Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to "pseudomyxoma peritonei"

Pathology of borderline (low malignant potential) ovarian tumours

Recent studies suggest that the borderline group of ovarian tumours can be subclassified into benign and malignant neoplasms. The survival for patients with serous borderline tumours confined to the ovaries is virtually 100%. Patients with serous borderline tumours with invasive peritoneal implants, and with micropapillary serous carcinomas (a distinctive neoplasm previously included in the borderline category), have a 30-40% mortality rate and therefore these tumours are classified as carcinomas. After these neoplasms are excluded, the remaining advanced stage serous borderline tumours (those with non-invasive implants) have a survival rate of nearly 100% and should be considered benign. Similarly, nearly all mucinous borderline tumours reported to display aggressive behaviour have been associated with pseudomyxoma peritonei, a condition now known to be of appendiceal origin. The remaining mucinous borderline tumours are always confined to the ovaries and have a benign behaviour. Since borderline tumours can now be classified into benign and malignant types, the category has no further utility.

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.

CT in pseudomyxoma peritonei: a review of 17 cases

AIM

To describe the computed tomography (CT) findings in pseudomyxoma peritonei.

MATERIALS AND METHOD

Two observers independently and retrospectively reviewed the CT images of 17 consecutive patients (nine women, eight men, mean age 53 years) with histologically proven pseudomyxoma peritonei.

RESULTS

Six patients had small volume disease where pseudomyxoma peritonei was present in focal collections in the peritoneal cavity. Eleven had large volume disease that completely, or almost completely, filled the peritoneal cavity. Pseudomyxoma peritonei is characterized by low attenuation mucinous ascites on CT. Areas of high attenuation, septae and calcification are seen more commonly within it as the volume of disease increases. The pattern of accumulation of pseudomyxoma peritonei follows the normal flow of peritoneal fluid. It initially seeds at sites of relative stasis and as large volume disease develops it fills the remaining spaces in the peritoneal cavity and pressure effects dominate imaging. Pseudomyxoma peritonei may extend into hernial orifices or the pleural cavity.

CONCLUSION

Pseudomyxoma peritonei is difficult to diagnose clinically. However, the pattern of accumulation of disease is predictable and can be recognized on CT.

Mucinous and nonmucinous appendiceal adenocarcinomas: different clinicopathological features but similar genetic alterations

The genetic alterations of appendiceal carcinomas have not been reported in detail. We studied the clinicopathological factors and genetic alterations including microsatellite instability, p53 overexpression, and mutations of the K-ras proto-oncogene of 30 appendiceal adenocarcinomas, consisting of 23 mucinous and 7 nonmucinous carcinomas. Sixteen (70%) mucinous carcinomas presented with pseudomyxoma peritonei, but 6 of 7 (86%) nonmucinous carcinomas presented with appendicitis (P =.002). All carcinomas were microsatellite stable, and p53 overexpression was present in only 1 of 30 (3%) carcinomas. K-ras mutation was present in 11 of 20 (55%) carcinomas, including 8 of 16 (50%) mucinous and 3 of 4 (75%) nonmucinous carcinomas. The mean survival of patients with mucinous carcinomas was 26 +/- 19 months compared with 13 +/- 9 months for patients with nonmucinous carcinomas (P =.0002). Our findings suggest that mucinous and nonmucinous carcinomas of appendix have similar genetic alterations, but different clinical presentation and prognosis.

Morbidity and mortality associated with intraperitoneal chemotherapy for Pseudomyxoma peritonei

BACKGROUND

Many centers include intraperitoneal chemotherapy for treatment of pseudomyxoma peritonei. This study documented the morbidity of intraperitoneal chemotherapy in a single institution.

METHODS

A retrospective review of pseudomyxoma peritonei over a 6-year period was undertaken. Treatment, morbidity, and outcome were documented.

RESULTS

Eleven patients were identified with an average of 1.9 debulking procedures and 0.8 chemotherapy courses (0.3 complete). Intraperitoneal chemotherapy was not completed in 5 patients because of complications (56%): severe abdominal pain, seizure, neutropenia, and thrombocytopenia (the latter resulted in 1 patient's death). There was no association between incomplete chemotherapy and recurrence. Recurrence was 64% in those without chemotherapy and 44% in those with. Follow-up averaged 26 months and actual 3-year survival was 60%.

CONCLUSIONS

Intraperitoneal chemotherapeutic morbidity and mortality were 56% and 11%, respectively. Chemotherapy was associated with decreased recurrence. To optimize outcomes, multicenter prospective trials will likely be required to further refine intraperitoneal chemotherapy protocols.

Staging ovarian cancer: role of imaging

Ovarian cancer is relatively common, and often presents at an advanced stage with widespread intraperitoneal metastases. The constellation of complex pelvic masses, ascites, omental cake, and other peritoneal implants is virtually diagnostic. All patients are potential surgical candidates, since suspected early stage disease is treated by a comprehensive staging laparotomy including total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy. Operable advanced disease is treated by surgical debulking and adjuvant combination chemotherapy. The role of imaging is to detect and characterize adnexal masses as likely malignant, recognize unusual findings that may suggest atypical pathology, demonstrate metastases in order to prevent under-staging, and detect specific sites of disease that may be unresectable. These aims are directly related to clinical management; characterization of an adnexal mass as malignant guides appropriate surgical referral, recognition of atypical pathology such as malignant granulosa cell tumor in a young woman may be an indication for fertility-preserving surgery. Demonstration of metastatic site-assists surgical planning, and detection of unresectable disease may be an indication for neoadjuvant (ie, preoperative) chemotherapy with interval debulking rather than primary debulking with adjuvan (postoperative) chemotherapy.

Pedunculated peritoneal surface polyps in pseudomyxoma peritonei syndrome

AIMS

Pseudomyxoma peritonei syndrome is a rare disease that originates from an adenomatous lesion of the appendix that, from pressure, perforates to gain access to the free peritoneal cavity. The relative sparing of the small bowel surfaces allows for complete cytoreduction even though many kilograms of mucinous tumour exist at other sites within the abdomen and pelvis. The purpose of this study was to examine the mechanism whereby the small bowel remains free of gross tumour and peritoneal surface polyps form.

METHODS AND RESULTS

Peritoneal surface polyps were harvested and examined grossly and histologically. A hypothesis for their formation on small bowel and small bowel mesentery was proposed. Polyps are known to be associated with repeated motion of enteric contents moving past adenomatous tissue so that, over time, an elongated stalk is created. We have repeatedly observed pedunculated polyps on the peritoneal surface of the small bowel in patients with pseudomyxoma peritonei syndrome. No other site within the peritoneal cavity has had a pseudomyxoma polyp located upon its surface.

CONCLUSIONS

The peristaltic motion of the small bowel causes adherent adenomatous tissue to develop a stalk on the peritoneal surface. Motion not only creates polypoid lesions but also repeatedly clears mucinous tumour cells from the small bowel surface. With pseudomyxoma peritonei and with other types of cancerous dissemination, prevention of adherence by motion may interfere with the implantation of malignant cells.

Second-look surgery in patients with peritoneal dissemination from appendiceal malignancy: analysis of prognostic factors in 98 patients

OBJECTIVE

To establish selection criteria for reoperation in patients with peritoneal dissemination from appendiceal malignancy.

SUMMARY BACKGROUND DATA

The outcome of patients with mucinous appendiceal neoplasms with peritoneal surface dissemination has changed as a result of a better understanding of the clinical and pathologic features of this disease. This knowledge, combined with aggressive strategies for the use of perioperative intraperitoneal chemotherapy and peritonectomy procedures, has resulted in long-term disease-free survival in many of these patients. However, some of the patients develop progressive disease, and a question regarding additional surgery is appropriate. A critical analysis of the results of second-look surgery should assist in the management of patients with recurrent peritoneal surface dissemination of an appendiceal neoplasm.

METHODS

Three hundred twenty-one patients with epithelial peritoneal surface malignancy of appendiceal origin underwent surgery during a 12-year period. Ninety-eight of these patients (30.5%) underwent a second-look procedure. A database of selected clinical features regarding these 98 patients was gathered from the clinical records. A critical statistical analysis of these clinical features and their prognostic impact was performed using survival as an endpoint. All patients were managed by a treatment regimen that used cytoreductive surgery and intraperitoneal chemotherapy.

RESULTS

The overall 5-year survival rate of these 98 patients was 73.6%. This compared favorably with a 68% survival rate of 223 patients who did not undergo reoperation. Survival based on the number of cytoreductive surgeries and the free interval between them showed no significant difference. Patients who had second-look surgery with bowel obstruction as a symptom and those in whom the amount of tumor was increased or minimally decreased at the first and second cytoreductions had a significantly inferior 5-year survival rate. A complete second cytoreduction was associated with an improved 5-year survival rate.

CONCLUSIONS

Follow-up of patients treated for peritoneal dissemination from neoplasms of appendiceal origin is indicated. Selected patients in whom recurrence develops are candidates for repeat cytoreductive surgery plus intraperitoneal chemotherapy with curative intent.

Molecular genetic analysis of appendiceal mucinous adenomas in identical twins, including one with pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a clinical syndrome characterized by mucinous ascites and peritoneal lesions composed of histologically bland to low-grade adenomatous mucinous epithelium within pools of extracellular mucin, often with an associated mucinous adenoma of the appendix. There is evidence that the peritoneal lesions in PMP are clonally derived from the associated appendiceal adenoma. Little is known about the molecular genetic alterations or hereditary factors involved in the development of appendiceal mucinous tumors and PMP. We report the only known example of appendiceal mucinous adenomas in identical twin brothers, one of whom developed PMP. We analyzed the status of the K-RAS and APC genes in these tumors using digital polymerase chain reaction and digital single nucleotide polymorphism (SNP) assay. Identical K-RAS mutations were detected in the appendiceal adenoma and peritoneal tumor from the twin with PMP, whereas the adenoma from the other twin harbored a different mutation. Digital SNP analysis demonstrated loss of heterozygosity of APC only in the adenoma from the twin without PMP but not from the appendiceal or peritoneal tumors of the twin with PMP. The adjacent normal tissue in each case retained both APC alleles. The K-RAS mutational analysis supports the view that PMP is clonally derived from the associated appendiceal mucinous adenoma. The lack of loss of heterozygosity of APC in the adenoma and peritoneal tumor from the twin with PMP suggests that loss of heterozygosity of APC is not necessarily involved in the development of all appendiceal adenomas or PMP. The different types of mutations in K-RAS and the different allelic status of the APC locus in the tumors from both twins suggest that mutation in K-RAS and loss of heterozygosity of APC occurs somatically in adenomas and is independent of the identical genetic background of the twins.

Gelatinous ascites: a cytohistologic study of pseudomyxoma peritonei in 67 patients

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare condition characterized by gelatinous ascites. Although the histologic attributes of PMP have been well studied, the cytologic features remain ill defined.

METHODS

We reviewed the peritoneal washings (PW) in 67 patients with PMP to identify cytomorphologic features useful in classifying cases as either disseminated peritoneal adenomucinosis (DPAM) or peritoneal mucinous carcinomatosis (PMCA). Histologic specimens were correlated with the cytologic diagnoses. Correlation between cytologic diagnosis and patient outcome was investigated.

RESULTS

Neoplastic epithelial cells were identified in 63 of 67 PW (94%). Concordance with the histologic diagnosis was obtained in 61 of 63 cases. Of these 36.5% were cytologically classified as DPAM with primary appendiceal neoplasms in 19 cases. Thirty-four of 63 cases (53.9%) were cytologically diagnosed as PMCA based on PW cytology. Most were of appendiceal or colonic origin. Four cases displayed cytologic features of both DPAM and PMCA. Two discordant cases each with a cytologic diagnosis of PMCA had an appendiceal adenoma. Acellular mucin alone was identified in the PW in four cases. Analysis of follow-up data revealed that cases diagnosed as DPAM had a better prognosis than those diagnosed as PMCA.

CONCLUSIONS

Cytomorphologic features of epithelial cells in PW material can accurately categorize cases of PMP as either DPAM or PMCA. Furthermore, this categorization appears to have important prognostic implications.

Patients with pseudomyxoma peritonei associated with disseminated peritoneal adenomucinosis have a significantly more favorable prognosis than patients with peritoneal mucinous carcinomatosis

BACKGROUND

Pseudomyxoma peritonei (PMP) is a poorly understood condition characterized by disseminated intraperitoneal mucinous tumors, often with mucinous ascites. The term PMP has been applied historically as a pathologic diagnostic term to both benign and malignant mucinous neoplasms that produce abundant extracellular mucin, resulting in a variable and poorly predictable prognosis. A recent study reported a pathologic classification that separated patients into prognostically distinct groups, but the follow-up was relatively short.

METHODS

Long-term follow-up data were analyzed for a previously reported series of 109 patients with PMP to examine the prognostic utility of a pathologic classification system that divided patients into three groups: disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinomatosis (PMCA), and peritoneal mucinous carcinomatosis with intermediate or discordant features (PMCA-I/D). Patients whose tumors were classified 25 DPAM (n = 65 patients) had disease that was characterized by histologically bland to low-grade adenomatous mucinous epithelium associated with abundant extracellular mucin and fibrosis, often with an identifiable appendiceal mucinous adenoma that was the source of the peritoneal lesions. Patients whose tumors were classified 25 PMCA (n = 30 patients) had disease that was characterized by peritoneal lesions that displayed the cytologic and architectural features of mucinous carcinoma associated with extracellular mucin, often with an identifiable invasive mucinous adenocarcinoma of the gastrointestinal tract. Patients whose tumors were classified 25 PMCA-I (n = 11 patients) had peritoneal lesions that combined the features of DPAM and PMCA derived from well differentiated mucinous adenocarcinomas associated with adenomas. Patients whose tumors were classified 25 PMCA-D (n = 3 patients) had markedly atypical appendiceal adenomas associated with peritoneal lesions similar to PMCA.

RESULTS

Patients with DPAM had 5-year and 10-year survival rates of 75% and 68%, respectively (mean follow-up, 96 months; median follow-up, 104 months). Patients with PMCA and PMCA-I/D had a significantly worse prognosis, with 5-year and 10-year survival rates, respectively, of 50% and 21% for PMCA-I/D (mean follow-up, 58 months; median follow-up, 51 months) and 14% and 3% for PMCA (mean follow-up, 27 months; median follow-up, 16 months; P = 0.0001).

CONCLUSIONS

The term PMP should be used only as a clinical descriptor for patients who have the syndrome of mucinous ascites accompanied by a characteristic distribution of peritoneal mucinous tumors with the pathologic features of DPAM. DPAM should be used as a pathologic diagnostic term for patients with the bland peritoneal mucinous tumors associated with ruptured appendiceal mucinous adenomas and PMP. These patients should not be diagnosed with carcinoma, because they have disease that is distinct pathologically and prognostically from PMCA.

Extensive surgical cytoreduction and intraoperative hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei

BACKGROUND

Pseudomyxoma peritonei remains a fatal disease. However, extensive surgical cytoreduction combined with intraoperative heated intraperitoneal chemotherapy (HIPEC) has recently emerged as a new treatment modality, which might improve survival.

METHODS

Patients underwent treatment if the tumour appeared to be technically resectable on preoperative abdominal computed tomography and there were no distant metastases. After aggressive surgical cytoreduction, HIPEC with the administration of mitomycin C was performed for 90 min. Depending on histological grading, patients received adjuvant 5-fluorouracil and leucovorin therapy.

RESULTS

Forty-six patients were treated. Optimal surgical cytoreduction was obtained in 40 patients. Postoperative surgical complications occurred in 18 patients. Four patients died as a direct result of the treatment. Bone marrow suppression due to mitomycin C toxicity occurred in 22 patients. There was no other major toxicity related to the HIPEC procedure. After a median follow-up of 12 months, 40 patients are alive, eight of whom have proven recurrence. The actuarial survival rate (Kaplan-Meier) at 3 years was 81 per cent.

CONCLUSION

These results confirm that extensive surgery combined with HIPEC is feasible in patients with pseudomyxoma peritonei and that improved long-term survival might be achieved.

Histopathologic analysis in 46 patients with pseudomyxoma peritonei syndrome: failure versus success with a second-look operation

Pseudomyxoma peritonei syndrome is a disease characterized by mucinous ascites and mucinous tumor disseminated on peritoneal surfaces; the disease almost always originates from a perforated appendiceal epithelial tumor. Histopathologic assessment of aggressive versus noninvasive character of the mucinous tumor has been shown to have an impact on survival in patients treated with cytoreductive surgery and intraperitoneal chemotherapy. Out of a database of 312 patients having a complete cytoreduction for pseudomyxoma peritonei syndrome, 46 patients (24 male and 22 female) had at least one second-look surgery. Before this review, all 46 of these patients were clinically uniformly categorized with a diagnosis of pseudomyxoma peritonei. Using the criteria described by Ronnett and colleagues, all specimens from the multiple surgical procedures performed on these patients were reviewed and reclassified as disseminated peritoneal adenomucinosis (adenomucinosis), adenomucinosis/mucinous adenocarcinoma (hybrid), or mucinous adenocarcinoma. The review was performed in a blinded fashion by a single pathologist (HY). To facilitate a critical evaluation of these histopathologic assessments, the patients were separated into two groups: (1) 19 patients who had a second-look surgery that was unsuccessful in that they went on to die of their disease or in that they currently have disease progression and a limited survival and (2) 27 patients who had a successful second look and currently continue disease free with a minimum 3-year follow-up period. As a result of this review, 11 of 19 patients with an unsuccessful second look and originally designated pseudomyxoma peritonei were reclassified as hybrid-type malignancy (four patients) or mucinous adenocarcinoma (seven patients). Only two patients were reclassified in the successful second-look group (P =.0005). Transitions from a less aggressive to a more invasive histology from one cytoreduction to the next occurred on 13 occasions in patients whose second-look surgery failed and in one patient with a successful second-look surgery (P <.0001). Seven patients retained a histologic classification of disseminated peritoneal adenomucinosis but went on to die of an aggressive disease process. Clinical assessments suggested that failure of second-look surgery for pseudomyxoma peritonei was associated with a biologically more aggressive disease. Unsuccessful second-look surgery for patients with a clinical diagnosis of pseudomyxoma peritonei tumor was often related to an inaccurate initial histologic classification of appendiceal mucinous tumor. Also, a transition from less to more aggressive histology was frequently seen in patients dying of this disease. Assessment of tumor histology can predict the outcome if a uniform surgical treatment is used in patients with peritoneal dissemination of mucinous epithelial tumors of the appendix.

Pseudomyxoma peritonei in a hernia sac: analysis of 20 patients in whom mucoid fluid was found during a hernia repair

INTRODUCTION

Pseudomyxoma peritonei syndrome is a rare disease that causes extensive accumulation of non-invasive mucinous tumour and mucinous fluid throughout the abdomen and pelvis. The primary tumour is a perforated appendiceal adenoma or mucinous adenocarcinoma. In patients with an open processus vaginalis or other peritoneal defect, the adenomatous epithelial cells may accumulate within the hernia sac, causing mucoid fluid to be present at the time of hernia repair.

MATERIALS AND METHODS

From February 1991 to September 1997, the diagnosis of pseudomyxoma peritonei syndrome was established in 20 patients in whom mucoid material was found in a hernia sac during a hernia repair. Clinical features of these patients were critically evaluated using the completeness of cytoreduction as an endpoint.

RESULTS

The treatments delivered at the time of hernia repair had no impact on the outcome. A lack of interim events vs the use of interim treatments between hernia repair and definitive cytoreduction was significant in relation to a complete vs incomplete cytoreduction. Non-aggressive histology and an interval of less than 1 year was statistically significantly associated with a favourable outcome from surgical intervention.

CONCLUSION

When mucoid fluid is encountered at the time of a hernia repair, recovery of that fluid and the hernia sac for histologic study is important. When adenomatous epithelial cells are present, a CT scan should be performed to look for the typical distribution of mucinous tumour and fluid that suggests the pseudomyxoma peritonei syndrome. If the diagnosis can be confirmed, referral to a centre experienced in the treatment of this rare disease is suggested.

Colloid (mucinous noncystic) carcinoma of the pancreas

In the past, colloid (mucinous noncystic) carcinoma (CC) of the pancreas had been included under the category of ordinary ductal adenocarcinoma, a tumor with a dismal prognosis, or was frequently misdiagnosed as mucinous cystadenocarcinoma. The clinicopathologic features of CC have not yet been well characterized, because most cases on record have been parts of studies on either mucinous cystic neoplasms (MCN) or intraductal papillary mucinous neoplasms (IPMN), with which colloid carcinomas are frequently associated. To determine the clinicopathologic characteristics of CC, 17 pancreatic tumors composed predominantly (>80%) of CC (defined as nodular extracellular mucin lakes with scanty malignant epithelial cells) and in which the invasive carcinoma measured larger than 1 cm were studied. Ten of these were originally classified as mucinous ductal adenocarcinoma and four as mucinous cystadenocarcinoma. The mean age of the patients was 61 years; 9 were men and 8 were women. The mean size of the CC was 5.3 cm (range, 1.2-16 cm). In more than half of the patients, CC represented the invasive component of an IPMN (in nine cases) or MCN (in one case). The tumors were composed of well-defined pools of mucin with sparse malignant cells in various patterns of distribution. Signet-ring cells floating in the mucin (but not as individual cells infiltrating stroma, a characteristic finding of signet-ring cell adenocarcinomas) were commonly identified and were prominent in five cases. Perineurial invasion was noted in six cases and regional lymph node metastases in eight. Mutation in codon 12 of the k-ras gene was detected in only 4 of 12 cases studied and p53 mutation in 2 of 9. Immunohistochemical and histochemical mucin stains suggested luminalization of the basal aspects of the cells. Five-year survival was 57%. At an overall mean follow up of 57 months, 10 patients were alive with no evidence of disease (median, 79 mos), including four with lymph node metastasis, three others with perineurial invasion, and another with vascular invasion. Four patients died of disease (18, 18, 25, and 26 mos), and three died of thromboembolism (with persistent disease) at 2, 5, 10 months. All seven patients who died with or of tumor had undergone incisional biopsy of the tumor either before the operation or intraoperatively, whereas none of the patients who were alive had incisional biopsy. When compared with 82 cases of resectable ordinary ductal adenocarcinoma on whom follow-up and staging information was complete, it was found that the patients with CC present with larger tumors (p = 0.03) but lower stage (p = 0.01). The prognosis of CC is significantly better: 2-year and 5-year survival are 70% versus 28% and 57% versus 12%, respectively (p = 0.001). In conclusion, pancreatic CC may occur with or without an identifiable IPMN and MCN component, and should be distinguished from mucinous cystadenocarcinoma, ordinary ductal adenocarcinoma, and signet-ring cell adenocarcinoma. CC of the pancreas is associated with a significantly better prognosis than ordinary ductal adenocarcinoma. In addition to its distinctive morphologic and clinical characteristics, CC of the pancreas also appears to have a low incidence of mutation in codon 12 of the k-ras gene. In cases with a clinical suspicion of colloid carcinoma, the possibility that an incisional biopsy may contribute to thromboembolic complications or even dissemination of the tumor may need to be considered. The luminalization of the basal aspects of the tumor cells may be the cause of stromal mucin accumulation that characterizes colloid carcinoma and may act as a containing factor.

Mucinous tumors of the ovary: a clinicopathologic study of 196 borderline tumors (of intestinal type) and carcinomas, including an evaluation of 11 cases with 'pseudomyxoma peritonei'

Mucinous ovarian neoplasms other than cystadenomas and adenofibromas have been classified as either borderline tumors or carcinomas for many years. Borderline tumors have been subdivided more recently into endocervical-like (mullerian) and intestinal forms. Such a distinction is rarely made in the mucinous carcinoma category. We did not encounter a pure endocervical-like carcinoma in the present series. Criteria for distinguishing an intestinal-type mucinous borderline tumor from a mucinous carcinoma have been controversial. In this study of 164 mucinous borderline tumors of intestinal type and 32 mucinous carcinomas, the former were further subdivided into 74 cases with epithelial atypia only and 90 with focal intraepithelial carcinoma. Of the 67 stage I tumors in the borderline (with atypia) category, all 49 with follow-up data were clinically benign; in the seven cases that had been designated stage III, the intraoperative appearance was that of "pseudomyxoma peritonei," which was fatal in four cases. Most of these tumors, however, were probably metastatic to the ovary rather than truly primary borderline tumors, although failure to examine the appendix in six cases compromised their interpretation. All 90 mucinous borderline tumors that had foci of intraepithelial carcinoma were recorded as stage I, but two of the 69 patients with follow-up data (3%) had fatal recurrences. Both of these tumors were incompletely staged, however, and one had ruptured intraoperatively. Thirty-two invasive carcinomas were subdivided into 12 expansile and 20 infiltrative subtypes; within the latter category seven tumors were only microinvasive. All 12 carcinomas with only expansile invasion were stage I; none of the 10 with follow-up data recurred. All seven microinvasive infiltrative carcinomas were stage I; none of the five with follow-up data recurred. One of five patients with stage I infiltrative carcinomas that were more than microinvasive and were adequately followed had a fatal recurrence, but staging had been incomplete in that case. Seven of the remaining eight infiltrative carcinomas were higher than stage I: five of the six (83%) with follow-up data persisted or recurred and were fatal. Considering all stages, increasing tumor grade in the carcinoma category correlated with an unfavorable outcome. However, grade did not influence prognosis in stage I carcinomas. Among 13 stage I cases in all categories with either preoperative or intraoperative tumor rupture and follow-up data, one recurred, a tumor in the borderline with intraepithelial carcinoma category. "Pseudomyxoma peritonei" is an ill-defined term and should not be used as a pathologic diagnosis. The presence of mucin in the abdominal cavity requires careful histologic evaluation to characterize it for prognostic purposes. Adequate and sometimes extensive sampling of mucinous ovarian tumors, the appendix and the peritoneum in cases of "pseudomyxoma peritonei" is necessary to achieve an accurate diagnosis and prognosis.

Clinical presentation of the Pseudomyxoma peritonei syndrome

BACKGROUND

Pseudomyxoma peritonei syndrome is characterized by a gradual expansion of mucoid tumour and fluid at specific sites within abdominopelvic regions as a result of a perforated appendiceal adenoma. The aim was to analyse the presenting symptoms and signs of patients with this condition.

METHODS

Of 410 patients with appendiceal tumours 217 had the diagnosis of pseudomyxoma peritonei syndrome with histological confirmation. A retrospective review of the clinical characteristics that determine presentation was performed.

RESULTS

Overall, suspected acute appendicitis was the most common presentation (27 per cent). For women the diagnosis was most commonly made while being evaluated for an ovarian mass (39 per cent). Increasing abdominal girth was the second most common presentation overall (23 per cent). Thirty patients (14 per cent) presented with new-onset hernia, of which the majority (26) were inguinal hernias.

CONCLUSION

Consideration of appendicitis, increased abdominal girth, ovarian mass and new-onset hernia as caused by this syndrome may facilitate diagnosis and definitive treatment.

Mucocele of the appendix secondary to endometriosis. Report of two cases, one with localized pseudomyxoma peritonei

This report documents 2 cases of obstructive mucocele of the appendix secondary to endometriosis of the appendix. In 1 case, the tip of the mucocele was ruptured and associated with localized pseudomyxoma peritonei. Mucoceles of the appendix usually are associated with hyperplastic or neoplastic mucosal proliferation; obstruction, particularly that due to endometriosis, is an infrequent cause. Occurrence of localized pseudomyxoma peritonei associated with appendiceal endometriosis and mucocele has not been reported previously.

The coexistence of low-grade mucinous neoplasms of the appendix and appendiceal diverticula: a possible role in the pathogenesis of pseudomyxoma peritonei

We examined 38 appendectomies with diagnoses of mucocele, diverticulum, or adenoma to study the coincidence of appendiceal diverticula and appendiceal low-grade mucinous neoplasms and to examine the possible role of diverticula in the pathogenesis of pseudomyxoma peritonei. Invasive adenocarcinomas and retention cysts were excluded (six cases). Cases were classified as adenomas or mucinous tumors of unknown malignant potential, with or without diverticula. Medical records were reviewed for multiple parameters, including presenting symptoms, presence of pseudomyxoma peritonei, and presence of associated malignancies. Binomial statistics were used to calculate the probability that the observed prevalence of low-grade mucinous neoplasms and diverticula together was significantly different from the expected prevalence of diverticula or low-grade mucinous neoplasms alone, using historical controls from the literature. Twenty-five percent of the total cases (8 of 32) contained both a low-grade mucinous neoplasm (7 cystadenomas and 1 mucinous tumor of unknown malignant potential) and a diverticulum. Thus, 8 of 19 low-grade mucinous neoplasms (42%) were associated with diverticula. Of the appendices with both low-grade mucinous neoplasms and diverticula, three contained dissecting acellular mucin within the appendiceal wall, four showed diverticular perforation, and one had pseudomyxoma peritonei associated with the ruptured diverticulum. A significant percentage (P < .001) of cases contained low-grade mucinous neoplasms and diverticula together. The case of coexistent low-grade mucinous neoplasm, diverticulum, and pseudomyxoma peritonei suggests that diverticula could play a role in the pathogenesis of pseudomyxoma peritonei. This could occur either by involvement of preexisting diverticula by the neoplasm or by distention of the appendiceal lumen by mucin, leading to increased intraluminal pressure and subsequent diverticulum formation at a weak area in the wall. Either mechanism might allow low-grade mucinous neoplasms to penetrate the appendiceal wall more easily.

Recent advances in immunohistochemistry in the diagnosis of ovarian neoplasms

This leader reviews recent advances in immunohistochemistry that are useful in the diagnosis of ovarian neoplasms. These include the value of different anticytokeratin antibodies in the distinction between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. These antibodies have also helped to clarify the origin of the peritoneal disease in most cases of pseudomyxoma peritonei. The value of antibodies against so called tumour specific antigens, such as CA125 and HAM56, in determining the ovarian origin of an adenocarcinoma is also reviewed. In recent years, several studies have investigated the value of a variety of monoclonal antibodies in the diagnosis of ovarian sex cord stromal tumours and in the distinction between these neoplasms and their histological mimics. These antibodies include those directed against inhibin, CD99, Mullerian inhibiting substance, relaxin like factor, melan A, and calretinin. Of these, anti-alpha inhibin appears to be of most diagnostic value. It is stressed that these antibodies should always be used as part of a larger panel and not in isolation.

Congenital pleuroperitoneal communication in a patient with pseudomyxoma peritonei

BACKGROUND AND OBJECTIVES

Pseudomyxoma peritonei syndrome is a rare disease arising from a perforated appendiceal adenoma. The syndrome is characterized by progressive accumulation of mucinous ascites and tumor within the peritoneal cavity. Direct extension of pseudomyxoma peritonei to the pleural cavity is uncommon and has been associated with surgical penetration of the diaphragm at the time of cytoreduction.

METHODS

We review the case of a patient who presented with mucoid peritoneal and pleural fluid consistent with spontaneous pleural spread of pseudomyxoma peritonei.

RESULTS

Surgical exploration confirmed direct pleuroperitoneal communication by macroscopic diaphragmatic fenestration.

CONCLUSIONS

This is a rare phenomenon. We outline a therapeutic approach to be applied when pleural involvement is suspected in patients with pseudomyxoma peritonei syndrome.

American Joint Committee on Cancer prognostic factors consensus conference

BACKGROUND

The American Joint Committee on Cancer (AJCC) published the 1st edition of the Cancer Staging Manual in 1977 and began using T (tumor extent), N (regional lymph node status), and M (the presence or absence of distant metastasis) in an organized staging scheme to express the extent of disease in a number of cancer sites. The goal of this program has been to provide physicians and others with a useful methodology to plan treatment, project prognosis, and measure outcome end results. Until recent years, this system has incorporated only elements of anatomic extent of the tumors determined by clinical and pathologic methods. At the present time an increasing number of nonanatomic cancer prognostic factors are being identified and studied. Some of these factors currently are being used for outcome predictions and treatment decisions.

METHODS

To begin the process of identifying and validating these prognostic factors to refine the present TNM system, the AJCC convened a Prognostic Factors Consensus Conference to evaluate the roles of biologic, genetic, molecular, and other nonanatomic factors in staging cancer. Working groups were appointed for carcinomas of the breast, colorectum, prostate, and ovary and experts in each of these areas were invited to participate. Emphasis was placed on evaluating existing data and the correlation of these data with survival.

RESULTS

None of the groups believed that there were sufficient data at the present time to merit incorporation of serum markers into the TNM system for the four tumors under consideration, although this soon might become possible in prostate carcinoma after the evaluation of survival data from multiple institutions. Recommendations were made regarding the emerging sentinel lymph node technique, the need for an increased use of histopathology in the staging of breast and ovarian carcinomas, and the use of additional histologic staining techniques for the detection of "micrometastases" in lymph nodes. A number of additional recommendations were made for changes to the TNM system that did not involve serum markers and other nonanatomic cancer prognostic factors.

CONCLUSIONS

These recommendations are presented for the purpose of discussion and evaluation and do not yet represent formal proposals for a change in the AJCC TNM system of staging.

Disseminated peritoneal adenomucinosis: a critical review

BACKGROUND

The term pseudomyxoma peritonei has been used in reference to any condition, benign or malignant, in which the peritoneal cavity becomes filled with a gelatinous substance. The term is nonspecific and does not denote therapeutic or prognostic significance. Controversy centers around which patients benefit from and should be treated by aggressive surgical debulking.

METHODS

A review of the current literature pertaining to the classification, treatment, and prognosis of patients with pseudomyxoma peritonei was undertaken.

RESULTS

Disseminated peritoneal adenomucinosis refers to a subset of patients with pseudomyxoma peritonei who derive the greatest long-term benefit from multimodality therapy including aggressive surgical debulking. These patients have a benign form of the disease in which the peritoneal implants are derived from the extrusion of epithelial cells from an adenoma of the appendix. The pathophysiology of mucin deposition is defined by the redistribution phenomenon. The adenomatous cells are distributed according to the fluid flow and gravitational forces within the peritoneal cavity. The small bowel is relatively spared until late in the disease (visceral sparing), and therefore aggressive surgical debulking should be attempted at the first laparotomy by an experienced surgeon. Preoperative computed tomographic imaging can establish the diagnosis and aid in defining which groups of patients are resectable for cure.

CONCLUSIONS

Attempts at curative treatment should include aggressive debulking and intraperitoneal chemotherapy. Those patients with a high-grade malignant process should be treated symptomatically, because aggressive therapy is associated with high morbidity rates and no long-term improvement in survival.

Imaging of mucocoele of the appendix with emphasis on the CT findings: a report of 10 cases

AIM

Mucocoele of the appendix denotes an obstructive dilatation of the appendiceal lumen due to abnormal accumulation of mucus. It is sometimes associated with pseudomyxoma peritonei, which predicts a malignant origin. We present the CT findings and additional imaging studies of 10 patients with neoplastic appendiceal mucocoele and discuss the clinical implications.

MATERIALS AND METHODS

Abdominal CT findings from 10 patients with appendiceal mucocoele were reviewed. Barium enema, US and MRI were additionally performed in three patients. There were five men and five women aged 45-80 years. Special attention was directed to the shape and nature of the mass, its relation to the caecum and the presence of ascites or peritoneal implants, as well as possible additional ovarian tumours in female patients.

RESULTS

The mucocoele was an incidental finding in five patients. They were either spherical or elongated cystic lesions, attached to the wall of the caecum, six of them with mural calcification. Ascites were present in six patients and hypodense large peritoneal implants representing pseudomyxoma peritonei in four. Pathologically the series included five cases of cystadenoma (in one, a malignant pseudomyxoma peritonei subsequently developed), four cases of cystadenocarcinoma and one villous adenoma (this patient later developed pseudomyxoma peritonei). Pseudomyxoma peritonei was found in five cases. Three women had associated ovarian cystic tumour.

CONCLUSION

The appearance of an appendiceal mucocoele is quite characteristic and can be diagnosed on CT. CT can also depict additional findings suggesting pseudomyxoma peritonei. In women with an appendiceal mucocoele the ovaries should be examined closely for cystic tumour and vice versa.

[Treatment of peritoneal carcinomatosis using complete excision and intraperitoneal chemohyperthermia. A phase I-II study defining the best technical procedures]

OBJECTIVES

The complete or quasi complete resection of peritoneal carcinomatosis (PC) followed with IPCH is potentially able to cure some patients with a disease confined to the peritoneum. The aim of this prospective phase I-II study was to elaborate an efficient IPCH procedure with a good thermal homogeneity and a good spatial diffusion, which should be reproductible (and so standardizable and exportable), and to appreciate its tolerance and its carcinologic impact.

PATIENTS AND METHODS

Seven IPCH procedures were successively tested in 32 patients (for a total of 35 IPCH); each of these were tested in at least four patients before being modified for technical or tolerance reason. Five of them were followed with an immediate postoperative intraperitoneal chemotherapy (IPIC) lasting four days. Thermal homogeneity was measured with six thermal probes situated in different places inside the abdominal cavity. Spatial diffusion was studied in the last patients by adding methylene blue in the IPCH liquid. The precise extent of the PC was reported, for each intra-abdominal region, and scored with a peritoneal index (ranging from 1 to 39). The mean follow-up was 23.85 months for the series.

RESULTS

Procedures with the closure of the abdomen were not efficient: thermal homogeneity was almost satisfactory when only the skin was closed, but these 'closed' procedures did not permit the treatment of all the risky surfaces. The peritoneal cavity 'expander' did not permit the treatment of the parietal wound, and an undetermined amount of the perfusion oozed out at its periphery. The open technique by tracking the skin upwards was the best one. Death occurred in three patients (9.4%), and complications occurred in 24 patients (75%) during the postoperative course. Intra-abdominal complications were significantly correlated (P = 0.02) with the peritoneal index (scoring the extent of the PC). The two year survival rate was 60%, and PC did not recur in 50% of the patients.

CONCLUSION

An efficient and reproducible procedure for IPCH was defined: an open procedure with an upwards traction of the skin. The post-IPCH IPIC was abandoned because it did not treat all the risky peritoneal surfaces. Patients with an extended PC and with extraperitoneal localization did not seem to have benefited from this therapeutic approach. Progress is needed in the chemotherapeutical procedure and indications must be more finely defined.

Evaluation of diagnostic criteria and behavior of ovarian intestinal-type mucinous tumors: atypical proliferative (borderline) tumors and intraepithelial, microinvasive, invasive, and metastatic carcinomas

Histologic criteria for the distinction of ovarian mucinous borderline tumors (MBTs) from invasive mucinous carcinomas (MUCCAs) and the definitions of intraepithelial (noninvasive) carcinoma and microinvasion are controversial. Accurate assessment of the behavior of these tumors has been obscured by inclusion of cases of pseudomyxoma peritonei (PMP), an entity of extraovarian origin, and misclassification of the ovarian tumors in PMP and metastatic mucinous carcinomas (METCAs) as either advanced-stage MBTs or primary ovarian MUCCAs. One hundred thirty-six intestinal-type ovarian mucinous tumors without PMP were evaluated for the presence of stromal invasion, marked cytologic atypia, epithelial stratification of more than three cell layers, and necrosis. Criteria for the diagnosis of MBT, MBT with intraepithelial carcinoma, MBT with microinvasion (MIBT), MUCCA, and METCA were established and correlated with behavior. Twenty-three (59%) of 39 patients whose tumors had stromal invasion of more than 5 mm died of disease. Stromal invasion of more than 5 mm was the sole feature that correlated with a poor prognosis. In the absence of this feature, marked cytologic atypia, epithelial stratification of more than three layers, microinvasion (<5 mm), or necrosis did not have an adverse effect on survival. Tumors were classified as MBT (n = 65; 48%) based on absence of stromal invasion, regardless of degree of cytologic atypia or epithelial stratification; of these, 28 (43%) qualified as intraepithelial carcinoma based on epithelial stratification of more than three cell layers or marked cytologic atypia. Tumors with stromal invasion of less than 5 mm were classified as MIBT (n = 8; 6%). Tumors with stromal invasion of more than 5 mm were classified as MUCCA (n = 24; 18%). Tumors with a nodular pattern of stromal invasion, morphology inconsistent with ovarian origin, or a primary site elsewhere were classified as METCA (n = 35; 26%). Four tumors could not be definitively classified. Of the 86 cases with follow-up (median, 33 months) all MBTs (n = 44) and MIBTs (n = 6) were stage I, with 5-year survival rates of 100%. MUCCAs (n = 17) that were stage I had a 5-year survival rate of 91%; all patients with advanced-stage MUCCA died of disease. Five-year survival rate for METCAs (n = 19) was 11%. METCAs were more common than MUCCAs but can mimic MUCCAs and MBTs clinically and histologically. In the absence of a primary site elsewhere, METCA should be strongly suspected when there is bilateral surface involvement and a characteristic nodular pattern of invasion. It is important to recognize this pattern because 5-year survival rate for METCA (11%) was substantially less than that of MUCCA (all stages, 51%) and MBT (100%). Because all MBTs, regardless of degree of atypia or stratification, were stage I and benign, we prefer to designate them as atypical proliferative mucinous tumors. Marked cytologic atypia, epithelial stratification of more than three layers, and microinvasion (<5 mm) had no effect on the behavior of MBT. Noninvasive mucinous tumors with marked cytologic atypia or excessive epithelial stratification can be interpreted as atypical proliferative tumors with intraepithelial carcinoma and those with microinvasion can be designated as atypical proliferative tumors with microinvasion; these tumors appear to represent transitional stages in ovarian mucinous carcinogenesis.

Molecular genetic evidence supporting the clonality and appendiceal origin of Pseudomyxoma peritonei in women

Pseudomyxoma peritonei (PMP) is a poorly understood condition characterized by mucinous ascites and multifocal peritoneal mucinous tumors. Women with PMP often have mucinous tumors involving both the appendix and the ovaries. Several previous histopathological and immunohistochemical studies of PMP have suggested that most, if not all, cases of PMP in women are derived from mucinous adenomas of the appendix rather than from primary ovarian tumors. A few studies of the molecular genetics of PMP have been recently reported. However, these studies analyzed only a small number of cases and some included a heterogeneous group of mucinous tumors, including both benign and malignant appendiceal and ovarian tumors. We analyzed K-ras mutations and allelic losses of chromosomes 18q, 17p, 5q, and 6q in a substantial number of morphologically uniform cases of PMP with synchronous ovarian and appendiceal tumors as well as in appendiceal mucinous adenomas (MAs) and ovarian mucinous tumors of low malignant potential (MLMPs) unassociated with PMP. Each of the 16 PMP cases (100%) analyzed demonstrated identical K-ras mutations in the appendiceal adenoma and corresponding synchronous ovarian tumor. K-ras mutations were identified in 11 of 16 (69%) appendiceal MAs unassociated with PMP and in 12 of 16 (75%) ovarian MLMPs unassociated with PMP. Two PMP cases showed identical allelic losses in the matched ovarian and appendiceal tumors. A discordant pattern of allelic loss between the ovarian and appendiceal tumors at one or two of the loci tested was observed in six PMP cases. In all but one instance, LOH was observed in the ovarian tumor, whereas both alleles were retained in the matched appendiceal lesion, suggesting tumor progression in a secondary (metastatic) site. Our findings strongly support the conclusion that mucinous tumors involving the appendix and ovaries in women with PMP are clonal and derived from a single site, most likely the appendix.

Pseudomyxoma peritonei in the pleural cavity: report of a case

PURPOSE

Pseudomyxoma peritonei is a rare disease characterized by mucinous ascites and associated with ruptured mucocele, cystadenoma, and low-grade carcinoma arising from the appendix, ovaries, or colon. Metastases and extraperitoneal involvement are extremely rare events.

METHOD

This is a case report of a patient with pseudomyxoma peritonei with pleural involvement.

RESULTS

A 38-year-old male patient with a pseudomyxoma peritonei from appendiceal origin underwent an extensive cytoreduction procedure. During the operation pleural involvement was noted. This was later confirmed by thoracoscopy. An expectant policy was followed until the patient became symptomatic with progressive disease in the abdomen and both pleural cavities. With systemic chemotherapy (5-fluorouracil and leucovorin), a good clinical response was obtained, and the patient was alive with stable disease 2.5 years after the first diagnosis.

CONCLUSIONS

Involvement of the pleural cavity by pseudomyxoma peritonei is rare and carries an unfavorable prognosis. Whenever possible, the same guidelines as for intra-abdominal disease should be followed: extensive cytoreductive procedures with local and/or systemic chemotherapy. In our patient we hope to achieve a prolonged palliation with systemic chemotherapy.

Pseudomyxoma peritonei

BACKGROUND

Pseudomyxoma peritonei is an unusual condition in which gelatinous fluid collections are associated with mucinous implants on the peritoneal surfaces and omentum. The pathological origin and ideal treatment of the condition are subjects of debate.

METHODS

An unrestricted Medline search over 1986-1997 was performed for pseudomyxoma peritonei.

RESULTS AND CONCLUSIONS

There is increasing evidence that pseudomyxoma peritonei is a neoplastic condition which usually arises from a primary adenoma or adenocarcinoma of the appendix. Reported series include a spectrum of pathological lesions, from entirely benign ruptured mucocele to advanced carcinoma. This, and the rarity of the condition, limit the conclusions that can be drawn regarding its treatment and prognosis. Most authorities agree that a thorough surgical debulking should be made. In most cases this will be a difficult and time-consuming undertaking, possibly requiring cooperation between two or more specialists and consideration of delivering intraperitoneal adjuvant therapy during or immediately after surgery. Treatment therefore requires a planned approach with accurate preoperative assessment of the diagnosis and the extent of the condition. There is some largely anecdotal evidence in favour of intraperitoneal chemotherapy and radioisotope treatment. Ultraradical surgery, with heated intraoperative and further postoperative chemotherapy, is strongly advocated by one group but remains contentious. The majority of patients will eventually suffer recurrence. The 5-year survival rate ranges from 53 to 75 per cent, but outcomes vary widely between relatively benign and malignant subgroups.

Pseudomyxoma peritonei--a heterogenous disease

OBJECTIVE

To evaluate the origin of pseudomyxoma peritonei (PMP) in Chinese women.

METHODS

The clinicopathologic features of 15 cases of PMP were reviewed. Immunostaining using antibodies for CK7 and CK20 was performed in the ovarian, appendiceal and peritoneal lesions of these cases.

RESULTS

Appendiceal pathology was documented in five cases, including four mucinous cystadenoma and one simple mucocele. Eight ovarian tumors were found, including seven mucinous cystadenocarcinomas of low malignant potential and one mucinous cystadenoma. Synchronous ovarian and appendiceal lesions were discovered in three cases. One patient had adenocarcinoma of the pancreas. The origin of mucin production was not known in four cases with metastatic adenocarcinoma found in two of them. Immunoreactivity for CK20 was demonstrated in the tissues derived from the peritoneum, ovary, appendix and pancreas while only 23% (3 out of 13 women) of the peritoneal lesions and 33% (2 out of 6 women) of the ovarian tumors were immunoreactive for CK7.

CONCLUSIONS

PMP is a heterogeneous lesion, which may develop from mucinous metaplasia of the peritoneum or from appendiceal, or ovarian lesions. Careful examination of the ovary and appendix with performance of appendectomy is advised in every case of PMP. Immunohistochemical examination of the peritoneal, ovarian or appendiceal lesions using antibodies, in particular that for CK7 would help in defining the origin of mucin production.

Ultrasound features of disseminated adenomucinosis (pseudomyxoma)

Pseudomyxoma is a clinical entity in which the peritoneal surfaces and omentum are involved with gelatinous, mucinous implants, and often massive gelatinous ascites. Most cases originate from ruptured ovarian cysts or appendiceal mucoceles, and involve only the intraperitoneal cavity. This report describes a case of disseminated adenomucinosis, the benign form of pseudomyxoma, with both peritoneal and retroperitoneal involvement. The diagnosis was suggested by real-time ultrasound and confirmed at surgery. The ultrasound characteristics of this rare entity and the differential diagnoses are discussed.

Intraperitoneal chemotherapy and cytoreductive surgery for the prevention and treatment of peritoneal carcinomatosis and sarcomatosis

Intraperitoneal chemotherapy and cytoreductive surgery have been combined to reach treatment objectives in patients with peritoneal carcinomatosis or sarcomatosis that neither modality by itself can achieve. These treatments must be combined with the proper selection of patients in order to observe "high value" results from therapy. There are three principles of management to support treatments for peritoneal carcinomatosis and sarcomatosis. First, the clinician must select patients who have isolated disease distributed on the surfaces of abdominal and pelvic structures. Patients treated for peritoneal implants who have persistent disease at other sites will profit little or not at all. Second, this disease must be reduced to its lowest possible mass by peritonectomy procedures and resections of viscera. Third, maximal intraperitoneal and systemic chemotherapy are utilized to eradicate the disease on peritoneal surfaces as well as control the primary or recurrent tumor. These principles of management and a presentation of the results achieved to date are reviewed.

Pulmonary metastases in pseudomyxoma peritonei syndrome

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare disease arising from a mucinous cystadenoma of appendiceal origin. The syndrome has been characterized by progressive growth of mucinous tumors, tense mucinous ascites, and ultimately death. Abdominal and pelvic recurrence after resection of intraperitoneal disease occurs in all patients unless adjunctive measures are taken. Local spread of PMP by direct extension to the pleural or pericardial space is uncommon but has been reported in the literature. Here we report development of pulmonary parenchymal metastases after treatment for PMP.

METHODS

The charts of 3 patients were retrospectively reviewed for the presentation and management of metastatic PMP.

RESULTS

Three patients underwent resection for pulmonary parenchymal metastases of PMP. All patients recovered uneventfully. The continue to do well after 2 to 8 years of follow-up.

CONCLUSIONS

Pulmonary metastasectomy for PMP is safe and effective after treatment of intraperitoneal disease.

The morphologic spectrum of ovarian metastases of appendiceal adenocarcinomas: a clinicopathologic and immunohistochemical analysis of tumors often misinterpreted as primary ovarian tumors or metastatic tumors from other gastrointestinal sites

Twenty cases of ovarian metastases derived from appendiceal adenocarcinomas were analyzed. The most common presentation was a pelvic mass. The appendiceal and ovarian tumors were diagnosed concurrently in 15 cases; in the remaining five, the ovarian tumors were diagnosed before the appendiceal tumor. The appendiceal adenocarcinomas demonstrated four morphologic patterns: 1) signet ring cell type, with or without glandular or goblet cell differentiation (14 cases); 2) mixed signet ring cell and intestinal type (two cases); 3) intestinal type (two cases); and 4) typical colorectal type (two cases). The ovarian tumors were bilateral in 16 cases and were histologically similar to the associated appendiceal tumor in each case. Ovarian metastases that demonstrate signet ring cell, glandular, and goblet cell differentiation mimic metastases from gastric adenocarcinoma. Those that are derived from well-differentiated mucinous appendiceal adenocarcinomas mimic primary ovarian mucinous tumors and metastases from the pancreas and biliary tract. Metastases of appendiceal adenocarcinomas of colorectal type simulate both metastatic colorectal carcinoma and primary ovarian endometrioid carcinomas. The appendiceal and ovarian tumors were immunophenotypically identical in each case. Approximately 50% of the appendiceal and ovarian tumors were positive for cytokeratin 7 (CK 7), and all were positive for cytokeratin 20 (CK 20). CK 20 positivity of the ovarian tumors is consistent with gastrointestinal origin; CK 7 positivity does not confirm ovarian origin, because appendiceal carcinomas are positive in 50% of cases. Metastatic appendiceal adenocarcinoma should be considered in the differential diagnosis of mucinous ovarian tumors with signet ring cell, goblet cell, or intestinal type differentiation, especially when these tumors are associated with extraovarian disease and are bilateral.

Mucinous tumors of the vermiform appendix and ovary, and pseudomyxoma peritonei: histogenetic implications of cytokeratin 7 expression

Cytokeratin 7 (CK-7) has been shown to be uncommonly expressed in colonic epithelial tumors, as opposed to ovarian epithelial tumors, which are always CK-7 positive. The authors investigated the expression of CK-7 in 17 appendiceal cystadenomas and carcinomas, 20 mucinous borderline tumors of the ovary, 10 cases of simultaneous mucinous tumors of the appendix and ovary, three so-called high-stage mucinous borderline tumors of the ovary, and three cases of pseudomyxoma peritonei (PP) of unknown origin. Nine appendiceal cystadenomas were CK-7 negative; two of these were associated with PP, and the peritoneal lesions were negative as well. Three cystadenomas were CK-7 positive. Three appendiceal carcinomas were CK-7 negative, and in one case the metastases were also negative. Two carcinomas were CK-7 positive. All 20 ovarian borderline tumors were CK-7 positive. Six cases of simultaneous mucinous tumors of the ovary and appendix were CK-7 negative, as were their peritoneal mucinous deposits. Four cases showed a positive reaction in both appendiceal and ovarian sites. Two of three so-called high-stage ovarian borderline tumors were CK-7 negative. All three cases of PP of unknown origin were CK-7 negative. In conclusion, appendiceal cystadenomas are often CK-7 negative, whereas ovarian mucinous borderline tumors are always CK-7 positive. The concordant staining pattern for CK-7 of simultaneous mucinous tumors involving the appendix and ovary (60% of which were CK-7 negative) supports an appendiceal origin for these tumors. Our results also support an appendiceal (or colonic) source for any CK-7-negative mucinous tumor involving the ovary or the peritoneum. Furthermore, our findings are in agreement with the assumption that mucinous borderline-like tumors in the ovary associated with PP are not ovarian in origin but are often, if not always, metastatic from an appendiceal (or other) mucinous tumor.

Atypical cilia in testicular cells from normal rats

During our observations solitary cilia have been noted in Sertoli cells, fibroblasts and myoid cells of the rat testes. They mostly presented a 9 + 0 pattern and appeared similar to those previously reported in other cell types. In the present report, we describe their structure and analyze their putative functional significance.

Malignancy in Peutz-Jeghers syndrome? The pitfall of pseudo-invasion

Peutz-Jeghers syndrome is a malignancy-associated polyposis syndrome. We describe a histopathologic phenomenon easily encountered when examining the nature of Peutz-Jeghers polyps but that is underreported in the literature. This phenomenon of "pseudo-invasion" may mimic invasive carcinoma due to epithelial displacement and erroneously give the impression, both macroscopically and microscopically, that a malignancy is involved. This potential pitfall is illustrated by the case of a patient with Peutz-Jeghers syndrome who was thought to harbor a metastasizing adenocarcinoma in his small bowel with peritoneal metastasis as a perioperative finding. Histologic examination, however, revealed pseudo-invasion.

Patterns of failure following treatment of pseudomyxoma peritonei of appendiceal origin

Pseudomyxoma peritonei is a rare disease caused by a perforated adenoma of the appendix. It results in extensive accumulation of mucinous tumour at specific locations within the abdomen and pelvis. The study was undertaken to examine patterns of recurrence in patients with grade I disease treated by cytoreductive surgery and early postoperative intraperitoneal chemotherapy. After a median follow-up of 1.9 years (range 0.5-7.4 years) 42 out of 118 patients had recurred. In 32 patients, detailed information regarding the anatomical location of recurrent tumour from CT-scan and second-look laparotomy were available and these form the basis of this study. The volume of recurrent tumour was recorded at eight abdominal sites, the laparotomy scar and at suture lines. Patient, tumour and treatment factors were analysed for possible relationship with the pattern of recurrence. With recurrence, true metastatic disease was observed in 3 patients and a distinctly higher grade of intraperitoneal tumour in another patient. Pleural spread of pseudomyxoma was found in 6 patients, always related to entering the pleural cavity during cytoreduction (P = 0.000031). Two abdominal sites consistently had an increase in tumour deposits at re-operation as compared to the initial cytoreduction. Small bowel had large deposits at re-operation in 17% versus 3% at initial cytoreduction and retroperitoneal surfaces 10% versus 0%. Recurrences were most frequent in the left subhepatic/lesser omentum area (28%), while the right subdiaphragmatic area (3%) was least involved. Pseudomyxoma peritonei recurrence in the laparotomy scar was found in 15/29 patients (52%), significantly more frequent if tumour had been present at former laparotomy scars during cytoreduction (P = 0.042). In 15/25 (60%) of patients, recurrences were found at suture lines. Differences in the completeness of cytoreduction, inadequate distribution of intraperitoneal chemotherapy to upper abdominal and small bowel surfaces, and entrapment of tumour within suture lines were thought to be causal factors consistent with this pattern of recurrence. Consequences for future treatment strategies are discussed.