Association of mucinous tumors of the ovary and appendix. A clinicopathologic study of 25 cases

[Mucinous tumors of the peritoneum]

INTRODUCTION

Disseminated peritoneal seeding of mucin-forming tumors is a rare malignant disease with variable prognosis. Histomorphological criteria are instrumental in the prognostic assessment. The past 10 years have led to a standardization of nomenclature and subsequently to the establishment of therapeutic standards. This article aims to provide the current status of the pathological classification, staging, and grading.

METHOD AND MATERIAL

Selective literature search in PubMed and Medline RESULTS: The vast majority of disseminated peritoneal mucinous diseases that correspond to the clinical presentation of pseudomyxoma peritonei (PMP) arise from mucinous tumors of the vermiform appendix. Here are to be distinguished: 1) low-grade appendiceal mucinous neoplasms (LAMN), 2) (very rare) high-grade appendiceal mucinous neoplasms (HAMN), 3) mucinous adenocarcinoma without signet ring cells (G2) and 4) mucinous adenocarcinoma with signet ring cells or signet ring cell carcinoma (G3). Other primary tumors only rarely induce PMP. Terms such as mucocele or mucinous cystadenoma of the appendix correspond to LAMN and should no longer be used. Prognostic distinctions are further made between low-grade PMP, which usually arises from LAMN, and the prognostically less favorable high-grade PMP, which usually arises from mucinous/signet ring cell adenocarcinoma or the rare HAMN. Disseminated peritoneal mucinous disease/PMP must then be further distinguished from prognostically excellent local mucin formation of the peri-appendix region.

DISCUSSION

The currently valid nomenclature, as it has emerged from consensus meetings and in parts has also found its way into the current WHO 2019, has significantly contributed to the fact that the prognosis of patients today can be better estimated and effective forms of treatment could be developed.

Rare presentation of low-grade appendiceal mucinous neoplasms (LAMN) as an appendicular lump: A case report

Introduction

The prevalence of appendiceal mucinous neoplasms (AMN) is about 0.2%-0.3% in the specimens of the appendix. The LAMN may appear unremarkable or can present as mucin-filled, crystally dilated tissues. The diagnosis of early-stage AMN is mostly incidental. It is of vital importance to know the features of LAMN for a timely diagnosis.

Case presentation

A 46-year-old male came with the complaint of right iliac fossa swelling along with severe intensity pain and a single episode of vomiting. A 4 × 4cm tender, soft, cystic, mobile swelling was found upon the examination. Contrast-enhanced Computerized tomography (CT) scan of the abdomen revealed the appendix diameter of 10mm well-circumscribed cystic measuring 2.1 × 2 cm. Therefore, an open resection surgery was performed. The histopathological report revealed an intraepithelial lesion composed of flat mucinous epithelial cells having eosinophilic cytoplasm and low-grade nuclear atypia.

Case discussion

The AMNs are very rare neoplasms. The imaging modalities that can be diagnostic methods are abdominal and transvaginal ultrasonography (US), and abdominal computed tomography (CT). The low-grade features of the appendiceal mucinous neoplasms have the possibility of recurrence. The CT-scan findings of appendiceal lump>1.3cm along with cystic dilation and the calcification of the wall are the suggestive features of AMN. There is a high chance of dissemination and port site seeding in case of pneumoperitoneum.

Conclusion

This rare case suggests the significance of adding AMNs as a differential diagnosis in patients with abdominal pain and choosing the right approach to treat such patients to avoid complications.

Second primary malignancies after ovarian cancer: A SEER-based analysis (1975-2016)

OBJECTIVE

To investigate the risk of occurrence of second primary malignancies (SPMs) in survivors of ovarian cancer (OC) using large data from the Surveillance, Epidemiology, and End Results (SEER) database.

MATERIALS AND METHODS

Multiple primaries standardized incidence ratios (MP-SIRs) to calculate the risk of developing second primary malignancies after a diagnosis of ovarian cancer.

RESULTS

Of our included 59,880 women with OC, 3972 cases (6.6%) developed 4495 s primary malignancies over an average follow-up period of 114.39 (±102.66) months. Overall, the risk of occurrence of second primary malignancies after a diagnosis of OC was greater than what would be expected for a reference US population (SIR = 1.05, 95%CI = 1.02-1.08, p-value < 0.05). The occurrence of second myeloid malignancies and second thyroid cancer were most notable across our latency periods. Among the most significant second primary malignancies by latency were malignancies of the appendix (SIR = 14.04, 95%CI = 5.65-28.93, p-value <0.05) at 2-11 months, the small intestine (SIR = 3.15, 95%CI = 1.76-5.2, p-value <0.05) at 12-59 months, and the urinary bladder (SIR = 1.63, 95%CI = 1.3-2.02, p-value <0.05) after 10 years of an OC diagnosis.

CONCLUSION

Women with OC are at significant risk for the development of second primary malignancies across all sites, as compared to a reference US population, and may benefit from second primary malignancies site-specific screening post-diagnosis.

Frozen Section Diagnosis of Ovarian Epithelial Tumors: Diagnostic Pearls and Pitfalls

CONTEXT.—

Epithelial tumors of the ovary are one of the most frequently encountered gynecologic specimens in the frozen section laboratory. The preoperative diagnostic workup of an ovarian mass is typically limited to imaging studies and serum markers, both of which suffer from low sensitivity and specificity. Therefore, intraoperative frozen section evaluation is crucial for determining the required extent of surgery, that is, cystectomy for benign tumors, oophorectomy or limited surgical staging for borderline tumors in younger patients to preserve fertility, or extensive staging procedure for ovarian carcinomas. Ovarian epithelial tumors may exhibit a wide range of morphologic patterns, which often overlap with each other and can mimic a variety of other ovarian nonepithelial neoplasms as well. A combination of careful gross examination, appropriate sampling and interpretation of morphologic findings, and familiarity with the clinical context is the key to the accurate frozen section diagnosis and successful intraoperative consultation.

OBJECTIVE.—

To review the salient frozen section diagnostic features of ovarian epithelial tumors, with special emphasis on useful clinicopathologic and morphologic clues and potential diagnostic pitfalls.

DATA SOURCES.—

Review of the literature and personal experience of the author.

CONCLUSIONS.—

Frozen section evaluation of ovarian tumors continues to pose a significant diagnostic challenge for practicing pathologists. This review article presents detailed discussions of the most common clinical scenarios and diagnostic problems encountered during intraoperative frozen section evaluation of mucinous, serous, endometrioid, and clear cell ovarian tumors.

SATB2 Versus CDX2: A Battle Royale for Diagnostic Supremacy in Mucinous Tumors

CONTEXT.—

Metastatic mucinous tumors present a diagnostic challenge for pathologists as tumor histomorphology is often nonspecific and optimal immunoprofiles are still under investigation.

OBJECTIVE.—

To present a head-to-head comparison of special AT-rich sequence-binding protein 2 (SATB2) and caudal type homeobox 2 (CDX2) expression in a diverse array of primary mucinous tumors.

DESIGN.—

SATB2 and CDX2 immunohistochemical stains were performed on whole sections from 44 mucinous colorectal carcinomas and 175 noncolorectal mucinous tumors. A nuclear scoring system measuring intensity (0-3+) and percentage staining (0 = <5%, 1 = 5%-49%, 2 = ≥50%) was implemented, producing an additive histologic score (H-score).

RESULTS.—

SATB2 demonstrated acceptable accuracy at low to moderate expression levels (H-scores of 1-4). With these H-score cutoffs, overall accuracy was greater than 90%. In contrast, CDX2's accuracy rivaled that of SATB2 only at an H-score of 5 (89.0%), as its specificity suffered at lower expression levels (<70.0% at H-scores of 1-4). Using a moderate H-score cutoff of 3 or higher, significant differences for both sensitivity and specificity were identified between SATB2 and CDX2 (P = .01 for sensitivity and P < .001 for specificity), though these stains were near equivalent when each was interpreted as positive at its respective optimal H-score (SATB2 ≥ 3 and CDX2 = 5).

CONCLUSIONS.—

SATB2 is a more accurate marker of colorectal origin across a variety of expression levels compared with CDX2 when applied to mucinous tumors from a host of primary sites. However, these stains are near equivalent when each is interpreted at its optimal expression level.

Mucinous appendiceal neoplasms: Incidence, diagnosis and surgical treatment

INTRODUCTION

Mucinous tumors of the appendix are a rare pathology, with a prevalence below 0.5%. Clinical presentation usually occurs during the sixth decade of life, and mucinous tumors can clinically mimic acute appendicitis. The aim of this study is to describe the clinical and demographic variables, therapeutic procedure and diagnosis of these tumors. We analyze the association between mucinous tumors and pseudomyxoma peritonei (PP), as well as the association with colorectal and ovarian tumors.

METHODS

A retrospective study was performed including patients who underwent an appendectomy between December 2003 and December 2014.

RESULTS

Seventy-two mucinous tumors of the appendix were identified among 7.717 patients reviewed, resulting in a prevalence of 0.9%. Mean age at presentation was 64 years, 62% patients were female and 38% males. An incidental diagnosis was made in 43% of patients. Mucinous tumors of low malignant potential were significantly related to the presence of pseudomyxoma peritonei, identified in 16 (22%) of the cases. We also observed an increased risk of ovarian mucinous tumors in patients with a diagnosis of appendiceal mucinous neoplasm. In our sample, 22 (30.5%) patients showed a synchronous or metachronous colorectal cancer.

CONCLUSIONS

Appendiceal mucinous tumors are frequently an incidental finding. The diagnosis of mucinous tumors of low malignant potential is a factor associated with the development of pseudomyxoma peritonei. Histologic tumor grade and the presence of peritoneal dissemination will determine surgical treatment that can vary, from appendectomy to cytoreductive surgery.

Dual Immunostain With SATB2 and CK20 Differentiates Appendiceal Mucinous Neoplasms From Ovarian Mucinous Neoplasms

OBJECTIVES

Determination of the primary site of origin for mucinous neoplasms identified in the peritoneal and/or pelvic cavities may be challenging, with major differential diagnoses including appendiceal mucinous neoplasm (AMN) and ovarian mucinous neoplasm (OMN). Special AT-rich sequence binding protein 2 (SATB2) has been shown to be highly selectively expressed in the lower gastrointestinal tract, including the appendix.

METHODS

We investigated the utility of a dual stain (DS) with SATB2 or caudal type homeobox 2 (CDX2) and cytokeratin 20 (CK20) or villin in distinguishing AMNs from OMNs. Tissue microarrays with 40 AMNs and 18 OMNs were stained with SATB2 or CDX2 paired with either CK20 or villin.

RESULTS

SATB2 single stain showed a good sensitivity of 83% and the highest specificity of 78% for AMNs over OMNs among all four stains. DS with SATB2 and villin showed an identical sensitivity of 78% but specificity increased to 94%, while DS with SATB2 and CK20 showed a sensitivity of 80% and a specificity of 100%. In contrast, DS with CDX2 and CK20/villin showed slightly higher sensitivity but much lower specificity.

CONCLUSIONS

DS with SATB2/CK20 shows the greatest potential clinical utility in distinguishing AMNs from OMNs and is superior to DS with CDX2/CK20. Importantly, DS could be helpful for specimens with limited tissues.

Synchronous Ovarian and Appendiceal Mucinous Neoplasms in the Absence of Pseudomyxoma Peritonei

Background

Synchronous ovarian/appendiceal mucinous neoplasms sometimes occur in the absence of clinical pseudomyxoma peritonei (PMP), which raises a question about whether the 2 tumors could be independent.

Methods

We identified 11 cases of synchronous ovarian/appendiceal mucinous neoplasms without PMP and subclassified them into groups 1 and 2 based on the presence or absence of microscopic peritoneal/ovarian surface mucin deposits. A 7-marker panel (CK7, CK20, CDX2, PAX8, MUC1, MUC2, and MUC5AC) immunohistochemistry was performed on both tumors.

Results

Between the 2 groups, there were no significant differences in age, laterality, size, and histology of ovarian/appendiceal tumors. In group 1, 2 of 4 cases developed PMP later, and both had ovarian surface and contralateral ovarian involvement and appendiceal perforation with microscopic mucin deposits on the peritoneum. No patients in group 2 developed PMP. All group 1 cases showed a high degree of concordance of immunoprofile between the synchronous tumors, with an identical expression of appendiceal pattern in greater than 90% of the markers. In group 2, only 1 of 7 cases showed concordance in all markers.

Conclusions

If peritoneal mucin deposits present, even microscopic and acellular, the synchronous tumors are most likely of a single appendiceal origin. Otherwise, they are more heterogeneous, and some may be truly dual primaries.

Causes of hepatic capsular retraction: a pictorial essay

Abstract

Hepatic capsular retraction refers to the loss of the normal convex hepatic contour, with the formation of an area of flattening or concavity. This can result from myriad causes, including intrinsic hepatic conditions such as cirrhosis, biliary obstruction, benign tumours, malignancy and infections, as well as extrahepatic causes such as trauma. This article aims to provide familiarity with this wide spectrum of conditions, including mimics of hepatic capsular retraction, by highlighting the anatomic, pathologic and imaging features that help distinguish these entities from one another.

Teaching Points

• Hepatic capsular retraction can occur due to various intrinsic or extrinsic hepatic causes.

• Hepatic capsular retraction is observed in both benign and malignant conditions.

• Recognising associated imaging features can help elicit causes of hepatic capsular retraction.

Low-grade Appendiceal Mucinous Neoplasm of Uncertain Malignant Potential (LAMN-UMP): Prognostic Factors and Implications for Treatment and Follow-up

BACKGROUND

Low-grade appendiceal mucinous neoplasm of uncertain malignant potential are poorly understood lesions characterized by extraluminal mucin or fibrosis with neoplastic cells confined to the appendiceal lumen. The purpose of this study is to investigate the clinical and pathologic parameters of these lesions to optimize our understanding and management of these tumors.

METHODS

Subjects with these tumors were identified from the appendiceal tumor databases at the University of Texas MD Anderson Cancer Center. Univariate and multivariate Cox proportional hazards regression analyses assessed relationships between clinicopathologic variables [including age, gender, margin status and serum levels of the tumor markers carcinoembryonic antigen (CEA), cancer antigen (CA)-125, and CA19-9] disease-free survival, postrecurrence survival and overall survival.

RESULTS

Ninety-eight subjects with this disease were identified. Most patients did not experience disease recurrence after initial appendectomy. At last follow-up, 25 (26 %) had disease recurrence or died. Of the 20 patients who had disease recurrence, 5 (25 %) died, and 15 (75 %) were alive. Disease-free survival was significantly reduced with positive margin status (p = 0.02) and elevated serum levels of CEA (p < 0.001), CA19-9 (p = 0.01), or CA-125 (p = 0.002) at the time of appendectomy. The median postrecurrence survival time was 4.7 years and the 5-year postrecurrence survival rate was 41 % (standard error = 18 %).

CONCLUSIONS

Patients with Low-grade appendiceal mucinous neoplasm of uncertain malignant potential who have negative margins and normal tumor marker levels have a lower risk for recurrence. In these patients, expectant management is sufficient. Elevated tumor marker levels at the time of appendectomy marks an increased risk of recurrence or death and signals the need for closer monitoring or intervention.

Significance of epithelial cell clusters in pseudomyxoma peritonei

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterised by distension of the peritoneum by jelly-like ascites. Cytological evaluation of peritoneal fluid is often an initial diagnostic test for possible ovarian and/or appendiceal primary tumours.

AIMS AND OBJECTIVES

The present work was conducted to study the usefulness of peritoneal fluid cytomorphology in the early diagnosis of PMP and to evaluate the significance of the presence of epithelial cell (EC) clusters and their prognostic implications.

MATERIALS AND METHODS

We evaluated the detailed cytological features of 21 cases of PMP retrospectively. Both conventional and liquid-based cytology smears of peritoneal fluid were reviewed, cytological features were compared with histological findings and cases were classified into disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis (PMCA).

RESULTS

In our study, the common causes of PMP were primary gastrointestinal malignancies (appendix and colorectal, 57.14%), followed by primary ovarian mucinous neoplasms (28.57%) and synchronous ovarian and appendicular tumours (14.28%). Thick mucinous material was present in all cases (100%). ECs were present in 18 of 21 (85.17%) patients, with mild nuclear atypia in the majority of cases. Histiocytes, mesothelial cells and fibroblast-like, spindle-shaped cells with entrapped mucin were also noted in the background. The cases of PMCA showed greater numbers of EC clusters in cytology smears and these patients had recurrent episodes of PMP.

CONCLUSION

On cytomorphology, high-grade tumours were more cellular and frequently showed EC clusters with moderate to severe atypia, prominent nucleoli and mitosis, and were more prone to PMCA.

How our practice of histopathology, especially tumour pathology has changed in the last two decades: reflections from a major referral center in Pakistan

Continued advances in the field of histo-pathology (and cyto-pathology) over the past two decades have resulted in dramatic changes in the manner in which these disciplines are now practiced. This is especially true in the setting of a large university hospital where the role of pathologists as clinicians (diagnosticians), undergraduate and postgraduate educators, and researchers has evolved considerably. The world around us has changed significantly during this period bringing about a considerable change in our lifestyles and the way we live. This is the world of the internet and the world-wide web, the world of Google and Wikipedia, of Youtube and Facebook where anyone can obtain any information one desires at the push of a button. The practice of histo (and cyto) pathology has also evolved in line with these changes. For those practicing this discipline in a poor, developing country these changes have been breathtaking. This is an attempt to document these changes as experienced by histo (and cyto) pathologists practicing in the biggest center for Histopathology in Pakistan, a developing country in South Asia with a large (180 million) and ever growing population. The Section of Histopathology, Department of Pathology and Microbiology at the Aga Khan University Hospital (AKUH) in Karachi, Pakistan's largest city has since its inception in the mid-1980s transformed the way histopathology is practiced in Pakistan by incorporating modern methods and rescuing histopathology in Pakistan from the primitive and outdated groove in which it was stuck for decades. It set histopathology in Pakistan firmly on the path of modernity and change which are essential for better patient management and care through accurate and complete diagnosis and more recently prognostic and predictive information as well.

[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.

Current concepts in pseudomyxoma peritonei

Each year, about two per million individuals will be diagnosed with pseudomyxoma peritonei, a disease characterised by the intra-abdominal growth of neoplastic mucin-secreting cells on peritoneal surfaces. The distribution of the disease within the abdomen is not random but depends on physiological principles. Most cases derive from neoplasms of the appendix. In the past, the ovary was considered a common primary site. However, we now know that the ovary is only rarely the source of pseudomyxoma, and that lesions which would previously have been called "borderline mucinous tumours of the ovary" are typically metastatic from the appendix. The grade of the neoplastic cells in pseudomyxoma is an important prognostic factor, but unfortunately there is no consensus on terminology. An international expert group of pathologists and clinicians is currently working on the harmonisation of terminology in this field. Expertise in the management of pseudomyxoma can be achieved by concentrating the treatment of patients in specialised centres or through the development of 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.

Determining the site of origin of mucinous adenocarcinoma: an immunohistochemical study of 175 cases

Mucinous adenocarcinomas (MAs) of various origins may have a similar histologic appearance and frequently metastasize to distant sites, which often causes diagnostic problems in surgical pathology practice. The immunohistochemical profiles of MAs of various origins have not been well studied. We investigated the expression of 10 immunohistochemical markers (CK7, CK20, CDX-2, β-catenin, MUC-1, MUC-2, MUC-6, ER, WT-1, and PAX-8) in 175 cases of MA, including 69 cases from the lower gastrointestinal (GI) tract, 41 from the upper GI tract, 27 from gynecologic organs, 4 from the urinary bladder, 18 from the breast, and 16 from the lung. We found that lower GI MAs (colon, rectum, and anus) frequently expressed CDX-2 (42 of 42, 100%; 33 of 42 with homogenous positivity, 79%), MUC-2 (42 of 42; 100%), CK20 (41 of 42; 98%), and β-catenin (nuclear) (27 of 42; 64%) and rarely expressed MUC-6 (2 of 42; 5%) and CK7 (8 of 42; 19%). Most of the CK7-positive cases were from the rectum and anus (7 of 8; 88%). The expression of these markers in appendiceal MAs was similar to that of low GI tract MAs, except for a lower percentage of homogenous CDX-2 (3 of 27; 11%) and nuclear β-catenin (3 of 27; 11%) expression. Unlike their lower GI tract counterparts, the upper GI tract MAs (ampulla, pancreas/biliary tree, and stomach/esophagus) frequently expressed CK7 (38 of 41; 93%) and MUC-6 (31 of 41; 76%) and were rarely homogenously positive for CDX-2 (4 of 41; 10%) and nuclear positive for β-catenin (8 of 41; 19%). Breast MAs were frequently positive for CK7 (18 of 18; 100%), MUC-1 (18 of 18; 100%), MUC-2 (18 of 18; 100%), ER (16 of 18; 89%), MUC-6 (9 of 18; 50%), and WT-1 (9 of 18; 50%). Lung MAs were frequently positive for CK7 (16 of 16; 100%) and MUC-1 (15 of 16; 94%). Gynecologic MAs were positive for CK7 (25 of 27; 93%) and PAX-8 (13 of 27; 48%). We conclude that homogenous CDX-2 and nuclear β-catenin expressions are commonly seen in lower GI tract MAs. In contrast, appendiceal MAs are usually heterogenously positive for CDX-2 and show cytoplasmic positivity for β-catenin. Unlike lower GI tract MAs, upper GI tract MAs are frequently positive for CK7 and MUC-6. As is the case in appendiceal MAs, the upper GI tract MAs may also be heterogenously positive for CDX-2. Breast MAs are positive for ER and WT-1, whereas gynecologic MAs are positive for PAX-8 and negative for WT-1.

Mucinous Neoplasms of the Appendix and Peritoneum

Context.—Appendiceal mucinous neoplasms are considered enigmatic tumors of unpredictable biologic potential. Their importance lies in their potential to spread to the peritoneum and viscera in the form of gelatinous mucin deposits. Extra-appendiceal spread of these tumors is the most common etiology of pseudomyxoma peritonei, which is a descriptive term encompassing a number of neoplastic and nonneoplastic peritoneal disorders. Many studies aimed at evaluating the biologic importance of appendiceal mucinous neoplasms and pseudomyxoma peritonei have employed inconsistent histologic criteria for their diagnosis and descriptive terminology for their classification. As a result, appendiceal mucinous neoplasms and associated peritoneal disease represents one of the most confusing and controversial areas in gastrointestinal pathology.

Objectives.—To summarize the literature regarding the biologic potential of appendiceal mucinous neoplasms and pseudomyxoma peritonei and to discuss the similarities and differences between proposed systems for their classification.

Data Sources.—Literature review and case-derived material.

Conclusions.—Many studies have contributed to an increased understanding of the natural progression of mucinous neoplasms of the appendix and peritoneum, and the adoption of a uniform reporting system, as advocated by the American Joint Committee on Cancer and the World Health Organization, will facilitate clear communication among pathologists and clinical colleagues.

Mucinous metaplasia of the fallopian tube: a diagnostic pitfall mimicking metastasis

Interpretation of the mucinous change in the fallopian tubes has been difficult because several reports consider this mucinous change as a metastasis from a mucinous tumor. To clarify this issue, we decided to retrospectively review salpingectomies from 3 institutions looking for mucinous change in the fallopian tubes and documented the clinical history of these patients. Twenty-three cases of fallopian tubes with mucinous changes were found, including 11 patients without evidence of malignancy, 4 patients with mucinous ovarian tumors, 5 patients with nonmucinous gynecologic tumors, 2 patients with mucinous appendiceal neoplasm, and 1 patient with colon carcinoma. As mucinous changes are seen in several patients who do not have a malignant tumor, we believe that these changes represent a metaplastic process. The mucinous changes are frequently seen with chronic inflammation and/or other metaplastic changes and without cytologic evidence of malignancy.

Appendiceal mucinous neoplasms: controversial issues

Low grade appendiceal mucinous neoplasms can spread to the peritoneum as pseudomyxoma peritonei even though they are not obviously invasive in the appendix. During the past several decades, several problematic issues surrounding this enigmatic tumor have been debated in the literature, including appropriate nomenclature for the appendiceal tumors and their peritoneal metastases. In this article, the most contentious issues in the area of appendiceal mucinous tumors are examined. First, the classification systems that have been proposed for these tumors are compared in the context of whether the appendiceal mucinous tumors are ruptured adenomas or invasive carcinomas. The controversy about the nature of pseudomyxoma peritonei and its classification systems is discussed in the following section. A brief discussion follows that examines the issue of localized pseudomyxoma peritonei and its clinical significance. Next reviewed is the largely resolved controversy about whether ovarian mucinous tumors in this setting are separate primaries or are metastases from the appendiceal tumor. Finally, the controversy about the most effective treatment of patients with pseudomyxoma peritonei is discussed.

Pathophysiology and biology of peritoneal carcinomatosis

Peritoneal carcinomatosis represents a devastating form of cancer progression with a very poor prognosis. Its complex pathogenesis is represented by a dynamic process comprising several steps. To the best of our knowledge pathogenesis can be partly explained by 3 major molecular pathways: (1) dissemination from the primary tumor; (2) primary tumor of peritoneum; and (3) independent origins of the primary tumor and peritoneal implants. These are not mutually exclusive and combinations of different mechanisms could occur inside a single case. There are still several aspects which need explanation by future studies. A comprehensive understanding of molecular events involved in peritoneal carcinomatosis is of paramount importance and should be systematically pursued not only to identify novel strategies for the prevention of the condition, but also to obtain therapeutic advances, through the identification of surrogate markers of prognosis and development of future molecular targeted therapies.

Secondary tumors and tumorlike lesions of the peritoneal cavity: imaging features with pathologic correlation

Tumors and tumorlike lesions that secondarily involve the mesothelial or submesothelial layers of the peritoneum are a diverse group of disorders that range in biologic behavior from benign to highly malignant. The anatomy of peritoneal ligaments and mesenteries and the normal circulation of peritoneal fluid dictate location and distribution of these diseases within the peritoneal cavity. Peritoneal carcinomatosis is the most common secondary tumor to affect the peritoneal cavity. When it arises from carcinomas of the gastrointestinal tract or ovary, the prognosis is grave. However, when low-grade mucinous adenocarcinoma of the appendix spreads to the peritoneal cavity, the consequence is typically pseudomyxoma peritonei, which is a clinical syndrome, characterized by recurrent and recalcitrant voluminous mucinous ascites due to surface growth on the peritoneum without significant invasion of underlying tissues. Carcinomas from elsewhere in the body, as well as lymphomas and sarcomas, may also produce diffuse peritoneal metastasis. Granulomatous peritonitis is the consequence of disseminated infection such as tuberculosis or histoplasmosis, foreign materials, or rupture of a tumor or hollow viscus. Finally, a group of benign miscellaneous conditions that range from common disorders such as endometriosis and splenosis to very rare conditions such as gliomatosis peritonei and melanosis may also affect the peritoneum diffusely. Secondary tumors and tumorlike lesions of the peritoneum have overlapping imaging features when compared with each other and primary peritoneal tumors. Knowledge of peritoneal anatomy, normal fluid circulation within the peritoneal cavity, and clinical and pathologic features of secondary peritoneal lesions is essential for identification of these lesions.

An ovarian tumour with a potential appendiceal origin

A 14-year-old girl underwent left oopherectomy for a multicystic ovarian mass. Histology revealed this to be an intestinal type mucinous borderline tumour (IMBT). In view of this, a semi-urgent laparoscopic appendicectomy was carried out. The appendix was histologically normal. IMBT of the ovary is a mucinous tumour with atypical proliferation of the goblet cell containing epithelium. It is known to occur simultaneously with tumours of the appendix. Paediatric surgeons need to be aware of this rare tumour and when operating on any ovarian pathology should always inspect the peritoneal cavity for mucinous deposits and examine the appendix.

[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.

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.

CDX-2 expression in pseudomyxoma peritonei: a clinicopathological study of 42 cases

AIMS

CDX-2 is a highly sensitive and specific marker of intestinal epithelial cells and their neoplastic counterparts. CDX-2 status in pseudomyxoma peritonei (PMP) has been barely reported. The aim of this study was to investigate the clinicopathological features of 42 cases of PMP with a special emphasis on CDX-2.

METHODS AND RESULTS

All patients were treated by cytoreduction. Immunohistochemistry was performed for CDX-2, MUC-2, MUC-5AC, cytokeratin (CK) 7 and CK20. Statistical correlation was evaluated for age, sex, completeness of cytoreduction and histological subtype with overall and progression-free survival (OS and PFS). PMP consisted of 32 cases of disseminated peritoneal adenomucinosis and 10 cases of peritoneal mucinous carcinomatosis. The appendix evaluated in 25 cases showed two mucinous adenocarcinomas and 21 low-grade appendiceal mucinous neoplasms. CDX-2 was diffusely positive in 40 cases, with the remaining two cases being focally positive. All cases demonstrated diffuse reactions to CK20 and MUC-2, and variable reactions to MUC-5AC, while CK7 was variably positive in 38 cases. Five-year OS was 97%. Histological type was significantly correlated with PFS (P=0.02).

CONCLUSIONS

CDX-2 is diffusely and strongly positive in PMP. This is a useful marker to confirm an appendiceal origin of PMP, particularly when used in conjunction with CK7, CK20, MUC-2 and MUC-5AC.

A specific cadherin phenotype may characterise the disseminating yet non-metastatic behaviour of pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a rare neoplasm of mainly appendiceal origin, characterised by excess intra-abdominal mucin production leading to high morbidity and mortality. While histological features are frequently indolent, this tumour disseminates aggressively throughout the abdominal cavity, yet seldom metastasises. This study determined the expression of several markers of colorectal differentiation (carcinoembryonic antigen (CEA), cytokeratins (CK20 and CK7), epithelial membrane antigen), mucin production (MUC-2, interleukin-9 (IL-9), IL-9 receptor (IL-9Rα)), and cell adhesion (N- and E-cadherin, vimentin) in PMP tissue (n=26) compared with expressions in normal colonic mucosa (n=19) and colorectal adenocarcinoma (n=26). Expressions of CEA and cytokeratins were similar for PMP as those in colorectal adenocarcinomas with the exception that the CK20−/CK7− pattern was rare in PMP (Fisher's exact test: P=0.001). Similarly, expressions of mucin-related proteins were comparable for adenocarcinoma and PMP, with the exception that IL-9 expression was uncommon in adenocarcinoma (P=0.009). Pseudomyxoma peritonei demonstrated a specific pattern of adhesion-related protein expressions of increased N-cadherin, reduced E-cadherin, and increased vimentin (P=0.004), a phenotype suggesting a possible epithelial–mesenchymal transition state. Primary PMP cell cultures were successfully maintained and demonstrated marker expressions similar to those seen in in vivo tissues. These early characterisation studies demonstrate similarities between PMP and colorectal adenocarcinoma, but also reveal a specific cadherin phenotype that may characterise the distinct non-metastasising behaviour of PMP, and form the basis for future mechanistic and therapy-targeting research.

From krukenberg to today: the ever present problems posed by metastatic tumors in the ovary: part I. Historical perspective, general principles, mucinous tumors including the krukenberg tumor

This review considers historical aspects of metastatic tumors to the ovary, general principles that aid in their evaluation, and metastatic mucinous tumors, including the Krukenberg tumor. The historical timeline on the Krukenberg tumor dates back to the legendary Sir James Paget and the story is followed through the well-known, albeit flawed, contribution of Friedrich Krukenberg and others who have contributed important papers over the years, including the overlooked contribution of the French investigator Gauthier-Villars. Knowledge of metastatic colorectal carcinoma is traced back to the famed British surgeon Sir John Bland-Sutton and followed through to more recent contributions, including the important one of Lash and Hart. Contributions on mucinous tumors conclude the historical perspective, note being made of the recent evidence suggesting that the long held contention of Dr Robert E. Scully that ovarian mucinous tumors in patients with pseudomyxoma peritonei usually originate from the appendix is correct. The section on general principles highlights the many clinical, gross, microscopic, and special techniques such as immunohistochemistry that may aid in determining that an ovarian tumor is metastatic with emphasis on the first 3 mentioned aspects. Problematic features such as a tendency for metastatic tumors to be cystic, even when the primary tumors are not, and for many metastatic tumors to mature in the ovary (so-called maturation phenomenon), are emphasized. Of the many helpful findings that resolve the problem, the characteristic features of surface implants are highlighted. The contribution on the Krukenberg tumor reviews the varied microscopy of this tumor pointing out that the well-known pattern of signet-ring cells in a cellular stroma, albeit characteristic, is often not striking and frequently overshadowed by other microscopic features. The latter include, in many cases, a rather unique microcystic pattern. The final portion of the essay reviews mucinous tumors of non-Krukenberg type, beginning with those that originate from the appendix. The appendiceal neoplasms have distinctive features in most cases being particularly well differentiated, and this is also seen in their ovarian metastases. Other mucinous tumors that commonly simulate closely metastatic neoplasms, include those from the pancreas in particular, but also diverse other sites, are then reviewed.

Pseudomyxoma peritonei of appendiceal origin: a clinicopathologic analysis of 101 patients uniformly treated at a single institution, with literature review

Pseudomyxoma peritonei is a clinical term for gelatinous ascites, usually secondary to an appendiceal tumor. The pathologic classification of pseudomyxoma peritonei and its associated appendiceal tumors has been plagued with controversy and confusing terminology. In an effort to clarify this, we reviewed the pathology of 101 patients, all treated at our institution from 1993 to 2005, with pseudomyxoma peritonei of appendiceal origin. All patients were uniformly treated with our standardized protocol. This is the largest pathologic series solely devoted to appendiceal neoplasia with gelatinous ascites. The cases were assigned, according to previously published criteria, to the categories of disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinomatosis (PMCA), or PMCA with intermediate (well differentiated) features (PMCA-I), with the exception that any case with a signet-ring cell component was considered as PMCA and not PMCA-I. By histologic category, 58 patients had DPAM, 23 were PMCA, and 20 were PMCA-I.One-year, 3-year, and 5-year survival outcomes were not significantly different between DPAM and PMCA-I. DPAM and PMCA-I also exhibited a roughly equal incidence of parenchymal (beyond the serosa) organ invasion. Survival outcomes were significantly worse for PMCA, compared with PMCA-I and DPAM. After reviewing our data and the literature, mucinous carcinoma peritonei-low grade was applied to the low-grade histology of pseudomyxoma peritonei, including those cases referred to by some as DPAM in the same category as PMCA-I. Cases that are moderately differentiated to poorly differentiated are classified as mucinous carcinoma peritonei-high grade.

Retention mucocele of distal viable remnant tip of appendix: An unusually rare late surgical complication following incomplete appendectomy

A 67-year old man was presented with a 6-mo history of recurrent right lower quadrant abdominal pain. On physical examination, a vague mass was palpable in the right lumbar region. His routine laboratory tests were normal. Ultrasonography showed a hypoechoic lesion in the right lumbar region anterior to the right kidney with internal echoes and fluid components. Abdominal contrast-enhanced computed tomography (CECT) showed a well-defined hypodense cystic mass lesion lateral to the ascending colon/caecum, not communicating with the lumen of colon/caecum. After complete open excision of the cystic mass lesion, gross pathologic examination revealed a turgid cystic dilatation of appendiceal remnant filled with the mucinous material. On histopathological examination, mucinous cyst adenoma of appendix was confirmed. We report this rare unusual late complication of mucocele formation in the distal viable appendiceal remnant, which was leftover following incomplete retrograde appendectomy. This unusual complication is not described in the literature and we report it in order to highlight the fact that a high index of clinical and radiological suspicion is essential for the diagnosis of mucocele arising from a distal viable appendiceal remnant in a patient who has already undergone appendectomy presenting with recurrent abdominal pain.

Appendiceal mucinous tumors and pseudomyxoma peritonei: histologic features, diagnostic problems, and proposed classification

Pseudomyxoma peritonei is an overused and underspecified condition that has garnered much attention in the historic literature. In recent years, this condition has been convincingly linked to appendiceal mucinous neoplasms, yet there has been insufficient attention to the histologic characteristics, classification, and differential diagnostic considerations of these neoplasms when encountered by the surgical pathologist. This review provides a coherent approach to the diagnosis and classification of appendiceal mucinous tumors and the peritoneal implants associated with the pseudomyxoma peritonei syndrome with emphasis on differential diagnostic considerations and recommendations for the final pathology report.

Serosal involvement in gastrointestinal cancer: its assessment and significance

There is an increasing burden upon diagnostic histopathologists to identify accurately factors of prognostic and therapeutic implication in gastrointestinal cancer. It is perhaps partly because of the use of rigid sequential staging systems, such as the Dukes' classification, that some factors, perhaps most notably involvement of surgical margins (especially in rectal cancer) and serosal involvement (particularly in oesophageal, colonic and rectal cancer), have been relatively neglected until more recently. This is surprising and concerning because both of these pathologically derived parameters strongly correlate with subsequent locoregional recurrence and, ultimately, with prognosis. Whilst the occurrence and significance of serosal involvement have been well recognized in gastric cancer for many years, relatively little attention has been paid to the phenomenon in oesophageal cancer and yet both pleural and peritoneal involvement may be comparatively commonly identified in oesophageal cancer. Serosal involvement and transperitoneal spread are also of considerable prognostic importance in primary appendiceal carcinoma. Only more recently has the significance of serosal involvement been appreciated in colonic and rectal cancer. In the colon, the phenomenon is now recognized to be one of the most important factors in predicting transperitoneal spread and overall prognosis. Furthermore, there is increasing interest in alternative novel strategies, including intraperitoneal chemotherapy and radical peritoneal surgery, as legitimate therapeutic options in many gastrointestinal cancers.

Recovery from idiopathic thrombocytopenic purpura (ITP) following right hemicolectomy for mucocele of appendix

A 61-year-old woman with a 2-year medication-free history of idiopathic thrombocytopenic purpura was referred to our hospital complaining of right lower abdominal pain. The platelet count was about 3-4x10(4)/mm3. This patient was diagnosed with mucocele of the appendix on computed tomography and colonoscopy. We performed only right hemicolectomy without splenectomy. The pathological diagnosis was mucinous cystadenoma of the appendix. The platelet count increased to 18.1x10(4)/mm3 on postoperative-day 7, and remained stable, at 20-24x10(4)/mm3, for 14 months after the operation. Platelet-associated immunoglobulin G decreased remarkably after the operation, to 30.2 ng/10(7) cells, from 240 ng/10(7) cells preoperatively. We describe the first case of recovery from idiopathic thrombocytopenic purpura following right hemicolectomy performed for mucocele of the appendix. Considering our patients clinical course, it is possible that mucinous cystadenoma of the appendix may have influenced the thrombocytopenia. Findings in this patient suggest that mucocele of the appendix may be associated with a new diagnosis and idiopathic thrombocytopenic purpura treatment.

Cytoreductive surgery with intraperitoneal chemohyperthermia for the treatment of pseudomyxoma peritonei: a prospective study

PURPOSE

Pseudomyxoma peritonei is a rare disease. Recently, cytoreductive surgery with intraperitoneal hyperthermic chemotherapy has emerged as a promising treatment for this debilitating condition. The aim of this prospective study was to evaluate this treatment strategy.

METHOD

Twenty-seven patients with pseudomyxoma peritonei who were treated by cytoreductive surgery and intraperitoneal chemohyperthermia between 1997 and 2003 were identified from a prospective database.

RESULTS

Clinical presentation included suspected appendicitis (33 percent), increased abdominal girth (30 percent), and a suspected ovarian mass (26 percent). Twenty-two patients underwent surgery elsewhere before referral. Seventeen complications occurred in 12 patients (44 percent). Six were considered major: three anastomotic leaks, two pleural effusions, and one intra-abdominal abscess. Histologic examination demonstrated Grade 1, 2, and 3 disease in 8 (30 percent), 10 (37 percent), and 9 patients (33 percent), respectively. Pathologic grade showed a significant influence on the complication rate (P = 0 0.008). The actuarial five-year survival was 100 percent for patients with Grade 1 disease, whereas actuarial one-, two-, three-, and five-year survival for Grades 2 and 3 were 100, 80, 64, and 32 percent, respectively (P = 0.008).

CONCLUSIONS

Cytoreductive surgery with intraperitoneal hyperthermic chemotherapy is a feasible treatment for pseudomyxoma peritonei. It is associated with acceptable morbidity when performed by an experienced surgical team. Histologic grade is the major determinant of survival.

Pseudomyxoma peritonei and selected other aspects of the spread of appendiceal neoplasms

The varied aspects of spread of appendiceal neoplasms are reviewed with emphasis on the often clinically dramatic phenomenon known as pseudomyxoma peritonei, a term mostly used to describe grossly evident mucin within the peritoneal cavity. The majority of cases of pseudomyxoma peritonei result from tumors primary in the appendix, which are usually low-grade. On microscopic examination pseudomyxoma peritonei is typically characterized by large aggregates of mucin which may be relatively acellular or cellular containing strips of mucinous epithelium, mucinous epithelium encircling glands and cysts, or aggregates of mucinous epithelium lying within mucin pools. High-grade adenocarcinoma of the appendix may spread to the omentum and peritoneal surfaces without grossly striking mucin deposition and resemble spread of other high-grade gastrointestinal adenocarcinomas. In many cases of pseudomyxoma peritonei in females there is involvement of one, or more often, both ovaries. The size of the ovarian neoplasms characteristically dwarfs the often relatively unremarkable appearing appendix in these cases. The ovaries are typically multilocular, although one locule may dominate, and in cases in which the primary is a low-grade appendiceal mucinous neoplasm often have a "jelly-like" consistency. In cases of spread of frank adenocarcinomas the ovarian metastases typically have a more solid, albeit still somewhat gelatinous consistency. Microscopic examination of the ovaries typically shows surface involvement, a characteristic of spread to the ovaries in general, and the glands and cysts that replace most or all of the parenchyma are typically lined by tall mucin-rich cells with, in many cases, relatively bland microscopic features. In cases of frank adenocarcinoma, the tumors may mimic closely a primary mucinous adenocarcinoma of the ovary. Spread to the ovaries may also be seen in cases of frank intestinal-type adenocarcinoma primary in the appendix and the uncommon signet ring cell carcinoma of the appendix, the latter being one cause of the Krukenberg tumor. Occasional cases are reported in the literature of ovarian spread of goblet cell carcinoid tumor of the appendix, but in our opinion most of the primary tumors in those cases are better classified as adenocarcinomas, usually dominantly of signet-ring cell type, albeit sometimes with focal neuroendocrine differentiation. Other interesting aspects of spread of appendiceal neoplasms include to the lining of the uterus and the fallopian tube. In yet other cases the tumors may present clinically as incidentally discovered mucinous aggregates within hernia sac specimens or as a scrotal mass.

Allelic loss at 19q12 and Xq11-12 predict an adverse clinical outcome in patients with mucinous ovarian tumours of low malignant potential

Ovarian tumours of low malignant potential (LMP) are intermediate between adenomas and ovarian carcinomas. These tumours are often associated with a significantly better prognosis than ovarian carcinomas. However, a subset of these tumours can progress and become lethal. In order to seek sensitive diagnostic tools for monitoring patients after surgical operation, we performed a genome-wide scan for loss of heterozygosity (LOH) in 41 mucinous LMPs using 91 polymorphic microsatellite markers at an average interval of 50 cM across all of the human chromosomes and 25 LOH markers reportedly associated with ovarian carcinoma. In addition, we assessed whether clinicopathological parameters, microvessel density, Ki-67 labeling index, apoptotic index or p53 overexpression would be useful for predicting the postoperative outcome of LMP patients. Of the 116 markers examined, 19q12 and Xq11-12 showed significant correlation between postoperative progression-free survival time and LOH status (P<0.05). Patients with a high Ki-67 labeling index had a significantly poorer progression-free survival time than those with lower levels (P=0.042). Other clinicopathological factors and immunohistochemical analysis had no correlation with progression-free survival time in this series of patients. When the combination of LOH at 19q12 and/or Xq11-12 was assessed using Cox's regression analysis, patients with tumours that showed LOH at these positions were at greatest risk of progression (P=0.0073). These findings suggest that the identification of LOH at 19q12 and/or Xq11-12 in former mucinous LMP sites should alert the clinician to the presence of a potentially aggressive lesion in the coelomic epithelium, even if a distinction between second primary tumours or recurrence could not be determined.

Pseudomyxoma peritonei

Pseudomyxoma peritonei is a rare form of mucinous ascites associated with peritoneal and omental implants. The origin is controversial, and recent immunohistochemical and molecular genetic evidence suggests the appendix to be the likely site. The condition often presents as an incidental finding at laparotomy. Ultrasonography, computed tomography and magnetic resonance imaging aid in preoperative diagnosis. Treatment remains controversial, surgery being the main stay. The role of intraperitoneal and systemic chemotherapy is poorly defined. We review the literature on the pathology, clinical features and treatment options in pseudomyxoma peritonei.

Pseudomyxoma peritonei is a disease of MUC2-expressing goblet cells

Pseudomyxoma peritonei, a syndrome first described by Karl F. Rokitansky in 1842, is an enigmatic, often fatal intra-abdominal disease characterized by dissecting gelatinous ascites and multifocal peritoneal epithelial implants secreting copious globules of extracellular mucin. Although past interest in the syndrome has focused on the questions of the site of origin (appendix versus ovary), mechanisms of peritoneal spread (multicentricity, redistribution phenomenon, or metastasis), and the degree of malignant transformation present (adenoma, borderline tumor, or carcinoma), another important question is the mechanism behind the accumulation of extracellular mucin, the real cause of the disease's morbidity and mortality irrespective of the site of origin, mechanism of peritoneal spread, or transformed status of its epithelium. Taking advantage of the recently cloned human mucin genes, we decided to investigate this question. Our studies revealed that pseudomyxoma peritonei is a disease of MUC2-expressing goblet cells. These cells also express MUC5AC but the latter mucin is not specific for pseudomyxoma peritonei. MUC2 expression accounts for the voluminous deposits of extracellular mucin (mucin:cell ratios exceeding 10:1) and distinguishes pseudomyxoma peritonei secondarily involving the ovary from primary ovarian mucinous tumors with peritoneal implants. Because mucinous tumors of the appendix similarly express MUC2, the MUC2 expression profile also supports an appendiceal rather than ovarian origin for pseudomyxoma peritonei. Increased steady-state mRNA is observed in pooled cases of pseudomyxoma peritonei but does not occur on the basis of gene rearrangement or gene amplification. Primary epithelial cell cultures obtained from pseudomyxoma peritonei express MUC2 whose levels can be epigenetically regulated. These lines up-regulate MUC2 expression in response to both methylation inhibition by 5-azacytidine and exposure to Pseudomonas aeruginosa lipopolysaccharide, both of whose effects can be suppressed by genistein pretreatment. Both immunocytochemical as well as in situ hybridization studies with ancillary digital image analysis reveal that MUC2 expression in cases of pseudomyxoma peritonei is independent of the degrees of malignant transformation that are present and, in fact, reflects the constitutive levels of expression observed in normal goblet cells of the appendix. Extracellular mucin accumulates dramatically in pseudomyxoma peritonei because the number of MUC2-secreting cells dramatically increase and because this MUC2 has no place to drain. These studies suggest that pseudomyxoma peritonei should be regarded as a disease of MUC2-expressing goblet cells whose MUC2 expression might be susceptible to pharmacological targeting.

WT1 is an integral component of an antibody panel to distinguish pancreaticobiliary and some ovarian epithelial neoplasms

We investigated whether a panel of antibodies including WT1 could separate pancreaticobiliary and ovarian carcinomas by staining 64 pancreaticobiliary adenocarcinomas, 41 ovarian serous carcinomas, and 12 primary ovarian mucinous neoplasms with WT1, cytokeratin (CK) 17, CK20, carcinoembryonic antigen (CEA), and CA-125. Moderate or strong intensity reactivity in more than 25% of cells was a positive result. Of the ovarian serous carcinomas, 38 (93%) were WT1 reactive and 22 (54%) WT1 positive, 9 (22%) had CK20 reactivity, and 3 (7%) were CK20 positive in fewer than 50% of cells. All were CK17 or CEA nonreactive. Of the ovarian mucinous neoplasms, all were WT1 and CK17 nonreactive and 11 (92%) were CEA reactive, 8 (67%) CEA positive, 10 (83%) CK20 reactive, and 6 (50%) CK20 positive. Of the pancreaticobiliary adenocarcinomas, 19 (30%) were CK20 positive, 27 (42%) CK17 positive, and 52 (81%) CEA positive. All were WT1 nonreactive. A panel including WT1, CK17, CK20, and CEA is useful to distinguish pancreaticobiliary and ovarian serous carcinomas. Extensive CK17 reactivity is supportive of a pancreaticobiliary adenocarcinoma when the differential diagnosis includes ovarian mucinous neoplasm. None of the antibodies positively identified ovarian mucinous neoplasms.

Borderline ovarian tumors

Borderline ovarian tumors (BOTs) represent a small subset of epithelial ovarian cancers that were first described more than 70 years ago. Recognized in a systematic way in only the last three decades, BOTs occur most often in women in their reproductive years but are associated with an excellent long-term prognosis. The management of these tumors is primarily surgical, with the role of medical therapy a topic of ongoing research and debate.