Case Of Peritoneal Mesothelioma Research Articles

Long‐term outcomes and survival analysis of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei at a newly established peritoneal malignancy centre in Japan

AbstractBackgroundCytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is established in the management of pseudomyxoma peritonei (PMP), selected cases of peritoneal mesothelioma, and resectable colorectal or ovarian peritoneal metastases in Western countries. However, the efficacy and feasibility of these techniques are not well established in the Asian population, and little has been reported on long‐term survival outcomes for surgically resected PMP patients.Materials and MethodsRetrospective analysis of a prospective database of short‐ and longer‐term outcomes of consecutive patients who underwent CRS and HIPEC for PMP in a newly established peritoneal malignancy unit in Japan between 2010 and 2016.ResultsA total of 105 patients underwent CRS and HIPEC and 57 maximal tumor debulking (MTD) for pseudomyxoma peritonei. In the CRS group, the primary tumor was appendiceal in 94 patients (90%) followed by ovarian and colorectal. Major postoperative complications occurred in 22/105 patients (21%) with one in‐hospital mortality (0.9%). The 5‐year overall and disease‐free survival rates for the CRS group were 74.2% and 50.1%, respectively. Multivariate analysis revealed unfavorable histology to be the significant predictor of reduced overall and disease‐free survival. Completeness of cytoreduction, CA19‐9, and CA125 were also associated with disease‐free survival.ConclusionsThis is the first report on long‐term outcomes and survival analysis of CRS and HIPEC for PMP in the Asian population. CRS and HIPEC can be conducted with reasonable safety and favorable survival in a new center. Complete tumor removal and histological type are the strongest prognostic factors for both overall and disease‐free survival.

Benign Multicystic Peritoneal Mesothelioma: Two Rare Cases and Review of the Literature

Background:: Benign multicystic peritoneal mesothelioma is a multiloculated cystic mass which originates from the peritoneum. This rare tumor is usually seen in women of childbearing age and has a high recurrence rate after surgery. Case Presentation:: We present two benign multicystic peritoneal mesothelioma cases with different imaging modalities, which were also pathologically proven. Conclusion:: The imaging features which may be diagnostic should be well known as there are very few reports regarding this entity

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.

S3267 A Case of Spontaneous Resolution of Malignant Peritoneal Mesothelioma

Introduction: Malignant peritoneal mesothelioma (MPM) is an aggressive tumor of the peritoneum. Few cases have been reported in the literature describing spontaneous regression possibly related to immune reconstitution. Here in, we report a unique case of peritoneal mesothelioma that regressed over time. Case Description/Methods: A case of 44 y/o female with a history of severe psoriasis (on Humira) and NASH, coccidioidomycosis in 2018 (on ketoconazole) presented with jaundice and abdominal distention in September 2020. She was diagnosed with cirrhosis secondary to NASH, and DILI with a MELD score of 30. Ketoconazole and Humira were held. She was medically managed with furosemide and spironolactone. Her MELD score improved to 18. In January 2021, an orthotopic liver transplant (OLTx) was attempted but due to incidental finding of extensive peritoneal mesothelioma, this was aborted. MPM was confirmed on biopsy with cytokeratin 7+, calretinin+, WT1+, and p53 reactivity. The patient was not considered a candidate for cytoreductive surgery/hyperthermic intraperitoneal chemotherapy. She had multiple psoriatic flares which were managed with prednisone. A PET scan done in June 2022 revealed mild FDG uptake in sub-centimeter bilateral axillary and pelvic LN, cirrhotic liver, and splenomegaly. The patient denied the use of alternative medicine, except for the Atkins diet. She is now being considered for OLTx Discussion: We present a unique case of spontaneous regression of MPM and its association with psoriatic flare. Previous case reports suggest a co-relation of immune-mediated response with spontaneous regression.1 The immunologically relevant cytokines IF-alpha, IF-gama, and TNF-alpha can directly inhibit the growth of mesothelioma.2 These cytokines are elevated in psoriasis, which this case highlights. Trials with immunomodulatory agents e.g. CTLA-4 inhibitor have shown promising outcomes.3 However, little information is available about regression without any chemo/radiation/biologic therapy and the role of the innate immune response leading to tumor regression.

Development of a Crosswalk to Translate Italian Occupation Codes to ISCO-68 Codes.

In occupational epidemiology, job coding is an important-but time-consuming-step in assigning exposure. We implemented a tool (i.e. a crosswalk) to translate occupation codes from the Italian (ISTAT-CIP-91, n = 6319 five-digit job codes) to the International Standard Classification of Occupations (ISCO-68, n = 1881 five-digit job codes). The former is currently used in Italy for various purposes (e.g. in the National Mesothelioma Registry). The latter has been used in several studies on occupational cancers because it facilitates communication of results to the scientific community and, most importantly, because some job exposure matrices (JEMs) are based on international codes. Three authors created a table containing the crosswalk structure, providing an interpretation for each of the ISTAT-CIP-91 codes job descriptions and then manually recoding them according to ISCO-68. Two other authors independently revised it. The performance of the final version was assessed by comparison with results obtained by manual ISCO-68 coding performed in two previous case-control studies on asbestos and mesothelioma. More specifically, the automatically obtained ISCO-68 codes were merged with a JEM (DOM-JEM). The resulting individual asbestos exposure estimates (ever versus never exposed) were compared to those originally obtained (using the same DOM-JEM) from manual translation of ISTAT-CIP-91 to ISCO-68 (considered as the 'gold standard'). In the first study, among 159 peritoneal mesothelioma cases (400 job codes), Cohen's kappa was 0.91, sensitivity 0.95, and specificity 0.96. In the second study, among 716 pleural mesothelioma cases and controls (4400 job codes) kappa was 0.86, sensitivity 0.94, and specificity 0.91. Performance was better among in women. For men, performance was lower among cases than among controls (kappa 0.70, sensitivity 0.95, specificity 0.72 versus kappa 0.87, sensitivity 0.97, and specificity 0.92). In conclusion, the proposed tool allowed a rapid translation of thousands of job codes with good to excellent accuracy. The table containing ISTAT-CIP-91 codes and job descriptions and the corresponding ISCO-68 codes and job descriptions is made publicly available and can be freely used for epidemiological analyses in Italy and international collaborations.

S1681 Malignant Peritoneal Mesothelioma (PeM) With Rhabdoid Features Masquerading as Idiopathic Necrotizing Pancreatitis With Mucinous Ascites: A Case Report and Literature Review

Introduction: Malignant Mesothelioma (MM) is a great masquerader, presenting as infection, metastasis, other cancers or as a paraneoplastic syndrome. Malignant peritoneal mesothelioma (PeM) accounts for about 10-15% of all cases of mesothelioma. MM presenting with malignant gastrointestinal (GI) polyps is also rare, with only 16 reported cases of mesothelioma presenting as metastatic disease in the GI tract. Here, we present the clinicopathologic findings of a case of a malignant peritoneal rhabdoid mesothelioma presenting as a necrotizing pancreatic mass, recurrent deep vein thrombosis (DVT), chylous ascites, and late onset weight loss. Case Description/Methods: A 76-year-old female initially presenting with idiopathic necrotizing pancreatitis. She continued to report persistent vague lower and mid abdominal pain. Six months after her initial admission the patient developed a DVT and pulmonary embolism (PE) requiring thrombectomy and anticoagulation with a recurrent DVT requiring IVC filter placement. She continued to have recurrent ascites and an enlarging peripancreatic fluid collection. Multiple paracenteses were performed with studies negative for infection and cytology negative for malignancy; however, most samples could not be analyzed due to fluid viscosity. An endoscopic retrograde cholangiopancreatography was performed with pancreatic and biliary stents placed. Almost one year after the patient’s initial admission, cross-sectional abdominal imaging showed omental caking with enlargement of the proximal pancreas. An endoscopic ultrasound with fine needle aspiration was performed was non-diagnostic. Lymphangiogram performed chylous nature of ascites. MRI showed a large fluid volume surrounding the pancreas and extended into the pararenal spaces. There was a mass effect leading to displacement of the surrounding structures. Diagnostic laparoscopy showed abdominal wall and peritoneal implants in addition to a large, firm, and highly vascularized epigastric mass. Pathology showed peritoneal mesothelioma. Discussion: We have presented a case of PeM with rhabdoid features present in the peritoneum and in gastric polyps. PeMs are rare tumors with a non-specific clinical presentation. These lesions are also difficult to diagnose and definitive diagnosis of MPM requires surgically obtained tissue. To our knowledge, this is the first case with these features.

P55-10 A case of peritoneal mesothelioma that recurred 27 years later

Peritoneal mesothelioma is one of the rare cancers for no effective treatment has been developed. This time, the patient was diagnosed with fallopian tube cancer at the first onset and did surgery and chemotherapy, but 27 years later, she had abdominal mass, peritoneal mesothelioma and ascites. We report including a review of the literature. A 64-year-old woman. No medical history. Onset in X-27 with a right abdominal mass. A diagnosis was right fallopian tube tumor, and laparotomy and total hysterectomy were performed. Pathological diagnosis was low to moderately differentiated adenocarcinoma. Five courses of CEP therapy were performed, and then with remission in X-27. In year X, she had a right abdominal mass, peritoneal dissemination, and ascites. Diagnosis of moderately differentiated adenocarcinoma by biopsy. Six courses of TC (+ BV) therapy were performed, and a remission was obtained on CT. Year X biopsy added immunostaining to diagnose mesothelioma. Reexamination of histopathological specimens from X-27, immunostaining could not be added, but HE staining did not show proliferation of epithelial cells. The main tumor was the mesothelium, which was re-diagnosed as mesothelioma. The tissue specimens of X-27 and X were very similar. Unlike peritoneal cancer, peritoneal mesothelioma is a malignant tumor derived from mesothelial cells and is a rare cancer, and difficult to treatment. The effects of surgery and radiation therapy are limited. CDDP + PEM therapy is often selected as the drug therapy according to pleural mesothelioma, but there is currently no treatment indicated or approved for. This time, we experienced a case in which both initial and recurrence were effective by ovarian cancer regimen, and we believe that it could be considered as one of the active treatments for peritoneal mesothelioma.

Malignant Peritoneal Mesothelioma with Rhabdoid Features Masquerading as Idiopathic Necrotizing Pancreatitis with Mucinous Ascites: A Case Report and Literature Review

Background: Malignant peritoneal mesothelioma (PeM) is a rare form of malignant mesothelioma that accounts for 10-15% of all cases of mesothelioma. Of these rare tumors, the rhabdoid subtype is exceptionally infrequent with only three cases reported in the current literature. PeM most commonly presents with non-specific symptoms such as abdominal distention, anorexia and weight loss that are difficult to diagnose until the disease is advanced. In this case report, we present a case of malignant peritoneal rhabdoid mesothelioma and review the literature. Case presentation: The patient is a 76-year-old woman who originally presented with necrotizing pancreatitis one year prior to diagnosis. The patient continued to complain of abdominal pain, nausea, vomiting, and weight loss. She experienced recurrent deep vein thrombosis (DVT), recurrent chylous, and mucinous ascites. Diagnostic work-up including MRI, repeat CT, EUS, and MRCP were inconclusive. Additionally, cytology from multiple paracenteses were negative for malignancy. Diagnostic laparoscopy revealed diffuse carcinomatosis, abdominal wall and peritoneal implants and a large epigastric mass. Biopsies of lesions taken during the procedure were identified as peritoneal mesothelioma. Conclusions: To our knowledge, we have presented the first case of PeM with rhabdoid features present in the peritoneum and in gastric polyps. The large amount of histopathogical variation of these tumors requires surgical biopsy, as cytology alone is non-diagnostic.

Multidisciplinary Approach to Diagnosing and Managing a Case of Peritoneal Mesothelioma

Peritoneal mesothelioma is a rare cause of a peritoneal mass in adults and can occur in malignant or benign forms. Compared to the pleural variant of mesothelioma, the peritoneal form is understudied due to the small number of reported cases. We present a case of an 84-year-old male with a history of asbestos exposure who initially presented for an aggravated hernia, was found to have an incidental mass on imaging, and ultimately was diagnosed with malignant peritoneal mesothelioma (MPM)1 likely related to prior asbestos exposure. This case study will provide a review of literature and discuss the role of imaging for MPM.

Peritoneal mesothelioma and asbestos exposure: a population-based case–control study in Lombardy, Italy

ObjectivesAsbestos is the main risk factor for peritoneal mesothelioma (PeM). However, due to its rarity, PeM has rarely been investigated in community-based studies. We examined the association between asbestos exposure...

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort.

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US. Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB). Methods: 888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses data and associated biospecimens for over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier's method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal). Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were younger than 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and having combination treatment of surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort.

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US. Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB). Methods: 888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier's method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal). Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were below the age of 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and had treatment that consisted of combining surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Genomic changes of chromosomes 8p23.1 and 1q21: Novel mutations in malignant mesothelioma

IntroductionMalignant mesothelioma is an aggressive malignancy of the thoracic cavity caused by prior asbestos exposure. In the peritoneum the mesothelioma is an extremely rare condition. In the present preliminary study, high-resolution array-comparative genomic hybridization (a-CGH) was performed to identify genetic imbalances in a series of malignant peritoneal mesothelioma cases. Materials and methodsBetween 1990 and 2008, among the cases recorded in the Apulia Mesothelioma Register, we found 22 peritoneal mesothelioma cases. CGH-array was performed on samples from all patients. ResultsThe CGH-array analysis revealed multiple chromosomal imbalances. Interestingly, deletion at 8p23.1 was observed in 12 cases. Furthermore, another novel deletion at 1q21 was present in 11. Often, 1q21 and 8p23.1 losses were present in the same patient (7 cases). Losses of BAP1 and CDKN2A loci were not detected. DiscussionThe region at 8p23.1 contains the beta-defensin gene cluster (DEF) and 1q21 contains ubiquitin conjugating enzyme E2 (UBE2Q1). We hypotesized that the loss of function of ubiquitination, as well as of the defensins, could play an important role in the initial development and subsequent progression of mesothelioma.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US. Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB). Methods: 888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses data and associated biospecimens for over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier’s method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal). Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were younger than 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and having combination treatment of surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort.

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US. Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB). Methods: 888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier's method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal). Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were below the age of 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and had treatment that consisted of combining surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment is associated with improved survival compared to local therapy alone.

Immunohistochemistry in Peritoneal Mesothelioma: A Single-Center Experience of 244 Cases.

- Diagnosis of malignant mesothelioma is more common in the chest than it is in the abdomen. Most published immunohistochemistry data are more applicable to pleural than to peritoneal mesothelioma. - To clarify the practical utility of 17 immunohistochemistry markers in the differential diagnosis of peritoneal mesothelioma with an emphasis on stains for which there is either contradictory information or a paucity of literature. - Consultation files of peritoneal mesothelioma diagnoses rendered from 1999 to 2014 were reviewed; 244 cases were identified. The results of immunohistochemistry markers performed were tabulated. - Immunohistochemistry markers positive in peritoneal mesothelioma in order of sensitivity were calretinin (244 of 244; 100%), WT1 (205 of 218; 94%), CK5/6 (173 of 194; 89%), mesothelin (132 of 150; 88%), and D2-40 (78 of 97; 80%). Markers used to differentiate carcinoma from mesothelioma showed immunoreactivity in peritoneal mesothelioma: estrogen receptor (2 of 84; 2%), B72.3 (6 of 196; 3%), CK20 (5 of 116; 4%), CD15 (7 of 192; 4%), p63 (3 of 62; 5%), carcinoembryonic antigen (9 of 199; 5%), PAX8 (12 of 191; 6%), progesterone receptor (5 of 71; 7%), Ber-EP4 (17 of 209; 8%), and CD138 (9 of 91; 10%). BAP1 loss, increasingly used in the differential diagnosis of benign versus malignant mesothelial proliferation, occured in 55% (99 of 181) of peritoneal mesothelioma cases. - The results support the experience that there is no definitive marker to rule out malignant mesothelioma, including PAX8, estrogen receptor, progesterone receptor, and p63 immunoreactivity. The high rate of immunoreactivity for mesothelin may have a role as a predictive marker for immune targeting. BAP1 loss of 55% in this cohort of peritoneal mesothelioma confirms published observations, and BAP1 retention is seen in a significant proportion of neoplastic cases.

Peritoneal Mesothelioma: A Rare Cause of Abdominal Ascites

Mesothelioma is a fatal malignancy typically located in the pleura of men in their 50's, many years after asbestos exposure. Peritoneal mesothelioma is rare and may be difficult to diagnose by cytologic analysis of ascetic fluid as it is often negative or inconclusive. Patients commonly present with nonspecific symptoms, however, the Gastroenterologist may be called to consider this in the work-up of ascites. A 23 year old female presented with increased abdominal girth, weight gain, and abdominal cramping. Pelvic ultrasound revealed moderate to large amount of simple-appearing nonspecific free fluid in the cul-de-sac and bilateral adnexal regions. Various examinations over the next few months revealed increased free fluid progressing to perihepatic ascites. Transvaginal paracentesis was performed with fluid sent for cytology revealing reactive mesothelial cells. The patient underwent exploratory laparoscopy and ascites analysis showed low serum ascites albumin gradient (SAAG) with high total protein. During the laparoscopy, several nodules attached to the peritoneum in the upper abdomen were biopsied. Histologic and immunohistochemical analysis of the biopsies demonstrated malignant mesothelioma, epithelioid type. The patient was subsequently referred to a tertiary cancer center for treatment with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.Figure 1Figure 2Figure 3This is a case of peritoneal mesothelioma, a rare fatal tumor, presenting with malignancy-related ascites in a young woman. Occupational and environmental exposure to asbestos remains the leading cause of mesothelioma with exposure preceding diagnosis by 15-60 years. 85% of cases of mesothelioma occur in men in their mid-50's who have identifiable asbestos exposure. This patient presents a rare case: a young female with peritoneal mesothelioma with no identifiable asbestos exposure. There are only 200-400 cases of peritoneal mesothelioma diagnosed in the United States each year which account for 10-15% of cases of mesothelioma overall. Symptoms are often non-specific and routine laboratory tests are not helpful in making this diagnosis. Although cytology of ascites fluid is usually helpful with peritoneal carcinomatosis, it is often inconclusive in instances of peritoneal mesothelioma, as demonstrated in this patient. Review of the literature indicates that this diagnosis was expected to peak in 2015 making increased awareness of this disease and its diagnostic challenges vital.

Asbestos content of lung tissue in patients with malignant peritoneal mesothelioma: A study of 42 cases

ABSTRACTLung tissue from 42 peritoneal mesothelioma cases was analyzed by light microscopy and scanning electron microscopy/energy dispersive spectrometry. There were 34 men and 8 women with a mean age of 61 ± 10 years. Also, 17% of cases had histologically confirmed asbestosis, and 26% had only parietal pleural plaques. The asbestos body count exceeded our normal range in 22 of 42 cases (52%). Cases with asbestos-related pulmonary disease had higher fiber burdens than those without. The vast majority of fibers were commercial amphiboles (amosite with lesser amounts of crocidolite). These findings concur with previously published epidemiological observations.

Malignant Peritoneum Mesothelioma with Hepatic Involvement: A Single Institution Experience in 5 Patients and Review of the Literature.

Malignant peritoneal mesothelioma with invasion of the liver is an invariably fatal disease. We aimed to clarify the characteristics of malignant peritoneal mesothelioma cases with liver involvement. The clinical presentation, computed tomography images, and immunohistochemical and histopathological features of 5 patients with malignant peritoneal mesothelioma and liver involvement were evaluated. The diagnosis was established by imaging and immune profiles of the tumours. A review of 8 cases with primary or invading malignant mesothelioma in liver is presented. All 5 mesothelioma cases were asbestos-related. CT images of malignant peritoneal mesothelioma with the liver involvement typically showed that the lesion grew inside the liver along the capsule and was possibly accompanied by capsule breakthrough and extrahepatic infiltration. The tumours exhibited a common epithelioid appearance in all 5 patients and most cases revealed positive Cal, CK, and MC with negative CEA and HeP. Different from our findings, the review of literature revealed that most malignant mesothelioma of liver was due to primary intrahepatic malignant mesothelioma. Finally, we concluded that the diagnosis of malignant peritoneal mesothelioma cases with liver invasion is reliably achieved by the history of asbestos exposure, the characteristic CT imaging, and immune profiles of the tumours.

Utility of BAP1 Immunohistochemistry and p16 (CDKN2A) FISH in the Diagnosis of Malignant Mesothelioma in Effusion Cytology Specimens.

The diagnosis of malignant mesothelioma in effusion cytology specimens is controversial. BAP1 immunohistochemistry and p16 fluorescence in situ hybridization (FISH) have recently been reported as reliable markers of malignancy in biopsies of mesothelioma. To determine whether these markers, singly or in combination, might also be useful in effusion cytology specimens, we examined 15 biopsies of epithelial mesotheliomas and 3 benign mesothelial reactions and corresponding effusion cytology paraffin-embedded cell blocks. Four cytology specimens were too scanty for p16 FISH analysis but were interpretable for BAP1 immunohistochemistry. Overall, loss of BAP1 and/or deletion of p16 was seen in 11/11 (100%) of matched cytology and tissue biopsy specimens. BAP1 loss alone was seen in 10/15 (67%) biopsies and 10/15 (67%) cytology specimens. Homozygous deletion of p16 by FISH was found in 12/15 (80%) biopsy specimens and 8/11 (73%) evaluable cytology specimens. Seven of 15 (47%) biopsies and 5/11 (42%) cytology specimens showed loss of both markers. All mesothelioma biopsy/cytology pairs showed exactly the same pattern of BAP1 or p16 retention or loss in the biopsy and cytology specimens. The 2 peritoneal mesothelioma cases demonstrated loss of BAP1 but not p16. None of the benign mesothelial reactions or corresponding cytology specimens showed loss of either marker. We conclude that both BAP1 immunohistochemistry and p16 FISH analysis provide reliable markers of mesothelial malignancy in effusion cytology specimens, especially where the atypical mesothelial proliferation is well sampled. BAP1 is easier to interpret with scanty specimens. On the basis of small numbers of cases, use of both markers appears to increase sensitivity.