High-grade Mucinous Carcinoma Peritonei Research Articles

Establishment and characterization of NCC-PMP2-C1: a novel patient-derived cell line of pseudomyxoma peritonei with signet ring cells.

Pseudomyxoma peritonei (PMP) is a rare phenomenon, characterized by accumulation of mucus in the abdominal cavity due to a mucinous neoplasm. Histologically, PMP is divided into three prognostic classes, namely low-grade mucinous carcinoma peritonei (LGMCP), high-grade mucinous carcinoma peritonei (HGMCP), and high-grade mucinous carcinoma peritonei with signet ring cells (HGMCP-S); HGMCP-S exhibits the worst prognosis. Complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have been established as the standard therapy for PMP. However, 50% of patients with PMP experience a recurrence, and 30-40% are unable to receive the standard treatment due to invasive diseases. Therefore, novel therapies are required for their treatment. Although patient-derived cell lines are important tools for basic and pre-clinical research, PMP cell lines derived from patients with HGMCP-S have never been reported. Thus, we established a novel PMP cell line NCC-PMP2-C1, using surgically resected tumor tissue from a patient with HGMCP-S. NCC-PMP2-C1 cells were maintained for more than five months and passaged 30 times under culture conditions. NCC-PMP2-C1 cells exhibited multiple deletions and somatic mutations, slow growth, histological features, and dissemination of tumor cells in nude mice. Screening for the anti-proliferative effects of anti-cancer drugs on cells revealed that bortezomib, mubritinib, and romidepsin had a significant response against NCC-PMP2-C1 cells. Thus, the NCC-PMP2-C1 cell line is the first PMP cell line harboring signet ring cells and will be a valuable resource for basic and preclinical studies of HGMCP-S.

Long-term survival following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in Waikato, Aotearoa New Zealand: a 12-year experience.

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have improved survival for selected cases of peritoneal surface malignancy. In 2008, a CRS/HIPEC service was first established in Aotearoa New Zealand (AoNZ) at Waikato and Braemar Hospitals in the Waikato region. This is a retrospective review of a prospectively maintained database of all patients undergoing CRS/HIPEC from 1 January 2008 to 1 November 2020 at Waikato and Braemar Hospitals. We analysed long-term survival and predictors of survival for each tumour type. 240 procedures were performed for 221 patients, including 22 re-do procedures. Cases had a median peritoneal cancer index of 16. Complete cytoreduction (CC0-1) was achieved in 196 cases (81.7%). All complete cytoreduction cases received HIPEC. There were 152 pseudomyxoma peritonei (PMP), 39 colorectal cancers (CRC), 29 appendiceal cancers, eight ovarian cancers, six peritoneal mesotheliomas, and six other cancers. The 5-year overall survival (OS) for PMP with acellular mucin, low-grade mucinous carcinoma peritonei, and high-grade mucinous carcinoma peritonei with or without signet cells were 91.6%, 80.5%, and 72.2%, respectively. 2- and 5-year OS in CRC were 56.7% and 40.4%. The achievement of complete cytoreduction improved the 5-year OS to 87.9% across all PMP and 45.1% in colorectal cancer. Incomplete cytoreduction predicted worse survival in appendiceal PMP. In colorectal cancer, worse survival was predicted in those who had incomplete cytoreduction, liver metastasis, and presentation with obstruction and perforation. Favourable long-term outcomes following CRS/HIPEC for peritoneal surface malignancy have been achieved in AoNZ through the Waikato peritonectomy service.

Whole-Exome Sequencing Identifies Mutation Profile and Mutation Signature-Based Clustering Associated with Prognosis in Appendiceal Pseudomyxoma Peritonei.

This work describes exhaustive mutation profile of PMP based on WES data and derives ten mutation signatures, which divides patients into two clusters and serve as an independent prognostic factor associated with 3-year survival.

S2046 High-Grade Mucinous Adenocarcinoma of the Appendix With Signet Features and Omental Metastasis

Introduction: Primary adenocarcinoma of the appendix is an uncommon malignancy of the gastrointestinal tract. It was first described in 1882 and constitutes around 0.12 to 2.6 cases per one million people per year. In addition, signet-ring cell carcinoma of the appendix is extremely rare, it constitutes approximately 4% of all primary appendiceal neoplasms. There are few reported cases of primary signet cell appendiceal carcinoma. In this present report, we describe a rare case of primary signet ring cell carcinoma of the appendix with omental metastases in an 81-year-old male who underwent laparoscopic appendectomy. Case Description/Methods: We present a case of an 81-year-old male who had prior negative esophagogastroduodenoscopy (EGD) and colonoscopy in 2017 who presented to an urgent care in January 2021 with abdominal pain. Lab work was unremarkable, and the patient was sent home with instructions to visit the emergency department (ED) if he experienced fever, increased abdominal pain, or blood in the stool. Patient presented to the emergency department with increased abdominal pain in April 2021, and Computed Tomography (CT) scan of abdomen and pelvis with intravenous contrast showed a cystic appendiceal lesion with right peritoneal nodularity suspicious for peritoneal carcinomatosis. Therefore, the patient underwent appendectomy the following day revealing poorly differentiated, high-grade appendiceal adenocarcinoma with signet ring features, pT4a disease. Patient had a diagnostic laparoscopy in June 2021 and was found to have diffuse peritoneal carcinomatosis. Multiple biopsies were obtained and came back positive with high-grade mucinous adenocarcinoma with signet ring features. Patient agreed to pursue systemic chemotherapy. He was initiated on Capecitabine (Xeloda) 2000 mg tab PO, twice daily for 14 days and off for 7 days. Bevacizumab (Avastin) 7.5 mg IV infusion every 3 weeks (Figure). Discussion: Patients with appendiceal neoplasms may have vague lower abdominal pain but are usually asymptomatic with incidental diagnosis on imaging or appendectomy. Signet ring adenocarcinoma of the appendix typically secretes mucin leading to metastasis throughout the peritoneum and eventual obstruction. Treatment is based on stage and histology. Surgical resection and peritoneal debulking is possible. High-grade tumors require further prospective trials to evaluate treatment, but treatment options include surgical management, HIPEC, and systemic chemotherapy.Figure 1.: Histologic examination showing a signet cell carcinoma of the appendix infiltrating the peritoneum and diaphragm. (A) right lower quadrant peritoneum biopsy, (H&E stain 100x): High grade mucinous carcinoma peritonei with signet ring cells. Pool of mucin with a cluster of epithelium that shows signs of metastatic carcinoma (enlarged nuclei, atypia, pleomorphic changes). (B, C, and D) Right diaphragm peritoneum biopsy. High grade mucinous carcinoma peritonei with signet ring cells. Image B at 100x, C at 200x, and D at 400x. (E & F) immunohistochemical cytokeratin stain (AE1/AE3) shows strong positivity of high grade carcinoma. E at 100x, and F at 400x.

New insights in the pathology of peritoneal surface malignancy.

Pathology is central to the management of peritoneal surface malignancy. This article highlights some recent advances that have had an impact on patient management or could do so in the near future. Malignant peritoneal mesothelioma, particularly the epithelioid subtype, is amenable to radical therapy in selected cases, and factors such as ki67 proliferation index, expression of BAP1 and mutation in CDKN2A show promise as prognostic indicators. Our understanding of multicystic mesothelioma has improved in recent years; it is a true neoplasm for which surgery may be indicated. Serous carcinomas involving the peritoneum are now known to originate from tubal epithelium. They are of two distinct types, high grade and low grade, which are now recognized as different neoplasms with distinctive features, oncogenesis and behavior. Pseudomyxoma peritonei (PMP) is an unusual condition that usually arises from an appendiceal mucinous neoplasm. Recent consensus in the classification and nomenclature of these lesions is discussed, including the distinction between low grade and high grade appendiceal mucinous neoplasms (HAMN), and the diagnostic criteria for appendiceal adenocarcinoma. PMP is divided into four prognostic groups: acellular mucin, low grade mucinous carcinoma peritonei, high grade mucinous carcinoma peritonei, and high grade mucinous carcinoma peritonei with signet ring cells. The pseudomyxoma microbiome is a promising area for clinical intervention but has been the subject of little research activity. Goblet cell adenocarcinoma (previously known as 'goblet cell carcinoid') is a distinctive type of appendiceal adenocarcinoma. Its behavior correlates with histologic features, but no general consensus for classification has been reached.

Patients undergoing cytoreductive surgery for peritoneal malignancy of appendiceal origin should be consented for umbilical excision as 30% have umbilical infiltration

Cytoreductive surgery (CRS) for peritoneal malignancy has traditionally included umbilical excision with no published evidence on the incidence of umbilical involvement. The primary aim of this work was to determine the incidence of umbilical involvement in patients undergoing CRS for peritoneal malignancy of appendiceal origin. The secondary aim was to investigate the relationship of umbilical involvement with prior surgery affecting the umbilicus, such as diagnostic laparoscopy and midline laparotomy. This study is from a national referral centre in the United Kingdom for appendiceal tumours and peritoneal malignancy. It is a retrospective analysis from a dedicated prospective database. We evaluated the most recent 200 consecutive patients who underwent CRS for peritoneal malignancy of appendiceal origin where all pathology specimens were reported by a recognized expert pathologist in appendiceal tumours and peritoneal malignancy. From June 2016 to September 2019, 200 consecutive patients had CRS and 178 had umbilical excision. Of these 54/178 (30.3%) had disease involving the umbilicus. The pathological findings in the 178 patients were low-grade mucinous carcinoma peritonei in 90/178 (50.6%), high-grade mucinous carcinoma peritonei in 31/178 (17.4%), metastatic appendiceal adenocarcinoma in 29/178 (16.4%) and diffuse acellular mucin in 28/178 (15.7%). Umbilical involvement was found in 25/90 (27.8%) with low-grade, 11/31 (35.5%) with high-grade, 8/29 (27.6%) with adenocarcinoma and 10/28 (35.7%) of patients with acellular mucin. In the 54 patients with umbilical disease, 30/54 (55.6%) had previous diagnostic surgery affecting the umbilicus. In the 124 patients without umbilical disease, 76/124 (61.2%) had prior surgery involving the umbilicus. The difference between the groups was not significant (p=0.24). In patients with peritoneal malignancy of appendiceal origin, approximately 30% have umbilical involvement, irrespective of the primary appendiceal pathology. Umbilical involvement was not associated with prior surgery involving the umbilicus. This is the first report to document the incidence of umbilical pathology and supports consideration of routine umbilical excision in CRS for peritoneal malignancy.

Clinicopathological Characteristics of Pseudomyxoma Peritonei Originated from Ovaries.

ObjectiveThis study aims to demonstrate clinicopathological characteristics and immunohistopathological phenotypes of pseudomyxoma peritonei (PMP) originated from ovaries.MethodsThe primary origin of PMP was explored by reviewing H&E sections retrospectively and performing a series of immunohistochemical staining on CK7, CK20, CDX2, CEA, Villin, SATB2, CA125, ER, PR, and MUC.ResultsAmong 310 PMP patients, a few originated from extra-appendix, whereas eight cases were of ovarian origin (2.6%), including three teratoma-associated ovarian mucinous tumors and five primary ovarian mucinous tumors with spontaneous or iatrogenic rupture, respectively. Most peritoneal metastases were acellular mucin or low-grade mucinous carcinoma peritonei (6/8, 75%), while the rest were high-grade mucinous carcinoma peritonei (2/8, 25%). Tumors were positive for CK20, CDX2, CEA, and Villin. SATB2 was specifically diffuse positive in teratoma-associated ovarian mucinous tumors, and negative in primary ovarian mucinous tumors. Differential expression of MUC was observed in these tumors.ConclusionPMP of ovarian origin is extremely rare. The precise diagnosis requires serial sections of the appendix or suspicious tissue to exclude appendiceal mucinous neoplasms, as well as comprehensive analysis of clinical features, surgical findings, histopathological characteristics, and immunohistochemistry on specific biomarkers.

Clinical evaluation of tumor-stroma ratio in pseudomyxoma peritonei from the appendix

To evaluate the effect of tumor-stroma ratio (TSR) on disease progression and prognosis of pseudomyxoma peritonei (PMP) from the appendix. The study included 30 PMP patients with complete individual patient data, who underwent cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) in Beijing Shijitan Hospital. Image-Pro Plus was used to quantitatively analyze the proportion of tumor and stromal areas in hematoxylin-eosin staining pathological images, from which TSR was derived. Correlation studies were conducted to evaluate the relationships between TSR and clinicopathological features, immunohistochemical characteristics, and prognosis of PMP. Among 30 PMP patients, there were 16 males (53.3%) and 14 females (46.7%), with the mean age of (54.9±2.3) years. There were 15 cases (50.0%) of low-grade mucinous carcinoma peritonei (LMCP) and high-grade mucinous carcinoma peritonei (HMCP), respectively, with vascular tumor emboli occurring in 4 cases (13.3%), nerve invasion occurring in 3 cases (10.0%), and lymphatic metastasis occurring in 4 cases (13.3%). The median peritoneal cancer index (PCI) score was 36 (range: 3-39). The median TSR was 8% (range: 2%-24%), with TSR≤10% in 19 cases (63.3%) and TSR>10% in 11 cases (36.7%). Immunohistochemistry showed that 16 cases (53.3%) had Ki67 label index ≤ 50% and 14 cases (46.7%) > 50%. The mutation rate of p53 was 56.7% and the loss rate of MMR protein was 11.8%. In addition, the expression rates of MUC2, MUC5AC, CDX2, CK7, and CK20 were 66.7%, 100.0%, 82.6%, 56.0%, and 92.3%, respectively. There were significant correlations between TSR and histopathological types, nerve invasion, Ki67 label index, and p53 mutation (P<0.05 for all). At the end of the last follow-up, 21 patients (70.0%) died and 9 patients (30.0%) survived, including 6 patients survived with tumor. The median overall survival (OS) was 12.7 months (95%CI: 10.4-11.5 months), and the 1-, 2-, and 3-year survival rates were 60.5%, 32.3%, and 27.7%, respectively. The median OS was 19.4 months (95%CI: 3.0-35.9 months) in the TSR≤10% group, versus 12.6 months (95%CI: 0.7-24.5 months) in the TSR>10% group (χ2=3.996, P=0.046). TSR is correlated with histopathological types, tumor proliferation, invasion behaviors and prognosis of PMP, thus could be a new prognostic indicator for PMP.

Pathological prognostic factors of pseudomyxoma peritonei: comprehensive clinicopathological analysis of 155 cases

Pseudomyxoma peritonei (PMP) is an extremely rare malignancy, characterized by extensive peritoneal implantation and colloidal ascites. This study was to explore the pathological prognostic factors of PMP. Specimens from 155 PMP patients were analyzed by H&E and immunohistochemistry. Parameters included primary tumor location, histological grade, lymph node metastasis, tumor emboli in the blood and lymph vessels, perineural invasion, Ki67 labeling index, p53, mismatch repair (MMR) gene mutations, MUC1, MUC2, MUC5AC, and MUC6. Clinicopathological and follow-up data were subjected to univariate and multivariate analyses. The patients included 63.2% (n = 98) low-grade mucinous carcinoma peritonei, 31.6% (n = 49) high-grade mucinous carcinoma peritonei and 5.2% (n = 8) high-grade mucinous carcinoma peritonei with signet ring cells. There were 9.7% (n = 15) with lymph node metastasis; 11.6% (n = 18) with angiolymphatic invasion; 6.3% (n = 8) with defective MMR (dMMR); 35.5% (n = 55) with Ki67 labeling index ≥ 50%; 36.1% (n = 56) with p53 mutation. For PMP from appendiceal origin (n = 140), univariate analysis identified 10 potential prognostic factors. But Multivariate analysis identified only histologic grade was the independent prognostic factor for OS. Mortality risk of high-grade peritoneal mucinous carcinoma or high-grade peritoneal mucinous carcinoma with signet ring cells was 7.056 times (P < .0001, 95% CI: 2.701-18.435) or 27.224 times (P < .0001, 95% CI: 6.207-119.408), respectively, higher than low-grade. For PMP from the appendiceal origin, histological grade could be the only independent prognostic factor.

Establishment of patient derived xenograft model of high-grade mucinous carcinoma peritonei accompanied with signet ring cells and identification of biological characteristics

Objective: To establish the patient derived xenograft (PDX) model of pseudomyxoma peritonei (PMP), and identify the key characteristics of tumor biology of this model, in order to provide a reliable model for studying the pathological mechanisms and new therapeutic strategies of PMP. Methods: PMP tumor tissue was obtained from surgery and cut into pieces after washing. Then tumor pieces were implanted subcutaneously in BAL B/c-nu mice for 6 stable passages. In the 7th passage, tumor tissue was implanted orthotopically into abdomen. Subcutaneous tumor and orthotopic tumor were then homogenized to make tumor cell suspension, implanted into abdomen of 10 BAL B/c-nu mice through midline laparotomy, 100 μl for each. The key experimental parameters including body weight changes in the observation period, experimental peritoneal cancer index (ePCI) score at the autopsy, histopathological and immunohistochemical characteristics, and gene expression profiles by high-throughput whole-genome exon sequencing were detected and recorded. Results: The successful rate of established orthotopic PDX model of human PMP was 100% (10/10). The animals showed smooth body weight increases after tumor inoculation until day 27, then the body weight began to decrease steadily. Widespread tumor dissemination of PMP tumor through the whole abdomen was found by autopsy, including the diaphragm, liver, spleen, stomach, kidney, parietal peritoneum, bowel and mesenterium. Gelatinous ascites was also observed in abdominopelvic cavity. The ePCI score ranged from 5 to 9, with a 8 of median ePCI. Histopathological studies showed peritoneal mucinous carcinomatosis accompanied with signet ring cells (PMCA-S), obvious tumor cell atypia and parenchymal invasion.Immunohistochemistry showed the expressions of MUC1, MUC2, MUC5AC, CEA, CA199, CK20, CDX-2 and Ki-67 were positive, MUC6, CK7 and p53 were negative. Whole-exome sequencing identified that the most significant genetic alteration is the exon10 missense mutation c. 1621A>C of KIT gene, the mutation abundance was 89.7%. Conclusion: PDX model of PMCA-S is successfully established, which displays the characters of high-degree malignancy, high proliferation and strong aggressiveness.

Experimental study on the efficacy and toxicity of intraperitoneal injection of 5-fluorouracil to treat PDX model of pseudomyxoma peritonei

Objective To evaluate the efficacy and toxicity of intraperitoneal injection of 5-fluorouracil (5-Fu) in patient derived xenograft (PDX) model of pseudomyxoma peritonei (PMP). Methods One PMP tumor from surgery was used to establish PMP PDX models, which were equally randomized into control (no treatment), vehicle (normal saline, 0.2 ml) and treatment (5-Fu, 50 mg/kg, 0.2 ml) groups. Experimental peritoneal cancer index (ePCI) score, body weight, and pathological examination were performed to evaluate the efficacy and toxicity. Results PDX models replicating human PMP were established and diagnosed as high grade mucinous carcinoma peritonei with signet ring cells. Average ePCI score of treatment group was significantly lower than control and vehicle groups [(0.9±1.2) points vs. (3.6±1.7) points vs. (2.7±1.1) points, F=9.253, P<0.01]. Histopathological study revealed obvious tumor necrosis and reduced signet ring cells in the treatment group. The Ki-67 label index of treatment group was significantly lower than control group and vehicle group [(57.3±15.1)% vs. (72.2±15.1)% vs. (70.0±14.0)%, F=4.923, P<0.05]. The body weight of treatment group was significantly lower than control group and vehicle group [(19.7±2.8) g vs. (22.7±1.8) g vs. (21.9±1.7) g, F=4.654, P<0.05]. Major toxicities in the treatment group were animal death (10.0%), congestive splenomegaly (88.9%), lymphocyte accumulation (77.8%), bile canaliculus hyperplasia and obstruction (22.2%), cholestasis (100.0%), and acidophilic body (55.6%) in the liver. Conclusion In the PDX model of human PMP, intraperitoneal injection of 5-Fu could inhibit tumor proliferation and progression, with lowered ePCI score and reduced Ki-67, and toxicity was mainly on liver. Key words: Pseudomyxoma peritonei; PDX model; 5-Fluorouracil; Intraperitoneal injection; Organ toxicity

Pathological prognostic factors of pseudomyxoma peritonei

Objective: To analyze the pathological features of pseudomyxoma peritonei (PMP) in correlation with the survival status and independent prognostic factors. Methods: One-hundred and fifty-five PMP specimens were collected at Beijing Shijitan Hospital, Capital Medical University, from 2012 to 2018. Conventional histopathological evaluation was performed to document the primary tumor site, histopathological type, lymph nodes metastasis, tumor emboli in the blood and lymph vessels, nerve invasion and cellular density. The immunohistochemical parameters including Ki-67, p53, MMR-related protein, MUC2 and MUC5AC were analyzed. Clinical follow-up data were reviewed to correlate with pathological prognostic factors using Kaplan-Meier estimator and Cox proportional hazards regression model for univariate and multivariate analysis. Results: Among 155 PMP patients, there were 77 males and 78 females. There were 98 cases (63.2%) of low-grade peritoneal mucinous carcinomatosis, 49 cases (31.6%) of high-grade peritoneal mucinous carcinomatosis, 8 cases (5.2%) of high-grade mucinous carcinoma peritonei with signet ring cells; only 15 cases (9.7%) with lymph node metastasis; 18 cases (11.6%) with tumor emboli in the blood and lymph vessels; 8/126 (6.3%) were positive dMMR; 100 cases (64.5%) had Ki-67 label index <50%, and 56 cases(36.1%) presented with mutant type p53. Univariate analysis revealed 11 survival-related pathological parameters including gender, age, primary tumor site, histopathological type, lymph node metastasis, tumor emboli in the blood and lymph vessels, nerve invasion, cellular density, Ki-67 label index rate, p53 and dMMR. Multivariate analysis identified 4 independent prognostic factors including the histopathological type (HR 59.78, P<0.01), lymph node metastasis (HR 3.74, P=0.028), nerve invasion (HR 7.81, P=0.007) and dMMR (HR 9.82, P<0.01). Conclusions: Histopathological type is the most important prognostic factor of PMP with dMMR as an independent molecular prognostic indicator.

Systemic chemotherapy before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in patients with high-grade mucinous carcinoma peritonei of appendiceal origin

BackgroundThe role of systemic chemotherapy (SC) before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in appendiceal high-grade mucinous carcinoma peritonei (HGMCP) is controversial. We analyzed the effect of SC prior to CRS/HIPEC in HGMCP. MethodsA prospective database of CRS/HIPEC procedures for HGMCP without signet ring cells and with signet ring cells (HGMCP-S) from 1998 to 2017 was reviewed. Exclusion criteria was prior surgery >5 regions or >2 regimens of prior SC. Perioperative variables were analyzed. ResultsThere were 140 HGMCP/HGMCP-S identified: 64 with prior SC (preSC) and 76 without (noSC). Groups were balanced for lymph node status, complete cytoreduction rate, disease burden, complications, and postoperative SC. PreSC had more HGMCP-S, moderately/poorly differentiated histology, and longer time-to-surgery (median: 6 vs 2 months, p < 0.001). Median overall survival (mOS) was 40 vs 86 and median progression-free survival (mPFS) was 19 vs 43 months for preSC vs noSC, respectively (p = 0.006 and p = 0.007). In HGMCP-S subanalysis, mOS was 25 vs 39 and mPFS 16 vs 29 months for preSC vs noSC, respectively (p = 0.188 and p = 0.063). In moderately/poorly differentiated histology subanalysis, mOS was 38 vs 56 and mPFS 18 vs 29 months in preSC vs noSC, respectively (p = 0.199 and 0.082). Prior SC was not linked to improved OS or PFS in non-signet ring HGMCP or well-differentiated histology subanalysis. ConclusionPrior SC was not associated with less disease burden, better cytoreduction rates, or improved clinical outcomes in HGMCP, regardless of histopathologic subtype. Traditional SC agents may not be effective in HGMCP in the neoadjuvant setting.

Outcomes in Peritoneal Dissemination from Signet Ring Cell Carcinoma of the Appendix Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is standard treatment for peritoneal dissemination from appendiceal cancer (AC); however, its role in high-grade histopathologic subtypes (high-grade mucinous carcinoma peritonei [HGMCP] and HGMCP with signet ring cells [HGMCP-S]) is controversial due to their aggressive behavior. This study analyzed clinical outcomes of high-grade AC after CRS/HIPEC. A prospective database of CRS/HIPEC procedures for HGMCP performed from 1998-2017 was reviewed. Perioperative variables and survival were analyzed. Eighty-six HGMCP and 65 HGMCP-S were identified. HGMCP had more positive tumor markers (TM) (CEA/CA-125/CA-19-9) than HGMCP-S (63% vs 40%, p=0.005). HGMCP had higher Peritoneal Cancer Index (32 vs 26, p=0.097) and was less likely to have positive lymph nodes (LN) than HGMCP-S (28% vs 69%, p=<0.001). Complete cytoreduction was achieved in 84% and 83%, respectively. PFS at 3- and 5-years was 59% and 48% for HGMCP vs 31% and 14% for HGMCP-S. Median PFS was 4.3 and 1.6 years, respectively (p<0.001). OS at 3- and 5-years was 84% and 64% in HGMCP vs 38% and 25% in HGMCP-S. Median OS was 7.5 and 2.2 years, respectively (p<0.001). LN negative HGMCP-S had longer median PFS and OS than LN positive HGMCP-S (PFS: 3.4 vs 1.5 years, p=0.03; OS: 5.6 vs 2.1 months, p=0.021). The aggressive histology of HGMCP-S is associated with poor OS, has fewer abnormal TM, and is more likely to have positive LN. However, CRS/HIPEC can achieve a 5-year survival of 25%, which may improve to 51% with negative LN.

Cytoreductive Surgery Plus Hyperthermic Intraperitoneal Chemotherapy for Pseudomyxoma Peritonei Arising from Urachus.

Pseudomyxoma peritonei (PMP) is a rare locoregional disease characterized by disseminated intraperitoneal mucinous tumors. However, little is known about PMP from urachal neoplasm as a result of its rarity. A total of 9 patients with PMP of urachal origin were treated by cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) in our institution. All specimens of surgeries were submitted for pathologic examination. Representative slides of tumors and normal urachus were submitted for immunohistochemical staining. Four patients were men; the median age was 48years (range 27-65years). Initial radiologic examination of all patients showed a cystic tumor located between posterior aspect of umbilicus and the dome of urinary bladder, with or without leaking mucin. Complete CRS and HIPEC were performed in all patients. Until the latest follow-up, local recurrence occurred in 1 patient. Other 8 patients had a median disease-free survival of 27.5months. Primary urachal tumors of 9 cases were all mucinous adenocarcinoma. Six patients had low-grade mucinous carcinoma peritonei, and 3 patients had high-grade mucinous carcinoma peritonei. Signet ring cells were noted in 4 patients. All tumor specimens of 9 patients were diffuse positive for CK-20, CDX-2, MUC-2, and MUC-5AC, and were variant positive for CK-7. PMP arising from urachus comes from neoplastic cells with development of intestinal-type mucinous neoplasm. It shares a similar pathophysiology as PMP from appendix. CRS including total urethrectomy, partial cystectomy, and peritonectomy plus HIPEC can be considered as a new option of treatment for PMP originating from urachus.

Perioperative systemic chemotherapy for appendiceal mucinous carcinoma peritonei treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

The role of systemic chemotherapy (SC) in conjunction with cytoreductive surgery (CS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in appendiceal mucinous carcinoma peritonei (MCP) is unknown. A retrospective review (1999-2011) of MCP patients who had undergone CS/HIPEC with or without perioperative SC. Twenty-two low-grade MCP patients treated with CS/HIPEC and SC were matched to patients who received CS/HIPEC alone. Median overall survival (OS) was 107 months for patients treated with perioperative SC compared to 72 without (P = 0.46). CS/HIPEC was performed on 109 patients with high-grade MCP: 70 were treated with perioperative SC, while 39 were not. Median OS (22.1 vs. 19.6 months, P = 0.74) and progression-free survival (PFS) (10.9 vs. 7.0 months, P = 0.47) were similar in patients treated with SC compared to CS/HIPEC alone. Progression while on pre-operative SC was seen in eight patients (17%), while four (8%) had a partial response. Treatment with post-operative SC was associated with longer PFS (13.6 months) compared to pre-operative SC (6.8 months, P < 0.01) and CS/HIPEC alone (7.0 months, P = 0.03). Post-operative SC appears to improve PFS in patients with high-grade appendiceal MCP treated with CS/HIPEC. In contrast, there is no evidence to support the routine use of perioperative SC in low-grade disease.

Pseudomyxoma Peritonei: More Questions Than Answers

Pseudomyxoma Peritonei: More Questions Than Answers

Pleuropulmonary Involvement in Pseudomyxoma Peritonei: Morphologic Assessment and Literature Review

Intrathoracic spread in patients with pseudomyxoma peritonei (PP) is rare. We reviewed 101 patients uniformly treated at our institution for PP of appendiceal origin. In that study, we suggested mucinous carcinoma peritonei (MCP) as the pathologic terminology for all cases of PP. Four patients had pathologically documented pleuropulmonary involvement. We subsequently examined another patient with pleural invasion. Of 5 patients, 3 had low-grade histologic features in the peritoneum; these showed variably proliferative, bland-appearing neoplastic cells arising from low-grade appendiceal mucinous neoplasms. In 2 cases, 1 or more pulmonary parenchymal metastases of low histologic grade developed. The lack of pleural involvement argued against transdiaphragmatic tumor extension. The third patient with low-grade MCP had direct extension through the left diaphragm involving the left pleural and pericardial spaces without pulmonary parenchymal involvement. In the 2 patients with high-grade MCP, right-sided pleural effusions developed. Neither patient had documented injury to the diaphragm. Pleural cytologic examination revealed high-grade adenocarcinoma cells singly, in small clusters, and in large spheres. The smear backgrounds contained wispy mucin. None of the 5 patients developed thoracic lymph nodal metastases. Although rare, mucinous neoplasms from PP may involve the thorax.

Pleuropulmonary Involvement in Pseudomyxoma Peritonei

Intrathoracic spread in patients with pseudomyxoma peritonei (PP) is rare. We reviewed 101 patients uniformly treated at our institution for PP of appendiceal origin. In that study, we suggested mucinous carcinoma peritonei (MCP) as the pathologic terminology for all cases of PP. Four patients had pathologically documented pleuropulmonary involvement. We subsequently examined another patient with pleural invasion. Of 5 patients, 3 had low-grade histologic features in the peritoneum; these showed variably proliferative, bland-appearing neoplastic cells arising from low-grade appendiceal mucinous neoplasms. In 2 cases, 1 or more pulmonary parenchymal metastases of low histologic grade developed. The lack of pleural involvement argued against transdiaphragmatic tumor extension. The third patient with low-grade MCP had direct extension through the left diaphragm involving the left pleural and pericardial spaces without pulmonary parenchymal involvement. In the 2 patients with high-grade MCP, right-sided pleural effusions developed. Neither patient had documented injury to the diaphragm. Pleural cytologic examination revealed high-grade adenocarcinoma cells singly, in small clusters, and in large spheres. The smear backgrounds contained wispy mucin. None of the 5 patients developed thoracic lymph nodal metastases. Although rare, mucinous neoplasms from PP may involve the thorax.