Pseudomyxoma peritonei caused by acute pancreatitis in intraductal papillary mucinous carcinoma of the pancreas

A case of pseudomyxoma peritonei arising from a perforated intraductal papillary mucinous neoplasm that underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Pseudomyxoma peritonei (PMP) of pancreatic origin arising from an intraductal papillary mucinous neoplasm (IPMN) is rare. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been established as the optimal treatment for PMP. However, the benefits and safety of CRS with HIPEC for treating PMP of pancreatic origin remain unclear. Herein, we describe a case of PMP of pancreatic origin that was treated with CRS and HIPEC without postoperative complications. A 75-year-old woman was referred to our department. Computed tomography (CT) revealed a multilocular cystic tumor in the pancreatic tail, notable mucinous ascites in the abdominal cavity, and scalloping of the liver and spleen. CT did not reveal the appendix, and the ovaries were normal in size. The patient was diagnosed with PMP of pancreatic origin, and CRS and HIPEC were performed. Intraoperatively, the pancreatic tumor was perforated, and there was a large amount of mucinous ascites. We performed distal pancreatectomy in addition to CRS and HIPEC, with no intraoperative complications. The postoperative course was uneventful, and the patient survived after 6 months without recurrence. CRS with HIPEC may be a feasible treatment option for PMP of pancreatic origin.

Immunohistochemical staining as supportive diagnostic tool for pseudomyxoma peritonei arising from intraductal papillary mucinous neoplasm: A report of two cases and literature review

BACKGROUND/OBJECTIVES

Pseudomyxoma peritonei (PMP) arising from an intraductal papillary mucinous neoplasm of the pancreas (IPMN) is a rare condition. The diagnosis of IPMN as the origin of PMP is mainly inferred from the clinical course and the exclusion of PMP from other organs. The pathological diagnosis has not yet been established. To evaluate the usefulness of immunohistochemical staining for the diagnosis of the primary lesion of PMP as IPMN.

METHODS

There are 2 cases of PMP arising from IPMN between March 2010 and December 2019 at National Center for Global Health and Medicine. A PubMed search that reported PMP arising from IPMN identified 16 additional cases. Diagnostic methods and clinicopathological features of 18 cases were compared.

RESULTS

Four cases including our two cases used immunohistochemical staining for the diagnosis of PMP arising from IPMN. The correspondence of the immunohistochemical staining between PMP and IPMN was shown in the three cases including previously reported two cases and one of our two cases to identify the primary lesion of PMP as IPMN. In addition, we revealed that the comparison of the immunostaining pattern of PMP with the representative immunostaining pattern of the candidate primary lesions is helpful for the diagnosis of the primary lesion of PMP.

CONCLUSIONS

Immunohistochemical staining is helpful to identify the primary lesion of PMP as IPMN.

Pseudomyxoma Peritonei After a Total Pancreatectomy for Intraductal Papillary Mucinous Neoplasm With Colloid Carcinoma in Lynch Syndrome

We report a case of pseudomyxoma peritonei (PMP) arising in a 62-year-old male patient with Lynch syndrome (LS). The patient's medical history included an adenocarcinoma of the colon for which a right hemicolectomy was performed and a pancreatectomy due to an intraductal papillary mucinous neoplasm (IPMN) with invasive colloid carcinoma. It was considered that the PMP could be a metastasis of the earlier colonic or pancreatic carcinoma. The pancreatic carcinoma, colon carcinoma, and PMP tissues were examined, and immunohistochemical and molecular analyses were performed to determine the PMP origin. Histopathologic examination revealed morphological similarities with the pancreatic colloid carcinoma, and further immunohistochemical and molecular analyses, including a shared GNAS mutation, confirmed the pancreatic origin of the PMP. In conclusion, this is a unique case of a patient with LS presenting with PMP originating from an IPMN with invasive colloid carcinoma, several years after pancreatectomy. The present case has important diagnostic implications. The IPMN should be considered as a rare extracolonic manifestation of LS, and pancreatic carcinoma origin should be considered in patients presenting with PMP. This case report highlights the added value of molecular diagnostics in daily pathology practice.

Successful management of life-threatening bleeding of intraductal papillary mucinous neoplasms in the pancreatic head

Complications associated with intraductal papillary mucinous neoplasms, such as acute pancreatitis, perforation, and fistula formation, have been documented. Intraductal papillary mucinous neoplasm with intratumoral hemorrhage is rare. To the best of our knowledge, there have been no previous reports of intraductal papillary mucinous neoplasm rupture and bleeding with intra-abdominal hemorrhage. A 74-year-old woman complained of acute upper right abdominal pain. She was under follow-up for an intraductal papillary mucinous neoplasm in the pancreatic head. Contrast-enhanced computed tomography revealed intraductal papillary mucinous neoplasm rupture and bleeding with intra-abdominal hemorrhage. The bleeding was treated with selective endovascular embolization of a branch of the gastroduodenal artery. Follow-up examinations are recommended even for intraductal papillary mucinous neoplasm patients without malignant findings because of the potential risk of rupture and bleeding with intra-abdominal hemorrhage. Clinicians should be aware of this possibility to ensure that patients are appropriately treated.

A Rare Case of Intraductal Tubulopapillary Neoplasm of the Pancreas Rupturing and Causing Acute Peritonitis

An intraductal tubulopapillary neoplasm (ITPN) is a very rare pancreatic tumor. Here we report an extremely rare case of an ITPN rupturing and causing acute peritonitis. A 50-year-old woman presented with left flank pain and vomiting. A computed tomography (CT) scan revealed gigantic multilocular cysts in the pancreatic tail and massive fluid collection in the abdominal cavity. The serum, urine, and abdominal fluid amylase levels were highly elevated, so she was conservatively treated with intraperitoneal drainage and antibiotics for a diagnosis of ruptured pancreatic cysts. After this patient recovered, a CT scan revealed a 2-cm low-density mass located in the body of the pancreas. This was diagnosed as a pancreatic ductal adenocarcinoma of the pancreatic body with an intraductal papillary mucinous neoplasm, and a distal pancreatectomy was performed. The tumor was composed of cuboidal high-grade dysplastic cells proliferating in a tubulopapillary growth pattern without mucin production. An immunohistochemical examination revealed that the tumor cells were positive for MUC1 and CK7, but negative for MUC5AC. These features led to the final diagnosis of ITPN. In this case, the solid ITPN growth obstructed the lumen of the main pancreatic duct, and the intraductal pressure of the distal side rose gradually. Then, pancreatic cysts formed and burst into the abdominal cavity when the intraductal pressure was at its maximum. However, an ITPN consists of high-grade atypical cells derived from the pancreatic ductal epithelium in principle, so the rupture may be an independent risk factor for peritonitis carcinomatosa in the future.

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.

Pathological features and diagnosis of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a noninvasive epithelial neoplasm of mucin-producing cells arising in the main duct (MD) and/or branch ducts (BD) of the pancreas. Involved ducts are dilated and filled with neoplastic papillae and mucus in variable intensity. IPMN lacks ovarian-type stroma, unlike mucinous cystic neoplasm, and is defined as a grossly visible entity (≥ 5 mm), unlike pancreatic intraepithelial neoplasm. With the use of high-resolution imaging techniques, very small IPMNs are increasingly being identified. Most IPMNs are solitary and located in the pancreatic head, although 20%-40% are multifocal. Macroscopic classification in MD type, BD type and mixed or combined type reflects biological differences with important prognostic and preoperative clinical management implications. Based on cytoarchitectural atypia, IPMN is classified into low-grade, intermediate-grade and high-grade dysplasia. Based on histological features and mucin (MUC) immunophenotype, IPMNs are classified into gastric, intestinal, pancreatobiliary and oncocytic types. These different phenotypes can be observed together, with the IPMN classified according to the predominant type. Two pathways have been suggested: gastric phenotype corresponds to less aggressive uncommitted cells (MUC1 -, MUC2 -, MUC5AC +, MUC6 +) with the capacity to evolve to intestinal phenotype (intestinal pathway) (MUC1 -, MUC2 +, MUC5AC +, MUC6 - or weak +) or pancreatobiliary /oncocytic phenotypes (pyloropancreatic pathway) (MUC1 +, MUC 2-, MUC5AC +, MUC 6 +) becoming more aggressive. Prognosis of IPMN is excellent but critically worsens when invasive carcinoma arises (about 40% of IPMNs), except in some cases of minimal invasion. The clinical challenge is to establish which IPMNs should be removed because of their higher risk of developing invasive cancer. Once resected, they must be extensively sampled or, much better, submitted in its entirety for microscopic study to completely rule out associated invasive carcinoma.

Pseudomyxoma peritonei of 92 Chinese patients: Clinical characteristics, pathological classification and prognostic factors

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.

Intraductal papillary mucinous neoplasm (IPMN) with extra-pancreatic mucin: a case series and review of the literature

BACKGROUND

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.

AIM

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.

RESULTS

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.

CONCLUSIONS

At this time, there is scant reporting and consensus for the treatment of IPMN with extra-pancreatic mucin.

Pseudomyxoma peritonei (mucinous carcinoma peritonei) preceded by intraductal papillary neoplasm of the bile duct

Pseudomyxoma peritonei (mucinous carcinoma peritonei) is a rare clinical disease. Although most cases derive from appendiceal mucinous tumors, a few are associated with pancreatic intraductal papillary mucinous neoplasms. Intraductal papillary neoplasms of the bile duct share many similarities with pancreatic intraductal papillary mucinous neoplasms and are thought to be their biliary counterparts. We report a case of low-grade intraductal papillary neoplasm of the bile duct who developed pseudomyxoma peritonei 6 years after surgical treatment of the primary biliary tumor. To the best of our knowledge, this is the first case of pseudomyxoma peritonei associated with intraductal papillary neoplasm of the bile duct. The tumor recurrence in our case may be due to tumor spillage at the time of the first surgery, since there is no recurrent biliary tumor in the preserved liver lobe. Prevention of spillage of epithelial cell-containing mucin during surgical operations is important in treating intraductal papillary neoplasms of the bile duct.

Histological origin of pseudomyxoma peritonei in Chinese women: Clinicopathology and immunohistochemistry

AIM: To investigate the histological origin of pseudomyxoma peritonei (PMP) in Chinese women.

METHODS: The clinical and pathological data were reviewed for 35 women with PMP, and specimens of the peritoneal, appendiceal and ovarian lesions of each patient were examined using the PV-6000 immunohistochemistry method. Antibodies included cytokeratin (CK)7, CK20, mucin (MUC)-1, MUC-2, carbohydrate antigen (CA)-125, estrogen receptor (ER), and progesterone receptor (PR).

RESULTS: Abundant colloidal mucinous tumors were observed in the peritoneum in all 35 cases. Thirty-one patients had a history of appendectomy, 28 of whom had mucinous lesions. There was one patient with appendicitis, one whose appendix showed no apparent pathological changes, and one with unknown surgical pathology. Ovarian mucinous tumors were found in 24 patients. The tumors were bilateral in 13 patients, on the right-side in nine, and on the left side in two. Twenty patients had combined appendiceal and ovarian lesions; 16 of whom had undergone initial surgery for appendiceal lesions. Four patients had undergone initial surgery for ovarian lesions, and relapse occurred in these patients at 1, 11, 32 and 85 mo after initial surgery. Appendiceal mucinous tumors were found in each of these four patients. Thirty-three of the 35 patients showed peritoneal lesions that were positive for CK20 and MUC-2, but negative for CK7, MUC-1, CA125, ER and PR. The expression patterns in the appendix and the ovary were similar to those of the peritoneal lesions. In one of the remaining two cases, CK20, CK7 and MUC-2 were positive, and MUC-1, CA125, ER and PR were negative. The ovaries were not resected. The appendix of one patient was removed at another hospital, and no specimen was evaluated. In the other case, the appendix appeared to be normal during surgery, and was not resected. Peritoneal and ovarian lesions were negative for CK20, MUC-2, CK7, MUC-1, CA125, ER and PR.

CONCLUSION: Most PMP originated from the appendix. Among women with PMP, the ovarian tumors were implanted rather than primary. For patients with PMP, appendectomy should be performed routinely. The ovaries, especially the right ovaries should be explored.

Rare pancreatic neoplasms: the utility of endoscopic ultrasound-guided fine-needle aspiration-a large single center study

BACKGROUND

Tumors other than ductal adenocarcinomas constitute 10%-15% of all pancreatic tumors. We describe the performance and pitfalls of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for diagnosis of these rare pancreatic tumors and their characteristic cytopathological features.

METHODS

The records of 455 pancreatic fine-needle aspiration procedures done between March 1997 and August 2006 at Aichi Cancer Center, Nagoya, Japan, were reviewed. Besides cytology, aspirated material was routinely submitted in formalin for cell-block analysis. The reference standard for final diagnosis was surgical pathology from resected specimens.

RESULTS

Twenty-eight rare (nonductal adenocarcinomas) pancreatic tumors were identified. Overall, EUS-FNA with the results of cytology, cell-block processing, and immunohistochemistry could correctly diagnose the type of neoplasm in 19 (67.9%) cases. EUS-FNA could distinguish benign from malignant rare tumors with a sensitivity of 69.2%, a specificity of 100%, positive predictive value of 100%, negative predictive value of 79.0%, and accuracy of 85.7%. None of three malignant pancreatic endocrine neoplasms could be diagnosed as malignant. An adequate core tissue sample could be obtained in 21 cases (75.0%) and provide a histopathological diagnosis in 19 (67.9%) cases. EUS-FNA could change the presumptive diagnosis in 11 (39.3%) cases. Specific immunochemical studies were useful adjuncts to the diagnosis. No major or minor complication was noted in any patient.

CONCLUSIONS

Pancreatic neoplasms other than ductal adenocarcinomas have diverse imaging and histopathological features. EUS-FNA is accurate and safe for their identification.

Cystic neoplasms of the exocrine pancreas

The increasing use of radiological imaging has led to greater detection of small and asymptomatic cystic lesions of the pancreas. Most are resectable, but not all are neoplastic. This review provides an update on the histopathology, immunohistochemistry, molecular biology, pathogenesis and management of cystic neoplasms of the exocrine pancreas. These include the serous, the mucinous cystic, the intraductal papillary mucinous and the solid pseudopapillary neoplasms. Recently reported variants are described and very rare cystic variants of other pancreatic epithelial and mesenchymal neoplasms are briefly mentioned.

Intraductal papillary mucinous carcinoma with atypical manifestations: Report of two cases

Intraductal papillary mucinous neoplasms (IPMNs) are a well-characterized group of mucin-producing cystic neoplasms of the clear malignant potential type. We report here two cases of intraductal papillary mucinous carcinoma (IPMC) with atypical manifestations. In one case, we discussed a pseudomyxoma peritonei caused by a ruptured IPMC. In the other case we discussed the fistulization of IPMC into the stomach and duodenum. These two cases suggest that IPMN can either spontaneously rupture causing mucinous materials to spill into the free abdominal cavity or directly invade adjacent organs resulting in fistula development.