A Role for PET/CT in Response Assessment of Malignant Pleural 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.

The role of volumetric method in the assessment of chemotherapy response and predicting survival in malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a pleural tumor with high mortality rate and short-term survival expectancy after diagnosis. Assessment of the response to chemotherapy, which is the first choice in treatment of MPM, is important for the transition to alternative chemotherapy protocols and immunotherapy. There is no clarity in the response to chemotherapy treatment. OBJECTIVE: Our study aims to compare the assessment of chemotherapy response using the Modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria and volumetric measurements and to correlate with median survival. MATERIALS AND METHODS: Thirty-two patients (16 females and 16 males) were included in the study, and their ages ranged from 28 to 78 years. Chemotherapy response was determined by both mRECIST and volumetric approach. Tumor volume was measured by linear interpolation and semi-automatic segmentation. Log-rank multiple cutoff analysis was used to determine appropriate cutoff values of volumetric response criteria. RESULTS: According to both mRECIST and volumetric approach, median survival times in partial response, stable disease, and progressive disease groups were 24, 15, and 9 months, respectively. The survival times of the three groups were different (logrank: 17.76; P < 0.001) by mRECIST. The survival of the progressive disease group was shorter than that of the other groups (logrank: 18.91; P < 0.001) by volumetric approach. CONCLUSIONS: In the assessment of chemotherapy response, even though classifications obtained according to the mRECIST criteria and volumetric measurements are statistically compatible, we think that the measurement of the volumetric values will increase the standardization. In our study, threshold values for volumetric measurements were determined; however, these values should be supported by large-scale multicenter studies.

Imaging Assessment of Visceral Pleural Surface Invasion by Lung Cancer: Comparison of CT and Contrast-Enhanced Radial T1-Weighted Gradient Echo 3-Tesla MRI.

OBJECTIVE: To compare the diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3-tesla (3T) magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of visceral pleural surface invasion (VPSI). Visceral pleural invasion by non-small-cell lung cancer (NSCLC) can be classified into two types: PL1 (without VPSI), invasion of the elastic layer of the visceral pleura without reaching the visceral pleural surface, and PL2 (with VPSI), full invasion of the visceral pleura. MATERIALS AND METHODS: Thirty-three patients with pathologically confirmed VPSI by NSCLC were retrospectively reviewed. Multidetector CT and contrast-enhanced 3T MRI with a free-breathing radial three-dimensional fat-suppressed volumetric interpolated breath-hold examination (VIBE) pulse sequence were compared in terms of the length of contact, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. Supplemental evaluation of the tumor-pleura interface (smooth versus irregular) could only be performed with MRI (not discernible on CT). RESULTS: At the tumor-pleura interface, radial VIBE MRI revealed a smooth margin in 20 of 21 patients without VPSI and an irregular margin in 10 of 12 patients with VPSI, yielding an accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F-score for VPSI detection of 91%, 83%, 95%, 91%, 91%, and 87%, respectively. The McNemar test and receiver operating characteristics curve analysis revealed no significant differences between the diagnostic accuracies of CT and MRI for evaluating the contact length, angle of mass margin, or arch distance-to-maximum tumor diameter ratio as predictors of VPSI. CONCLUSION: The diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3T MRI and CT were equal in terms of the contact length, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. The advantage of MRI is its clear depiction of the tumor-pleura interface margin, facilitating VPSI detection.

A comparison between MRI and CT in the assessment of primary tumour volume in mesothelioma.

INTRODUCTION: Primary tumour staging in Malignant Pleural Mesothelioma (MPM) using Computed Tomography (CT) imaging is confounded by perception errors reflecting low spatial resolution between tumour and adjacent structures. Augmentation using perfusion CT is constrained by radiation dosage. In this study, we evaluated an alternative tumour staging method using perfusion-tuned Magnetic Resonance Imaging (MRI). METHODS: Consecutive patients with suspected MPM were recruited to a prospective observational study. All had MRI (T1-weighted, isotropic, contrast-enhanced 3-Tesla perfusion imaging) and CT (contrast-enhanced) pre-biopsy. Patients diagnosed with MPM underwent MRI and CT volumetry, with readers blinded to clinical data. MRI volumetry was semi-automated, using signal intensity limits from perfusion studies to grow tumour regions within a pleural volume. A similar CT method was not possible, therefore all visible tumour was manually segmented. MRI and CT volumes were compared (agreement, correlation, analysis time, reproducibility) and associations with survival examined using Cox regression. RESULTS: 58 patients were recruited and had MRI before biopsy. 31/58 were diagnosed with MPM and these scans were used for volumetry. Mean (SD) MRI and CT volumes were 370 cm3 and 302 cm3, respectively. MRI volumes were larger (average bias 61.9 cm3 (SD 116), 95 % limits (-165.5 - 289 cm3), moderately correlated with CT (r = 0.56, p = 0.002) and independently associated with survival (HR 4.03 (95 % CI 1.5-11.55), p = 0.006). CT volumes were not associated with survival, took longer to compute than MRI volumes (mean (SD) 151 (19) v 14 (2) minutes, p=<0.0001) and were less reproducible (inter-observer ICC 0.72 for CT, 0.96 for MRI). CONCLUSIONS: MRI and CT generate different tumour volumes in MPM. In this study, MRI volumes were larger and were independently associated with survival. MRI volumetry was quicker and more reproducible than CT.

Preoperative assessment of parietal pleural invasion/adhesion of subpleural lung cancer: advantage of software-assisted analysis of 4-dimensional dynamic-ventilation computed tomography.

OBJECTIVE: To evaluate the accuracy of four-dimensional (4D) dynamic-ventilation computed tomography (CT) scanning coupled with our novel image analysis software to diagnose parietal pleural invasion/adhesion of peripheral (subpleural) lung cancer. METHODS: Eighteen patients with subpleural lung cancer underwent both 4D dynamic-ventilation CT during free breathing and conventional (static) chest CT during preoperative assessment. The absence of parietal pleural invasion/adhesion was surgically confirmed in 13 patients, while the presence of parietal pleural invasion/adhesion was confirmed in 5 patients. Two chest radiologists, who were blinded to patient status, cooperatively evaluated the presence of pleural invasion/adhesion using two different imaging modalities: (i) conventional high-resolution CT images, reconstructed in the axial, coronal, and sagittal directions, and (ii) 4D dynamic-ventilation CT images combined with a color map created by image analysis software to visualize movement differences between the lung surface and chest wall. Parameters of diagnostic accuracy were assessed, including a receiver operating characteristic analysis. RESULTS: Software-assisted 4D dynamic-ventilation CT images achieved perfect diagnostic accuracy for pleural invasion/adhesion (sensitivity, 100%; specificity, 100%; area under the curve [AUC], 1.000) compared to conventional chest CT (sensitivity, 60%; specificity, 77%; AUC, 0.846). CONCLUSION: Software-assisted 4D dynamic-ventilation CT can be considered as a novel imaging approach for accurate preoperative analysis of pleural invasion/adhesion of peripheral lung cancer. KEY POINTS: • 4D dynamic-ventilation CT can correctly assess parietal pleural invasion/adhesion of peripheral lung cancer. • A unique color map clearly demonstrates parietal pleural invasion/adhesion. • Our technique can be expanded to diagnose "benign" pleural adhesions for safer thoracoscopic surgery.

Dynamic contrast-enhanced CT for the assessment of tumour response in malignant pleural mesothelioma: a pilot study.

OBJECTIVES: The aim of this pilot study was to investigate the utility of haemodynamic parameters derived from dynamic contrast-enhanced computed tomography (DCE-CT) scans in the assessment of tumour response to treatment in malignant pleural mesothelioma (MPM) patients. METHODS: The patient cohort included nine patients undergoing chemotherapy and five patients on observation. Each patient underwent two DCE-CT scans separated by approximately 2 months. The DCE-CT parameters of tissue blood flow (BF) and tissue blood volume (BV) were obtained within the dynamically imaged tumour. Mean relative changes in tumour DCE-CT parameters between scans were compared between the on-treatment and on-observation cohorts. DCE-CT parameter changes were correlated with relative change in tumour bulk evaluated according to the modified RECIST protocol. RESULTS: Differing trends in relative change in BF and BV between scans were found between the two patient groups (p = 0.19 and p = 0.06 for BF and BV, respectively). No significant rank correlations were found when comparing relative changes in DCE-CT parameters with relative change in tumour bulk. CONCLUSIONS: Differing trends in the relative change of BF and BV between patients on treatment and on observation indicate the potential of DCE-CT for the assessment of pharmacodynamic endpoints with respect to treatment in MPM. A future study with a larger patient cohort and unified treatment regimens should be undertaken to confirm the results of this pilot study. KEY POINTS: • CT-derived haemodynamic parameters show differing trends between malignant pleural mesothelioma patients on treatment and patients off treatment • Changes in haemodynamic parameters do not correlate with changes in tumour bulk as measured according to the modified RECIST protocol • Differing trends across the two patient groups indicate the potential sensitivity of DCE-CT to assess pharmacodynamic endpoints in the treatment of MPM.

Tumor Growth Assessment by Computed Tomography Perfusion Imaging (CTPI), Perfusion-Weighted Imaging (PWI), and Diffusion-Weighted Imaging (DWI) in a Rabbit Pleural Squamous Cell Carcinoma VX2-Implanted Model.

BACKGROUND Computed tomography perfusion imaging (CTPI) and perfusion-weighted imaging (PWI) are non-invasive technologies that can quantify tumor vascularity and blood flow. This study explored the blood flow information, tumor cell viability, and hydrothoraces in a rabbit pleural VX2-implanted model through use of CTPI, PWI, and DWI. MATERIAL AND METHODS A pleural VX2-implanted model was established in 58 New Zealand white rabbits. CTPI, PWI, and DWI were applied with a 16-slice spiral CT and an Archival 1.5 T dual-gradient MRI. RESULTS Compared with muscle tissue, PV, PEI, and BV of parietal and visceral pleural tumor implantation rabbits showed significant differences. The t values of PV, PEI, and BV between parietal and visceral pleura were 2.08, 2.29, and 2.88, respectively. Compared with muscle tissue, WIR, WOR, and MAXR of parietal and visceral pleural tumor implantation rabbits showed significant differences. In parietal pleural tumor implantation rabbits, the section surface of lesion tissues was 5.2±2.7 cm². Hydrothorax appeared 6.0±2.0 days after tumor implantation. The mean value of ADC was 1.5±0.6. In visceral pleural tumor implantation rabbits, the section surface of lesion tissues was 1.6±0.8 cm². Hydrothorax appeared 7.0±3.0 days after tumor implantation. The mean value of ADC was 1.4±0.5. The t values of the above 3 indices for the parietal and visceral pleura were 1.85, 1.83, and 1.76, respectively (P<0.05). CONCLUSIONS The combined application of CTPI, PWI, and DWI accurately and visually reflects the blood perfusion of tumor tissues and quantitatively analyzes blood flow information and the mechanism underlying hydrothorax generation in tumor tissues.

Revised Modified Response Evaluation Criteria in Solid Tumors for Assessment of Response in Malignant Pleural Mesothelioma (Version 1.1).

INTRODUCTION: Malignant pleural mesothelioma poses unique difficulties in tumor measurement and response assessment; however, robust and reproducible assessment of response is critically important in the conduct, interpretation, and reporting of clinical trials. METHODS: The current de facto standard for the assessment of mesothelioma tumor response, "modified RECIST" (Response Evaluation Criteria in Solid Tumors), was published in 2004 as a research paper. Practical application of the modified RECIST guidelines has suffered from varied interpretations, resulting in inaccuracies and inconsistencies in tumor response assessment across and within mesothelioma clinical trials. The presented "modified RECIST 1.1 for mesothelioma" response assessment guidelines provide a much-needed update that incorporates recommendations from RECIST 1.1 and approaches to other practical issues, including: (1) definition of minimally measurable disease; (2) definition of measurable lesions; (3) acceptable measurement location; (4) non-pleural disease considerations; (5) characterization of non-measurable pleural disease; (6) assessment of pathological lymph nodes; (7) establishing progressive disease; and (8) accommodations for bilateral pleural disease. RESULTS: These modified RECIST 1.1 guidelines for mesothelioma tumor response collate and apply research published since the development of modified RECIST, align modified RECIST with RECIST 1.1, address those aspects of tumor measurement that were neglected or not well characterized in the modified RECIST paper, and clarify ambiguous or difficult measurement issues that have been highlighted through the subsequent decade of clinical trials research. CONCLUSION: Adoption of the modified RECIST 1.1 guidelines for mesothelioma is recommended to harmonize the application of tumor measurement and response assessment across the next generation of clinical trials in this disease.

Metabolic response assessment with 18F-FDG-PET/CT is superior to modified RECIST for the evaluation of response to platinum-based doublet chemotherapy in malignant pleural mesothelioma.

PURPOSE: Efficient monitoring of tumor responsiveness to chemotherapy is essential to mitigate high mortality risks and cytotoxic effects of chemotherapeutics. However, there is no consensus on the most suitable diagnostic technique/parameters for assessing response to chemotherapy in malignant pleural mesothelioma (MPM). We compared the tumor responsiveness of MPM patients as assessed using modified RECIST (mRECIST) criteria and integrated 18F-FDG-PET/CT. METHODS: Histologically confirmed MPM patients (N=82) who were treated with three cycles of cisplatin and pemetrexed, or carboplatin and pemetrexed, were included. mRECIST and integrated 18F-FDG-PET/CT were used to evaluate MPM tumor response to chemotherapy. Metabolic non-responders were defined as those with a 25% or greater increase in SUVmax compared with the previous value. Time to progression (TTP) and overall survival (OS) were compared between metabolic-responders and non-responders. RESULTS: After three cycles of chemotherapy, 62(75.6%) of the patients were classified as having SD, 15 (18%) with partial remission (PR), and 5 (6%) with progressive disease (PD), based on mRECIST criteria. The cumulative median OS was 728.0days (95% confidence interval [CI]: 545.9-910.1) and cumulative median TTP was 365.0days (95% CI: 296.9-433.1). For the 82 patients, the disease control rate was 93.9%, whereas the metabolic response rate was only 71.9% (p<0.001). All PD and PR patients were found to be metabolic responders on 18F-FDG-PET/CT; however, among the 62mRECIST SD patients, 18 (29%) were classified as metabolic non-responders. The median TTP for metabolic responders was 13.7 months, while it was 10.0 months for non-responders(p<0.001). Metabolic responders had a trend toward longer OS, although the difference did not reach statistical significance (metabolic responders:33.9 months; non-responders: 21.6 months; p>0.05). CONCLUSION: Several mRECIST-confirmed SD MPM patients may be classified as metabolic non-responders on18F-FDGPET/CT. Metabolic response is significantly correlated with the median TTP, suggesting it should be included in the evaluation of the response to chemotherapy in MPM patients classified as mRECIST SD, to identify non-responders.

Computer-aided volumetric assessment of malignant pleural mesothelioma on CT using a random walk-based method.

OBJECTIVE: The aim of this study is to assess the performance of a computer-aided semi-automated algorithm we have adapted for the purpose of segmenting malignant pleural mesothelioma (MPM) on CT. METHODS: Forty-five CT scans were collected from 15 patients (M:F [Formula: see text] 10:5, mean age 62.8 years) in a multi-centre clinical drug trial. A computer-aided random walk-based algorithm was applied to segment the tumour; the results were then compared to radiologist-drawn contours and correlated with measurements made using the MPM-adapted Response Evaluation Criteria in Solid Tumour (modified RECIST). RESULTS: A mean accuracy (Sørensen-Dice index) of 0.825 (95% CI [0.758, 0.892]) was achieved. Compared to a median measurement time of 68.1 min (range [40.2, 102.4]) for manual delineation, the median running time of our algorithm was 23.1 min (range [10.9, 37.0]). A linear correlation (Pearson's correlation coefficient: 0.6392, [Formula: see text]) was established between the changes in modified RECIST and computed tumour volume. CONCLUSION: Volumetric tumour segmentation offers a potential solution to the challenges in quantifying MPM. Computer-assisted methods such as the one presented in this study facilitate this in an accurate and time-efficient manner and provide additional morphological information about the tumour's evolution over time.

Assessment of objective responses in thymic epithelial tumors using ITMIG modified criteria.

OBJECTIVES: Pleural metastases of thymic epithelial tumors (TETs) are relatively common, and this unique growth pattern makes the use of RECIST (response evaluation criteria in solid tumors) response criteria difficult. To standardize tumor measurement in TETs, the International Thymic Malignancy Interest Group (ITMIG) has proposed newly developed criteria. We compared evaluation of objective response between ITMIG modified criteria and RECIST 1.1 in patients with TET treated with systemic chemotherapy. PATIENTS AND METHODS: We retrospectively evaluated the tumor response of 40 patients with unresectable TET who were enrolled in a phase II clinical trial using ITMIG modified criteria, and compared the findings with prospectively evaluated tumor response assessed by RECIST 1.1. Agreement analyses for the response at each time point, including overall response and declaring progression, were performed and the time to progression (TTP) was also assessed using the two different measurements. RESULTS: The overall response rate assessed by the two methods did not differ significantly, with kappa value of 0.897. Agreement analysis for declaring progression of disease (PD) at the date of RECIST 1.1-designated PD showed 95% concordance rate with ITMIG modified criteria (p=1.000, kappa index=0.875). The median TTP according to RECIST 1.1 and ITMIG modified criteria was 8.4 and 7.9 months (p=0.983), respectively. Validation with another cohort of 27 TET patients treated with neoadjuvant chemotherapy also showed a 96% concordance rate in overall response between the two different criteria. CONCLUSIONS: ITMIG modified criteria showed a high concordance rate with RECIST 1.1 criteria in response assessment of TETs. Given the rarity of TETs, further evaluation of ITMIG modified criteria in a larger number of patients will be required before their implementation in clinical trials.

Feasibility and performance of an adaptive contrast-oriented FDG PET/CT quantification technique for global disease assessment of malignant pleural mesothelioma and a brief review of the literature.

OBJECTIVE: Treatment of malignant pleural mesothelioma (MPM) remains very challenging. Assessment of response to treatment is necessary for modifying treatment and using new drugs. Global disease assessment (GDA) by implementing image processing methods to extract more information out of positron emission tomography (PET) images may provide reliable information. In this study we show the feasibility of this method of semi-quantification in patients with mesothelioma, and compare it with the conventional methods. We also present a review of the literature about this topic. METHODS: Nineteen subjects with histologically proven MPM who had undergone fluoride-18-fluorodeoxyglucose PET/computed tomography ((18)F-FDG PET/CT) before and after treatment were included in this study. An adaptive contrast-oriented thresholding algorithm was used for the image analysis and semi-quantification. Metabolic tumor volume (MTV), maximum and mean standardized uptake volume (SUVmax, SUVmean) and total lesion glycolysis (TLG) were calculated for each region of interest. The global tumor glycolysis (GTG) was obtained by summing up all TLG. Treatment response was assessed by the European Organisation for Research and Treatment of Cancer (EORTC) criteria and the changes of GTG. Agreement between global disease assessment and conventional method was also determined. RESULTS: In patients with progressive disease based on EORTC criteria, GTG showed an increase of 150.7 but in patients with stable or partial response, GTG showed a decrease of 433.1. The SUVmax of patients before treatment was 5.95 (SD: 2.93) and after the treatment it increased to 6.38 (SD: 3.19). Overall concordance of conventional method with GDA method was 57%. Concordance of progression of disease based on conventional method was 44%, stable disease was 85% and partial response was 33%. Discordance was 55%, 14% and 66%. CONCLUSIONS: Adaptive contrast-oriented thresholding algorithm is a promising method to quantify the whole tumor glycolysis in patients with mesothelioma. We are able to assess the total metabolic lesion volume, lesion glycolysis, SUVmax, tumor SUVmean and GTG for this particular tumor. Also we were able to demonstrate the potential use of this technique in the monitoring of treatment response. More studies comparing this technique with conventional and other global disease assessment methods are needed in order to clarify its role in the assessment of treatment response and prognosis of these patients.

Quantitative analyses at baseline and interim PET evaluation for response assessment and outcome definition in patients with malignant pleural mesothelioma.

PURPOSE: Quantitative analyses on FDG PET for response assessment are increasingly used in clinical studies, particularly with respect to tumours in which radiological assessment is challenging and complete metabolic response is rarely achieved after treatment. A typical example is malignant pleural mesothelioma (MPM), an aggressive tumour originating from mesothelial cells of the pleura. We present our results concerning the use of semiquantitative and quantitative parameters, evaluated at the baseline and interim PET examinations, for the prediction of treatment response and disease outcome in patients with MPM. METHODS: We retrospectively analysed data derived from 131 patients (88 men, 43 women; mean age 66 years) with MPM who were referred to our institution for treatment between May 2004 and July 2013. Patients were investigated using FDG PET at baseline and after two cycles of pemetrexed-based chemotherapy. Responses were determined using modified RECIST criteria based on the best CT response after treatment. Disease control rate, progression-free survival (PFS) and overall survival (OS) were calculated for the whole population and were correlated with semiquantitative and quantitative parameters evaluated at the baseline and interim PET examinations; these included SUVmax, total lesion glycolysis (TLG), percentage change in SUVmax (ΔSUVmax) and percentage change in TLG (ΔTLG). RESULTS: Disease control was achieved in 84.7 % of the patients, and median PFS and OS for the entire cohort were 7.2 and 14.3 months, respectively. The log-rank test showed a statistically significant difference in PFS between patients with radiological progression and those with partial response (PR) or stable disease (SD) (1.8 vs. 8.6 months, p < 0.001). Baseline SUVmax and TLG showed a statistically significant correlation with PFS and OS (p < 0.001). In the entire population, both ΔSUVmax and ΔTLG were correlated with disease control based on best CT response (p < 0.001). ΔSUVmax was significantly correlated with PFS in the entire population (p = 0.02) and with both PFS and OS in patients not undergoing talc pleurodesis (n = 65; p < 0.01 for PFS, p = 0.03 for OS), and in patients without pleurodesis presenting a SD and/or PR at CT after two cycles. CONCLUSION: These results confirm the role of FDG PET in the assessment of disease prognosis and treatment efficacy in MPM patients receiving first-line pemetrexed-based chemotherapy. In particular, metabolic response evaluated using ΔSUVmax can be used to predict outcome in MPM patients not undergoing talc pleurodesis who achieve SD and/or PR at the interim CT evaluation.

Image-guided pleural biopsy.

PURPOSE OF REVIEW: The most efficient and cost-effective approach to pleural exudates not diagnosed by means of thoracocentesis remains uncertain. Both closed pleural biopsy and thoracoscopy may be utilized for the acquisition of pleural tissue. This review will focus on the developments in image guidance of closed pleural biopsy. RECENT FINDINGS: Recent studies suggest that computed tomography and ultrasound guidance improve the yield and safety of closed pleural biopsy. Imaging is best suited to reduce the rate of false-negative biopsy in malignant pleural disease by enhanced targeting of localized pleural changes typically situated dorsolaterally close to the diaphragm. Pleural tuberculosis causes effusions with discrete and uniformly distributed pleural thickening, and evidence suggests that the utilization of imaging has little advantage in this setting apart from decreasing the risk associated with blind biopsy. Imaging also facilitates a directed repeat thoracocentesis in the same session. The cumulative yield of image-assisted repeat thoracocentesis and pleural biopsy has been reported to approach that of thoracoscopy, particularly in cases with pleural thickening, nodularity or pleural-based mass lesions. SUMMARY: Image-guided pleural biopsy combined with repeat thoracocentesis is a safe, inexpensive, accessible and sensitive method for further examination of patients with pleural exudates not diagnosed by initial thoracocentesis.

An elusive chest coin in an African child: a pleural fibroma's long, tortuous path to freedom.

Fibrous tumour of the pleural is rare and controversial tumor. Most of the reported cases is adults and the elderly. This case presentation is a solitary fibrous tumour in a fifteen year old girl, which to the best of our knowledge is the youngest report, who was sent for a psychiatric evaluation due to persistent complaint of "movement" in her chest, later referred to a tuberculosis clinic because of a chest radiograph report of loculated pleural effusion likely secondary to tuberculosis. She eventually had a chest computerized tomography and subsequent resection of the lesion. Histology confirmed the computerized tomography diagnosis of solitary fibrous tumour and there was no recurrence five years after excision. This report highlights the difficulty often encountered in developing countries where clinicians solely rely on clinical acumen for diagnosis and treatment due to poor patients' financial status and scarcely available diagnostic resources.

Accuracy of positron emission tomography in mediastinal node assessment in coal workers with lung cancer.

The purpose of this study was to explore the accuracy of (18)F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in the assessment of mediastinal lymph node in coal workers who had non-small cell lung cancer. We retrospectively reviewed 42 retired coal workers who had lung cancer without distant metastasis, between May 2007 and May 2010. Regarding the mediastinal lymph nodes, when the standard uptake value was greater than 2.5, it was considered "malignancy positive." After histological examination of the mediastinal lymph nodes, anthracotic and metastatic ones were detected. The results of PET/CT were analyzed to determine its accuracy. Of these 42 patients, PET/CT detected 47 positive mediastinal lymph nodes in 24 patients with a mean SUV maximum of 6.2 (2.6-13.8). One hundred and thirty-one mediastinal lymph node foci were dissected. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT in detecting nodal metastases were 84% (16/19), 65% (15/23), 66% (16/24), 83% (15/18), and 74% (31/42) on a per-patient basis, respectively. Mediastinal node staging with FDG-PET/CT in coal workers is insufficient due to the high false-positive rates due to the presence of pneumoconiosis. In these patients, an invasive technique such as mediastinoscopy seems mandatory for confirmation of ipsilateral or contralateral mediastinal lymph node metastasis.

[Usefulness of 18F-FDG PET-CT in the presurgical assessment of malignant pleural mesothelioma treated with neoadjuvant chemotherapy]. / Utilidad de la PET-TAC 18F-FDG en la valoración prequirúrgica del mesotelioma pleural maligno tras quimioterapia neoadyuvante.

Malignant pleural mesothelioma is a relatively rare, but highly aggressive, tumor, associated to exposure to asbestos, with a life expectancy between 9 and 17 months. Chest pain and dyspnea are the most frequent symptoms. The most commonly used therapy is surgery accompanied by chemotherapy. Preoperative assessment, after chemotherapy, has been done using magnetic resonance imaging and computed tomography (CT). However, these techniques cannot predict early response to therapy, because of the slow structural change of the tumor. The aim of this case report is to review and learn about the growing use of PET-CT imaging with (18)F-FDG in the preoperative staging of malignant pleural mesothelioma and its influence in selecting the most appropriate type of surgery.

Radiological assessment following thermoradiation therapy for primary pleural synovial sarcoma: case report.

Primary pleural synovial sarcoma is a rare disease with poor outcomes. Although hyperthermia therapy as part of a combined treatment regimen can offer improved local tumor control, only two reports of hyperthermia therapy for synovial sarcoma have appeared in the literature, and these sarcomas were not of pleuropulmonary origin. This report of an advanced inoperable primary pleural synovial sarcoma is the first to address the use of hyperthermia therapy in combination with chemoradiotherapy for this disease, together with radiological assessment following that therapy. Computed tomography performed after thermoradiation showed a decrease in tumor size and a characteristic unenhanced low-density area in the tumor suggesting that tumor necrosis resulted from the therapy. These image findings were helpful in assessing the tumor response to thermoradiation. We believe that hyperthermia therapy combined with chemoradiotherapy should be regarded as an option for advanced primary pleural synovial sarcoma. This would give computed tomography important role in evaluating this approach.

Utility of integrated computed tomography-positron emission tomography for selection of operable malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a primary malignancy characterized by local invasion of the pleura and metastasis. Despite advances in computed tomography (CT) and magnetic resonance imaging (MRI), accurately staging patients remains challenging. Recent studies have examined the use of integrated CT-positron emission tomography (PET) for staging patients. MATERIALS AND METHODS: Mayo Clinic databases were queried to identify cases with a histologic diagnosis of MPM from 2000 to 2006. Inclusion criteria were a diagnosis of MPM, an available CT scan, and an initial staging integrated CT-PET scan. A total of 35 patients were identified who met the inclusion criteria. Computed tomography and integrated CT-PET scans were reviewed by experienced radiologists. Laboratory parameters were reviewed. The Mayo Clinic tumor registry and Social Security database were queried for survival data in patients in which no follow-up was available. RESULTS: Findings on integrated CT-PET excluded 14 of 35 patients from surgical intervention. Extrapleural pneumonectomies (EPPs) were performed in 8 patients, and partial pleurectomies were performed in 2 patients. Upstaging from integrated CT-PET occurred in 70% of the patients when surgical pathology was available, 2 cases to an inoperable stage. Although not statistically significant, median survival was 20 months for patients undergoing an EPP and 12 months for patients excluded from surgical intervention by integrated CT-PET. CONCLUSION: Malignant pleural mesothelioma is a difficult disease to accurately stage. The most common reason for upstaging in our series was an increase in T (tumor; tumor-node-metastasis staging system) disease. Our data suggest that integrated CT-PET is excellent for detecting nodal and distant metastases. However, the ability of this imaging modality to correctly stage locoregional disease is not superior to the combination of CT and MRI as reported in the literature.

Diagnosis and staging of lung and pleural malignancy - an overview of tissue sampling techniques and the implications for pathological assessment.

Malignant diseases of the lungs and pleura are common causes of morbidity and mortality throughout the developed world. Determining the appropriate treatment strategies for an individual patient requires a multidisciplinary approach integrating input from many disciplines including pathology. In this overview, we discuss diagnosis of lung and pleural malignancy from the pathologist's perspective, placing particular emphasis on methods available to obtain material for pathological assessment, and their implications for diagnosis and provision of information to guide patient management.