Malignant Peritoneal Mesothelioma

Organoids derived from patients provide a new opportunity for research and individualized treatment of malignant peritoneal mesothelioma

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is an extremely rare and highly invasive tumor. Due to the lack of accurate models that reflect the biological characteristics of primary tumors, studying MPM remains challenging and is associated with an exceedingly unfavorable prognosis. This study was aimed to establish a new potential preclinical model for MPM using patient-derived MPM organoids (MPMOs) and to comprehensively evaluate the practicality of this model in medical research and its feasibility in guiding individualized patient treatment.

METHODS

MPMOs were constructed using tumor tissue from MPM patients. Histopathological analysis and whole genome sequencing (WGS) were employed to determine the ability of MPMOs to replicate the original tumor's genetic and histological characteristics. The subcutaneous and orthotopic xenograft models were employed to assess the feasibility of establishing an in vivo model of MPM. MPMOs were also used to conduct drug screening and compare the results with retrospective analysis of patients after treatment, in order to evaluate the potential of MPMOs in predicting the effectiveness of drugs in MPM patients.

RESULTS

We successfully established a culture method for human MPM organoids using tumor tissue from MPM patients and provided a comprehensive description of the necessary medium components for MPMOs. Pathological examination and WGS revealed that MPMOs accurately represented the histological characteristics and genomic heterogeneity of the original tumors. In terms of application, the success rate of creating subcutaneous and orthotopic xenograft models using MPMOs was 88% and 100% respectively. Drug sensitivity assays demonstrated that MPMOs have different medication responses, and these differences were compatible with the real situation of the patients.

CONCLUSION

This study presents a method for generating human MPM organoids, which can serve as a valuable research tool and contribute to the advancement of MPM research. Additionally, these organoids can be utilized as a means to evaluate the effectiveness of drug treatments for MPM patients, offering a model for personalized treatment approaches.

Malignant Peritoneal Mesothelioma: A Case Report

Malignant peritoneal mesothelioma (MPM) is a rare tumor of the serous membranes of the peritoneum and has been linked to exposure to asbestos and other risk factors. The clinical manifestations are vague, with a wide clinical spectrum, predominantly related to the abdominal involvement of the disease. Localized mesothelioma is an uncommon manifestation of the disease. Common symptoms include abdominal pain or abdominal distention, nausea, anorexia, and weight loss. Rarely, patients present with paraneoplastic syndrome. Due to the nonspecific symptoms, many patients already have advanced disease at the time of diagnosis. The authors report a case of a 75-year-old female patient who presented with symptoms of asthenia, anorexia, progressive paleness, and weight loss lasting five months. She reports later new-onset symptoms of diffuse abdominal pain and diarrhea associated with nausea. Laboratory tests showed anemia, mild leukocytosis, thrombocytosis, elevated C-reactive protein (CRP), and elevated liver enzymes. An abdominal and pelvic computed tomography (CT) scan revealed marked tissue thickening of an irregular and striated configuration of the leaflets and peritoneal reflections in an omental cake pattern, and a chest CT scan showed multiple bilateral pulmonary nodules, suggesting diffuse malignant disease. A CT-guided biopsy of a peritoneal implant was performed, establishing the diagnosis of malignant peritoneal mesothelioma. Due to rapid clinical deterioration, the patient did not receive any systemic treatment, surgery, or radiotherapy and was transitioned to comfort care. As in the presented case, most cases of MPM have diffuse peritoneal involvement at the time of diagnosis, although extra-abdominal involvement is very rare. This disease presentation is associated with high morbidity and mortality compared to cases of localized disease. There is no specific imaging diagnostic modality or valuable tumor markers for MPM. Although a CT scan remains important in the diagnostic approach, the changes found are not specific. Radiographically, MPM may present as mesenteric or parietal peritoneal nodules, visceral peritoneal thickening, ascites, or omental masses. Although these features may raise suspicion of MPM, a biopsy is necessary to confirm the diagnosis. Therefore, due to the rarity of this disease and its nonspecific signs or symptoms, MPM is difficult to diagnose, and the prognosis remains poor.

Medical-type peritoneal mesothelioma leading to death two months after onset of fever of unknown origin

In malignant mesotheliomas, cases involving the peritoneum as the primary site are rare, accounting for approximately 10% of all mesothelioma cases. We report a case of medical-type peritoneal mesothelioma leading to death 2 months after the onset of fever of unknown origin, along with a review of the literature. A 76-year-old man presented with a fever of unknown origin over 4 weeks. Thoracoabdominal computed tomography (CT) scan showed increased mesenteric adipose tissue density. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scan showed diffuse hyperaccumulation in the mesentery and hyperaccumulation in the intraperitoneal and parasternal lymph nodes. A thoracoscopic biopsy of the parasternal lymph nodes revealed metastatic peritoneal mesothelioma. The treatment plan was discussed with him and his family, and the best supportive care was provided. 2 months later, he died from multiple organ failure. Underlying malignant tumors cause 38% of mesenteric panniculitis cases. Symptoms accompanied by lymphadenopathy within the area of mesenteric panniculitis are highly suggestive of malignancy. Peritoneal mesothelioma can be classified as (1) classical, which is accompanied by abdominal pain, ascites, and abdominal masses; (2) surgical, which is accompanied by hernia incarceration and intestinal occlusion; and (3) medical, wherein systemic symptoms, such as fever and weight loss, are primarily observed. The medical-type peritoneal mesothelioma, wherein systemic symptoms are primarily observed, has a poorer prognosis than the other types. FDG-PET/CT is an effective diagnostic modality for peritoneal mesothelioma and typically shows diffuse hyperaccumulation along the peritoneal surface.

Survival Outcomes for Malignant Peritoneal Mesothelioma at Academic Versus Community Hospitals

BACKGROUND

Malignant peritoneal mesothelioma is a rare disease with poor outcomes. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy is the cornerstone of therapy. We aim to compare outcomes of malignant peritoneal mesothelioma treated at academic versus community hospitals.

METHODS

This was a retrospective cohort study using the National Cancer Database to identify patients with malignant peritoneal mesothelioma from 2004 to 2016. Patients were divided according to treating facility type: academic or community. Outcomes were assessed using log-rank tests, Cox proportional-hazard modeling, and Kaplan-Meier survival statistics.

RESULTS

In total, 2682 patients with malignant peritoneal mesothelioma were identified. A total of 1272 (47.4%) were treated at an academic facility and 1410 (52.6%) were treated at a community facility. Five hundred forty-six (42.9%) of patients at academic facilities underwent debulking or radical surgery compared to 286 (20.2%) at community facilities. Three hundred sixty-six (28.8%) of patients at academic facilities received chemotherapy on the same day as surgery compared to 147 (10.4%) of patients at community facilities. Unadjusted 5-year survival was 29.7% (95% CI 26.7-32.7) for academic centers compared to 18.3% (95% CI 16.0-20.7) for community centers. In multivariable analysis, community facility was an independent predictor of increased risk of death (HR: 1.19, 95% CI 1.08-1.32, p = 0.001).

CONCLUSIONS

We demonstrate better survival outcomes for malignant peritoneal mesothelioma treated at academic compared to community facilities. Patients at academic centers underwent surgery and received chemotherapy on the same day as surgery more frequently than those at community centers, suggesting that malignant peritoneal mesothelioma patients may be better served at experienced academic centers.

Malignant peritoneal mesothelioma: prognostic significance of clinical and pathologic parameters and validation of a nuclear-grading system in a multi-institutional series of 225 cases

Malignant peritoneal mesothelioma historically carried a grim prognosis, but outcomes have improved substantially in recent decades. The prognostic significance of clinical, morphologic, and immunophenotypic features remains ill-defined. This multi-institutional cohort comprises 225 malignant peritoneal mesotheliomas, which were assessed for 21 clinical, morphologic, and immunohistochemical parameters. For epithelioid mesotheliomas, combining nuclear pleomorphism and mitotic index yielded a composite nuclear grade, using a previously standardized grading system. Correlation of clinical, morphologic, and immunohistochemical parameters with overall and disease-free survival was examined by univariate and multivariate analyses. On univariate analysis, longer overall survival was significantly associated with diagnosis after 2000 (P = 0.0001), age <60 years (P = 0.0001), ECOG performance status 0 or 1 (P = 0.01), absence of radiographic lymph-node metastasis (P = 0.04), cytoreduction surgery (P < 0.0001), hyperthermic intraperitoneal chemotherapy (P = 0.0001), peritoneal carcinomatosis index <27 (P = 0.01), absence of necrosis (P = 0.007), and epithelioid histotype (P < 0.0001). Among epithelioid malignant mesotheliomas only, longer overall survival was further associated with female sex (P = 0.03), tubulopapillary architecture (P = 0.005), low nuclear pleomorphism (P < 0.0001), low mitotic index (P = 0.0007), and low composite nuclear grade (P < 0.0001). On multivariate analyses, the low composite nuclear grade was independently associated with longer overall and disease-free survival (P < 0.0001). Our data further clarify the interactions of clinical and pathologic features in peritoneal mesothelioma prognosis and validate the prognostic significance of a standardized nuclear-grading system in epithelioid malignant mesothelioma of the peritoneum.

The Role of Hyperthermic Intraperitoneal Chemotherapy for Non-colorectal Peritoneal Surface Malignancies

BACKGROUND

Peritoneal carcinomatosis, from a variety of gastrointestinal and gynecological malignancies, has been historically challenging to treat and there remains a wide range of biologic aggressiveness in these patients. Malignancies commonly associated with PC include those of colorectal, appendiceal, gastric, ovarian, sarcoma, small intestinal, and primary peritoneal origin among others. Advances in our understanding of this unique disease process have led to significant interest in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as an emerging treatment option. The goal of CRS-HIPEC is to remove all visible macroscopic disease while preserving organ function, and then treat microscopic disease through perfusion of the peritoneal cavity with heated chemotherapy.

PURPOSE

Although recent reviews have focused on the management of peritoneal carcinomatosis secondary to colorectal cancer given the publication of several recent randomized controlled trials, the purpose of the current review is to summarize the evidence on CRS-HIPEC for non-colorectal peritoneal surface malignancies, including appendiceal neoplasms, malignant peritoneal mesothelioma, gastric cancer, and ovarian cancer.

RESULTS

While retrospective studies have clarified the importance of prognostic factors such as the peritoneal carcinomatosis index, completeness of cytoreduction, histopathological characteristics, and lymph node positivity, the lack of convincing level 1 evidence for the use of CRS-HIPEC has led to it remaining a highly controversial topic.

CONCLUSION

The decision to utilize CRS-HIPEC should involve a multidisciplinary team approach and evaluation of prognostic factors to balance the short-term morbidity of the operation with maximum long-term benefits. Large, multi-institutional groups and ongoing trials hold promise for clarifying the role of CRS-HIPEC in peritoneal surface malignancies.

Well-Differentiated Papillary Mesothelioma of the Peritoneum: A Retrospective Study from the RENAPE Observational Registry

BACKGROUND

Well-differentiated papillary mesothelioma of the peritoneum (WDPMP) is a rare entity. Questions regarding management are still being debated as no more than 50 cases have been reported in the literature.

OBJECTIVE

We aimed to analyze the clinical, therapeutic, and prognostic data of patients with WDPMP from the RENAPE observational registry.

PATIENTS AND METHODS

All patients diagnosed with WDPMP and prospectively included in the RENAPE national registry between 2010 and 2018 were also included in our study. Expert pathologists from the RENA-PATH group confirmed all cases. All clinical, therapeutic, postoperative, and prognostic data were extracted and analyzed.

RESULTS

We report on 56 patients with a mean age of 52 years (range 21-74). WDPMP was incidentally diagnosed during imaging or surgery in 16% and 36% of patients, respectively, and an association with synchronous malignancy was found in 18% of patients. Nine lesions showed discrete signs of fatty invasion. The median Peritoneal Cancer Index was 11 (range 0-33). Eleven patients were treated with definitive excision, 4 were treated with cytoreductive surgery (CRS) only, 37 were treated with CRS and hyperthermic intraperitoneal chemotherapy (HIPEC), and 2 were treated with CRS plus HIPEC plus early postoperative intraperitoneal chemotherapy. CRS was considered to be complete in 90% of cases. One patient died postoperatively and 16 patients (31%) faced postoperative complications. The median disease-free survival was 144 months; Four patients relapsed, with a median period of 27 months. No prognostic factors could be identified.

CONCLUSIONS

Our analysis confirms the favorable prognosis of WDPMP. CRS and HIPEC could be a therapeutic option for diffuse, symptomatic, and/or recurrent disease.

Malignant peritoneal mesothelioma in a patient with intestinal fistula, incisional hernia and abdominal infection: A case report

Malignant mesothelioma is a rare type of cancer, most commonly associated with exposure to asbestos. Mesothelioma of the peritoneum, the membrane lining the abdominal cavity, is extremely rare. The current study reports the case of a 60-year-old female who presented with intestinal fistula, recurrent incisional hernia and abdominal infection, with no history of asbestos exposure, and was diagnosed with clear cell MPM. Computed tomography scans of the abdomen revealed extensive small bowel adhesions and massive peritoneal effusion. Histological examination of biopsy specimens indicated a diagnosis of malignant peritoneal mesothelioma with clear cell morphology. A laparotomy was performed, with subsequent resection of the bowel with fistula. Follow-up examination performed at 1-year post-surgery revealed that the patient was alive and in generally good health.

[Metastasis revealing malignant peritoneum mesothelioma: About the difficulty to identify the primary tumors]

Peritoneal malignant mesothelioma is a rare and extremely aggressive tumor that is sometimes difficult to diagnose. We report two cases of metastatic malignant peritoneal mesothelioma. In one case, malignant metastatic cells were identified in cervical lymph nodes while in the other case, the cells were found in the liver. In both cases, metastases were identified before discovering the primary tumor. This led to the misdiagnosis of carcinoma of unknown origin. Nevertheless, the histological and immuno-histochemical patterns were typical of malignant mesothelioma. Regarding metastasis of unknown origin, a differentiation of epithelioid peritoneal malignant mesothelioma and adenocarcinoma proved to be difficult. Therefore, we discuss the diagnostic usefulness of immuno-histochemical mesothelioma markers.

Licochalcone A induces apoptosis in malignant pleural mesothelioma through downregulation of Sp1 and subsequent activation of mitochondria-related apoptotic pathway

Licochalcone A (LCA) is a natural product derived from the roots of Glycyrrhiza inflata exhibiting a wide range of bioactivities such as antitumor, anti-oxidant and anti-bacterial effects. Malignant pleural mesothelioma (MPM) is an extremely aggressive type of cancer with a poor prognosis because of its rapid progression. However, LCA has not been investigated concerning its effects on MPM. Preliminarily, we observed that LCA negatively modulated not only cell growth, but also specificity protein 1 (Sp1) expression in MSTO-211H and H28 cell lines. It was found that IC50 values of LCA for growth inhibition of MSTO-211H and H28 cells were approximately 26 and 30 µM, respectively. Consistent with downregulation of Sp1, expression of Sp1 regulatory proteins such as Cyclin D1, Mcl-1 and Survivin was substantially diminished. Mechanistically, LCA triggered the mitochondrial apoptotic pathway by affecting the ratio of mitochondrial proapoptotic Bax to anti-apoptotic Bcl-xL. Bid induced loss of mitochondrial membrane potential, eventually leading to multi-caspase activation and increased sub-G1 population. Moreover, nuclear staining with DAPI highlighted nuclear condensation and fragmentation of apoptotic features. Flow cytometry analyses after staining cells with Annexin V and propiodium iodide corroborated LCA-mediated apoptotic cell death of MPM cells. In conclusion, these results present that LCA may be a potential bioactive material to control human MPM cells by apoptosis via the downregulation of Sp1.

Advances in malignant peritoneal mesothelioma

BACKGROUND

Malignant mesothelioma is a rare, insidious, and aggressive tumor arising from the mesothelial surface of pleural and peritoneal cavities, the pericardium, or the tunica vaginalis, with an increasing incidence worldwide, high misdiagnosis rate, and overall negative prognosis. A total of 20% of all cases is peritoneum in origin.

METHODS

The present study is a review of literatures focusing on the advances in epidemiology, clinical presentations, radiological features, diagnosis, misdiagnosis, management, and prognostic factors of malignant peritoneal mesothelioma (MPM) occurred in the past decades.

RESULTS

Asbestos, SV40, and radiation exposures have been demonstrated to be correlated with the pathogenesis of MPM. The main presentations are abdominal distension and pain. Computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography (PET) play an important role in the preoperative imaging and staging. Definitive diagnosis is made on the basis of immunohistochemistry. Prognostic factors have been identified and verified. Negative indicators include advanced age, male gender, poor performance status, non-epithelial histology, and absence of surgery. The management of MPM has evolved from single chemotherapy to multimodality treatment of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), chemotherapy, radiotherapy, and immunotherapy. Promising results have been achieved after a combined treatment of CRS and HIPEC, with an elevated median survival time of 29.5-92 months and a 5-year survival rate of 39-63%.

CONCLUSIONS

CRS and HIPEC represent the standard treatment strategy for selected patients with MPM, and patients with unresectable tumors can benefit from the combined treatment of chemotherapy, radiotherapy, and immunotherapy.

Peritoneal mesothelioma: current status and future directions

Peritoneal mesothelioma is a rare malignancy where life expectancy with systemic chemotherapy remains poor. Most patients with this disease are diagnosed late with extensive peritoneal disease burden leading to nausea, pain, and abdominal distention as a result of ascites and a partial bowel obstruction. A newly proposed staging system comprising elements of the tumor burden measured by the peritoneal cancer index, abdominal nodal status, and extra-abdominal metastases has been demonstrated to reliably stratify patient outcomes based on staging subgroups after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. This new staging system may form the basis of selecting patients for radical surgery and improve survival outcomes.

18F-FDG PET/CT in a recurrent diffuse malignant peritoneal mesothelioma

Peritoneal mesothelioma is a rare and aggressive tumor. Early diagnosis of the disease is difficult, delaying effective treatment. We report a case of recurrent, biphasic, diffuse, malignant peritoneal mesothelioma. Initial abdominal computed tomography showed abnormal but nonspecific findings suggestive of an ovarian malignancy, with a negative endoscopy and laboratory studies. An abdominal exploratory laparotomy found widespread malignancy within the peritoneum with a pathological diagnosis of peritoneal mesothelioma. A PET/CT imaging showed diffusely increased metabolic activity throughout the peritoneum, with no evidence of thoracic or pleural involvement. This case demonstrates the PET/CT findings seen with malignant recurrent peritoneal mesothelioma.

Two cases of malignant peritoneal mesothelioma without asbestos exposure: cytologic and immunohistochemical features

Approximately half a century has passed since asbestos was first reported to be the main cause of malignant mesothelioma; yet the incidence of this disease continues to increase worldwide. Twenty percent of cases occur without prior asbestos exposure, and in these patients, malignant peritoneal mesothelioma is more common than malignant pleural mesothelioma. Here, we report the cytomorphologic and immunohistochemical features of 2 cases of malignant peritoneal mesothelioma where there was no history of asbestos exposure. Ascitic cytology showed that most cells were isolated and that clusters were rarely observed, but the findings were consistent with malignant mesothelioma in both cases. Immunohistochemical analysis for epithelial membrane antigen, calretinin, vimentin, β-catenin, melan-A, glucose transporter-1, cytokeratin CAM5.2, Wilms tumor antigen-1, D2-40, CD146, progesterone receptor, estrogen receptor, and cytokeratin 5/6 was indicative of malignant mesothelioma. In malignant mesothelioma without prior asbestos exposure, the etiology and prognostic significance is still unclear. Further study is needed to clarify this point.

Diffuse malignant peritoneal mesothelioma--an update on treatment

Mesotheliomas are aggressive and lethal neoplasms arising from mesothelial cells lining the pleura, peritoneum, tunica vaginalis testis and pericardium. Malignant peritoneal mesothelioma accounts for about 30% of all mesotheliomas. Asbestos is the main known cause of the disease. Presenting symptoms in these patients include: ascites, abdominal pain, asthenia, weight loss, anorexia, abdominal mass, fever, diarrhea and vomiting. Electron microscopy, immunohistochemistry, computed tomography scan, echotomography, magnetic resonance imaging, positron emission tomography and laparoscopy are used in diagnosis and follow-up. Chemotherapy alone is considered as a palliative treatment for these patients who are not eligible for radical surgery. The most promising non-surgical approach today in the management of peritoneal mesothelioma is the use of the combination chemotherapy regime of an antifolate (pemetrexed and raltitrexed) and a platinum based (cisplatin) agent with a median survival of about 12-14 months. Due to peritoneal confinement of malignant mesothelioma and low occurrence of metastasis, a locoregional approach consisting of cytoreductive surgery and perioperative intraperitoneal chemotherapy has been introduced as a curative treatment option over the last decade with an overall 5-year survival rate of 29-63%. In this locoregional approach, surgery can separate the adhesions and remove the bulky tumor, leaving microscopic residual tumors much more susceptible to the killing effect of chemotherapeutic drugs. Here in St. George hospital, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (using cisplatin and doxorubicin) resulted in significant survival advantage. This article describes how the prognosis of the disease has changed over the last decade.

Malignant peritoneal mesothelioma presenting with persistent high fever

Malignant peritoneal mesothelioma (MPM) is a rare tumor that develops in the peritoneum. In this paper, we describe an extremely rare case of MPM metastasizing to the appendix in a 48-year-old female who initially presented with a persistent high fever. The woman reported a slight lower abdominal discomfort which had been relieved by urination for four months. She had lost 5 kg of weight. There was no nausea, vomiting, diarrhea, abdominal pain, or abdominal distension. Many broad spectrum antibiotics were given without relief of fever. Computed tomography (CT) scans revealed a thickened omentum majus and diffused multiple omental nodules. An omentectomy, appendectomy, and adnexectomy were carried out. A gross pathologic specimen of omentum tissue revealed a firm gray-white mass. Microscopic and immunohistochemical examinations confirmed the diagnosis of appendiceal and bilateral adnexal metastases of an MPM. These results suggest that MPM should be considered in the differential diagnosis of unexplained persistent high fever. Awareness of such atypical presentations of mesothelioma may help to make a correct diagnosis.

Primary peritoneal mesothelioma: case series and literature review

Primary peritoneal mesothelioma is a rare and aggressive tumour. We present six consecutive cases treated by our institution in the last three years. All were between 56-65 years old and only one gave a history of direct contact with asbestos. Four of the patients showed a thrombocytosis on presentation but other blood tests and evaluation of ascitic fluid were normal. In all cases, the diagnosis was made through investigation of mixed abdominal symptoms with CT scanning and laparoscopic biopsy. Despite the use of modern chemotherapy, response to treatment was unpredictable, with survival from ten weeks to three years.

Malignant abdominal mesothelioma: defining the role of surgery

OBJECTIVE

Determine the role of surgery for patients with malignant abdominal mesotheliomas (MAMs).

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1973-2005) was queried.

RESULTS

Overall, 10,589 cases of malignant mesotheliomas were identified. Of these, 9,211 cases were thoracic (TM) and 1,112 cases were MAM (10.5%). Patients with TM presented with more localized disease than those patients with MAM (P < 0.001). MAM more often affected younger patients (63 years vs. 71 years) (P < 0.001). The annual incidence of MAM was approximately 1.00 case per 100,000 in 2005. Overall median survival for MAM patients was 8 months, with a significant difference between women and men (13 months vs. 6 months, respectively) (P < 0.001). Patients who successfully underwent surgical resection had a considerably longer median survival (20 months vs. 4 months, P < 0.001) as well as a significantly higher 5-year survival (28% vs. 12%, P < 0.001). Multivariate analysis identified that a poorly differentiated tumor grade, failure to undertake surgical resection, advanced age, and male gender were all independent predictors of poorer outcome.

CONCLUSION

Surgical extirpation of MAM may be associated with significantly improved survival. All patients with MAM should be evaluated for potential surgical resection.

Peritoneal mesothelioma presenting as an acute surgical abdomen due to jejunal perforation

BACKGROUND

Peritoneal mesothelioma is a rare disease associated with poor prognosis. Acute abdomen as the first presentation is an extremely rare occurrence. We report an exceptional case of a patient who was found to have a jejunal perforation due to infiltration of peritoneal mesothelioma.

METHODS

A 62-year-old man was admitted with clinical signs of peritonitis. Computerized tomographic scans showed a mass distal to the ligament of Treitz, thickening of the mesentery and a small amount of ascites.

RESULTS

Emergency laparotomy revealed a perforated tumor 15 cm distal to the ligament of Treitz and diffuse peritoneal disease. Segmental small bowel resection and suboptimal cytoreduction were performed. Histopathology and immunohistochemistry showed infiltration of malignant mesothelioma. During the postoperative period pleural mesothelioma was also diagnosed. Despite adjuvant chemotherapy, the patient died of disseminated progressive disease 7 months after surgery.

CONCLUSIONS

Peritoneal mesothelioma is a rare malignancy with grim prognosis. Small bowel involvement is a poor prognostic indicator. Our case of a small bowel perforation due to direct infiltration by peritoneal mesothelioma appears to be the first reported in the English literature.