Computed Tomographic Characterization of Malignant Peritoneal Mesothelioma

Malignant peritoneal mesothelioma with massive ascites as the first symptom: A case report

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is an extremely rare tumor with nonspecific clinical manifestations, which is extremely difficult to diagnose. Herein, we reported a case of MPM in the abdominal cavity with massive short-term ascites as the first symptom.

CASE SUMMARY

A 65-year-old woman presented to the hospital with abdominal pain, distention, and shortness of breath that persisted for 15 d. The serum CA-125 level was 1075 U/mL. The abdominal computed tomography showed massive ascites and no obvious tumor lesions. The pathological examination of the ascitic fluid showed numerous heterotypic cells with some papillary structures. The immunohistochemistry and fluorescence in situ hybridization showed the deletion of CDX2 (-), WT-1 (-), Ki-67 (about 10% +), CEA (-), Glut-1 (+++), desmin (-), PD-L1 (-), and CDKN2A (P16). The final diagnosis was MPM. The patient refused tumor cytoreductive surgery and received two cycles of cisplatin plus pemetrexed bidirectional chemotherapy. In the second cycle, she received an additional cycle of hyperthermic intraperitoneal chemotherapy and immune checkpoint inhibitor therapy due to massive recalcitrant ascites. She died of disease progression 2 mo after diagnosis.

CONCLUSION

In case of massive unexplained ascites, the possibility of MPM should not be excluded to avoid misdiagnosis and delay in treatment.

The role of imaging in diagnosis and management of malignant peritoneal mesothelioma: a systematic review

PURPOSE

Imaging of the peritoneum and related pathology is a challenge. Among peritoneal diseases, malignant peritoneal mesothelioma (MPeM) is an uncommon tumor with poor prognosis. To date, there are no specific guidelines or imaging protocols dedicated for the peritoneum and MPeM. The objective of this study was to analyze the literature describing imaging modalities used for MPeM to determine their relative clinical efficacy and review commonly reported imaging features of MPeM to promote standardized reporting.

METHODS

We performed a systematic review of original research articles discussing imaging modalities in MPeM from 1999 to 2020. Effectiveness measures and common findings were compared across imaging modalities.

RESULTS

Among 582 studies analyzed, the most-used imaging modality was CT (54.3%). In the differentiation of MPeM from peritoneal carcinomatosis, one study found CT had a diagnostic sensitivity of 53%, specificity of 100%, and accuracy of 68%. Two studies found fluorodeoxyglucose positron emission tomography (FDG-PET) had sensitivity of 86-92%, specificity of 83-89%, and accuracy of 87-89%. Another study found magnetic resonance imaging (MRI) was the best predictor of the peritoneal carcinomatosis index. Characteristics shown to best differentiate MPeM from other diseases included ascites, peritoneal thickening, mesenteric thickening, pleural plaques, maximum tumor dimension, and number of masses.

CONCLUSION

Most published MPeM imaging studies utilized CT. PET/CT or MRI appear promising, and future studies should compare effectiveness of these modalities. MPeM imaging reports should highlight ascites, number of and maximum tumor dimension, peritoneal/mesenteric thickening, and associated pleural plaques, allowing for better aggregation of MPeM imaging data across studies.

CT imaging review of uncommon peritoneal-based neoplasms: beyond carcinomatosis

Pathologic involvement of the peritoneum can result from a wide variety of conditions, including both neoplastic and non-neoplastic entities. Neoplastic involvement of the peritoneal ligaments, mesenteries, and spaces from malignant spread of epithelial cancers, termed peritoneal carcinomatosis, is frequently encountered at CT evaluation. However, a host of other more unusual benign and malignant neoplasms can manifest with peritoneal disease, including both primary and secondary peritoneal processes, many of which can closely mimic peritoneal carcinomatosis at CT. In this review, we discuss a wide array of unusual peritoneal-based neoplasms that can resemble the more common peritoneal carcinomatosis. Beyond reviewing the salient features for each of these entities, particular emphasis is placed on any specific clinical and CT imaging clues that may allow the interpreting radiologist to appropriately narrow the differential diagnosis and, in some cases, make an imaging-specific diagnosis.

Prognostic role of radiological peritoneal cancer index in malignant peritoneal mesothelioma: national cohort study

Malignant peritoneal mesothelioma (MPeM) is a rare cancer of the mesothelial cells of the peritoneum. Computed tomography (CT) is considered the standard for first-line imaging of MPeM, diagnosis and risk stratification remains challenging. Peritoneal cancer index (PCI), as assessed by CT, is utilized in the prognostic assessment of other malignant intra-abdominal conditions; however, there is limited data concerning the utility of PCI in the diagnosis and workup of MPeM. We studied a retrospective cohort of all patients diagnosed with MPeM from 2000 to 2012 in Finland. CT and magnetic resonance imaging (MRI) were reviewed and scored by an experienced and blinded, board-certified abdominal radiologist. Additional clinical data and outcomes were obtained from Finnish Cancer Registry (FCR), the Workers' Compensations Center (WCC), and Statistics Finland (SF). Abdominal CT or MRI was available for 53 of 90 patients. The median radiographic PCI was 25. PCI score was correlated with overall survival (p = 0.004, Exp(B) = 1.064, 95% CI 1.020-1.110). PCI score ≥ 30 was associated with worse survival (p = 0.002), while PCI ≤ 19 was associated with improved overall survival (p = 0.001). Our study indicates that radiological PCI is prognostic in MPeM and should be assessed during radiographic workup and integrated into clinical decision-making.

Management of Malignant Peritoneal Mesothelioma Using Cytoreductive Surgery and Perioperative Chemotherapy

Malignant peritoneal mesothelioma is a rare disease, with approximately 800 new patients per year in the United States. Its natural history is defined by progression restricted to the peritoneal space. In the past, patients with this disease had a limited lifespan of approximately 1 year. Numerous single-institution studies as well as a systematic review have reported median survival of 3 to 5 years with a combination of cytoreductive surgery and hyperthermic perioperative chemotherapy. These markedly improved survival statistics were achieved in experienced centers with 1% mortality and 20% morbidity rates. Data have shown that knowledgeable patient selection is required to prevent patients unlikely to benefit from undergoing these interventions. The conclusion is that patients with peritoneal mesothelioma can experience long-term progression-free survival or significant palliation with cytoreductive surgery plus hyperthermic perioperative chemotherapy. This management plan should be considered the standard of care for properly selected patients with malignant peritoneal mesothelioma at experienced centers around the world.

Targeting microRNA to improve diagnostic and therapeutic approaches for malignant mesothelioma

Malignant mesothelioma is an aggressive and often fatal cancer associated with asbestos exposure. The disease originates in the mesothelial lining of the serosal cavities, most commonly affecting the pleura. Survival rates are low as diagnosis often occurs at an advanced stage and current treatments are limited. Identifying new diagnostic and therapeutic targets for mesothelioma remains a priority, particularly for the new wave of victims exposed to asbestos through do-it-yourself renovations and in countries where asbestos is still mined and used. Recent advances have demonstrated a biological role for the small but powerful gene regulators microRNA (miRNA) in mesothelioma. A number of potential therapeutic targets have been identified. MiRNA have also become popular as potential biomarkers for mesothelioma due to their stable expression in bodily fluid and tissues. In this review, we highlight the current challenges associated with the diagnosis and treatment of mesothelioma and discuss how targeting miRNA may improve diagnostic, prognostic and therapeutic approaches.

CT differentiation of diffuse malignant peritoneal mesothelioma and peritoneal carcinomatosis

BACKGROUND AND AIM

Diffuse malignant peritoneal mesothelioma (DMPM) and peritoneal carcinomatosis (PC) have similar imaging in computer tomography (CT). We aimed to distinguish them.

METHODS

Computer tomography findings were evaluated in 48 DMPM and 47 PC for the peritoneal, mesenteric, omentum, lymph nodes, viscera infiltration, ascites and pleural plaques.

RESULTS

Two groups had no difference in terms of thickness, clinical manifestation, diameter of lymph nodes, ascites, and viscera infiltration. But they showed differences in the following: Ratio of asbestos exposure in DMPM group was higher. Smooth and irregular peritoneal thickening were more seen in DMPM group; peritoneal nodules were more commonly detected in PC group. Forty-eight cases of peritoneum in DMPM showed mild enhanced, while 14 patients in PC showed severe enhanced. Nodular type of omentum was more common in PC group than in DMPM group; omental cake was more commonly detected in DMPM group. Mesentery involvement was more commonly seen in DMPM group. Location of enlarged lymph nodes in cardiophrenic region was more frequently identified in DMPM, whereas location of enlarged lymph nodes in retroperitoneal region was more frequently identified in PC. Lymph nodes fusion was more frequently visualized in PC. Fixation of the intestinal wall was more common in DMPM. Pleural plaque was more common in DMPM. PC had distant metastasis except primary foci and peritoneum. In PC, tumor origins were ovary in 10, digestive system in 21, breast in one.

CONCLUSION

Using a combination of CT findings may increase our ability to distinguish PC from DMPM.

CT-Enteroclysis in the preoperative assessment of the small-bowel involvement in patients with peritoneal carcinomatosis, candidates for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

PURPOSE

To assess the performance of CT-Enteroclysis (CTE) in the preoperative evaluation of the small bowel (SB) involvement in patients with peritoneal carcinomatosis (PC), candidates for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

MATERIAL AND METHODS

In this prospective study, 48 consecutive patients (37 women, 11 men, mean age: 57.02 years) with PC of different primaries, eligible for cytoreductive surgery and HIPEC underwent CTE before surgery. Lesions were gathered according to their location (SB wall or mesentery), distribution (jejunum/ileum, proximal/distal) and lesion size (LS, where LS0 is the absence of disease, LS1 < 1 cm, LS < 1-5 cm, and LS3 > 5 cm in maximal diameter). The preoperative CTE classification was correlated with surgical scoring of PC in the SB.

RESULTS

CTE was found to have sensitivity 92%, specificity 96%, PPV 97%, NPV 91%, in assessing PC in the SB/mesentery. CTE exhibited "excellent" agreement with surgical classification of disease extent (overall kappa-weighted coefficient of agreement (κ (w)) was 0.962). Patients (n = 6) found inoperable at surgery manifested extensive plaque-like cover of the SB wall/mesentery on CTE.

CONCLUSIONS

CTE may be considered a reliable imaging technique for the preoperative evaluation of the extent and distribution of PC in the SB/mesentery in order to assist surgical planning or to prevent unnecessary surgery.

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.

Diffuse malignant peritoneal mesothelioma presenting as intestinal obstruction

Diffuse malignant peritoneal mesothelioma (DMPM) represents 90% of all peritoneal forms of mesothelioma. It affects mainly patients 50-69 years old. In 50% of cases there is a history of asbestos exposure. The clinical presentation of the disease is not characteristic: nonspecific abdominal pain, weight loss, and abdominal distension are common. Ascites occurs in 90% of the patients. Bowel obstruction is a late manifestation. We present three patients with DMPM, without a history of asbestos exposure and without ascites, who presented with complete bowel obstruction. All patients underwent emergency operations, and palliative surgical procedures were performed. Each patient died within 3 to 6 months postoperatively.

Malignant peritoneal mesothelioma

Malignant mesothelioma is a highly aggressive neoplasm. The incidence of malignant mesothelioma is increasing worldwide. Diffuse malignant peritoneal mesothelioma (DMPM) represents one-fourth of all mesotheliomas. Association of asbestos exposure with DMPM has been observed, especially in males. The great majority of patients present with abdominal pain and distension, caused by accumulation of tumors and ascitic fluid. In the past, DMPM was considered a pre-terminal condition; therefore attracted little attention. Patients invariably died from their disease within a year. Recently, several prospective trials have demonstrated a median survival of 40 to 90 mo and 5-year survival of 30% to 60% after combined treatment using cytoreductive surgery and perioperative intraperitoneal chemotherapy. This remarkable improvement in survival has prompted new search into the medical science related to DMPM, a disease previously ignored as uninteresting. This review article focuses on the key advances in the epidemiology, diagnosis, staging, treatments and prognosis of DMPM that have occurred in the past decade.

Current status and future directions: management of colon cancer with peritoneal dissemination

Colorectal cancer is one of the most common cancers worldwide, and although it carries a favorable prognosis when detected at early stages, it is associated with limited survival when metastatic disease is present. Modern systemic therapy has improved median survival in those patients with hematogenous dissemination, but the role of these newer combinations of cytotoxic chemotherapy and biological agents remains undefined in patients with peritoneal carcinomatosis. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have resulted in long-term good outcomes for patients whose carcinomatosis can be completely removed, but offers no advantage over supportive care for those patients with incomplete tumor removal. At the present time, we lack proven therapeutic strategies on how to treat a patient newly diagnosed with peritoneal carcinomatosis of colorectal origin. A large Phase III multi-institutional trial is being developed to address these issues, and will need full collaboration between medical and surgical oncologists.

The eligibility for local-regional treatment of peritoneal surface malignancy

At the Fifth International Workshop on Peritoneal Surface Malignancy, held in Milan, the consensus on technical aspects of cytoreductive surgery (CRS) for peritoneal surface malignancy was obtained through the Delphi process. General conflicting points concerning the eligibility to the local-regional therapy were discussed and voted.

Cytoreductive Surgery for Peritoneal Malignancies—Development of Standards of Care for the Community

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) continue to play an increasing role in the management of peritoneal surface malignancies of gastrointestinal origin. The prognosis of patients and the responses to cytoreductive surgery and HIPEC depend on the histology, the degree of malignant transformation, the adequacy of the cytoreductive surgery, and the response to systemic therapy. Continuous interaction between medical and surgical oncologists is needed to identify the most appropriate patients for and the most efficient sequence of the available therapeutic modalities.