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The fibroblast activation protein (FAP) is highly expressed in tumor and stromal cells of mesothelioma and thus is an interesting imaging and therapeutic target. Previous data on PET imaging with radiolabeled FAP inhibitors (FAPIs) suggest high potential for superior tumor detection. Here, we report the data of a large malignant pleural mesothelioma cohort within a 68 Ga-FAPI46 PET observational trial (NCT04571086). Methods: Of 43 eligible patients with suspected or proven malignant mesothelioma, 41 could be included in the data analysis of the 68 Ga-FAPI46 PET observational trial. All patients underwent 68 Ga-FAPI46 PET/CT, contrast-enhanced CT, and 18 F-FDG PET/CT. The primary study endpoint was the association of 68 Ga-FAPI46 PET uptake intensity and histopathologic FAP expression. Furthermore, secondary endpoints were detection rate and sensitivity, specificity, and positive and negative predictive values as compared with 18 F-FDG PET/CT. Datasets were interpreted by 2 masked readers. Results: The primary endpoint was met, and the association between 68 Ga-FAPI46 SUV max or SUV peak and histopathologic FAP expression was significant (SUV max : r = 0.49, P = 0.037; SUV peak : r = 0.51, P = 0.030). 68 Ga-FAPI46 and 18 F-FDG showed similar sensitivity by histopathologic validation on a per-patient (100.0% vs. 97.3%) and per region (98.0% vs. 95.9%) basis. Per-region analysis revealed higher 68 Ga-FAPI46 than 18 F-FDG specificity (81.1% vs. 36.8%) and positive predictive value (87.5% vs. 66.2%). Conclusion: We confirm an association of 68 Ga-FAPI46 uptake and histopathologic FAP expression in mesothelioma patients. Additionally, we report high sensitivity and superior specificity and positive predictive value for 68 Ga-FAPI46 versus 18 F-FDG., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

Abstract: We describe contrast-enhanced CT and FDG PET/CT findings in a case of thoracic SMARCA4-deficient undifferentiated tumor with extensive pleural involvement and mediastinal lymph node metastases. Contrast-enhanced CT showed multiple enhancing right-sided pleural masses and soft tissue plaques and enlarged mediastinal lymph nodes. The pleural lesions and mediastinal lymph nodes showed intense FDG uptake mimicking malignant pleural mesothelioma with mediastinal lymph node metastases., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Results for malignant pleural mesothelioma (MPM) patients following first-line treatment with nivolumab plus ipilimumab obtained with immunotherapy-modified PERCIST (imPERCIST), shown by [ 18 F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), and modified RECIST (mRECIST), shown by CT, were compared for response evaluation and prognosis prediction., Results: imPERCIST indicated nine progressive metabolic disease (PMD), eight stable metabolic disease (SMD), four partial metabolic response (PMR), and five complete metabolic response (CMR) cases. mRECIST showed nine with progressive disease (PD), nine stable disease (SD), seven partial response (PR), and one complete response (CR). Although high concordance was noted (κ = 0.827), imPERCIST correctly judged a greater percentage with CMR (15.4%). Following a median 10.0 months, 15 patients showed progression and eight died from MPM. With both, progression-free survival (PFS) and overall survival (OS) were significantly longer in patients without progression (CMR/PMR/SMD, CR/PR/SD, respectively) as compared to PMD/PD patients (imPERCIST p < 0.0001 and p = 0.015, respectively; mRECIST p < 0.0001 and p = 0.015, respectively)., Methods: Twenty-six patients (23 males, 3 females; median 73.5 years) with histologically proven MPM and no curative surgery received nivolumab plus ipilimumab combination therapy. FDG-PET/CT and diagnostic CT scanning at the baseline, and after 2-4 cycles (2 in three, 3 in 17, 4 in six patients) were performed. Therapeutic response findings evaluated using imPERCIST and mRECIST were compared. PFS and OS analyses were done using log-rank and Cox methods., Conclusion: For unresectable MPM patient examinations, FDG-PET and CT provide accurate findings for evaluating tumor response and also prognosis prediction following first-line nivolumab plus ipilimumab immunotherapy (approximately three cycles).

Abstract: Malignant pleural mesothelioma is a rare tumor with a poor prognosis. We describe a case of 55-year-old man without asbestos exposure history presenting with extensive lymph nodes with high 18 F-FDG uptake in PET/MRI but atypical pleural manifestations thereby being misdiagnosed for lymphoma. Pathological examination concludes for an epithelioid mesothelioma-associated lymph node metastasis. This case emphasizes that with the extensive lymph node abnormalities shown in PET imaging, in addition to the general consideration of lymphoma, it is still necessary to be vigilant about the possibility of mesothelioma and emphasizes the necessity of pathological examination., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: A 66-year-old man with local prostate adenocarcinoma underwent radical prostatectomy (Gleason score 3 + 4 = 7, pT2c) in 2016. Four years later, he presented with a hydrocele and cystic atypical change in the left scrotum and soft tissue in the left groin. Final histopathology revealed spermatic cord mesothelioma and left hemangiosis carcinomatosa. A bone biopsy of the sacrum revealed infiltrates of a prostatic adenocarcinoma with small cell neuroendocrine differentiation. Dual-tracer PET/CT imaging using 18F-FDG and 68Ga-PSMA was able to identify local recurrence of scrotal mesothelioma and differentiate metastases of prostate cancer from malignant mesothelioma., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Competing Interests: Competing interests: None declared.

Abstract: A 77-year-old man with a personal history of familial Mediterranean fever presented with a slowly enlarging tumefaction of the left abdominal wall and persistent inflammatory syndrome despite good adherence to colchicine. 18 F-FDG PET/CT showed a hypermetabolic muscular mass of the abdominal wall along with other hypermetabolic lesions including a peritoneal mass and several subcutaneous soft tissue nodules. CT-guided needle biopsy led to the diagnosis of a muscular localization of a malignant peritoneal mesothelioma, which is an extremely rare complication of familial Mediterranean fever. Six courses of chemotherapy with carboplatin and pemetrexed allowed an almost complete response., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Testicular tumors have many different manifestations. The majority of these cases are presented as an incidental finding during hydrocelectomy. Malignant mesotheliomas are uncommon tumours that can arise from the coelomic epithelium of the pleura, peritoneum, pericardium, and tunica vaginalis., Case Presentation: We present a 51-year-old South Asian (Indian) male patient with a rare case of mesothelioma, presenting with right hydrocele, to whom a right hydrocelectomy was performed. Any history of trauma or asbestos exposure was not present. Histopathological and immunohistochemistry reports revealed a malignant mesothelioma of tunica vaginalis. There was no invasion of the tumour to the epididymis and spermatic cord. Imaging studies showed no signs of metastasis. 1 month later, a high inguinal orchidectomy was performed. The patient underwent adjuvant chemotherapy thereafter and is still on follow-up., Conclusion: Although hydrocele is common, detailed evaluation is mandatory to rule out certain rare tumours-testicular and paratesticular variants., (© 2024. The Author(s).)

Malignant pericardial mesothelioma (MPM) is extremely rare, and peritoneal dissemination has not yet been reported. There is no consensus regarding appropriate pharmacological treatment for MPM, including immune checkpoint inhibitors (ICIs). We herein report a 36-year-old man with MPM diagnosed by peritoneal dissemination and treated with an ICI. Cytology of the ascites revealed malignant peritonitis, and a re-evaluation of a pericardial biopsy performed at the previous hospital led to a diagnosis of MPM. The patient was treated with nivolumab and showed a clinical response despite several complications, such as renal dysfunction and performance status deterioration. This case report provides suggestive information for the diagnosis and ICI therapy of a rare type of mesothelioma.

Introduction: Malignant pleural mesothelioma is difficult to prognosticate. F18-Fluorodeoxyglucose positron emission tomography (FDG PET) shows promise for response assessment but is confounded by talc pleurodesis. F18-Fluorothymidine (FLT) PET is an alternative tracer specific for proliferation. We compared the prognostic value of FDG and FLT PET and determined the influence of talc pleurodesis on these parameters., Methods: Overall, 29 prospectively recruited patients had FLT PET, FDG PET and CT-scans performed prior to and post one chemotherapy cycle; 10 had prior talc pleurodesis. Patients were followed for overall survival. CT response was assessed using mRECIST. Radiomic features were extracted using the MiM software platform. Changes in maximum SUV (SUVmax), mean SUV (SUVmean), FDG total lesion glycolysis (TLG), FLT total lesion proliferation (TLP) and metabolic tumour volume (MTV) after one chemotherapy cycle., Results: Cox univariate analysis demonstrated FDG PET radiomics were confounded by talc pleurodesis, and that percentage change in FLT MTV was predictive of overall survival. Cox multivariate analysis showed a 10% increase in FLT tumour volume corresponded with 9.5% worsened odds for overall survival (P = 0.028, HR = 1.095, 95% CI [1.010, 1.187]). No other variables were significant on multivariate analysis., Conclusion: This is the first prospective study showing the statistical significance of FLT PET tumour volumes for measuring mesothelioma treatment response. FLT may be better than FDG for monitoring mesothelioma treatment response, which could help optimise mesothelioma treatment regimes., (© 2023 The Authors. Journal of Medical Imaging and Radiation Oncology published by John Wiley & Sons Australia, Ltd on behalf of Royal Australian and New Zealand College of Radiologists.)

Abstract: Diffuse epithelioid malignant mesothelioma (MM) with metastasis to the ovary is rare. We reported FDG PET/CT findings in a 39-year-old woman with ovarian metastasis from diffuse epithelioid MM. The ultrasound findings at the external hospital revealed multiple masses in the hepatic hilus. FDG PET/CT examination was recommended to evaluate the nature of the lesions. It showed that 2 hypodense lesions in the perihepatic space had intense activity, and there was an additional FDG lesion in the right ovary, which was later confirmed as diffuse epithelioid MM with ovarian metastasis by pathological examination., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Neoadjuvant systemic therapy in resectable malignant pleural mesothelioma remains controversial and demonstrates variable responses. We sought to evaluate tumor thickness as a predictor of response to neoadjuvant therapy and as a prognostic marker for overall survival., Methods: Data from patients who underwent neoadjuvant therapy followed by cytoreductive surgery from 2002 to 2019 were reviewed. Baseline and postneoadjuvant therapy tumor thickness were measured on computed tomography. Radiological tumor response was categorized as progressive disease (≥20% increase), partial response (≥30% decrease), or stable disease (in between). Tumor response outcomes were modeled using logistic regression and multinomial regression models. Overall survival was evaluated based on tumor thickness and tumor response., Results: Of the 143 patients reviewed, 36 (25%) had progressive disease, 54 (38%) had stable disease, and 56 (39%) had partial response. The baseline tumor thickness of the progressive disease group (36 mm) was lower than in both stable disease and partial response groups (both 63 mm; P < .001). Both logistic regression and multinomial regression analyses demonstrated that thicker baseline tumor thickness was associated with decreased probability of progressive disease and increased probability of partial response. In a multivariable Cox model, thicker postneoadjuvant therapy tumor thickness was associated with worse overall survival (hazard ratio, 1.01, 95% confidence interval, 1.00-1.01, P = .008). The same trend was observed for thicker baseline tumor thickness (hazard ratio, 1.02, 95% confidence interval, 1.01-1.04, P = .008), and the risk was decreased in tumors with partial response (hazard ratio, 0.98, 95% confidence interval, 0.96-0.100, P = .014)., Conclusions: We present the first study demonstrating the relationship between baseline tumor thickness and differential radiographic response to neoadjuvant therapy and survival. Further studies are needed to validate tumor thickness as both a prognostic and predictive biomarker., (Copyright © 2022 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Malignant mesothelioma is a rare tumor arising from the mesothelial cells that line the pleura, pericardium, peritoneum, and tunica vaginalis. Imaging plays a primary role in the diagnosis, staging, and management of malignant mesothelioma. Multimodality imaging, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), and F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), is used in a variety of scenarios, including diagnosis, guidance for tissue sampling, staging, and reassessment of disease after therapy. CT is the primary imaging modality used in staging. MRI has superior contrast resolution compared with CT and can add value in terms of determining surgical resectability in equivocal cases. MRI can further assess the degree of local invasion, particularly into the mediastinum, chest wall, and diaphragm, for malignant pleural and pericardial mesotheliomas. FDG PET/CT plays a role in the diagnosis and staging of malignant pleural mesothelioma (MPM) and has been shown to be more accurate than CT, MRI, and PET alone in the staging of malignant pleural mesothelioma. PET/CT can also be used to target lesions for biopsy and to assess prognosis, treatment response, and tumor recurrence., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Malignant peritoneal mesothelioma (MPeM) is a rare disease with a poor prognosis that develops in the mesothelial cells of the peritoneum. We encountered a 48-year-old man with no prior asbestos exposure who visited our hospital with abdominal pain. Laboratory findings showed elevated C-reactive protein of 15.5 mg/dL. Contrast-enhanced computed tomography (CT) detected a Fitz-Hugh-Curtis syndrome-like contrast effect on the liver surface and thickening of the peritoneum. Blood culture, Mycobacterium tuberculosis-specific IFN-γ release assay, Chlamydia trachomatis and Neisseria gonorrhoeae DNA testing, and antinuclear antibody were all negative. CA125 was high at 124.8 U/mL. The laparoscopy for diagnostic purposes revealed adhesions between the liver surface and peritoneum in addition to numerous small and large white nodules on the peritoneum. Biopsy of the nodules confirmed the diagnosis of epithelial-type MPeM. Treatment was initiated with combined cisplatin and pemetrexed, and CT 6 months later showed a reduced contrast effect on the liver surface and improved peritoneal thickening. A Fitz-Hugh-Curtis syndrome-like contrast effect on the liver surface on contrast-enhanced CT may help identify MPeM., (© 2023. Japanese Society of Gastroenterology.)

Background: Pericardial calcification is usually a marker of chronic diseases, and its occurrence in rapidly progressing malignant primary pericardial mesothelioma (PPM) is extremely rare. Therefore, this atypical imaging appearance contributes to more frequent misdiagnosis of PPM. However, no systematic summary currently exists of the imaging characteristics of malignant pericardial calcification in PPM. In our report, its clinical characteristics are discussed in detail, to provide a reference to reduce the misdiagnosis rates of PPM., Case Presentation: A 50-year-old female patient was admitted to our hospital, presenting primarily with features suggestive of cardiac insufficiency. Chest computed tomography revealed significant pericardial thickening and localized calcification, suspicious of constrictive pericarditis. A chest examination performed through a midline incision showed a chronically inflamed and easily-ruptured pericardium that was closely adherent to the myocardium. Post-operative pathological examination confirmed a diagnosis of primary pericardial mesothelioma. Six weeks postoperatively, the patient experienced symptom recurrence and abandoned chemotherapy and radiation therapy. Nine months postoperatively, the patient died of heart failure., Conclusion: We report this case to highlight the rare finding of pericardial calcification in patients with primary pericardial mesothelioma. This case illustrated that confirmation of pericardial calcification cannot completely rule out rapidly developing PPM. Therefore, understanding the different radiological features of PPM can help to reduce its rate of early misdiagnosis., (© 2023. The Author(s).)

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A , and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A -, NF2 -, and BAP1 -altered mesotheliomas are under consideration. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

This study aims to develop poly lactic-co-glycolic acid (PLGA) nanoparticles with an innovative imaging-guided approach based on Boron Neutron Capture Therapy for the treatment of mesothelioma. The herein-reported results demonstrate that PLGA nanoparticles incorporating oligo-histidine chains and the dual Gd/B theranostic agent AT101 can successfully be exploited to deliver a therapeutic dose of boron to mesothelioma cells, significantly higher than in healthy mesothelial cells as assessed by ICP-MS and MRI. The selective release is pH responsive taking advantage of the slightly acidic pH of the tumour extracellular environment and triggered by the protonation of imidazole groups of histidine. After irradiation with thermal neutrons, tumoral and healthy cells survival and clonogenic ability were evaluated. Obtained results appear very promising, providing patients affected by this rare disease with an improved therapeutic option, exploiting PLGA nanoparticles., (© 2023. The Author(s).)

Objective: In the event of suspicion of malignant pleural mesothelioma (MPM) progression, imaging plays an important role. We aimed to evaluate the efficacy of 18 F-FDG PET/CT in monitoring disease progression by comparing it with CT, and estimate median overall survival (OS) according to progression status with CT and 18 F-FDG PET/CT., Materials and Methods: This was an observational, retrospective, single-institution study with MPM patients who had both 18 F-FDG PET/CT and CT for monitoring disease progression from March 2009 to February 2020. Clinical features, radiological findings, and progression status according to CT [radiologic progression negative (RPN), radiologic progression positive (RPP)] and 18 F-FDG PET/CT [metabolic progression negative (MPN), metabolic progression positive (MPP)] were recorded. The discrepancies and concordance between two methods were evaluated. The OS was estimated using the Kaplan-Meier method., Results: A total of 56 patients were included. There were thirty-one (55.3%) RPN and 25 (44.7%) RPP, while there were 26 (46.5%) MPN and 30 (53.5%) MPP. All RPP patients were also found to be MPP, however, among RPN, 5 patients (8.9% of all patients) were evaluated as MPP. The concordance between two methods in monitoring disease progression was very good (K = 0.423; p < 0.01). The OS was 26 ± 2.6 months in all patients. Kaplan-Meier curves between RPN and RPP, and between MPN and MPP did not show statistically significant differences (p = 0.56 and p = 0.25, respectively)., Conclusions: Both methods are equally acceptable in monitoring disease progression in MPM, even though 18 F-FDG PET/CT detected more progression than CT did., (Copyright © 2022 Sociedad Española de Medicina Nuclear e Imagen Molecular. Published by Elsevier España, S.L.U. All rights reserved.)

Abstract: Primary malignant mesothelioma is a rarity among malignant liver tumors. We present the case of a 48-year-old woman presenting with increasing upper abdominal discomfort and inappetence accompanied by a weight loss of approximately 10 kg. CT and MRI revealed a highly suspicious mass lesion in the liver. 18F-FDG PET/CT performed for staging showed a pathological 18F-FDG uptake of the known liver tumor. Histology and immunohistochemistry indicated mesothelioma of the liver. Herein we present a rare case of primary mesothelioma in the liver with CT, MRI, and 18F-FDG PET/CT., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Malignant pleural mesothelioma (MPM) is an aggressive and rare malignant pleural tumor. Methods: MPM patients diagnosed in Beijing Chaoyang Hospital and Beijing Tongren Hospital were the focus of this study. We collected and analyzed the histological, radiological, and metabolic features of MPM patients. At the same time, Cox univariable and multivariable analyses were used to explore the laboratory risk factors affecting the prognosis of MPM patients. Results: A total of 129 MPM patients were included in this study. MPM includes three main histological subtypes: epithelioid, sarcomatoid and biphasic. Among them, epithelial subtypes accounted for the highest proportion. Calretinin, Wilms' tumor gene (WT1), cytokeratin 5/6 (CK5/6), and D2-40 were the most useful mesothelial markers to support a MPM diagnosis. The imaging features of MPM patients are pleural thickening and pleural effusion. In PET-CT, the affected pleura showed obvious high uptake of tracer, and the degree was related to the specific subtype. The median follow-up time was 55.0 (30.0, 94.0) months. A total of 92 (71.3%) patients died during follow-up. The median survival time of patients was 21.0 (9.0, 48.0) months. The Cox multivariable analysis showed that age [hazard ratio (HR), 1.824; 95% confidence interval (CI) 1.159-2.872; p = 0.009; uncorrected], ESR (HR, 2.197; 95% CI 1.318-3.664; p = 0.003; with Bonferroni correction), lymphocytes (HR, 0.436; 95% CI 0.258-0.737; p = 0.002; with Bonferroni correction), platelets (HR, 1.802; 95% CI 1.084-2.997; p = 0.023; uncorrected) and total protein (HR, 0.625; 95% CI 0.394-0.990; p = 0.045; uncorrected) were independent risk factors for prognosis, after adjusting for confounding factors. Conclusions: Age, ESR, lymphocytes, platelets and total protein may be related to the prognosis of MPM patients. Summarizing the histological, radiological, and metabolic features of MPM patients in the two centers can increase clinicians' understanding of this rare tumor.

Background: In malignant pleural mesothelioma (MPM), complex tumour morphology results in inconsistent radiological response assessment. Promising volumetric methods require automation to be practical. We developed a fully automated Convolutional Neural Network (CNN) for this purpose, performed blinded validation and compared CNN and human response classification and survival prediction in patients treated with chemotherapy., Methods: In a multicentre retrospective cohort study; 183 CT datasets were split into training and internal validation (123 datasets (80 fully annotated); 108 patients; 1 centre) and external validation (60 datasets (all fully annotated); 30 patients; 3 centres). Detailed manual annotations were used to train the CNN, which used two-dimensional U-Net architecture. CNN performance was evaluated using correlation, Bland-Altman and Dice agreement. Volumetric response/progression were defined as ≤30%/≥20% change and compared with modified Response Evaluation Criteria In Solid Tumours (mRECIST) by Cohen's kappa. Survival was assessed using Kaplan-Meier methodology., Results: Human and artificial intelligence (AI) volumes were strongly correlated (validation set r=0.851, p<0.0001). Agreement was strong (validation set mean bias +31 cm 3 (p=0.182), 95% limits 345 to +407 cm 3 ). Infrequent AI segmentation errors (4/60 validation cases) were associated with fissural tumour, contralateral pleural thickening and adjacent atelectasis. Human and AI volumetric responses agreed in 20/30 (67%) validation cases κ=0.439 (0.178 to 0.700). AI and mRECIST agreed in 16/30 (55%) validation cases κ=0.284 (0.026 to 0.543). Higher baseline tumour volume was associated with shorter survival., Conclusion: We have developed and validated the first fully automated CNN for volumetric MPM segmentation. CNN performance may be further improved by enriching future training sets with morphologically challenging features. Volumetric response thresholds require further calibration in future studies., Competing Interests: Competing interests: ACK, GWC, ME, ST and KGB have no conflicts of interest to declare. OA, AJW, JV and KAG are employees of Canon Medical Research Europe., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Malignant mesothelioma is an aggressive tumor originating from the mesothelial cells and presenting in general with a very poor prognosis. The pleural localization represents the prevailing disease site, while peritoneal involvement is commonly rare. The WHO classifies mesotheliomas into epithelioid, biphasic, and sarcomatoid histotypes, having diverse outcome with the sarcomatoid or biphasic forms showing the poorest prognosis. Given the peculiar rind-like pattern of growth, mesothelioma assessment is rather challenging for medical imagers. Conventional imaging is principally based on contrast-enhanced CT, while the role of functional and metabolic imaging is regarded as complementary. By focusing essentially on the staging and restaging role of [18F]FDG PET/CT in malignant mesotheliomas, the present review will summarize the available data present in literature and provide some hints on alternative imaging and future perspectives. Given the prevailing incidence of pleural disease, the majority of the information will be addressed on malignant pleural mesothelioma, although a summary of principal characteristics and imaging findings in patients with peritoneal mesothelioma will be also provided., Competing Interests: Declaration of Competing Interest The other authors declare no conflicts of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A 67-year-old woman was referred to our hospital for cough and fever. Chest computed tomography (CT) showed some masses showing slightly enhanced effect in the pericardium. FDG-PET showed the accumulation of FDG in the masses. Thoracoscopic surgical biopsy was performed to establish the diagnosis. The histological study showed proliferation of short spindle-shaped cells surrounded by lymphocyte, and the spindle cells were immunohistochemically positive for cytokeratin AE1/AE3, WT-1, D2-40, CAM5.2, intelectin-1 and negative for CEA, TTF-1, napsin A, claudin-4, calretinin, MUC4, PAX8, CD30. These findings were compatible with epithelial pericardial malignant mesothelioma.

Malignant pleural mesothelioma is a rare type of cancer, whose incidence, however, is increasing and will presumably continue to rise in the coming years. Key features of this disease comprise its mantle-shaped, pleura-associated, often multifocal growth, which cause diagnostic challenges. A growing number of mesotheliomas are being treated with novel immunotherapies for which no image derived general response criteria have been established. However, recent studies indicate that FDG-PET/CT could be superior for response assessment compared to CT-based criteria. This article aims at providing an overview of response assessment criteria dedicated to malignant pleural mesothelioma, such as mRECIST, iRECIST, and PERCIST. In addition, the potential future role of PET/CT in the management of malignant pleural mesothelioma will also be discussed., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Lung cancer is the leading cause of cancer-related mortality in the United States. Accurate staging at initial diagnosis determines appropriate treatment and is the most important predictor of survival. Since 2018, the 8th edition of the TNM staging system has been used to stage lung cancer based on local tumor extent (T), nodal involvement (N), and metastases (M). 18 F fluorodeoxyglucose (FDG) PET/CT, which combines functional and anatomic imaging, is the standard of care and an integral part of clinical staging of patients with lung cancer. Malignant pleural mesothelioma (MPM), the most common primary malignant pleural tumor affecting the pleura is staged with 8th edition of TNM staging for MPM. 18 F FDG PET/CT is indicated in select patients who are surgical candidates to identify locally advanced tumor, nodal metastases, or extrathoracic metastases, which may preclude surgery., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Although the diagnosis of malignant pleural mesothelioma at an in situ stage was traditionally challenging, it is now possible owing to advances in molecular biological methods such as P16 fluorescence in situ hybridization or BRCA1-associated protein 1 immunohistochemistry. Here, we report the first case, to our knowledge, of total parietal pleurectomy for mesothelioma in situ. Future follow-up and accumulation of cases are necessary to determine whether total parietal pleurectomy could be applied as a treatment for mesothelioma in situ or not., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Mediastinal malignant pleural mesothelioma with signs of tamponade is rare. Indication for reoperation for recurrent malignant pleural mesothelioma is a controversial but viable option in selected patients. We report a case of a 68-year-old man presenting with epithelioid malignant pleural mesothelioma who underwent a total of three debulking surgeries (pleurectomy/decortication) combined with hyperthermic intrathoracic chemotherapy. Five years after the first procedure, a third urgent operation was performed for recurrence of a large mediastinal mesothelioma causing acute symptoms of pericardial constriction and tamponade. The patient was alive for eight years since the first treatment and 36 months after the second reoperation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Background: Adenomatoid mesothelioma is a rare subtype of malignant mesothelioma that can be confused with adenomatoid tumors, which are classified as benign. The clinical features and optimal management of adenomatoid mesothelioma have not been elucidated in the literature. In this report, we present an extremely rare case of adenomatoid mesothelioma that developed on the peritoneal surface of the diaphragm as well as a literature review of adenomatoid mesothelioma in the abdominal cavity., Case Presentation: The patient was a 61-year-old Japanese woman who had undergone resection of a malignant peripheral nerve sheath tumor of the hand 18 years prior. She was diagnosed with clinical stage I lung adenocarcinoma on follow-up chest radiography. Simultaneously, a 20-mm enhancing nodule with slow growth on the right diaphragm was detected on contrast-enhanced computed tomography. She presented no specific clinical symptoms. At this point, the lesion was suspected to be a hypervascular tumor of borderline malignancy, such as a solitary fibrous tumor. After a left upper lobectomy for lung adenocarcinoma, she was referred to our department, and laparoscopic tumor resection was performed. Adenomatoid tumors were also considered based on the histopathological and immunohistochemical analyses, but we made the final diagnosis of adenomatoid mesothelioma using the results of the genetic profile. The patient remains alive, with no recurrence noted 6 months after surgery., Conclusion: We encountered a valuable case of adenomatoid mesothelioma of peritoneal origin. There are some previously reported cases of adenomatoid mesothelioma and adenomatoid tumors that may need to be recategorized according to the current classification. It is important to accumulate and share new findings to clarify the clinicopathological characteristics and genetic status of adenomatoid mesothelioma., (© 2022. The Author(s).)

We report a case of localized malignant pleural mesothelioma (LMPM) of the interlobar fissure mimicking lung cancer. A 74-year-old woman presented with dyspnoea and a left pleural effusion. Chest computed tomography revealed a bulky mass, arising from the left lower lobe with intense uptake at the 18F-FDG PET. A left lower lobectomy was performed after thoracoscopic pleural biopsies. The final histology revealed an LMPM epithelioid like. We describe the diagnostic and curative path of the disease, speculating on the differential diagnosis and treatment of LMPM., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Localized malignant mesothelioma is rare. It has a histological pattern identical to diffuse malignant mesothelioma but without diffuse serosal spread. Localized malignant mesothelioma typically originates from the pleura, peritoneum or pericardium, but can occasionally develop from organs. Our cases represent what might be the largest mediastinal localized malignant mesothelioma described and the first presentation of the epithelioid type in the stomach of an adult., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.)

Background: The malignant pleural mesothelioma (MPM) response rate to chemotherapy is low. The identification of imaging biomarkers that could help guide the most effective therapy approach for individual patients is highly desirable. Our aim was to investigate the dynamic contrast-enhanced (DCE) MR parameters as predictors for progression-free (PFS) and overall survival (OS) in patients with MPM treated with cisplatin-based chemotherapy., Methods: Thirty-two consecutive patients with MPM were enrolled in this prospective study. Pretreatment and intratreatment DCE-MRI were scheduled in each patient. The DCE parameters were analyzed using the extended Tofts (ET) and the adiabatic approximation tissue homogeneity (AATH) model. Comparison analysis, logistic regression and ROC analysis were used to identify the predictors for the patient's outcome., Results: Patients with higher pretreatment ET and AATH-calculated K trans and v e values had longer OS (P≤.006). Patients with a more prominent reduction in ET-calculated K trans and k ep values during the early phase of chemotherapy had longer PFS (P =.008). No parameter was identified to predict PFS. Pre-treatment ET-calculated K trans was found to be an independent predictive marker for longer OS (P=.02) demonstrating the most favourable discrimination performance compared to other DCE parameters with an estimated sensitivity of 89% and specificity of 78% (AUC 0.9, 95% CI 0.74-0.98, cut off > 0.08 min -1 )., Conclusions: In the present study, higher pre-treatment ET-calculated K trans values were associated with longer OS. The results suggest that DCE-MRI might provide additional information for identifying MPM patients that may respond to chemotherapy., (© 2022. The Author(s).)

Malignant peritoneal mesothelioma is generally characterized by chief complaints such as abdominal mass and abdominal pain. We report a case of malignant peritoneal mesothelioma diagnosed as an inguinal mass. A 69-year-old man was referred to our hospital complaining of abdominal distension and swelling in the right inguinal region. Abdominal/pelvic contrast-enhanced computed tomography revealed a 22 cm tumor from the right inguinal canal to the peritoneal cavity and a large amount of ascites. Because imaging analyses revealed no metastasis, we planned tumor resection. We resected the tumor with the peritoneum and right testis and sampled some nodules in the mesentery. Histopathological examination of the tumor led to the diagnosis of epithelial malignant mesothelioma. Adhering to chemotherapy guidelines for pleural malignant mesothelioma, six courses of pemetrexed and cisplatin combination chemotherapy were performed. He is alive with no evidence of new local tumor or nodules in the mesentery 1 year postoperatively.

Objective: Pleurectomy/decortication has been preferably employed as a curative-intent surgery for malignant pleural mesothelioma. However, visceral pleurectomy during pleurectomy/decortication provides technical challenges. For visceral pleurectomy, pleural incisions are commonly made to create a dissection plane between the visceral pleura and the lung parenchyma, which may cause tumor dissemination and may not allow en bloc complete resection of the entire pleura. To overcome such potential disadvantages, we have developed a novel surgical technique without any pleural incision (non-incisional pleurectomy/decortication) to achieve en bloc removal of the entire pleura., Methods: A total of 36 consecutive patients who underwent non-incisional pleurectomy/decortication for malignant pleural mesothelioma from January 2017 through December 2020 in our institute were retrospectively reviewed to assess the feasibility., Results: Macroscopic complete resection was achieved in 31 patients (86.1%) with non-incisional pleurectomy/decortication. In the majority of patients (n = 29), en bloc complete resection of the entire pleura was achieved (without pleural laceration in 10 and with some pleural laceration in 19 patients). The total operation time and the duration of visceral pleurectomy were significantly shorter as compared with those for conventional pleurectomy/decortication (median, 350 versus 506 min [P = 0.011], and 43 versus 97 min [P < 0.001], respectively). Among 36 patients who underwent non-incisional pleurectomy/decortication, postoperative complications developed in 13 patients (36.1%), and one patient died on the postoperative day 95 caused by aggressive tumor progression of residual tumor., Conclusions: Non-incisional pleurectomy/decortication is a fast and feasible technique to achieve en bloc macroscopic complete resection for malignant pleural mesothelioma., (© 2021. The Japanese Association for Thoracic Surgery.)

2-deoxy-2-[ 18 F]fluoro-D-glucose [ 18 F]FDG-PET/CT represents the metabolic imaging of choice in various cancer types. Used either at diagnosis or during treatment response assessment, the modality allows for a more accurate definition of tumor extent compared to morphological imaging and is able to predict the therapeutic benefit earlier in time. Due to the aspecific uptake property of [ 18 F]FDG there is an overlap of its distribution in normal and pathological conditions, which can make the interpretation of the imaging challenging. Lung and pleural neoplasia are no exception to this, thus acknowledging of possible pitfalls and artifacts are mandatory for image interpretation. While most pitfalls and artifacts are common for all indications with metabolic imaging with [ 18 F]FDG-PET/CT, there are specific variants and pitfalls in lung cancer and malignant pleural mesothelioma. The aim of the present article is to shed light on the most frequent and relevant variants and pitfalls in [ 18 F]FDG-PET/CT imaging in lung cancer and malignant pleural mesothelioma., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In recent years, there has been a shift from extrapleural pneumonectomy (EPP) toward pleurectomy/decortication (P/D) as the preferred surgical technique. However, we occasionally encounter difficult cases wherein visceral pleurectomy requires conversion to EPP from P/D. We sought to clarify the preoperative risk factors and clinical outcomes associated with conversion to EPP. We compared and analyzed conversion to EPP and P/D between September 2012 and December 2019. Conversion to EPP was decided in case of diffuse tumor invasion to the pulmonary parenchyma or due to failure of decortication. Univariable regression analysis was performed to determine the association of preoperative variables with conversion to EPP. Survival was analyzed by the Kaplan-Meier method and log-rank test. Of the 181 patients who underwent intended P/D, 145 (80.1%) patients underwent P/D and 18 (9.9%) patients underwent conversion to EPP. The sum of 3-level pleural thickness (P < 0.001), maximum of 3-level pleural thickness (P = 0.006), and clinical T stage (P < 0.001) demonstrated association with conversion to EPP. Overall survival and progression-free survival were significantly worse in the conversion to EPP group (median overall survival, 29.2 months vs 57.0 months [P = 0.008]; median progression-free survival, 15.3 months vs 23.2 months [P = 0.005]. Our data show that approximately 1 of every 10 patients with P/D intention converted to EPP. Preoperative pleural thickness and clinical T stage may be risk factors associated with conversion to EPP. The survival rate of conversion to EPP was worse than that of P/D., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objectives: Tumor thickness and tumor volume measured by computed tomography (CT) were suggested as valuable prognosticator for patients' survival diagnosed with malignant pleural mesothelioma (MPM). The purpose was to assess the accuracy of CT scan based preoperatively measured tumor volume and thickness compared to actual tumor weight of resected MPM specimen and pathologically assessed tumor thickness, as well as an analysis of their impact on overall survival (OS)., Methods: Between 09/2013-08/2018, 74 patients were treated with induction chemotherapy followed by (extended) pleurectomy/decortication ((E)PD). In 53 patients, correlations were made between CT-measured volume and -tumor thickness (cTV and cTT) and actual tumor weight (pTW) based on the available values. Further cTV and pT/IMIG stage were correlated using Pearson correlation. Overall survival (OS) was calculated with Kaplan Meier analysis and tested with log rank test. For correlation with OS Kaplan-Meier curves were made and log rank test was performed for all measurements dichotomized at the median., Results: Median pathological tumor volume (pTV) and pTW were 530 ml [130 ml - 1000 ml] and 485 mg [95 g - 982 g] respectively. Median (IQR) cTV was 77.2 ml (35.0-238.0), median cTT was 9.0 mm (6.2-13.7). Significant association was found between cTV and pTV (R = 0.47, p < 0.001) and between cTT and IMIG stage (p = 0,001) at univariate analysis. Multivariate regression analysis revealed, that only cTV correlates with pTV. Median follow-up time was 36.3 months with 30 patients dead at the time of the analysis. Median OS was 23.7 months. 1-year and 3-year survival were 90 and 26% respectively and only the cTV remained statistically associated with OS., Conclusion: Preoperatively assessed CT tumor volume and actual tumor volume showed a significant correlation. CT tumor volume may predict pathological tumor volume as a reflection of tumor burden, which supports the integration of CT tumor volume into future staging systems., (© 2021. The Author(s).)

We present the case of a 65-year-old woman who presented with progressive dysphagia and was diagnosed with achalasia. She subsequently developed bilateral chylous pleural effusions, with no cause identified despite extensive investigations (including computed tomography (CT) scans, gastroscopy and medical thoracoscopy (MT)) and review at a dedicated pleural multidisciplinary team meeting.Despite optimal supportive management she deteriorated and was admitted to the intensive care unit, where she passed away due to sepsis and respiratory failure 10 months after initial presentation. A postmortem returned a diagnosis of epithelioid mesothelioma, encasing the carina, distal oesophagus and coeliac axis.Mesothelioma only very rarely presents with either chylous effusions or achalasia. Additionally while MT normally conveys excellent sensitivity for pleural malignancy, it was insufficient here. This case highlights how an unusually located mesothelioma can produce an unusual clinical picture. It also suggests a role for early video-assisted thoracoscopy to aid diagnosis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

A 70-year-old man with epithelioid malignant pleural mesothelioma was referred to the maxillofacial surgery department with a painful lesion on the lateral border of his tongue which interfered with swallowing. Physical examination demonstrated a 3 cm firm, non-ulcerated mass on the left lateral tongue, histologically shown to be metastatic epithelioid mesothelioma. MRI of the neck and CT scan of the thorax, abdomen and pelvis scans also demonstrated progressive local and metastatic disease. The patient was not felt to be fit for further treatment. More than 90% of oral cavity cancers are squamous cell carcinoma. All reported cases of metastasis of malignant mesothelioma to the tongue have been of the epithelioid subtype with 10 cases reported in the literature to date. Diagnosis is important as tongue lesions can significantly impact on quality of life and synchronous tongue primaries should be ruled out. Tongue lesions may herald metastases to other extrapleural locations., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Breast cancer may be associated with other primary cancers via germline mutations; however, sporadic occurrences of other malignancies are rare. With increased use of advanced breast cancer imaging, including MRI and PET/CT, other incidental synchronous cancers are increasingly identified. Such cases can represent unique diagnostic and treatment challenges. Here, we present a case of a young woman diagnosed with primary breast cancer who underwent imaging studies identifying an incidental primary peritoneal mesothelioma., (© 2021 Wiley Periodicals LLC.)

Aim: 18F-Fluorodeoxyglucose (FDG) PET/computerized tomography (CT) is a valuable method in the diagnosis of malignant pleural mesothelioma (MPM). But, some infections, particularly tuberculosis, are known to mimic cancer. We aimed to compare the FDG PET/CT findings of tuberculosis pleurisy (TP) and malignant mesothelioma and evaluate its role of differential diagnosis., Material and Method: We retrospectively reviewed the data from 85 patients (45 patients with MPM and 40 patients with TP) who underwent FDG PET/CT. All images were reevaluated and pleural thickening, maximum standardized uptake values (SUVmax), lymphatic uptake and accompanying parenchymal findings were noted., Results: There was no significant difference in age and sex between the two groups. Pleural thickening was more prominent in the MPM group. Mean pleural thickness was 21.4 ± 18.6 mm in the MPM group and 6.8 ± 3.5 mm in the TP group (P = 0.0). Besides pleural pathology, lymph nodes involvement in the thoracic (P = 0.0) and extrathoracic area (P = 0.34) and parenchymal findings were prominent in the TP group (P = 0.0). However, there was no significant difference in pleural SUVmax values between the two groups (P = 0.61)., Conclusion: Intense pleural FDG uptake can be observed in TP like malignant mesothelioma. For the evaluation of the pleural pathologies in the tuberculosis endemic countries, it should be considered that FDG PET/CT may have false-positive results. Evaluation of increased pleural FDG uptake together with the detected parenchymal findings and lymphatic involvement may help us to make more accurate interpretation of the diagnosis., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

A 38-year-old man was admitted to our hospital because of right chest pain and high fever. Chest X-ray and computed tomography scan revealed right pleural effusion and pleural thickness. Diagnosis of malignant mesothelioma was established by pleural biopsy. Serum level of granulocyte colony stimulating factor (G-CSF) was high. We performed extrapleural pneumonectomy which improved high fever and inflammation, however the patient died three months after surgery.

Malignant mesotheliomas (MMs) are malignancies of the mesothelium, with primary deposits originating in the pleura, peritoneum, pericardium and the tunica vaginalis (ie, testicular). Metastatic spread is commonly reported to affect the liver, adrenal glands, kidney and contralateral lung (in cases of malignant pleural mesothelioma). Metastases to distant sites are uncommon. Spread to the oral cavity in particular is very rare. A total of 23 cases of metastatic spread to the oral cavity have been reported in the literature to date; of those, 9 cases have been to the tongue. Given the rarity of the site of metastasis, the management remains challenging. This case highlights a rare site of metastasis in MM, discusses treatment options available and briefly talks about technical limitations in treating a mobile structure such as the tongue. Good palliative and supportive care is crucial in managing cases where no curative treatment is possible., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)