. Repeat CT Abdomen/Pelvis with contrast revealed significantly improved peritoneal carcinomatosis and multiloculated, multiseptated, low attenuation masses throughout the abdomen. CEA was 58.3 at five months post-operative from 159.6 preoperatively. Seven months post-operatively the patient was doing well without findings concerning for recurrent disease. DISCUSSION: The incidence of PMP is estimated to be 1-3 per million per year. The growth of appendiceal mucinous tumors is indolent, and they are frequently diagnosed incidentally during evaluation for other conditions. They are classically identified on colonoscopy as an abnormal appearing appendiceal orifice (“volcano sign”) atop a “mound” of normal-appearing mucosa. This case highlights the importance of considering extraluminal etiologies for unexpected findings on endoscopy.Figure 1.: Extrinsic-appearing mass in the descending colon.Figure 2.: Possible gastric mass or extrinsic compression in the gastric body.Figure 3.: CT Abdomen/Pelvis with oral and IV contrast showing diffuse low-density masses and ascites, distending the peritoneal cavity with scalloped appearance of the liver.

Pseudomyxoma Peritonei Arising From a Low-Grade Mucinous Neoplasm of the Urachus

Abstract Urachal mucinous tumors range from low-grade lesions traditionally called cystadenomas to frankly invasive mucinous adenocarcinomas. Occasionally, they can lead to the syndrome of pseudomyxoma peritonei (PMP). We report a patient who presented with abdominal distension and had raised tumor markers. A computed tomography scan revealed a calcified cystic lesion of the bladder dome together with features of PMP. These findings were confirmed at laparotomy, and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy was performed. Histologically, the urachal lesion was a low-grade urachal mucinous tumor (mucinous cystic tumor of low malignant potential). The peritoneal disease was associated with ovarian involvement and omental cake and was designated low-grade mucinous carcinoma peritonei on histology. The immunoprofile was typical for lesions of this type, featuring expression of CK20, CEA, and CDX2, but no expression of CK7. We review the literature of PMP arising from urachal primary neoplasms and identify 58 cases reported previously. Based on the limited data available, it appears that urachal lesions account for about 1 in 200 cases of PMP. Owing to the clinical and pathological similarities between urachal and appendiceal mucinous tumors, we recommend a simple classification based on the principles applied to appendiceal lesions and argue this is more appropriate than a classification based on ovarian nomenclature.

Clinicopathologic characteristics of pseudomyxoma peritonei

Objective: To analyze the relationship between clinicopathologic characteristics of pseudomyxoma peritonei (PMP) and its prognosis. Methods: Fifty-two cases of PMP collected from 2012 to 2017 at Beijing Shijitan Hospital, Capital Medical University were reviewed using the diagnostic criteria of WHO 2010. The histopathologic features, including original location, neural invasion and calcification were observed; and the relationship with prognosis was analyzed. Immunohistochemical staining for CK7, CK20 and CDX2 was performed on all cases. ER, PR, and p16 were additionally performed on those without clear origin. Results: Patients' mean age was 52.0 years, and included 29 males and 23 females. Thirty-two cases were derived from appendix; among them, 23 were low grade and 29 were high grade. Signet ring-cells, neural invasion and calcification were detected in 15, 12 and 9 cases respectively. Neural invasion was associated with adverse prognosis (P=0.025) and signet ring cell morphology (P<0.01). Prognosis was not related to gender, age, original location or grade. Conclusion: Neural invasion is not uncommon in PMP and predicts a bad prognosis.

Pseudomyxoma peritonei due to low-grade appendiceal mucinous neoplasm with symptoms of inguinal hernia and uterine prolapse: a case report and review of the literature

Pseudomyxoma peritonei (PMP) is an unusual condition in which massive amounts of mucinous ascites in conjunction with mucinous peritoneal and omental implants occur. We herein report a case of PMP due to low-grade appendiceal neoplasm (LAMN) and a literature review to clarify the clinical features of PMP. A 68-year-old female suffered from anorexia and abdominal distension and was referred to the emergency department of our hospital. Right-side inguinal hernia and uterine prolapse were revealed by a physical examination. Abdominal computed tomography at admission indicated massive ascites and a ruptured cystic mass in the lower-right abdomen. We diagnosed the patient with a ruptured appendiceal mucinous adenoma and PMP and scheduled a laparotomy. We performed an appendectomy containing the cystic mass, bilateral oophorectomy, and a biopsy for the peritoneum. We irrigated the abdominal cavity using 3000 ml of dextran solution. The macroscopic findings showed a ruptured cystic mass measuring 5 × 4 cm arising from the middle of the appendix. The bilateral ovaries and peritoneum were also covered with yellow mucin. The pathologic findings revealed the presence of low-grade atypical cells inside the capsule. However, no tumor cells were found on the surface of the ovary or peritoneum. A literature review revealed that the prognosis of PMP due to LAMN is relatively good, with a 5-year survival rate of 80%, and hernia is occasionally caused by PMP. According to this literature review, we knew this case might be a typical case. However, PMP is very rare; we need further follow-up data to select an optimal treatment for preventing the relapse of PMP.

An unusual case of pseudomyxoma peritonei associated with synchronous primary mucinous tumors of the ovary and appendix: A case report.

Pseudomyxoma peritonei (PMP) is a rare disease that usually originates from mucinous neoplasms of the appendix and, less commonly, from extra-appendiceal tumors, but it may also be caused by synchronous primary mucinous tumors of the ovary and appendix. The current study discusses the case of a 73-year-old female who presented with progressively worsening indigestion and abdominal distension. Magnetic resonance imaging of the pelvis revealed a large cystic mass with a thin enhancing septa arising from the right ovary and ascites with scalloping of the liver surface. On laparotomy, the patient was observed to have a large ruptured mass on the right ovary and a partially amputed distended appendix filled with mucin. The subsequent pathology report confirmed a borderline mucinous tumor of the right ovary and a low-grade appendiceal mucinous neoplasm associated with PMP. Immunohistochemical examination demonstrated the ovarian tumor stained strongly positive for cytokeratin (CK)-7, and negatively for CK-20 and homeobox protein CDX-2 (CDX2), whereas the appendiceal tumor stained negative for CK-7 and positive for CK-20 and CDX2. This study presents a rare case of PMP caused by synchronous primary mucinous tumors of the ovary and appendix in a postmenopausal female.

Multiple components of PKA and TGF-β pathways are mutated in pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is a subtype of mucinous adenocarcinoma mainly restricted to the peritoneal cavity and most commonly originating from the appendix. The genetic background of PMP is poorly understood and no targeted treatments are currently available for this fatal disease. While RAS signaling pathway is affected in most if not all PMP cases and over half of them also have a mutation in the GNAS gene, other genetic alterations and affected pathways are, to a large degree, poorly known. In this study, we sequenced whole coding genome of nine PMP tumors and paired normal tissues in order to identify additional, commonly mutated genes and signaling pathways affected in PMP. These exome sequencing results were validated with an ultra-deep amplicon sequencing method, leading to 14 validated variants. The validated results contain seven genes that contribute to the protein kinase A (PKA) pathway. PKA pathway, which also contains GNAS, is a major player of overproduction of mucin, which is the characteristic feature of PMP. In addition to PKA pathway, we identified mutations in six genes that belong to the transforming growth factor beta (TGF-β) pathway, which is a key regulator of cell proliferation. Since either GNAS mutation or an alternative mutation in the PKA pathway was identified in 8/9 patients, inhibition of the PKA pathway might reduce mucin production in most of the PMP patients and potentially suppress disease progression.