Pseudomyxoma peritonei: a cytohistopathologic study of nine cases

Validation of the AJCC 8th Edition Staging System for Disseminated Appendiceal Cancer Patients Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: A Multi-institutional Analysis

BACKGROUND

The AJCC 8th edition stratifies stage IV disseminated appendiceal cancer (dAC) patients based on grade and pathology. This study was designed to externally validate the staging system and to identify predictors of long-term survival.

METHODS

A 12-institution cohort of dAC patients treated with CRS ± HIPEC was retrospectively analyzed. Overall survival (OS) and recurrence-free survival (RFS) were analyzed by using Kaplan-Meier and log-rank tests. Univariate and multivariate cox-regression was performed to assess factors associated with OS and RFS.

RESULTS

Among 1009 patients, 708 had stage IVA and 301 had stage IVB disease. Median OS (120.4 mo vs. 47.2 mo) and RFS (79.3 mo vs. 19.8 mo) was significantly higher in stage IVA compared with IVB patients (p < 0.0001). RFS was greater among IVA-M1a (acellular mucin only) than IV M1b/G1 (well-differentiated cellular dissemination) patients (NR vs. 64 mo, p = 0.0004). Survival significantly differed between mucinous and nonmucinous tumors (OS 106.1 mo vs. 41.0 mo; RFS 46.7 mo vs. 21.2 mo, p < 0.05), and OS differed between well, moderate, and poorly differentiated (120.4 mo vs. 56.3 mo vs. 32.9 mo, p < 0.05). Both stage and grade were independent predictors of OS and RFS on multivariate analysis. Acellular mucin and mucinous histology were associated with better OS and RFS on univariate analysis only.

CONCLUSIONS

AJCC 8th edition performed well in predicting outcomes in this large cohort of dAC patients treated with CRS ± HIPEC. Separation of stage IVA patients based on the presence of acellular mucin improved prognostication, which may inform treatment and long-term, follow-up strategies.

Prognostic significance of the presence of epithelial cell clusters in the ascites of patients with pseudomyxoma peritonei

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare condition characterized by intraperitoneal accumulation of mucus due to mucinous neoplasia. The characteristic cytological feature of PMP in the ascites is abundant mucus with or without epithelial cell clusters. However, the prognostic significance of the presence of epithelial cell clusters has not been determined. This study aimed to determine the prognostic significance of epithelial cell clusters in the ascites of patients with PMP.

METHODS

Patients who were clinically and histopathologically diagnosed with PMP and who underwent intraoperative cytological examination of their ascites were included in this study. Cytological characteristics including mucus and epithelial cell clusters, nuclear atypia, and the presence of signet ring cells were investigated. Overall survival was compared based on the presence of epithelial cell clusters or nuclear atypia.

RESULTS

A total of 283 patients (199 women and 84 men) were investigated. The most common original site was the appendix (244 patients). Ninety patients (31.8%) had mucus without epithelial cell clusters (acellular mucin) while 193 (68.2%) had mucus with such clusters; 134 (69.4%) and 44 (22.8%) of these patients showed low-grade and high-grade nuclear features, respectively. Signet ring cells were detected in 15 patients (7.8%). The presence of epithelial cell clusters did not influence overall survival (P = .28); however, high-grade nuclear features and signet ring cell presence were significant negative prognostic factors (P < .001).

CONCLUSION

The presence of high-grade nuclear features or of signet ring cells should be carefully investigated in the cytological specimens of patients with PMP.

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.

Mucinous Balls Tangled With Mesothelial Cells and MUC2-Positive Cancer Cells in the Ascites of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is characterized by extensive mucinous ascites following rupture of mucinous neoplasms of an intra-abdominal origin, and contain secreted gel-forming mucins such as MUC2 and MUC5AC. We encountered a 66-year-old Japanese man complaining of abdominal distension. Ascites at the site was gelatinous upon gross examination, and needle aspirate smears showed histiocytes and many mucinous balls wrapped in spindle cells, which were positive for vimentin, pan-cytokeratin, and podoplanin. The cell block showed several adenocarcinoma clusters, which were positive for MUC2, MUC5AC, CK20, and CDX-2, and negative for CK7. From these findings, a diagnosis of PMP arising from colon cancer was indicated. Cytoreductive surgery was performed, and the cystic diverticulum was found to be infiltrated by tumor cells in the sigmoid colon that caused PMP. Mucinous balls surrounded by mesothelial cells and MUC2-positive adenocarcinoma cells are useful clues in the diagnosis of PMP. Diagn. Cytopathol. 2016;44:628-631. © 2016 Wiley Periodicals, Inc.

Pseudomyxoma peritonei: cytomorphologic findings and clinicopathologic correlates

INTRODUCTION

To analyze the cytomorphology and clinical correlates of pseudomyxoma peritonei (PP), a frequently fatal pathological entity defined by gelatinous ascites caused by slow but relentless accumulation of mucin produced by neoplastic glandular epithelium.

MATERIALS AND METHODS

A retrospective search of the electronic pathology data systems of three large tertiary care medical institutions revealed 41 cases from 32 patients with PP and corresponding abdominal fluid cytologic specimens. Cytologic material was available for review in 15 cases.

RESULTS

The primary tumor site was appendix in 25 (78.1%) of the 32 patients, other regions of the gastrointestinal tract in 2 (6.3%) patients, and in 5 (15.6%) patients, the primary could not be entirely identified. Of the 41 cases, only 15 had available cytologic slides to review. Extracellular mucin was a constant feature in all 15 (100%) cases, being abundant in 13 cases and focal in 2 cases. Predominance of mucin-secreting neoplastic epithelial cells were observed in 10 (66.7%) and muciphages in 11 (73.4%) cases. Cytopathologic interpretations were consistent with the subsequent histopathologic diagnosis in 30 of 32 cases (93.8%). There were two false negative cases, both of which showed scant mucinous material on second review.

CONCLUSIONS

PP is uncommonly encountered in routine cytopathology practice. The common denominator is the presence of an often-abundant extracellular mucin. Epithelial (glandular) component is usually scant. An accurate diagnosis in a fluid specimen requires proper identification of free/extracellular mucin as well as distinguishing the often "benign-appearing" epithelial cells from reactive mesothelial cells and histiocytes.

[Mucinous adenocarcinoma of the urachus and peritoneal pseudomyxoma]

The adenocarcinoma of the urachus is very rare tumor, with an incidence of 1/5.000.000 inhabitants, represents less than 0.001 of all types of bladder cancer. Peritoneal pseudomixoma is a rare neoplasm characterized by mucinous acites that involvement the peritoneal surface and omentum. Usually is associated with benign o malignant mucinous tumor of the appendix or ovary. In this paper, we present a case of peritoneal pseudomixoma caused by a mucinous adenocarcinoma of the urachus.

Serous and mucinous borderline (low malignant potential) tumors of the ovary

The prognosis for stage I serous borderline ovarian tumors (SBOTs) is thought to be excellent, despite rare, late recurrences. The behavior of advanced-stage SBOTs primarily depends on the invasiveness vs noninvasiveness of associated extraovarian implants. Pelvic and abdominal lymph node involvement and foci of microinvasion do not seem to adversely affect prognosis. Serous tumors with a micropapillary and/or cribriform growth pattern seem to be more frequently bilateral and exophytic and manifest at an advanced stage with a higher incidence of invasive implants than typical SBOTs. Molecular data suggest that such tumors may represent an intermediate stage in the typical SBOT-invasive low-grade serous carcinoma progression. Limited experience with endocervical (müllerian)-type mucinous borderline tumors shows a possible relation to SBOTs in clinicopathologic features and biologic behavior Intestinal-type mucinous borderline ovarian tumors (I-MBOTs) and well-differentiated mucinous carcinomas manifest at stage I in most cases; the prognosis is excellent. Mucinous tumors associated with pseudomyxoma peritonei are almost always secondary to similar tumors of the appendix or other gastrointestinal sites and should not be diagnosed as high-stage I-MBOTs. Rare primary ovarian mucinous tumors associated with pseudomyxoma peritonei are those arising in mature cystic teratomas. Advanced-stage ovarian mucinous carcinomas typically show frank, infiltrative-type invasion; the prognosis is poor.

Clinicopathological evidence of pseudomyxoma peritonei in a dog with intestinal mucinous adenocarcinoma

An 11-year-old, intact female Pekingese dog was presented because of chronic vomiting. Clinical examination and diagnostic imaging suggested the presence of an intestinal mass. Laparotomy was performed, and a gelatinous effusion associated with a suspected jejunal neoplasm was found. Accumulation of gelatinous material was grossly evident in several abdominal organs and parietal peritoneum. Cytopathological smears from this material showed macrophages, reactive mesothelial cells, and spindle cells embedded in a mucinous basophilic background. After spontaneous death, necropsy and histopathology were performed and showed the presence of an invasive mucinous adenocarcinoma with visceral and peritoneal metastases. The clinicopathological findings of this case report closely resemble those reported in human cases of pseudomyxoma peritonei.

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.

Epithelial cells and other cytologic features of pseudomyxoma peritonei in patients with ovarian and/or appendiceal mucinous neoplasms: a study of 12 patients including 5 men

BACKGROUND

Pseudomyxoma peritonei (PP) is a rare condition. Cytologic evaluation of peritoneal fluid often is an initial diagnostic test for possible ovarian and/or appendiceal primary tumors. Previous studies suggest that patients with PP who have epithelial cells (ECs) in their peritoneal fluid usually have a less favorable prognosis than patients with acellular PP. To the authors' knowledge, few reports of PP in the cytologic literature cite the presence of ECs.

METHODS

Twelve cases of PP diagnosed by cytologic examination at the University of Texas M. D. Anderson Cancer Center over 15 years were identified. In all cases, primary tumors were confirmed histologically. All available cytologic smears and cell block sections were reviewed for cytomorphology, with particular attention given to the presence of ECs. A correlation between the presence of ECs and patient outcome also was sought (median follow-up, 26 months).

RESULTS

Two patients had ovarian neoplasms, six patients (one female and five males) had appendiceal neoplasms, and four patients had synchronous ovarian and appendiceal tumors. Cytologic features included mucin pools (12 of 12 patients), ECs (11 of 12 patients), mesothelial or mesothelial-like cells (10 of 12 patients), histiocytes (11 of 12 patients), and fibroblast-like or spindle cells (6 of 12 patients). ECs were columnar with mucinous features in the majority of cases, and the number of ECs in each case was variable, ranging from 1+ (rare) to 3+ (many). Of the 11 patients with available follow-up data, 6 had recurrent disease, 4 had persistent disease, and 1 patient with acellular PP was alive without clinical evidence of disease after 24 months of follow-up.

CONCLUSIONS

Unlike previous PP cytology reports, the current study frequently identified ECs (92%). Because of the potential prognostic implication of ECs in patients with PP, a diligent search for ECs is warranted. Indication of the presence or absence of ECs in the cytology report may be useful when PP is diagnosed.

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.