Unusual origins of Pseudomyxoma peritonei

Progress in Biological Research and Treatment of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare disease characterized by extensive peritoneal implantation and mass secretion of mucus after primary mucinous tumors of the appendix or other organ ruptures. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is currently the preferred treatment, with excellent efficacy and safety, and is associated with breakthrough progress in long-term disease control and prolonged survival. However, the high recurrence rate of PMP is the key challenge in its treatment, which limits the clinical application of multiple rounds of CRS-HIPEC and does not benefit from conventional systemic chemotherapy. Therefore, the development of alternative therapies for patients with refractory or relapsing PMP is critical. The literature related to PMP research progress and treatment was searched in the Web of Science, PubMed, and Google Scholar databases, and a literature review was conducted. The overview of the biological research, treatment status, potential therapeutic strategies, current research limitations, and future directions associated with PMP are presented, focuses on CRS-HIPEC therapy and alternative or combination therapy strategies, and emphasizes the clinical transformation prospects of potential therapeutic strategies such as mucolytic agents and targeted therapy. It provides a theoretical reference for the treatment of PMP and the main directions for future research.

Establishment and characterization of NCC-PMP2-C1: a novel patient-derived cell line of pseudomyxoma peritonei with signet ring cells

Pseudomyxoma peritonei (PMP) is a rare phenomenon, characterized by accumulation of mucus in the abdominal cavity due to a mucinous neoplasm. Histologically, PMP is divided into three prognostic classes, namely low-grade mucinous carcinoma peritonei (LGMCP), high-grade mucinous carcinoma peritonei (HGMCP), and high-grade mucinous carcinoma peritonei with signet ring cells (HGMCP-S); HGMCP-S exhibits the worst prognosis. Complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have been established as the standard therapy for PMP. However, 50% of patients with PMP experience a recurrence, and 30-40% are unable to receive the standard treatment due to invasive diseases. Therefore, novel therapies are required for their treatment. Although patient-derived cell lines are important tools for basic and pre-clinical research, PMP cell lines derived from patients with HGMCP-S have never been reported. Thus, we established a novel PMP cell line NCC-PMP2-C1, using surgically resected tumor tissue from a patient with HGMCP-S. NCC-PMP2-C1 cells were maintained for more than five months and passaged 30 times under culture conditions. NCC-PMP2-C1 cells exhibited multiple deletions and somatic mutations, slow growth, histological features, and dissemination of tumor cells in nude mice. Screening for the anti-proliferative effects of anti-cancer drugs on cells revealed that bortezomib, mubritinib, and romidepsin had a significant response against NCC-PMP2-C1 cells. Thus, the NCC-PMP2-C1 cell line is the first PMP cell line harboring signet ring cells and will be a valuable resource for basic and preclinical studies of HGMCP-S.

Current Status of Treatment among Patients with Appendiceal Tumors-Old Challenges and New Solutions?

The 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system distinguishes four categories of appendiceal tumors (ATs): serrated lesions and polyps, mucinous neoplasms, adenocarcinomas, and neuroendocrine neoplasms (NENs). The differential diagnosis of ATs can be challenging in medical practice, due to their rarity and lack of data from randomized controlled trials on a large, diverse group of patients. ATs are usually noted in specimens obtained during appendectomies due to clinical acute appendicitis. In the European population, most ATs (65%) occur over the age of 50 and among women (56.8%). According to histological type, 54.6% are neuroendocrine tumors (NETs); 26.8% cystic, mucinous, and serous neoplasms; and 18.6% adenocarcinoma not otherwise specified (NOS). On pathologic analysis, most AT findings are benign lesions or small NENs that do not require further therapeutic measures. The presence of appendiceal mucinous neoplasm (AMN) can lead to pseudomyxoma peritonei (PMP). While the multimodal treatment for abdominal malignancies has evolved over the past several decades, the clinical workup and treatment of ATs remain a challenge. Therefore, this review aims to describe the diagnostic possibilities, molecular-based diagnosis, staging, differences in the treatment process, and prognostic factors associated with ATs.

A case of low-grade intestinal-type mucinous neoplasm of the fallopian tube with KRAS exon 2 mutation

Several types of mucinous lesions of the fallopian tube have been reported, including metaplastic and neoplastic lesions, most of which exhibit gastric phenotypes. Here, we report a unique case of a mucinous tumor arising in the right fallopian tube of a 36-year-old female who presented with refractory abdominal pain for approximately one year. Abdominal CT and MRI found a cystic lesion leading to the diagnosis of hematosalpinx, thus right salpingo-oophorectomy and appendectomy were performed. Macroscopic findings included cystic dilatation of the distal portion of the right fallopian tube, filled with gelatinous mucin. Histologically, mucinous columnar cells proliferated in papillary configurations in the cystic region without invasion, resembling low-grade appendiceal mucinous neoplasms. Immunohistochemical analysis revealed that the neoplastic cells expressed CDX-2 and SATB2, but not WT-1, PAX8, ER, PgR, or claudin 18. Sanger sequencing of the mucinous lesion identified a KRAS exon 2 mutation (p.G12A), confirming similar pathologic and genetic characteristics to ovarian mucinous borderline tumors. This rare low grade intestinal-type mucinous tumor indicates the fallopian tube epithelium can give rise to tumors resembling low-grade appendiceal mucinous neoplasms and cause pseudomyxoma peritonei without appendiceal lesions.

Pseudomyxoma Peritonei Arising from Urachal Mucinous Neoplasms: a Case Series and Updated Literature Review

To report a case series of patients with pseudomyxoma peritonei (PMP) from urachal mucinous neoplasm (UMN) treated with CRS and HIPEC at a high-volume referral centre, along with an updated literature review. Retrospective review of cases treated between 2000 and 2021. A literature review using MEDLINE and Google Scholar databases was performed. Clinical presentation of PMP from UMN is heterogeneous, and common symptoms are abdominal distension, weight loss, fatigue and haematuria. At least one tumour marker among CEA, CA 19.9, and CA 125 was elevated in the six cases reported, and 5/6 had a preoperative working diagnosis of urachal mucinous neoplasm suspected on detailed cross-sectional imaging. Complete cytoreduction was achieved in five cases, while one patient underwent maximal tumour debulking. Histological findings mirrored the findings of PMP from appendiceal mucinous neoplasms (AMN). Overall survival ranged between 43 and 141 months after complete cytoreduction. On literature review, 76 cases have been reported to date. Complete cytoreduction is associated with good prognosis for patients with PMP from UMN. A definitive classification system is still not available.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-022-01694-5.

Peritoneal Surface Malignancies Originating From Urachal Carcinoma: Case Reports and Review of the Literature

Urachal carcinoma (UC) is a rare and aggressive tumor arising from the urachal remnants, with the potential for peritoneal dissemination. Patients diagnosed with UC often have a poor prognosis. To date, there is no standardized treatment. Our objective is to present two cases of patients with peritoneal carcinomatosis (PC) secondary to an UC, who were treated with cytoreductive surgery (CRS) and hyperthermic peroperative intraperitoneal chemotherapy (HIPEC). A review of the literature on CRS and HIPEC in UC suggests CRS and HIPEC to be a safe and viable treatment option. Two patients with PC of UC underwent CRS and HIPEC in our institution. All available data were gathered and reported on. A literary search was carried out to find all available cases of patients with PC secondary to UC treated with CRS and HIPEC. Both patients underwent CRS and HIPEC and are currently free of recurrence. Literature research revealed nine other publications adding up to a total of 68 additional cases. CRS and HIPEC can provide satisfactory long-term oncological outcome with acceptable morbidity and mortality rates in patients with PC of urachal origin. It should be considered as a safe and feasible treatment option with curative potential.

The genetic profile and molecular subtypes of human pseudomyxoma peritonei and appendiceal mucinous neoplasms: a systematic review

Pseudomyxoma peritonei (PMP) is a rare, progressive, slowly growing neoplastic condition which is poorly understood, with a 5-year progression-free survival rate as low as 48%. PMP is most commonly caused by appendiceal mucinous neoplasms (AMN), and understanding their genetic biology and pathogenicity may allow for the development of better novel systemic treatments to target key deleterious mutations and the implicated pathways. The primary aim of this systematic review was to identify the genetic profile of histologically confirmed human PMP or AMN samples. The secondary aim was to identify whether genetic marks could be used to predict patient survival. Ovid EMBASE, Ovid MEDLINE, PubMed, and Web of Science were searched to identify studies investigating the genetic profile of histologically-confirmed human PMP or AMN samples. We review findings of 46 studies totalling 2181 tumour samples. The most frequently identified somatic gene mutations in patients with PMP included KRAS (38-100%), GNAS (17-100%), and TP53 (5-23%); however, there were conflicting results of their effect on survival. Three studies identified molecular subtypes based on gene expression profiles classifying patients into oncogene-enriched, immune-enriched, and mixed molecular subtypes with prognostic value. This review summarises the current literature surrounding genetic aberrations in PMP and AMNs and their potential utility for targeted therapy. Given the recent advances in clinical trials to directly target KRAS and GNAS mutations in other cancers, we propose a rationale to explore these mutations in future pre-clinical studies in PMP with a view for a future clinical trial.

Establishment and Characterization of NCC-PMP1-C1: A Novel Patient-Derived Cell Line of Metastatic Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is the intraperitoneal accumulation of mucus due to a mucinous tumor. PMP predominantly occurs in low-grade carcinomas. The incidence rate of PMP is one to two cases per million people per year. The standard therapy of PMP comprises complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. PMP recurs in about 50% of patients, and 30-40% are unable to receive the standard treatment because of its invasiveness. Therefore, novel therapies are of the utmost necessity. For basic and pre-clinical research, patient-derived cell lines are essential resources. However, only two PMP cell lines have been reported. Thus, we established a novel PMP cell line from resected metastatic PMP tissue. The cell line, named NCC-PMP1-C1, was maintained for more than 5 months and was passaged 25 times. NCC-PMP1-C1 cells demonstrated multiple amplifications and deletions, slow growth, tumorigenic ability, and dissemination of tumor cells in nude mice. We also used NCC-PMP1-C1 cells to screen drugs, which demonstrated a significant response to daunorubicin HCl, homoharringtonine, mitomycin C, and ponatinib. The NCC-PMP1-C1 cell line is the first PMP cell line derived from metastasized tissue and will be a potential resource for basic and pre-clinical research of metastasized PMP.

A case of Pseudomyxoma Peritonei of an unexpected origin

Background

Pseudomyxoma 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 presentation

A 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.

Conclusions

Detection 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.

Essentials for Pathological Evaluation of Peritoneal Surface Malignancies and Synoptic Reporting of Cytoreductive Surgery Specimens-A review and evidence-based guide

Peritoneal surface oncology has emerged as a subspecialty of surgical oncology, with the growing popularity of surgical treatment of peritoneal metastases comprising of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Pathological evaluation plays a key role in multidisciplinary management but there are still many areas where there are no guidelines or consensus on reporting. Some tumors presenting to a peritoneal surface oncology unit are rare and pathologists my not be familiar with diagnosing and classifying those. In this manuscript, we have reviewed the evidence regarding various aspects of histopathological evaluation of peritoneal tumors. It includes establishing a diagnosis, appropriate classification and staging of common and rare tumors and evaluation of pathological response to chemotherapy. In many instances, the information captured is of prognostic value alone with no direct therapeutic implications. But proper capturing of such information is vital for generating evidence that will guide future treatment trends and research. There are no guidelines/data set for reporting cytoreductive surgery specimens. Based on the authors' experience, a format for handling/grossing and synoptic reporting of these specimens is provided.

Recurrence of pseudomyxoma peritonei after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Background

Pseudomyxoma peritonei (PMP) is a rare clinical condition characterized by mucinous ascites, typically related to appendiceal or ovarian tumours. Current standard treatment involves cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), but recurrences occur in 20–30 per cent of patients. The aim of this study was to define the timing and patterns of recurrence to provide a basis for modifying follow‐up of these patients.

Methods

This observational study examined a prospectively developed multicentre national database (RENAPE working group) to identify patients with recurrence after optimal CRS and HIPEC for PMP. Postoperative complications, long‐term outcomes and potential prognostic factors were evaluated.

Results

Of 1411 patients with proven PMP, 948 were identified who had undergone curative CRS and HIPEC. Among these patients, 229 first recurrences (24·2 per cent) were identified: 196 (20·7 per cent) occurred within the first 5 years (early recurrence) and 30 (3·2 per cent) occurred between 5 and 10 years. Three patients developed a first recurrence more than 10 years after the original treatment. The mean(s.d.) time to first recurrence was 2·36(2·21) years. Preoperative chemotherapy and high‐grade pathology were significant factors for early recurrence. Overall survival for the entire group was 77·9 and 63·1 per cent at 5 and 10 years respectively. The principal site of recurrence was the peritoneum.

Conclusion

Recurrence of PMP was rare after 5 years and exceptional after 10 years.

Peritoneal Carcinomatosis of Urachus Origin Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC): An International Registry of 36 Patients

PURPOSE

Peritoneal carcinomatosis or pseudomyxoma peritonei from urachus is a rare form of presentation, often diagnosed at an advanced state of tumor burden. Because of its rarity, little is known about its natural history, prognosis, or optimal treatment. We searched a large international multicenter database of peritoneal surface disease to identify cases of peritoneal carcinomatosis of urachus that were treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) at expert centers. The aim is to improve knowledge and understanding of the disease and standardize its treatment.

METHODS

A prospective multicenter international database was retrospectively searched to identify all patients with urachus tumor and peritoneal metastases who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI). Postoperative complications, long-term results, and principal prognostic factors were analyzed.

RESULTS

The analysis included 36 patients. After median follow-up of 48 months, median overall survival (OS) was 58.5 months. Three- and 5-year OS was 55.4 and 46.2%, respectively. Patients who underwent complete macroscopic CRS had significantly better survival than those treated with incomplete CRS, with median OS not achieved and of 20.1 months, respectively [95% confidence interval (CI) 4.4-30.5, p < 0.001]. There were no postoperative deaths, and 37.9% of patients had major complications.

CONCLUSION

CRS and HIPEC may increase long-term survival in selected patients with peritoneal metastases of urachus origin, especially when complete CRS is achieved.

Biomarkers in Urachal Cancer and Adenocarcinomas in the Bladder: A Comprehensive Review Supplemented by Own Data

Urachal cancer (UrC) is a rare but aggressive cancer. Due to overlapping histomorphology, discrimination of urachal from primary bladder adenocarcinomas (PBAC) and adenocarcinomas secondarily involving the bladder (particularly colorectal adenocarcinomas, CRC) can be challenging. Therefore, we aimed to give an overview of helpful (immunohistochemical) biomarkers and clinicopathological factors in addition to survival analyses and included institutional data from 12 urachal adenocarcinomas. A PubMed search yielded 319 suitable studies since 1930 in the English literature with 1984 cases of UrC including 1834 adenocarcinomas (92%) and 150 nonadenocarcinomas (8%). UrC was more common in men (63%), showed a median age at diagnosis of 50.8 years and a median tumor size of 6.0 cm. No associations were noted for overall survival and progression-free survival (PFS) and clinicopathological factors beside a favorable PFS in male patients (p = 0.047). The immunohistochemical markers found to be potentially helpful in the differential diagnostic situation are AMACR and CK34βE12 (UrC versus CRC and PBAC), CK7, β-Catenin and CD15 (UrC and PBAC versus CRC), and CEA and GATA3 (UrC and CRC versus PBAC). Serum markers like CEA, CA19-9 and CA125 might additionally be useful in the follow-up and monitoring of UrC.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei of appendicular and extra-appendicular origin

BACKGROUND

The prognostic value of the primary neoplasm responsible for pseudomyxoma peritonei (PMP) remains poorly studied. The aim of this study was to determine the prognosis for patients with extra-appendicular PMP (EA-PMP) treated optimally with complete cytoreductive surgery (CCRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

All patients treated for PMP with CCRS and HIPEC between 1994 and 2016 were selected retrospectively from a French multicentre database. Patients with EA-PMP had pathologically confirmed non-neoplastic appendices and were matched in a 1 : 4 ratio with patients treated for appendicular PMP (A-PMP), based on a propensity score.

RESULTS

Some 726 patients were identified, of which 61 (EA-PMP group) were matched with 244 patients (A-PMP group). The origins of primary tumours in the EA-PMP group included the ovary (45 patients), colon (4), urachus (4), small bowel (1), pancreas (1) and unknown (6). The median peritoneal carcinomatosis index was comparable in EA-PMP and A-PMP groups (15·5 versus 18 respectively; P = 0·315). In-hospital mortality (3 versus 2·9 per cent; P = 1·000) and major morbidity 26 versus 25·0 per cent; P = 0·869) were also similar between the two groups. Median follow-up was 66·9 months. The 5-year overall survival rate was 87·8 (95 per cent c.i. 83·2 to 92·5) per cent in the A-PMP group and 87 (77 to 96) per cent in the EA-PMP group. The 5-year disease-free survival rate was 66·0 (58·7 to 73·4) per cent and 70 (53 to 83) per cent respectively.

CONCLUSION

Overall and disease-free survival following treatment with CCRS and HIPEC is similar in patients with pseudomyxoma peritonei of appendicular or extra-appendicular origin.

Management of Mucinous Urachal Neoplasm Presenting as Pseudomyxoma Peritonei

Background

Mucinous neoplasms of the urachus are rare malignancies so that the physicians’ index of suspicion for a timely and accurate diagnosis is low. Also, this disease may present with a wide variety of symptoms and signs.

Methods

Two patients with pseudomyxoma peritonei as the initial presentation of urachal mucinous adenocarcinoma were treated successfully. The medical literature regarding treatment options for this manifestation of the disease was searched.

Results

Two patients with large volume of pseudomyxoma peritonei originating in a mucinous urachal neoplasm were treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy. Our first patient required two reoperations to palliate the accumulation of gross mucinous ascites. She died 11 years after diagnosis with progression of mucinous adenocarcinoma resulting in starvation. The second patient had ostomy closure with second look surgery at one year after definitive treatment; four small tumor nodules were seen and easily resected. The patient is currently without evidence of disease and has a normal quality of life. Seven prior manuscripts that report a single case of pseudomyxoma peritonei were reviewed to explore the full range of treatment options and survival for this rare condition.

Conclusion

Cytoreductive surgery combined with perioperative intraperitoneal chemotherapy may be a new treatment option for mucinous urachal neoplasms presenting with pseudomyxoma peritonei. Other management strategies such as systemic chemotherapy seemed to hold little promise for this group of patients.

"The Jelly Belly": Diagnostic Dilemmas and Current Concepts

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare and poorly understood clinicopathological entity characterized by gelatinous ascites with neoplastic or non-neoplastic mucinous implants in the peritoneum. Although its origin was debated, current evidence in literature favours the appendix as the origin of the disease, over the ovaries. The changing terminologies in the classification of this entity pose diagnostic and management challenges.

CASE REPORTS

Herein, we report three cases of PMP in postmenopausal women, their clinical presentation, pathological staging based on the peritoneal tumor deposits and the treatment administered. Two patients recovered uneventfully, while one had recurrence of adenocarcinoma.

CONCLUSION

The rarity of this disease and the diagnostic challenges associated with it are discussed with an emphasis on the current concepts in its origin and management. Appropriate classification and complete removal of the tumor is mandated to prevent disease-related mortality.

Pseudomyxoma Peritonei of Extra-Appendiceal Origin: A Comparative Study

BACKGROUND

Pseudomyxoma peritonei (PMP) usually originates from appendiceal neoplasms and, less commonly, from extra-appendiceal lesions. To date, the clinical and therapeutic implications of extra-appendiceal origin are largely unknown.

METHODS

A prospective database of 225 PMP patients uniformly treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) was reviewed to identify cases with extra-appendiceal primaries. Histologically, negative appendix defined extra-appendiceal origin. Clinical, pathological, and immunohistochemical features (cytokeratin [CK]-20, CK-7, CDX-2, MUC-2, MUC-5A) were correlated with the site of origin. PMP was categorized into low or high grade, according to the 2010 World Health Organization (WHO) classification. The main independent variable for survival analysis was appendiceal versus extra-appendiceal primary.

RESULTS

In 19 patients (8.4 %), PMP origin was the ovary (n = 9), uterine cervix (n = 1), mature cystic teratomas (n = 4), and unknown (n = 5). Appendiceal and extra-appendiceal PMP groups were comparable for all characteristics, except for a prevalence of females in the latter. Median follow-up was 64.1 months (95 % confidence interval [CI] 53.9-80.1), and 10-year overall survival was 63.4 % (median 148.2 months; 95 % CI 131.2-165.2) for appendiceal PMP, and 62.0 % (median not reached) for extra-appendiceal PMP. The difference was not significant at univariate ( p = 0.297) and multivariate analysis (hazard ratio 1.51, 95 % CI 0.78-3.14; p = 0.278). High-grade peritoneal histology (p = 0.007), prior systemic chemotherapy (p = 0.003), more than four visceral resections (p = 0.011), and incomplete cytoreduction (p = 0.021) independently correlated with poorer survival.

CONCLUSIONS

Clinical-pathological features of PMP, and outcome after CRS/HIPEC, did not differ according to the primary site, thus suggesting that PMP is a relatively homogeneous disease that can be produced by a range of histopathologic entities. Extra-appendiceal origin does not contraindicate CRS/HIPEC.

Pathologic diagnosis, origin, and natural history of pseudomyxoma peritonei

Mucinous ascites and pools of mucin within the peritoneal cavity associated with neoplastic, mucinous epithelium are the characteristic features of pseudomyxoma peritonei (PMP). Clinically, PMP presents with abdominal distension and gelatinous ascites. In female patients, pelvic masses can be seen. Radiologic findings on computed tomography include scalloping of the hepatic and splenic margins and dense ascites. Surgically, PMP is encountered as grossly visible mucin in the peritoneal cavity. The presence of mucin outside of the appendix, in the right lower quadrant, and beyond is an important diagnostic finding. The appendix may be distended or ruptured. In women, there is often bilateral surface involvement of the ovaries, raising the differential diagnosis of primary ovarian neoplasms; however, these are extremely rare causes of PMP. Because of the association between appendiceal lesions and metastatic mucinous neoplasms of the ovary, appendectomy in the setting of any mucinous peritoneal or ovarian process may be prudent, even if the appendix is grossly normal. The gastrointestinal tract, especially the hepatopancreato biliary system, also needs to be assessed by the surgeon. Pathologically, PMP arises almost exclusively from low- or high-grade mucinous neoplasms of the appendix. These neoplasms must be distinguished both from rare benign causes of mucinous ascites and from nonappendiceal primary tumors. PMP has a protracted clinical course with progressive fibrous adhesions and obstructive disease; aggressive surgical and cytoreductive therapy with hyperthermic intraperitoneal chemotherapy has been reported to improve clinical outcomes.

Updates in the Pathologic Diagnosis and Classification of Epithelial Neoplasms of Urachal Origin

Since the publication of the World Health Organization "blue book" in 2004, several recent studies have provided new insights on the pathologic aspects of urachal neoplasms. The proposed updates include modified criteria for the diagnosis of urachal carcinoma. A uniform nomenclature for cystic tumors was lacking, and it is recommended that urachal mucinous cystic tumors should be separated and classified in a manner similar to ovarian mucinous neoplasms. The spectrum includes mucinous cystadenoma, mucinous cystic tumor of low malignant potential, mucinous cystic tumor of low malignant potential with intraepithelial carcinoma, and microscopically or frankly invasive mucinous cystadenocarcinoma, with 65% of cystic tumors classified as mucinous cystic tumor of low malignant potential. Most importantly, it has been shown that progression-free survival of noninvasive mucinous cystic tumors is significantly better than noncystic invasive adenocarcinoma. This development, along with prior descriptions of urachal villous adenoma, has also reaffirmed the occurrence of benign tumors of urachal epithelial origin. For noncystic (usual) invasive adenocarcinomas, the traditionally described histologic subtypes of enteric, mucinous, signet ring cell, not otherwise specified, and mixed remain appropriate, with 50% of tumors classified as mucinous subtype. Although this subtyping is helpful in diagnosis and differential diagnosis, the clinical significance of subtyping adenocarcinoma is still uncertain. Rare nonglandular morphologies such as urothelial, squamous, and neuroendocrine carcinoma in urachal carcinomas have been described in detail with proposals for their own set of diagnostic criteria. These criteria are based on unique features of urachal nonglandular carcinomas. Among the immunomarkers studied, only β-catenin and CK7 may be of help in the distinction of urachal from colorectal adenocarcinoma. Awareness of the expression profile of immunomarkers such as CDX2, P504S (racemase), PSMA, claudin-18, and REG IV in urachal tumors and in tumors in the differential diagnosis is important to avoid overreliance of these markers in the diagnosis. Limited studies have identified KRAS mutations interestingly only in mucinous adenocarcinoma and exclusive of MSI loss, and mutations in BRAF are not present. Several alternative tumor staging approaches (eg, Mayo, Ontario, TNM systems) different from the traditional staging proposed by Sheldon are used that provide better tumor distribution across stages; however, the prognostic utility of the stage substratification has yet to be validated in large prospective studies. Evidence though suggests that staging urachal cancer is most pertinent when dichotomized to tumors that have spread outside versus within the perivesical tissue. Only high tumor stage and residual tumor after surgery have been shown to be independent predictors of outcome. This review updates the contemporary classification of urachal epithelial tumors, which has informed the upcoming 2016 classification of World Health Organization tumors. We provide modified criteria for diagnosing urachal adenocarcinomas, which remains a clinico-pathologic exercise. The role of ancillary diagnostic methodology and issues pertaining to staging and prognostication are presented.

[Peritoneal pseudomyxoma: an overview emphasizing pathological assessment and therapeutic strategies]

Pseudomyxoma peritonei is a clinical entity characterized by a gelatinous ascite associated with mucinous tumor deposits spreading on peritoneal surface and potentially invading abdominal organs. It is considered as a tumor process linked, in most of cases, to a mucinous appendiceal neoplasm. Pseudomyxoma peritonei may benefit from a therapeutic strategy combining cytoreductive surgery and intra-peritoneal chemotherapy, which has led to a major prognosis improvement. Different classifications are available and the last one corresponds to the WHO 2010 version, which individualizes pseudomyxoma peritonei in two classes: low grade and high grade mucinous carcinoma. The very low frequency of this entity and its specific therapeutic strategy need specific health care centres, as well as physicians and pathologists collaborating through dedicated networks. The aim of this article is to summarize the pathology, causes, mechanisms and therapeutic approaches of pseudomyxoma peritonei, as well as their interfaces with dedicated networks.

Pseudomyxoma peritonei originating from urachus-case report and review of the literature

Pseudomyxoma peritonei (pmp) is a rare clinical condition defined as extensive intraperitoneal spread of mucus associated with a variety of mucinous tumours of varying biologic behavior. Although appendix or ovaries have usually been implicated as the primary site, cases have been reported in association with neoplastic lesions of other sites. Pseudomyxoma peritonei originating from urachal remnants is a unique entity, reported only 18 times in the English literature thus far. Considering the rarity of the lesion, we report the case of a 50-year-old man surgically treated for pmp associated with a low-grade mucinous urachal neoplasm. Unique aspects of case are the low histologic aggressiveness of the causative lesion (reported only twice worldwide) and the early stage of the disease, with a relatively small amount of intraperitoneal free mucin. Review of the literature about pmp in general and a collation of previously reported cases of pmp originating from the urachus are presented and discussed.

Pulmonary giant cell carcinoma associated with pseudomyxoma peritonei

Pulmonary giant cell carcinoma is a rare subtype of sarcomatoid carcinoma. Pseudomyxoma peritonei (PMP) is a rare condition in which gelatinous material accumulates within the peritoneal cavity. It is believed PMP arises from a primary appendiceal mucinous neoplasm that perforates the gut, causing mucinous ascites. There are sporadic reports of PMP associated with neoplasms of other organs, rarely the lung. Here, we report on a 60-year-old woman with pulmonary giant cell carcinoma associated with PMP. She presented with progressive dyspnea and abdominal distention. Abdominal computed tomography revealed moderately dense ascites without an obvious mass. Chest computed tomography revealed a large, solitary right lower-lobe lung mass. She underwent transbronchial fine-needle aspiration of the mass, and was diagnosed with pulmonary giant cell carcinoma. The ascites showed scattered malignant cells in a background of mucin, confirming PMP. To our knowledge, this is the first report of pulmonary giant cell carcinoma associated with PMP.

Complex mucinous cystadenoma of undetermined malignant potential of the urachus

Urachal mucinous neoplasms are rare and include both villous adenomas and invasive adenocarcinomas. These mucinous tumours should be completely excised as they can demonstrate aggressive clinical behaviour, including the development of pseudomyxoma peritonei. We describe a 70-year-old woman who presented with a lower abdominal mass and received a diagnosis of a rare, complex urachal mucinous cystadenoma of undetermined malignant potential. This tumour demonstrated extensive mucin extravasation into perivesical soft tissue, but was not associated with pseudomyxoma peritonei or any malignancy. Rarely described in the English literature, mucinous cystadenomas of the urachus should be treated similarly to their villous adenoma counterparts: with complete surgical excision to prevent local tumour recurrences.

Urachal mucinous tumor of uncertain malignant potential: a case report

Urachal mucinous tumor of uncertain malignant potential is very rare and is characterized by a multilocular cyst showing the proliferation of atypical mucin-secreting cells without stromal invasion. As in ovarian and appendiceal borderline tumors, it represents a transitional stage of mucinous carcinogenesis in the urachus. In addition, this tumor may recur locally and develop into pseudomyxoma peritonei. Due to its scarcity and diagnostic challenges, we report a mucinous tumor of uncertain malignant potential arising in the urachus.

[Peritoneal pseudomyxoma presenting as ascites in a patient with cirrhosis]

We present the case of a cirrhotic patient with ascites and an albumin gradient of less than 1.1 g/dl. After endoscopic tests, including upper gastrointestinal endoscopic ultrasound-guided fine-needle aspiration, exploratory laparoscopy was performed to provide the diagnosis, revealing mucin throughout the peritoneal cavity and nodules on the parietal and visceral peritoneum. Histopathological analysis established the diagnosis as peritoneal pseudomyxoma. This uncommon entity, which has a poor prognosis without treatment, is most frequently associated with mucinous tumors of the appendix, and secondly, with tumors of the ovary.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for patients with peritoneal carcinomatosis secondary to urachal adenocarcinoma

BACKGROUND AND OBJECTIVES

Urachal adenocarcinoma with peritoneal dissemination is an unusual presentation of a rare disease. It is associated with patients experiencing significant pain, poor outcomes, and historical median survival times between 12 and 24 months. We describe our 18-year experience in managing these patients with cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

Five patients who underwent six CRS with HIPEC for disseminated urachal cancer were identified. Demographics, perioperative data, and oncologic results were reviewed.

RESULTS

All patients successfully completed CRS followed by HIPEC with Mitomycin C. Three patients had prior urachal mass excision and one had previous cystoprostatectomy with ileal conduit. At time of surgery, complete resection of all visible disease was only achieved in two patients. All patients developed local or distant disease recurrence at a median of 13 months postoperatively (range 7-31). The majority of patients (3/5) underwent postoperative intravenous chemotherapy for recurrence (2) or residual disease (1). All patients died of their disease, with median survival following date of surgery of 27 months (range 21-87). Symptomatic control of peritoneal disease was achieved in 2/5 (40%) of the cases.

CONCLUSIONS

Urachal adenocarcinoma with peritoneal dissemination is an aggressive, rare disease, which is uniformly fatal. In our experience, CRS followed by HIPEC with Mitomycin C may increase patient survival and palliation, although further treatment improvements are clearly required.

Peritoneal pseudomyxoma arising from the urachus

Pseudomyxoma peritonei (PMP) arising from urachal tumors is extremely rare. To our knowledge, natural history, tumor biological behaviour, morbidity, treatment, and prognosis of PMP arising from the urachus are determined by the associated PMP. Management of urachal tumors with associated PMP should be based on aggressive locorregional therapy with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, similar to PMP arising from other origins.

Recurrent urachal mucinous adenocarcinoma presenting as bilateral ovarian tumors on cesarean delivery

Secondary ovarian cancers, Krukenberg tumors, are a distinctive subset of metastatic tumors arising from the gastrointestinal tract (stomach, colon, and appendix), the biliary system, the breast, or other genital organs. These tumors account for 5% of all ovarian malignancies. Such metastases could mimic primary mucinous ovarian adenocarcinomas. Metastases from the urinary tract are uncommon. Primary adenocarcinoma of the bladder accounts for less than 1% of all bladder malignancies; one third of these tumors are urachal in origin. Urachal cancers are rare and tend to occur in older men (mean age, 50-60 years); however, it was described previously in a 15-year-old girl. Symptoms include hematuria, dysuria, frequency, urgency, and recurrent urinary tract infections. These tumors have a predilection to locally spread to the surrounding organs. Ovarian metastasis is a rare event and is infrequently reported in literature.

Mucinous cystadenocarcinoma of the urachus associated with pseudomyxoma peritonei with emphasis on MR findings

Urachal mucinous cystadenocarcinoma associated with pseudomyxoma peritonei is extremely rare; only 11 cases are reported. We describe the characteristic imaging findings of this disorder and correlate imaging features by computed tomography, magnetic resonance imaging, and ultrasonography with operative findings and histopathologic specimens.

Experience with adjuvant chemotherapy for pseudomyxoma peritonei secondary to mucinous adenocarcinoma of the appendix with oxaliplatin/fluorouracil/leucovorin (FOLFOX4)

Background

Pseudomyxoma peritonei (PMP) is a rare condition characterized by mucinous tumors, disseminated intra-peritoneal implants, and mucinous ascites. So far its diagnosis remains challenging to most clinicians.

Case presentation

A 55-year-old male patient had suffered from acute onset of abdominal pain and abdominal distension for one day prior to his admission. Physical examination revealed tenderness over the right lower quadrant of the abdomen without diffuse muscle guarding. A large amount of ascites was identified by abdominal computed tomography (CT) scan. Paracentesis showed the appearance of sticky mucinous ascites. He underwent laparotomy under the impression of pseudomyxoma peritonei. There was a lot of mucinous ascites, one appendiceal tumor and multiple peritoneal implants disseminated from the subphrenic space to the recto-vesicle pouch. Pseudomyxoma Peritonei caused by mucinous adenocarcinoma of appendiceal origin, was confirmed by histopathology. We performed an excision of the appendiceal tumor combined with copious irrigation and debridement. After the operation, he received 10 cycles of systemic chemotherapy with FOLFOX4 regimen, without specific morbidity. Follow-up of abdominal CT and colonoscopy at post-operative 17 months showed excellent response without evidence of local recurrence or distal metastasis. He made an uneventful recovery (up to the present) for 21 months after the operation.

Conclusion

This case report emphasizes the possible new role of systemic chemotherapy in the treatment of patients with this rare clinical syndrome.

[Peritoneal gelatinous ascites]

Pseudomyxoma peritonei or gelatinous ascites is a rare clinical entity, and its pathogenesis remains obscure. It most often follows a mucinous tumor of the appendix. An ovarian origin in woman has been suggested but remains controversial. Its onset is often insidious: an increase in the abdominal perimeter may be the first sign noted. Preoperative diagnosis is facilitated by modern imaging techniques. Ultrasonography and computed tomography provide complementary signs: septa and scalloping of the liver margins, respectively. Effusion in the lesser peritoneal cavity suggests this diagnosis. Magnetic resonance imaging, by showing the gelatinous ascites, their septa and the scalloping of liver and spleen, can strengthen the probability of the diagnosis. Only laparotomy can confirm it, however. Appendectomy is required in all cases. Recurrence is more frequent in the forms associated with malignant or bipolar tumors. Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is the only therapy shown to be effective in cases of recurrence or malignant forms.

Appendiceal neoplasms and pseudomyxoma peritonei: a population based study

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare disease with an estimated incidence of 1 per million per year, and is thought to originate usually from an appendiceal mucinous epithelial neoplasm. However it is not known exactly how often these neoplasms lead to PMP. The aim of this study is to investigate the incidence of both lesions and their relation.

METHODS

The nationwide pathology database of the Netherlands (PALGA) was searched for the incidence of all appendectomies, the incidence of primary epithelial appendiceal lesions and the incidence and pathology history of patients with PMP. All regarded the 10-year period of 1995-2005.

RESULTS

In the 10-year period 167,744 appendectomies were performed in the Netherlands. An appendiceal lesion was found in 1482 appendiceal specimens (0.9%). Nine percent of these patients developed PMP. Coincidentally, an additional epithelial colonic neoplasm was found in 13% of patients with an appendiceal epithelial lesion. A mucinous epithelial neoplasm was identified in 0.3% (73% benign, 27% malignant) of appendiceal specimens and 20% of these patients developed PMP. For mucocele and non-mucinous neoplasm the association with PMP was only 2% and 3%, respectively. From the nationwide database 267 patients (62 men and 205 women) with PMP were identified, which demonstrates an incidence of PMP in the Netherlands approaching 2 per million per year. The primary site was identified in 68% and dominated by the appendix (82%).

CONCLUSIONS

Primary epithelial lesions of the appendix are rare. One third of these lesions are mucinous epithelial neoplasms and especially these tumours may progress into PMP. The incidence of PMP seems to be higher than thought before. Furthermore there is a considerable risk of an additional colonic epithelial neoplasm in patients with an epithelial neoplasm at appendectomy.

Survival analysis of pseudomyxoma peritonei patients treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

OBJECTIVE

To evaluate the survival of patients with pseudomyxoma peritonei (PMP) treated by cytoreductive surgery and intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC), and to identify factors with prognostic value.

SUMMARY BACKGROUND DATA

PMP is a clinical syndrome characterized by progressive intraperitoneal accumulation of mucous and mucinous implants, usually derived from a ruptured mucinous neoplasm of the appendix. Survival is dominated by pathology.

METHODS

A total of 103 patients (34 men and 69 women) treated at The Netherlands Cancer Institute between 1996 and 2004 were identified. Survival was calculated from date of initial treatment and corrected for a second procedure. PMP was pathologically categorized into disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinomatosis (PMCA), and an intermediate subtype (PMCA-I). Clinical and pathologic factors were analyzed to identify their prognostic value for survival.

RESULTS

Median follow-up was 51.5 months (range, 0.1-99.5 months). Recurrence developed in 44%. A second procedure for recurrence was performed in 11 patients. The median disease-free interval was 25.6 months (95% confidence interval [CI], 14.8-43.6 months). The 3-year and 5-year disease-free survival probability was 43.6% (95% CI, 34.4%-55.2%) and 37.4% (95% CI, 28.2%-49.5%), respectively. The disease-specific 3-year and 5-year survival probability was 70.9% (95% CI, 62.0%-81.2%) and 59.5% (95% CI 48.7%-72.5%), respectively. Factors associated with survival were pathological subtype, completeness of cytoreduction, and degree and location of tumor load (P < 0.05). The main prognostic factor, independently associated with survival, was the pathologic subtype (P < 0.01).

CONCLUSION

Cytoreductive surgery in combination with intraoperative HIPEC is a feasible treatment strategy for PMP in terms of survival. The pathologic subtype remains the dominant factor in survival. Patients should be centralized to improve survival by a combination of surgical experience and adequate patient selection.

Pseudomyxoma peritonei due to mucinous cystadenocarcinoma in situ of the urachus presenting as an inguinal hernia

Pseudomyxoma peritonei is generally caused by appendiceal and ovarian tumors. Other primary sites have been rarely reported. We describe herein the second reported case of pseudomyxoma peritonei due to mucinous cystadenocarcinoma of the urachus. A 54-year-old man was admitted with a left inguinal hernia that had developed several months prior to his admission. During herniorrhaphy, we found a large amount of gelatinous mucinous material in the indirect-hernia sac and made a diagnosis of pseudomyxoma peritonei on cytological grounds. At re-operation, the origin of the pseudomyxoma peritonei proved to be a ruptured urachal cyst. The urachal cyst and the dome of the urinary bladder were excised. In addition, we removed as much of the gelatinous material as possible. On histological examination, a unilocular cyst was found to consist of noninvasive mucinous adenocarcinoma. We succeeded in removing the rest of the mucinous material by postoperative intraperitoneal lavage with dextran solution, and have observed no evidence of recurrence for 7 years since the operation.

Pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a rare condition, which is known for its high mortality when not treated properly. The first step to improve prognosis of these patients is to recognize this clinical syndrome preferably in an early stage. Knowledge of pathogenesis and common diagnostic tools is essential in this regard. Treatment strategy for PMP should pursue complete cytoreduction and prevention of recurrence or progression. Combined modality treatment, consisting of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy, seems very efficient in this regard. This approach is currently carried out in many centers throughout the world with promising results and seems to win ground as the standard treatment approach.

Pseudomyxoma peritonei arising from colonic polyps

AIMS

Pseudomyxoma peritonei may have as its primary site a mucinous gastrointestinal adenoma or carcinoma that gains access to the peritoneal cavity. This manuscript describes this disease arising from a benign or malignant colonic polyp.

METHODS

From a database of over 1000 pseudomyxoma peritonei patients and colorectal carcinomatosis patients, three cases were identified in which the primary tumor site was a colonic polyp. The clinical history and course of these patients were studied.

RESULTS

In a review of the clinical management of these patients, all three had an event whereby neoplastic cells from the surface of the colonic polyp could have gained access to the free peritoneal cavity. The patients developed the characteristic pseudomyxoma peritonei syndrome. All three patients were treated with cytoreductive surgery plus perioperative hyperthermic intraperitoneal chemotherapy.

CONCLUSIONS

Colonic polyps can serve as a source of dysplastic cells whereby pseudomyxoma peritonei can result. Caution to prevent seeding to the free peritoneal cavity during surgery for colonic polyps should be observed. If pseudomyxoma peritonei develops, cytoreductive surgery and perioperative intraperitoneal chemotherapy should be considered for treatment.

Toxicity and mortality of cytoreduction and intraoperative hyperthermic intraperitoneal chemotherapy in pseudomyxoma peritonei--a report of 103 procedures

AIMS

To report on treatment related toxicity and mortality in patients with pseudomyxoma peritonei (PMP) treated by cytoreduction in combination with intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) and to identify prognostic factors.

METHODS

A review was performed of 103 procedures of cytoreduction and intraoperative HIPEC for PMP between 1996 and 2004. Toxicity was graded according to the National Cancer Institute Common Toxicity Criteria (NCI CTC) classification. A surgical complication was defined as any post-operative event that needed re-intervention. Pre and peroperative factors were studied on their relationship to toxicity and mortality.

RESULTS

The median hospital stay was 21 days (4-149) with a treatment related toxicity of 54% and a 30 days mortality of 3%. In univariate analysis, toxicity was associated with abdominal tumour load (p<0.01), completeness of cytoreduction (p<0.01), and age (p=0.05). Surgical complications, mainly small bowel perforations/suture leaks, were the main cause of toxicity. A favourable pathology decreased mortality.

CONCLUSIONS

Cytoreduction in combination with intraoperative HIPEC in PMP patients is a treatment with a relatively high toxicity, but a considerable long-term survival in selected patients. Toxicity is mainly surgery related. Concentration of cases to acquire sufficient experience and better selection on age, pathology, and extent of disease is essential to reduce treatment related toxicity and mortality.

Pseudomyxoma peritonei and the urinary tract: Involvement and treatment related complications

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by intraperitoneal accumulation of mucus produced by neoplastic cells of mostly appendiceal origin. The aim of this study was to analyze primary and secondary involvement and treatment-related complications of the urinary tract in PMP.

METHODS

A retrospective study of 92 patients with PMP, treated by cytoreduction and intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC) at The Netherlands Cancer Institute between 1996 and 2004.

RESULTS

Seven patients presented with involvement of the urinary tract. Major urologic complications occurred in five patients, of which two had secondary involvement of the urinary tract. Major urologic complications consisted predominantly of surgical complications related to the bladder. All patients with secondary involvement and/or urologic complications had undergone previous pelvic surgery.

CONCLUSIONS

The urinary tract is rarely involved in patients with PMP. Secondary involvement is mostly observed and may be a result of seeding of PMP of pelvic origin after prior pelvic surgery. There is a low urologic complication risk of treatment with cytoreduction and HIPEC. The combination of secondary involvement and previous pelvic surgery is an omen of treatment-related urologic complications, necessitating (surgical) re-interventions and further management in close collaboration with urologists.

Pseudomyxoma peritonei: a review of 62 cases

AIM

Pseudomyxoma peritonei (PMP) is a rare disease characterized by the abundance of mucus in the abdomen without extra-peritoneal growth.

METHODS

Our patients with PMP have been treated with cytoreduction and hyperthermic intraperitoneal chemotherapy since 1996. The clinical and histopathological features of PMP and the relation of these features with disease-free interval and survival were assessed.

RESULTS

Sixty-two patients with PMP (24 M/38 F) were studied. Adenomatous mucosal changes were present in 31 patients. In females, the ovaries were normal in 5 patients and pseudomyxoma ovarii was present in 20 patients. Patients with minimal atypia and with 1% focal proliferation or less (n=38) had a better survival (p=0.0008) than those with more focal proliferation (n=14).

CONCLUSION

In most patients with PMP the appendix is affected; in females the ovaries are usually also involved. Focal proliferation appears to be a prognostic factor.