We previously reported the presence of MUC2, MUC5AC and, for the first time, MUC5B in a 58-year-old male with pseudomyxoma peritonei (PMP). This is a report on the biochemical and immunohistochemical characterization of mucin in a 50-year-old female with the same rare illness. A right oophorectomy and appendicectomy and a resection of the involved omentum were performed. Approximately a litre of crude material in the sol and gel phases was obtained from the patient during laparotomy. This was briefly homogenized in 6 M guanidinium hydrochloride and proteolytic inhibitors and purified by density gradient centrifugation in caesium chloride. At laparotomy it was noted that the patient had appendiceal and ovarian masses as well as extensive mucinous deposits in the omentum and peritoneum. A mucinous adenocarcinoma of the appendix and ovary was confirmed on histology. The cells expressed both sulphated and non-sulphated acidic mucins. The presence of MUC2, MUC5AC, MUC5B and a-1-acid glycoprotein was shown by Western blotting and MUC4 by immunohistochemical staining. MUC1 and MUC6 were not detectable in the tissue. The study confirms that MUC2, MUC5AC and MUC5B are produced in the mucus of patients with PMP. The expression of MUC4 in this disease has not been previously reported.
MUC; Mucin; Mucus; Pseudomyxoma peritonei; Ovary
Background and Aims
Pseudomyxoma peritonei (PMP) is characterized by peritoneal tumors arising from a perforated appendiceal adenoma or adenocarcinoma, but associated entry of enteric bacteria in the peritoneum has not been considered as a cofactor. Because Gram-negative organisms can upregulate MUC2 mucin gene expression, we determined whether bacteria were detectable in PMP tissues.
In situ hybridization was performed on resection specimens from five control subjects with noninflamed, nonperforated, non-neoplastic appendix and 16 patients with PMP [six with disseminated peritoneal adenomucinosis (DPAM) and 10 with peritoneal mucinous carcinomatosis (PMCA)]. Specific probes were designed to recognize: (1) 16S rRNA common to multiple bacteria or specific to H. pylori; (2) H. pylori cagA virulence gene; or (3) MUC2 or MUC5AC apomucins. Specimens from one patient with PMCA were examined by ultra-structural immunohistochemistry. Bacterial density and apomucin expression were determined in four histopathological compartments (epithelia, inflammatory cells, stroma, and free mucus).
Enteric bacteria were detected in all specimens. Bacterial density and MUC2 expression were significantly (p < 0.05) higher in PMCA than in DPAM and controls and were highest in free mucin. MUC2 was also expressed in dysplastic epithelia and in associated inflammatory cells. MUC2 expression was significantly correlated with bacterial density.
Multiple enteric bacteria are present in PMP, and bacterial density and MUC2 expression is highest in the malignant form of PMP. Based on these observations, we propose that the bacteria observed in PMP may play a role in the mucinous ascites and perhaps promote carcinogenesis.
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.
pseudomyxoma peritonei; cytokeratins; cadherin; vimentin
Pseudomyxoma peritonei (PMP) is a rare malignant disease, most commonly originating from appendiceal lesions and characterized by accumulation of mucinous tumor tissue in the peritoneal cavity. Since the disease is infrequent, the task of carrying out studies of treatment efficacy and disease biology in the clinical setting is challenging, warranting the development of relevant in vitro and in vivo PMP models.
Human tumor tissue was implanted in the peritoneal cavity of nude mice to establish two orthotopic models exhibiting noninvasive intraperitoneal growth without metastasis development.
Xenograft tissues have retained essential properties of the original human tumors, such as macro- and microscopic growth patterns, mucin production as well as expression of carcinoembryonal antigen, cytokeratins 20 and 7 and the proliferation marker pKi67. Upon microscopic examination, the human tumors were categorized as the PMCA-I (peritoneal mucinous carcinomatosis of intermediate features) subtype, which was conserved through 14 examined passages in mice, for the first time modeling this particular histopathologic category.
In conclusion, two novel orthotopic models of human PMP have been established that consistently portray a distinct histopathologic subtype and reflect essential human tumor properties. Xenografts can easily and reproducibly be transferred to new generations of mice with acceptable passage periods, rendering the models as attractive tools for further studies of PMP biology and treatment.
Tumors of the appendix are rare entities causing mucoceles. The majority of them are discovered incidentally during investigation for other conditions. Laparoscopic surgery for appendiceal tumors is still controversial, as inadvertent rupture of the lesion due to improper handling will cause pseudomyxoma peritonei. The patient was incidentally discovered to have an appendiceal tumor and referred to us for laparoscopy. Because the tumor involved the entire appendix, a laparoscopic right hemicolectomy was performed without directly handling the tumor. Postoperative recovery was uneventful. Pathological diagnosis was low-grade appendiceal mucinous neoplasm. The safety of laparoscopic appendectomy for the management of incidentally discovered appendiceal tumors has not yet been established. Several reports in the literature support both laparoscopic and open surgery. The main concerns to be addressed are the adequacy of resection and intraperitoneal rupture of the tumor. Our patient successfully underwent laparoscopic surgery without any complications. A formal right hemicolectomy was performed because the tumor involved the entire appendix. We now think laparoscopic surgery for appendiceal tumors is safe, feasible, and even may be beneficial.
Appendiceal tumor; Appendicitis; Mucinous cystadenoma; Laparoscopic right hemicolectomy
Pseudomyxoma (PM) implies an accumulation of a large amount of mucins which show myxomatous appearances. PM Peritonei (PMP) is famous and the only example of PM. PMP means excessive accumulation of mucins and mucin-secreting cells in the peritoneal cavity. The causes of PMP are mostly mucinous tumors, both benign and malignant, of ovaries and vermiform appendix. The author experienced excessive accumulation of mucins and mucin-producing cells in the subcutis and deep soft tissue. This situation very resembled PMP. Thus, the author termed the lesion as PM cutis (PMC). A 57-year-old man admitted to our hospital because of multiple subcutaneous large tumors in the perianal skin. The tumors were deeply seated and soft. No biopsy was performed. Very large skin and subcutis resection of the perianal region was done. Grossly, the material was skin and sot tissue flap measuring 25x25x5cm. The subcutis and deep soft tissue were resected. On cut surface, the tumor was slimy liquid. Microscopical examination revealed a large amount of mucins pools and mucin-producing intestinal epithelium with mild atypia. The author diagnosed it metastatic extremely well differentiated adenocarcinoma producing mucins, and pointed out anorectal primary. Thus, Miles operation was performed, which showed tumor formation in the anus. The tumor was located from the submucosa to adventitia, and composed of mucin pools and mucins producing intestinal-type epithelium with atypia. Mucins histochemistry showed that the mucin pools and epithelial cytoplasm contained neutral, carboxylated, and sulfated mucins. Immunohistochemically, the tumor cells were positive for CKAE1/3, CKCAM5.2, CK7, CK8, CK19, CK20, CEA, CA19-9,CD68, MET, p53, MUC2, MUC5AC, KIT, PDGFRA, chromogranin, and Ki-67 (76%). They were negative for CK34BE12, CK5/6, CK14, CK18, EMA, vimentin, desmin, smooth muscle actin, p63, CD34, ER, PgR, CA125, MUC1, MUC6, CD45, CD10, synaptophysin, surfactant Apo-A, TTF-1, NCAM, bcl-2, CDX-2. Although the atypia is mild, the author diagnosed primary anorectal extremely well differentiated adenocarcinoma with excessive production of mucins. The author considers the cutaneous mucins and tumor cells are metastatic or directly invading lesions of the anal tumor. Thus, the author termed pseudomyxoma cutis (PMC) for the cutaneous lesion.
Pseudomyxoma; skin; anal; mucins; mucin producing tumor; immunohistochemistry
Pseudomyxoma peritonei (PMP) is a rare condition characterized by mucinous tumors, disseminated intra-peritoneal implants, and mucinous ascites. So far its diagnosis remains challenging to most clinicians.
A 55-year-old male patient had suffered from acute onset of abdominal pain and abdominal distension for one day prior to his admission. Physical examination revealed tenderness over the right lower quadrant of the abdomen without diffuse muscle guarding. A large amount of ascites was identified by abdominal computed tomography (CT) scan. Paracentesis showed the appearance of sticky mucinous ascites. He underwent laparotomy under the impression of pseudomyxoma peritonei. There was a lot of mucinous ascites, one appendiceal tumor and multiple peritoneal implants disseminated from the subphrenic space to the recto-vesicle pouch. Pseudomyxoma Peritonei caused by mucinous adenocarcinoma of appendiceal origin, was confirmed by histopathology. We performed an excision of the appendiceal tumor combined with copious irrigation and debridement. After the operation, he received 10 cycles of systemic chemotherapy with FOLFOX4 regimen, without specific morbidity. Follow-up of abdominal CT and colonoscopy at post-operative 17 months showed excellent response without evidence of local recurrence or distal metastasis. He made an uneventful recovery (up to the present) for 21 months after the operation.
This case report emphasizes the possible new role of systemic chemotherapy in the treatment of patients with this rare clinical syndrome.
Background and Objectives:
Pseudomyxoma peritonei results from ovarian and appendiceal mucinous tumors. Cyst rupture results in intraabdominal mucin accumulation, leading to abdominal distension. No effective treatment has yet been established. Pseudomyxoma peritonei is generally associated with a poor prognosis. In a recent Mayo Clinic report, the 5-year survival rate for this disease was 53% and the 10-year survival rate was 32%, while the Memorial Sloan-Kettering Cancer Center reported 5- and 10-year survival rates of 75% and 10%.
Methods and Results:
In this report, we describe 4 patients with a laparoscopically confirmed recurrence of pseudomyxoma peritonei who subsequently underwent repeated laparoscopic mucin removal.
Because laparoscopic surgery can be performed frequently, it appears that laparoscopic surgery, a minimally invasive procedure, greatly improves the quality of life of patients with pseudomyxoma peritonei.
Pseudomyxoma peritonei; Laparoscopic surgery; Mucin removal; Quality of life
Alimentary tract duplications are rare congenital anomalies. They most often become symptomatic in childhood and rarely undergo malignant transformation. Pseudomyxoma peritonei (PMP) is an equally uncommon condition, most frequently originating from a primary appendiceal mucinous neoplasm. We report an extremely unusual case of PMP arising from an intestinal duplication. A 67-year-old woman presented with vague upper abdominal pain, and, unexpectedly, explorative laparoscopy revealed diffuse jelly-like peritoneal implants. The histopathological diagnosis of a low-grade PMP or “disseminated peritoneal adenomucinosis” was made. At that moment, no primary tumor was found. During later surgery, a cystic lesion located in the mesentery of the small bowel could be resected. Histologically, the cyst wall clearly showed the concentric layering of a normal bowel wall. The mucosa, however, displayed a diffuse low-grade villous adenoma. We concluded that this histological picture was most consistent with a small intestinal duplication, containing a low-grade villous adenoma. The adenoma caused a mucocele, which subsequently leaked or ruptured, giving rise to noninvasive mucinous peritoneal implants or low-grade PMP, also known as “disseminated peritoneal adenomucinosis” (DPAM).
Pseudomyxoma peritonei is a clinical syndrome characterized by peritoneal dissemination of a mucinous tumor with mucinous ascites. The vast majority of the pseudomyxoma peritoneis are associated with mucinous neoplasms of the appendix. We describe a case of pseudomyxoma peritonei associated with mucinous adenocarcinoma of the cervix in a 60-year-old woman. The patient developed low grade mucinous peritoneal carcinomatosis 8 years after hysterectomy for cervical adenocarcinoma. No other primary mucinous tumor was identified and peritoneal carcinomatosis tested positive for high-risk human papilloma virus (HPV), showing both integrated and episomal pattern. HPV has been previously associated with development of cervical carcinomas (both squamous and mucinous) but neither has cervical adenocarcinoma nor HPV been implicated in development of pseudomyxoma peritonei. To the best of our knowledge, this is the first description of HPV-associated malignancy presenting as pseudomyxoma peritonei.
Two cases of mucinous cystadenoma of the appendix successfully treated by laparoscopy are reported. An 81-year-old woman with lower right back pain was diagnosed with mucinous cystadenoma of the appendix or appendiceal carcinoma and underwent elective laparoscopic surgery. The other case involved a 70-year-old man with hematochezia who was diagnosed with mucinous cystadenoma. He also underwent elective laparoscopic surgery. In these two cases, gauze was folded around the tumors rather than grasping them directly. The postoperative courses were uneventful, and these patients had no recurrent disease at 2-year follow-up. In such cases, surgical excision of the tumor without rupture is of paramount importance because rupture of the lesion can cause pseudomyxoma peritonei. Though appendiceal mucinous cystadenoma has been considered a contraindication of laparoscopic resection, it was possible to achieve this by using a laparoscopic procedure with a gauze technique.
Mucinous cystadenoma of the appendix; Laparoscopic surgery
Pseudomyxoma peritonei (PMP) is a malignancy characterized by dissemination of mucus-secreting cells throughout the peritoneum. This disease is associated with significant morbidity and mortality and despite effective treatment options for early-stage disease, patients with PMP often relapse. Thus, there is a need for additional treatment options to reduce relapse rate and increase long-term survival. A previous study identified the presence of both typed and non-culturable bacteria associated with PMP tissue and determined that increased bacterial density was associated with more severe disease. These findings highlighted the possible role for bacteria in PMP disease.
To more clearly define the bacterial communities associated with PMP disease, we employed a sequenced-based analysis to profile the bacterial populations found in PMP tumor and mucin tissue in 11 patients. Sequencing data were confirmed by in situ hybridization at multiple taxonomic depths and by culturing. A pilot clinical study was initiated to determine whether the addition of antibiotic therapy affected PMP patient outcome.
We determined that the types of bacteria present are highly conserved in all PMP patients; the dominant phyla are the Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. A core set of taxon-specific sequences were found in all 11 patients; many of these sequences were classified into taxonomic groups that also contain known human pathogens. In situ hybridization directly confirmed the presence of bacteria in PMP at multiple taxonomic depths and supported our sequence-based analysis. Furthermore, culturing of PMP tissue samples allowed us to isolate 11 different bacterial strains from eight independent patients, and in vitro analysis of subset of these isolates suggests that at least some of these strains may interact with the PMP-associated mucin MUC2. Finally, we provide evidence suggesting that targeting these bacteria with antibiotic treatment may increase the survival of PMP patients.
Using 16S amplicon-based sequencing, direct in situ hybridization analysis and culturing methods, we have identified numerous bacterial taxa that are consistently present in all PMP patients tested. Combined with data from a pilot clinical study, these data support the hypothesis that adding antimicrobials to the standard PMP treatment could improve PMP patient survival.
PMP; Pseudomyxoma peritonei; Peritoneal cancer; Microbiome; Microbiota
When a bulging appendiceal orifice is observed during surveillance colonoscopy, the possibility of appendiceal mucocele must be considered. Appendiceal mucocele is a rare group of lesions characterized by mucinous distension of the appendiceal lumen with the dangerous potential to rupture, resulting in the development of pseudomyxoma peritonei. Early recognition and diagnosis of appendiceal mucocele can prevent the dreaded complication of pseudomyxoma peritonei but it requires a high index of suspicion. Patients with inflammatory bowel disease are at increased risk for colorectal neoplasm but neoplasm of the appendix is infrequently reported. We report two of the first cases of appendiceal mucoceles diagnosed in patients with inflammatory bowel disease using endoscopic ultrasound.
Primary neoplastic lesions presenting with a mucocele of the appendix are very rare and can be divided into benign variants of mucinous adenomas or cystadenomas, mucinous tumours of uncertain malignant potential or mucinous cystadenocarcinomas. Most of these tumourous mucoceles are asymptomatic and are found incidentally. The major complication of neoplastic mucinous appendiceal tumours is the development of a pseudomyxoma peritonei due to spreading of mucin-producing cells within the abdominal cavity.
A 44-year-old man presented with a history of non-specific symptoms of right upper abdominal pain. Abdominal ultrasound and computed tomography scan identified a cystic mass consistent with the morphological characteristics of an echinococcal hydatid cyst. After completing systemic albendazole therapy, an explorative laparotomy revealed a cystic tumour of the appendix. Ileocaecal resection was performed and pathology reports confirmed the diagnosis of a mucinous cystadenoma of the appendix. The postoperative course was uneventful.
Here we present the case of a man with a mucinous cystadenoma of the appendix mimicking cystic hydatid disease. We discuss the importance of re-evaluation and differential diagnostic reflections in cases of appendiceal mucocele.
The incidence of cancer during pregnancy is approximately 1 in 1000. The most common types encountered during pregnancy are cervical, breast and ovarian. Epithelial tumors of the appendix on the other hand are rare and account for only approximately 1% of all colorectal neoplasms; the occurrence of this neoplasm during pregnancy is extremely rare.
The medical history of a 30 year old woman diagnosed at 17 weeks gestation with an appendiceal mucinous tumor with large volume pseudomyxoma peritonei was presented. Her pregnancy was preserved and she had an early vaginal delivery of a healthy baby at 35 weeks. At 2 1/2 weeks postpartum the patient underwent extensive cytoreductive surgery and intraperitoneal chemotherapy. She remains disease-free 5 years after her initial diagnosis. A literature review of this clinical situation and a discussion of treatment plans were presented.
The management of an appendiceal tumor with pseudomyxoma peritonei diagnosed during pregnancy requires full knowledge of the natural history of this disease to achieve a balance of concern for maternal survival and fetal health.
Pseudomyxoma peritonei (PMP) is a rare tumor syndrome that can be diagnosed in association with mucinous ovarian tumors of low malignant potential. Surgical debulking is the primary treatment modality as chemotherapy has generally proven ineffective in this slowly progressive tumor. When patients with PMP are not surgical candidates, there is no effective treatment, and patients will die of progressive disease. We report two patients with PMP with associated mucinous ovarian tumor of low malignant potential treated with Bevacizumab therapy. Both patients demonstrated disease response to single agent Bevacizumab therapy. One patient had a prolonged response while on therapy, remained stable for 6 months when treatment was held, and then after progressing responded to a second course of therapy. We discuss here (1) the clinical features which may predict a better response to Bevacizumab therapy, and (2) evidence for the use of chemotherapy for inoperable PMP. These cases suggest that Bevacizumab may represent a rare effective therapy for patients with inoperable PMP with ovarian involvement and should be considered for clinical trials in this patient population.
Pseudomyxoma; Ovarian tumor of low malignant potential; Bevacizumab
Pseudomyxoma peritonei (PMP) is classified into pathologically and prognostically distinct categories, such as disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis. There is overwhelming evidence that DPAM arises from a mucinous adenoma of the appendix. The one exception to this is the presentation of a mature ovarian cystic teratoma as PMP where the appendix is normal. This report describes such a case and discusses the presentation, histopathology, and treatment options.
pseudomyxoma peritonei; ovarian cystic teratoma; appendiceal mucinous adenoma; disseminated peritoneal adenomucinosis
In the past, mucinous appendiceal tumors and the pseudomyxoma peritonei syndrome were treated with serial debulking procedures. Some benefit was achieved, but no long-term survivals were seen. A new standard of care that involves the complete removal of all visible disease using peritonectomy procedures combined with intraperitoneal chemotherapy washing has developed. This new approach is jeopardized when extensive prior surgical procedures have violated the peritoneum as a first line of defense of the host against carcinomatosis. In patients who have a complete cytoreduction, a 5-year survival of 80% is expected. In patients who have an incomplete cytoreduction, no 10-year survivors are seen. These studies suggest a new standard of care for appendiceal mucinous tumors with peritoneal dissemination.
Cytoreductive surgery; peritonectomy procedures; intraperitoneal chemotherapy; adenomucinosis; mucinous carcinomatosis
AIM: To assess the clinicopathologic features and its relationship with prognosis of pseudomyxoma peritonei (PMP) in Chinese patients.
METHODS: The clinicopathologic features and follow-up data of 92 patients with PMP were reviewed and retrospectively analyzed. The cases were categorized into three groups: disseminated peritoneal adenomucinosis (DPAM), peritoneal mucinous carcinomatosis (PMCA), and peritoneal mucinous carcinomatosis with intermediate or discordant features (PMCA-I/D). The log-rank test was used to analyze survival for each group and various clinicopathological parameters. Multivariate Cox proportional-hazard models were constructed to determine the important factors associated with survival.
RESULTS: The median age at diagnosis was 51.9 years (range: 22-76 years). The median follow up was 124 mo. The 3-, 5- and 10-year survival rates were 74.0%, 67.4% and 49.1%, respectively. There were 49 (53.2%) patients with DPAM, 26 (28.3%) with PMCA-I and 17 (18.5%) with PMCA. Patients with DPAM, PMCA-I/D and PMCA exhibited statistically significant difference in survival (P = 0.001). The 3 year survival for DPAM, PMCAI/D and PMCA was 97.0%, 80.0% and 67.0%, respectively; the 5 year survival was 80.0%, 67.0% and 50.0%, respectively; and the 10 year survival was 65.0%, 28.0% and 14.0%, respectively. Survival rate was significantly lowest in patients < 40 age years of age (P = 0.011). Appendiceal tumor and extra-ovarian parenchymal organ involvement were significantly related to overall survival. Patients with appendiceal mucinous adenocarcinoma (MACA) showed the significantly poorer prognosis (P = 0.011). Multivariate analysis showed that pathological classification, age, appendiceal tumor were significant related to overall survival.
CONCLUSION: The clinical process “PMP” should be pathologically classified into DPAM, PMCA and PMCA-I/D. Pathological classification, age, appendiceal MACA are survival independent predictors in Chinese patients with PMP.
Pseudomyxoma peritonei; Pathologic; Clinical; Classification; Prognosis
Pseudomyxoma peritonei (PMP) is a rare, chronic, relapsing, diagnostically challenging and poorly understood disease characterized by disseminated mucinous ascites and peritoneal implants.
We report two cases of PMP that represent the two biological variants of disseminated peritoneal adenomucinosis (DPAM) – the benign variant and the peritoneal mucinous carcinomatosis (PMCA) – the malignant variant, both of which were characterized by multiple relapses and progression of the disease despite aggressive management.
Even with a better understanding and recent advances in the management of these cases, PMP remains an enigmatic disease with a protracted clinical course characterized by multiple recurrences despite surgery and/or chemotherapy. Recognition of PMP as a delayed consequence years later should alert all surgeons to be extremely vigilant when treating mucinous neoplasms of the appendix, with special care being directed towards adequate excision and thorough debridement at the initial diagnosis.
Intraductal papillary mucinous neoplasm (IPMN) is an increasingly recognized pancreatic neoplasm characterized by excessive mucin secretion by ductal epithelial cells resulting in a cystic dilation of the pancreatic duct.
The objective of this study was to review Thomas Jefferson University’s experience and the literature to determine the significance of extra-pancreatic mucin when associated with an IPMN.
A retrospective analysis at our institution revealed only two cases of IPMN associated with extra-pancreatic mucin, which were classic IPMNs with rupture of the pancreatic duct and peritoneal mucin spillage. This specific finding is not previously described, although is assumed as five cases were reported in the literature with IPMN and mucin extension demonstrated by pseudomyxoma peritonei (PMP). We propose IPMN of the pancreas may be grossly compared to a mucocele of the appendix, as both are characterized by excessive secretion of mucin by ductal epithelial cells. A morbid complication of a mucocele is PMP. The presence of extra-pancreatic mucin with an IPMN could present a rare but important marker of the eventual seeding of tumor outside the primary IPMN. This has been documented with cases of iatrogenic spilling of pancreatic mucin, as well as multiple cases of IPMN associated with pseudomyxoma peritonei.
At this time, there is scant reporting and consensus for the treatment of IPMN with extra-pancreatic mucin.
Intraductal papillary mucinous neoplasm (IPMN); Extra-pancreatic mucin; Pancreatic cancer; Pseudomyxoma peritonei
Introduction. Increasing numbers of patients with pseudomyxoma peritonei (PMP) of appendiceal origin are being evaluated with a low tumor burden. We explored a minimally invasive approach for this group of patients. Materials and Methods. We designed a protocol in which patients with a PMP diagnosis would have a diagnostic laparoscopy. If limited carcinomatosis (PCI ≤ 10) is identified, the procedure will continue laparoscopically. If extensive carcinomatosis (PCI > 10) is found, then the procedure will be converted to an open approach. Results. From December 2008 to December 2011, 19 patients had a complete cytoreduction and HIPEC: 18 of them (95%) were done laparoscopically and 1 of them (5%) was converted to an open procedure. Mean PCI was 4.2. Grade 3 morbidity was 0, and one patient (5%) experienced a grade 4 complication, needing a reoperation for an internal hernia. There were no mortalities. Mean length of hospital stay was 5.3 days. At a mean follow-up of 17 months (1–37) all 19 patients are alive and free of disease. Conclusion. This study demonstrates that cytoreductive surgery and HIPEC via the laparoscopic route is feasible and safe and should be offered to patients with limited pseudomyxoma peritonei of appendiceal origin.
Ten cases of mucocele of the vermiform appendix are described. Eight cases were of mucinous cystadenoma of the appendix and six cases showed acute inflammation. Two of the six cases showed pseudoinvasion of the appendix and in a further case the appendix had perforated with extrusion of a misplaced neoplasm. Two cases were of mucinous cystadenocarcinoma and one of these was diagnosed as `pseudomyxoma peritonei'. `Pseudomyxoma peritonei' is a misnomer and is caused by dissemination of a mucinous cystadenocarcinoma within the peritoneal cavity. The special problems of histological diagnosis are discussed.
Pseudomyxoma peritonei (PMP) is characteristically divided into two histopathological subtypes; disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis (PMCA). The latter is associated with a worse prognosis. However, even within the DPAM group, there is a considerable variation in outcome. In this study we investigate the role of baseline serum tumor markers CA 19-9, CEA and CA-125 in further stratifying survival.
Over 16 years, 218 patients with PMP were treated with cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy (PIC) at our institution. A CA-125 level of >35 U/L, CA 19-9 of >40 U/mL and CEA of >3 ng/mL were considered positive or elevated outside the laboratory reference range. The impact of clinicopathologic and treatment-related variables on overall survival (OS) was analyzed with the Kaplan Meier method. Survival curves were compared using the log-rank test. Variables deemed significant by univariate analyses were entered into multivariate analysis using the Cox proportional hazards model.
Within the DPAM group, the 5-year survival of patients who were CA 19-9 positive versus those with normal values were 58% and 90% respectively (P<0.001). Other variables found to negatively impact on OS in univariate analyses were completeness of cytoreduction (CC) score 2/3 (P<0.001), peritoneal cancer index (PCI) >25 (P<0.001) and male gender (P=0.017). In the Cox regression model, only CA 19-9 positivity was found to be an independent prognostic factor for OS (P=0.034). In addition to marker positivity, the absolute level of CA 19-9 was also prognostically significant. In patients with CA 19-9>1,000 U/mL, the 5-year survival was 23%, in contrast to 90% in patients with CA 19-9<100 U/mL (P<0.001).
In the PMCA cohort, only CC-score was found to be associated with OS (P<0.001).
Our study provides relevant prognostic information for the DPAM subtype in staging and prioritizing surgery; as even in apparently indolent disease, some patients have poorer survival. CA 19-9 elevation may also be useful in identifying patients who would potentially benefit from adjuvant therapy and/or closer post-operative surveillance.
The potential role of CA 19-9 in mediating tumor cell adhesion and disease progression in PMP should be further investigated to deepen our understanding of the disease’s inherent biological behavior. If a true relationship exists, CA 19-9 may be a conceivable target for immunotherapy.
Carbohydrate antigen 19-9 (CA 19-9); pseudomyxoma peritonei (PMP); disseminated peritoneal adenomucinosis (DPAM); peritoneal mucinous carcinomatosis (PMCA)
Mucinous cystadenocarcinoma (MCA) in the breast is a rare neoplasm. There have been 13 cases of primary breast MCA reported. The MCA presents as a large, partially cystic mass in postmenopausal woman with a good prognosis. The microscopic findings resemble those of ovarian, pancreatic, or appendiceal MCA. The aspiration findings showed mucin-containing cell clusters in the background of mucin and necrotic material. The cell clusters had intracytoplasmic mucin displacing atypical nuclei to the periphery. Histologically, the tumor revealed an abundant mucin pool with small floating clusters of mucin-containing tumor cells. There were also small cysts lined by a single layer of tall columnar mucinous cells, resembling those of the uterine endocervix. The cancer cells were positive for mucin (MUC) 5 and negative for MUC2 and MUC6. This mucin profile is different from ordinary mucinous carcinoma and may be a unique characteristic of breast MCA.
Mucinous cystadenocarcinoma; Breast; MUC5; MUC2