Multicystic mesothelioma: Operative and long-term outcomes with cytoreductive surgery and hyperthermic intra peritoneal chemotherapy

Multicystic peritoneal mesothelioma in the myometrium during pregnancy: A case report and literature review

Multicystic peritoneal mesothelioma (MCPM) is a rare tumor originating from mesothelial cells, primarily affecting women of reproductive age and typically found in the pelvic peritoneum. Its occurrence in the myometrium is extremely rare. Currently, there have been no reported cases of MCPM in the myometrium during pregnancy, and existing clinical guidelines do not provide specific management recommendations for this condition. This article aimed to explore the diagnosis, management, and treatment for MCPM in the myometrium during pregnancy, thereby providing a valuable reference for clinicians dealing with similar cases.

Acute kidney injury after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy - A systematic review

The use of nephrotoxic chemotherapeutic agents during hyperthermic intraperitoneal chemotherapy (HIPEC), carries the risk of postoperative acute kidney injury (AKI). The available evidence on this subject is sparse with variability in the reported incidence of AKI. In this systematic review, the aim was to analyse the incidence, risk factors, and preventive measures for AKI after cytoreductive surgery and HIPEC. A systematic literature search was conducted using the terms 'Acute kidney injury', 'Acute kidney failure', 'Acute renal failure', 'Acute renal impairment', 'HIPEC Surgery', 'Cytoreductive Surgery', 'Heated Chemotherapy' on PubMed, Scopus, clinical trial.gov, POPLINE and Google Scholar. Randomized controlled trials, cohort studies and observational studies published from January 2000-December 2020 were included. The systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021247781). Data from 16 articles, which included 1622 patients, was included. The incidence AKI by any definition, was 23.36 %. The highest incidence of AKI (45.45 %) was reported after paclitaxel-HIPEC. The incidence of AKI after cisplatin-HIPEC was 34.7 %. Cisplatin HIPEC was the most common factor associated with AKI in 7/16 studies followed by pre-existing comorbidities and low intraoperative diuresis in 4 and 3 studies respectively. The perioperative use of sodium thiosulfate and amifostine led to a significant reduction in the incidence of AKI. The reported incidence of AKI after CRS-HIPEC is high. Identifying preoperative risk factors, optimising comorbidities, maintaining perioperative haemodynamic stability, perioperative use of sodium thiosulfate, maintaining adequate diuresis could reduce the incidence of AKI.

Guidelines for Pathologic Diagnosis of Mesothelioma: 2023 Update of the Consensus Statement From the International Mesothelioma Interest Group

CONTEXT.—

Mesothelioma is an uncommon tumor that can be difficult to diagnose.

OBJECTIVE.—

To provide updated, practical guidelines for the pathologic diagnosis of mesothelioma.

DATA SOURCES.—

Pathologists involved in the International Mesothelioma Interest Group and others with expertise in mesothelioma contributed to this update. Reference material includes peer-reviewed publications and textbooks.

CONCLUSIONS.—

There was consensus opinion regarding guidelines for (1) histomorphologic diagnosis of mesothelial tumors, including distinction of epithelioid, biphasic, and sarcomatoid mesothelioma; recognition of morphologic variants and patterns; and recognition of common morphologic pitfalls; (2) molecular pathogenesis of mesothelioma; (3) application of immunohistochemical markers to establish mesothelial lineage and distinguish mesothelioma from common morphologic differentials; (4) application of ancillary studies to distinguish benign from malignant mesothelial proliferations, including BAP1 and MTAP immunostains; novel immunomarkers such as Merlin and p53; fluorescence in situ hybridization (FISH) for homozygous deletion of CDKN2A; and novel molecular assays; (5) practical recommendations for routine reporting of mesothelioma, including grading epithelioid mesothelioma and other prognostic parameters; (6) diagnosis of mesothelioma in situ; (7) cytologic diagnosis of mesothelioma, including use of immunostains and molecular assays; and (8) features of nonmalignant peritoneal mesothelial lesions.

A case of benign multicystic peritoneal mesothelioma

Benign Multicystic Peritoneal Mesothelioma (BMPM) is an exceedingly rare benign abdominal neoplasm with fewer than 200 cases reported worldwide. Owing to its rarity, vague clinical picture, and elusive causes, diagnosis is often delayed or missed. Histopathological examination and immunohistochemical staining are crucial for definitive diagnosis. However, due to lack of substantial literature, the standard of care and future prognosis remain subjects of inquiry. We present a case report of one female patient diagnosed with BMPM and treated with surgical resection.

Large and Extensive Multilocular Peritoneal Inclusion Cysts Lack Genomic Alterations and Follow an Indolent Clinical Course Despite Rare Recurrences

Peritoneal inclusion cysts (PICs) are unilocular or multilocular cystic lesions lined by bland mesothelial cells. While most are small and localized, rare examples may be large or multifocal with diffuse peritoneal involvement, causing clinical and even pathologic concern for malignancy. We examined 20 PIC, including 8 large solitary and 12 multifocal lesions. Solitary PIC were found in 7 female and 1 male patients ranging from 19 to 55 (median: 37) years. Expanded collagenous (n=2) or edematous (n=1) areas were occasionally seen in the septae, and 1 had microscopic foci of myxoid stroma. Four had hobnail cells, and 1 had minor areas of papillary mesothelial hyperplasia. Multifocal PICs occurred in 9 female and 3 male patients ranging from 26 to 80 (median: 53) years. Three showed extensive associated fibrosis with entrapment of preexisting adipose tissue, 2 had areas resembling granulation tissue, and 3 had scattered foci of myxoid stroma. Hobnail cells were present in 9, papillary mesothelial hyperplasia in 2, entrapped single cells in 1, and 2 had areas resembling adenomatoid tumors. Two of the multifocal PICs had limited local recurrences at 18 and 21 months. No patients died of disease. Clonal alterations were not identified in any of the tested PICs (mutational and fusion analysis in 5, chromosomal microarray in 1). Despite limited local recurrences, we demonstrate that even large and multifocal PICs may lack identifiable genomic alterations and are associated with benign outcomes.

[Gender medicine in peritoneal diseases]

Diseases of the peritoneum are divided into benign and malignant, whereby malignant diseases are more frequent. The incidence of peritoneal metastases is difficult to determine as they are frequently not listed separately in cancer databases and registries. Peritoneal metastases can be caused by many primary tumors but are particularly frequent in gastric, ovarian and colorectal carcinomas. Systemic chemotherapy shows gender-specific differences in the tolerability, especially gastrointestinal side effects and hematological toxicity occur more often in women. Surgical treatment options in selected patients include cytoreductive surgery with or without hyperthermic intraperitoneal chemoperfusion (HIPEC). The treatment recommendations depend on the primary tumor entity and the stage of the disease. Hysterectomy and/or salpingo-oophorectomy is often necessary during cytoreductive surgery. As the incidence of cancerous diseases is increasing in younger patients, the aspect of fertility is becoming increasingly more important. The iatrogenically induced menopause is another aspect that needs to be addressed after these types of procedures. Women with gastric and colorectal cancer tend to have a slightly better survival rate, especially in localized tumors; however, in advanced tumor stages the survival rates are comparable. Even if gender-specific differences in incidence, treatment response and adverse events are conspicuous, there is so far no exact explanation for these differences. More studies are needed in order to treat both genders as adequately as possible, with low adverse events and to achieve the best possible outcome.

Nephrotoxicity Associated with Cytoreductive Surgery Combined with Cisplatin-Based Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Malignant Disease: A Systematic Review and Meta-Analysis

Background: Cisplatin is employed in hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery (CRS) for peritoneal surface malignancies (PSMs). The main concern regarding intraperitoneal cisplatin administration is nephrotoxicity. Numerous reports in this context are available. Our objective was to conduct a systematic review and meta-analysis to assess cisplatin-based HIPEC-related nephrotoxicity (CHRN). Methods: A systematic literature review on CHRN after CRS for the treatment of PSMs was performed. The literature search was carried out using Medline, Cochrane, and Embase. The last day of the search was 23 October 2023. PRISMA guidelines were used. A meta-analysis was then conducted. The main endpoint was the incidence of acute and chronic renal impairment after CHRN. Secondary endpoints included the potential impact of several clinical variables on the primary endpoint and a critical appraisal of the different renal impairment scales employed. Results: Our study included 26 articles with a total sample of 1473 patients. The incidence of acute kidney injury (AKI) was 18.6% (95% CI: 13.6-25%, range of true effects 3-59%). For chronic kidney disease, it was 7% (95% CI: 3-15.3%, range of true effects 1-53%). The variables that statistically influenced these results were the scale used to measure renal insufficiency, the use of nephroprotective agents, and the presence of pre-existing renal disease. Conclusions: The reported incidence of renal impairment following cisplatin-based HIPEC is highly variable. The incidence of renal failure obtained in this meta-analysis should be used as a reference for subsequent reports on this topic. Further prospective studies are warranted to establish optimal and standardized management.

Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) for peritoneal mesothelioma: Canadian practices and outcomes

INTRODUCTION

Peritoneal mesothelioma (PM) is a rare malignancy originating from the peritoneal lining. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) is the standard-of-care for patients with isolated PM. Due to a paucity of prospective data there are several different HIPEC protocols. The aims of this study are to describe the CRS and HIPEC protocols for PM and patient outcomes across Canada.

METHODS

A multicenter retrospective study was performed on patients diagnosed and treated for PM with CRS and HIPEC in four major peritoneal disease centers in Canada between 2000 and 2021. Data on patient characteristics, treatment patterns, postoperative morbidity, recurrence, and survival were collected.

RESULTS

A total of 72 patients were identified. Mean age was 52 years (17-75) and 37.5% were male. Epithelioid (70.1%) and multicystic (13%) mesothelioma were the most common subtypes. Twenty-one patients (30%) were treated with neoadjuvant chemotherapy. CRS and HIPEC was performed in 64 patients (91.4%). Of these, the mean PCI was 22 (2-39) and cisplatin+doxorubicin was the most common HIPEC regimen (n = 33, 51.6%). A semi-closed coliseum technique was used in 68.8% of HIPECs and the mean duration of surgery was 486 min (90-1052). Clavien-Dindo III or IV complications occurred in 12 patients (16.9%). With a median follow-up of 24 months (0.2-104.4), we found a 5-year overall survival of 61% and a 5-year recurrence-free survival of 35%.

CONCLUSION

CRS and HIPEC is a safe and effective treatment modality for well-selected patients with PM, with some achieving prolonged survival.

Rare Variants of Malignant Peritoneal Mesothelioma: a Literature Review

Primary peritoneal mesothelioma (PM) is a rare and aggressive malignancy that arises from the peritoneum and classified into diffuse malignant peritoneum mesothelioma (DMPM) and borderline variants, viz. multicystic peritoneal mesothelioma (MCPM) and well-differentiated papillary peritoneal mesothelioma (WDPPM). The borderline variants are rarer than conventional DMPM, are less aggressive form accounting for 3-5% of all cases of peritoneal mesothelioma. In this narrative review article, we have discussed the pathogenesis, clinical presentation, natural history, and management of these rarer variants of PM, viz. MCPM and WDPPM. Histologically, MCPM typically consists of small cysts composed of mesothelial epithelium with benign bland cuboidal cells with clear fluids; cells lack cellular atypia and have increased number of mitoses. WDPPM has specific papillary component with myxoid plump cores and single layer of bland mesothelial cells. Both the variants commonly present as incidental finding or symptoms of chronic abdominal pain, chronic pelvic inflammatory disease, pelvic mass, and infertility. In the absence of treatment, these diseases are slow growing with major concerns being that both the variants have malignant transformation capabilities and a high rate of recurrence. In the light of current evidences, it is recommended that MCPM and WDPPM patients should be offered a complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy consisting of cisplatin and doxorubicin. Collaborative multi-institutional studies are needed to generate more data and formulate robust guidelines.

Peritoneal Mesothelioma: Systematic Review of Hyperthermic Intraperitoneal Chemotherapy (HIPEC) Protocol Outcomes

Diffuse malignant peritoneal mesothelioma (DMPM) prognosis was improved by the locoregional treatment combining cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). HIPEC is a multiparametric treatment with multiple protocols proposed and reviewed in this work. A systematic review of medical literature was performed according to PRISMA guidelines. The search strategy used "malignant peritoneal mesothelioma" and "HIPEC" as keywords in three databases. Studies were included if reporting precisely the HIPEC regimen and the related outcomes, if comparing regimen, or if reporting national/international guidelines. The GRADE methodology was used to rate the level of evidence. Twenty-eight studies were included in this review: 1 was a meta-analysis, 18 reported cohort outcomes, 4 retrospectively compared HIPEC regimens, and 5 were guidelines. Six HIPEC regimens were found, 4 with one drug (cisplatin, mitomycine-C, carboplatin, oxaliplatin), 2 using two drugs (cisplatin-doxorubicin or cisplatin-mitomycine-C). Cisplatin, up to 250 mg/m2 over 90 min, appeared as the key HIPEC drug with a toxicity profile well controlled by the concomitant intravenous perfusion of sodium thiosulfate. Comparative studies tended to show that a bi-drug regimen led to better long-term oncologic outcomes, with cisplatin 50 mg/m2 plus doxorubicin 15 mg/m2 being safe and more efficient. This late protocol was the most widely used and recommended in 3 out of 4 international guidelines. Cisplatin was the preferred drug for HIPEC in DMPM patients. Most of the time, it was combined with doxorubicin for 90 min. A harmonization of protocols and further comparative studies are needed to optimize HIPEC regimen choice.

Diagnostic and Therapeutic Pathway in Diffuse Malignant Peritoneal Mesothelioma

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare form of mesothelioma that carries a very poor prognosis. The 5-year overall survival is about 20% (±5.9). Survival is optimal for patients suitable for cytoreductive surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), with a median OS ranging from 34 to 92 months. However, selecting patients for surgery remains a complex task and requires a careful preoperative workup, rational analysis of prognostic profiles, and risk prediction models. Systemic chemotherapy could be offered: (1) in the adjuvant setting for high-risk patients; (2) for patients not eligible for CRS; and (3) for those with recurrent disease. It mainly includes the combination of Platin compound with Pemetrexed or immunotherapy. The biology of DMPM is still largely unknown. However, progress has been made on some fronts, such as telomere maintenance mechanisms, deregulation of apoptosis, tyrosine kinase pathways, and mutation of BRCA1-associated protein 1 (BAP1). Future perspectives should include translational research to improve our understanding of the disease biology to identify druggable targets. We should also clear the role of immune checkpoint inhibitors and investigate new locoregional technologies, such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) or normothermic intraperitoneal chemotherapy (NIPEC).

Acute presentation of multi-cystic peritoneal mesothelioma

Multi-cystic peritoneal mesothelioma (MCPM) is a rare intra-abdominal neoplasm that occurs most commonly in young females. The disease usually presents as an incidental finding or with sub-acute abdominal pain. The mainstay of treatment is complete excision; however, local recurrence frequently occurs and malignant transformation has been reported. We describe a unique case of MCPM that presented with acute abdominal pain.

A 32-year-old female presented with a 24-hour history of abdominal pain. Computed tomography abdomen demonstrated a low-density mass with surrounding inflammatory changes anterior to the ascending colon, which was initially thought to represent an abscess. A percutaneous drain was inserted; however, only clear fluid was aspirated and the lesion did not resolve. The patient subsequently underwent laparoscopy which identified a cystic structure overlying the ascending colon. The structure was excised whole with histology demonstrating MCPM. The patient recovered from surgery and will undergo a period of surveillance.

Multicystic peritoneal mesothelioma treated with cytoreductive surgery followed or not by hyperthermic intraperitoneal chemotherapy: results from a large multicentric cohort

BACKGROUND

Multicystic peritoneal mesothelioma (MCPM) is a rare, slowly growing, condition prone to recur after surgery. The role of hyperthermic intraperitoneal chemotherapy (HIPEC) added to complete cytoreductive surgery (CRS) remains controversial and difficult to assess. As patients are mostly reproductive age women, surgical approach, and fertility considerations are important aspects of the management. This observational retrospective review aimed to accurate treatment strategy reflections.

METHODS

The RENAPE database (French expert centers network) was analyzed over a 1999-2019 period. MCPM patients treated with CRS were included. A special focus on HIPEC, mini-invasive approach, and fertility considerations was performed.

RESULTS

Overall 60 patients (50 women) were included with a median PCI of 10 (4-14) allowing 97% of complete surgery, followed by HIPEC in 82% of patients. A quarter of patients had a laparoscopic approach. Twelve patients (20%) recurred with a 3-year recurrence free survival of 84.2% (95% confidence interval 74.7-95.0). The hazard of recurrence was numerically reduced among patients receiving HIPEC, however, not statistically significant (hazard ratio 0.41, 0.12-1.42, p = 0.200). A severe post-operative adverse event occurred in 22% of patients with five patients submitted to a subsequent reoperation. Among four patients with a childbearing desire, three were successful (two had a laparoscopic-CRS-HIPEC and one a conventional CRS without HIPEC).

CONCLUSION

MCPM patients treatment should aim at a complete CRS. The intraoperative treatment options as laparoscopic approach, fertility function sparing and HIPEC should be discussed in expert centers to propose the most appropriate strategy.

The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis: a systematic review including evidence from Japan

The prognosis of peritoneal carcinomatosis is poor. However, the emergence of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) as a treatment option has prolonged survival and it can even potentially cure patients with peritoneal carcinomatosis. Randomized controlled studies and other observational studies indicated that this combined therapy potentially improved the prognosis of patients with colon, gastric, and ovarian cancers with acceptable morbidity and mortality rates. Even in rarer diseases, such as pseudomyxoma peritonei and malignant peritoneal mesothelioma, CRS + HIPEC markedly improved the prognoses over those with conventional treatment. Based on the accumulated evidence, clinical guidelines recommend CRS + HIPEC for selected patients with peritoneal carcinomatosis. However, several issues still need to be overcome. A standard method for HIPEC has not yet been established. Furthermore, the criteria employed for patient selection need to be clarified to achieve real benefits. The peritoneal cancer index, chemo-sensitivity and several biological markers are considered to be key factors.

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.

Outcomes of multicystic peritoneal mesothelioma treatment with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

BACKGROUND

Multicystic peritoneal mesothelioma (MCPM) is a rare neoplasm, generally considered a borderline malignancy, best treated by cytoreductive surgery (CRS) to remove macroscopic disease, combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Owing to its rarity, little has been published on clinical presentation, clinical behaviour over time, or an optimal treatment approach.

METHODS

A prospectively developed peritoneal malignancy database was interrogated for the years 2001-2018. Details on all patients with MCPM as a definitive diagnosis after CRS and HIPEC were analysed, including previous interventions, mode of presentation, surgical treatment, postoperative outcomes, and late follow-up information from abdominal CT and tumour markers.

RESULTS

Some 40 patients with MCPM underwent CRS and HIPEC between 2001 and 2018. Of these, 32 presented with abdominal pain, distension or bloating, six patients presented with recurrence following previous surgery at the referring hospitals, and two had coincidental diagnoses during a surgical procedure. CRS involved peritonectomy in all 40 patients. Bowel resection was required in 18 patients, and seven had a temporary stoma. Thirty-eight patients were considered to have undergone a complete macroscopic tumour removal (completeness of cytoreduction CC0), and two had residual tumour nodules less than 2.5 mm in size, classified as CC1. Median duration of follow-up was 65 (range 48-79) months. There were no deaths during follow-up. The Kaplan-Meier-predicted recurrence-free interval was 115.4 months.

CONCLUSION

MCPM is a rare peritoneal neoplasm with a heterogeneous pattern of presentation. CRS and HIPEC is an effective management option for this group of patients, with favourable long-term survival.

Multicystic peritoneal mesothelioma treated with complete cytoreductive surgery, peritonectomy and hyperthermic intra-peritoneal chemotherapy-A case report

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Multicystic Peritoneal mesothelioma is a distinct type of peritoneal mesothelioma with borderline malignant potential and tendency to recur after tumor debulking.

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Morphologically MCPM has grapelike cysts filled with clear fluid and microscopically it has cystic spaces lined by cuboidal epithelium.

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There are areas of increased proliferative activity in the background of benign cyst representing potential for aggressiveness.

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Peritoneal free floating cysts can be formed from disintegration of main mass and deposit in other areas to form metastatic deposits.

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Comprehensive treatment – Complete cytoreduction, involved peritonectomy and HIPEC is required for treatment of macroscopic tumor and microscopic residue.

Background

Multicystic Peritoneal mesothelioma is a rare and distinct variety of peritoneal mesothelioma with borderline malignant potential. Conventional Tumor bulking has been associated with recurrence of 45–50 %. Hence a comprehensive treatment with Complete cytoreductive surgery with involved field peritonectomy (CRS) and Hyperthermic Intra-peritoneal chemotherapy (HIPEC) is being increasingly adopted for MCPM.

Case presentation

A 47 year old lady evaluated for peri-menopausal disturbance was diagnosed to have a multicystic lesion in the pelvis. With a preoperative suspicion of diagnosis of pseudomyxoma peritonei, CRS with HIPEC was planned. On exploration a diffuse multicystic mass was found in omentum and pouch of douglas with typical morphological features of MCPM. Complete cytoreduction was achieved with anterolateral and sub-diaphragmatic peritonectomy, omentectomy and panhystrectomy. HIPEC was performed with cisplatin 50 mg/m² for 40 min. Pathological examination revealed MCPM of omentum and uterine surface with focal clusters of mesothelial proliferation. However there was low proliferative activity 1–2 %.

Discussion

MCPM presents with wide spread peritoneal spread but with relative sparing of visceral invasion. Literature review suggests the disease spread is similar to PMP and treatment with CCRS and HIPEC has yielded long term survivals in MCPM.

Conclusions

This patient with voluminous disease burden in abdomen required surgical management and HIPEC for her condition. Whether CCRS alone without HIPEC can be an alternative for limited disease will be interesting research for future clinical reports.

Localized malignant mesothelioma, an unusual and poorly characterized neoplasm of serosal origin: best current evidence from the literature and the International Mesothelioma Panel

Localized malignant mesotheliomas (LMM) is an uncommon and poorly recognized neoplasm. Its pathologic diagnosis is often surprising in patients with serosal/subserosal based localized tumors that are clinically suspicious for metastatic lesions or primary sarcomas. Once a tumor is diagnosed as "mesothelioma", LMM is often mistaken for diffuse malignant mesothelioma (DMM). Best currently available evidence about LMM was collected from the literature and cases diagnosed by members of the International Mesothelioma Panel (IMP). One hundred and one (101) LMM have been reported in the English literature. Patients had localized tumors with identical histopathologic features to DMM. Patients ranged in age from 6 to 82 years; 75% were men. Most (82%) of the tumors were intrathoracic. Others presented as intrahepatic, mesenteric, gastric, pancreatic, umbilical, splenic, and abdominal wall lesions. Tumors varied in size from 0.6 to 15 cm. Most patients underwent surgical resection and/or chemotherapy or radiation therapy. Median survival in a subset of patients was 29 months. Seventy two additional LMM from IMP institutions ranged in age from 28 to 95 years; 58.3% were men. Sixty tumors (83.3%) were intrathoracic, others presented in intraabdominal sites. Tumors varied in size from 1.2 to 19 cm. Median survival for 51 cases was 134 months. Best evidence was used to formulate guidelines for the diagnosis of LMM. It is important to distinguish LMM from DMM as their treatment and prognosis is different. A multidisciplinary approach is needed for the diagnosis of LMM as it shows identical histopathology and immunophenotype to DMM.

Peritoneal mesothelioma in Sweden: A population-based study

The study aim was to report survival and morbidity of all patients in Sweden with peritoneal mesothelioma treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) as well as investigate whether the survival has increased on a population level since this treatment was nationalized 2011. Study data were collected from the Swedish HIPEC registry and the Swedish National Cancer Registry. All patients with peritoneal mesothelioma scheduled for CRS/HIPEC treatment in Sweden January 2011 to March 2018 were retrieved from the Swedish HIPEC registry. Clinicopathological and survival data were collected. For population‐level analysis, all patients with diffuse malignant peritoneal mesothelioma (DMPM) were identified from the Swedish National Cancer Registry and data were retrieved from two separate 5‐year time periods: 1999‐2003 and 2011‐2015. Thirty‐two patients were accepted for CRS/HIPEC. Four were open/close cases. Two‐year survival rate was 84% or 59% when excluding borderline peritoneal mesotheliomas (n = 17). Median overall survival was not reached. Grade III‐IV Clavien‐Dindo events occurred in 22% with no mortality. From the national cancer registry, 102 DMPM cases were retrieved: 40 cases between 1999 and 2003, and 62 cases between 2011 and 2015 (corresponding to an increase from 0.9 to 1.24/million/year, P = .04). Six patients (10%) received CRS/HIPEC in the second period. Median OS increased between periods from 7 to 15 months and 5‐year survival from 14% to 29% (P = .03). Peritoneal mesothelioma of both borderline and DMPM subtypes undergoing CRS/HIPEC have good long‐term survival. The incidence of DMPM in Sweden has increased. Overall survival has increased alongside the introduction of CRS/HIPEC, which may be a contributing factor.

Multicystic peritoneal mesothelioma: a systematic review of the literature

Multicystic peritoneal mesothelioma (MCPM) is a particularly rare and benign neoplasm that arises from the peritoneum in reproductive aged females. Its etiopathogenesis is still unclear. The current prevailing theory supports the idea that the tumor is the result of an excessive inflammatory process. Because of a lack of clinical and imaging presentation, the diagnosis is intricate, and heavily relies on case reports and short studies. A histological analysis with immunohistochemistry is required for a definitive diagnosis. To date, there is no standard treatment recommended for MCPM. However, some studies suggest proceeding with a cytoreductive surgery and a hyperthermic intraperitoneal chemotherapy combining CISPLATIN and DOXORUBICIN, due to a high incidence of recurrence rate after medical treatment or surgery alone and potential malignant transformation.

Peritoneal cavernous hemangiomatosis: A case report

BACKGROUND

Cavernous hemangiomatosis in the liver and spleen has been reported, but it occurs less commonly in the peritoneum. Here we report a case of peritoneal cavernous hemangiomatosis and share some valuable information about this disease.

CASE SUMMARY

A 57-year-old Chinese man had a huge abdominal mass with abdominal distention and a significant reduction of food consumption. An enhanced abdominal and pelvic computed tomography and positron emission tomography–computed tomography revealed multiple cystic masses on the peritoneum, greater omentum, small intestinal mesentery and the surface of the spleen, and a high maximum standardized uptake value of the largest cystic lesion. Exploratory laparotomy was performed, and multiple cystic masses were found on the surface of the peritoneum, greater omentum, mesentery of the small intestine, and surface of the liver and spleen. Dark red bloody cystic fluid was present in the cystic tumor. Pathological examination showed that in the stromal components, the irregular vascular wall was thin. The vessel lumen was interlinked, and the lumen was lined with flat endothelium. According to the intraoperative findings and pathologic results, the patient was diagnosed with peritoneal cavernous hemangiomatosis.

CONCLUSION

The possibility of peritoneal cavernous hemangiomatosis should be considered when multiple cystic masses are found in the abdominal cavity by preoperative examination.