Long-term outcomes and risk factors of residual thoracic spaces after pleurectomy/decortication for mesothelioma.

OBJECTIVES: The residual thoracic spaces (RTS) after pleurectomy/decortication (P/D) remain unexplored to date. Hence, this study aims to examine the details and risk factors of RTS during the 3 post-P/D months. METHODS: We retrospectively examined patients who underwent neoadjuvant chemotherapy, followed by P/D for malignant pleural mesothelioma from September 2012 to December 2020. The RTS group included cases of residual thoracic cavity unaccompanied by pleural effusion on 3 postoperative months computed tomography. We determined risk factors for RTS using univariable and multivariable analyses. RESULTS: Of 170 patients examined, 58 (34.1%) were in the RTS group and 112 (65.9%) in the non-RTS group. In the RTS group, 43 patients recovered from RTS during the follow-up period; 4 patients developed chronic fistular empyema, while 2 required fenestration and 2 were thoracoscopic debridement. Besides, 11 patients exhibited RTS continuously. The univariable analysis revealed that compared with the non-RTS group, the RTS group reported a significantly longer postoperative air leak (>7 days; P < 0.01) and right P/D (P = 0.04). The multivariable analysis demonstrated that longer postoperative air leak (>7 days) remained a risk factor for RTS (odds ratio 2.5, 95% confidence interval: 1.3-4.9, P < 0.01). CONCLUSIONS: RTS was a postoperative event that frequently observed in patients undergoing P/D. Overall, the current study findings suggest longer postoperative air leak (>7 days) as a significant risk factor for RTS.

Incidence and Risk Factors of Chest Wall Metastasis at Biopsy Sites in Patients with Malignant Pleural Mesothelioma.

To investigate the incidence and risk factors of chest wall metastasis (CWM) at biopsy sites in patients with malignant pleural mesothelioma (MPM). This retrospective cohort study was conducted in 262 consecutive MPM patients who underwent multimodal treatment in which including neoadjuvant chemotherapy (NAC) and curative-intent surgery, from August 2009 to March 2021. CWM was evaluated radiologically (r-CWM) and pathologically (p-CWM). We also investigated the risk factors of p-CWM and the consistency between r-CWM and p-CWM. Of 262 patients, 25 patients were excluded from analysis due to missing data or impossibility of evaluation. Of the eligible 237 patients, pleural biopsy was performed via video-assisted thoracoscopic surgery in 197 (83.1%) and medical thoracoscopy in 40 (16.9%). Pleurodesis was performed after pleural biopsy in 74 patients (31.2%). All patients received NAC followed by curative-intent surgery. Radiological examination showed r-CWM in 43 patients (18.1%), while pathological examination showed p-CWM in 135 patients (57.0%). The incidence of p-CWM was significantly higher in the patients who received pleurodesis after pleural biopsy (77.0% vs. 47.9%, <0.001). Multivariate logistic regression analysis for p-CWM revealed that pleurodesis is an independent risk factor of p-CWM (adjusted hazard ratio, 3.46; 95% confidence interval, 1.84−6.52, <0.001). CWM at the biopsy site was pathologically proven in more than half of the patients (57.0%) who received NAC followed by curative-intent surgery, which was higher than the numbers diagnosed by radiological examinations (p-CWM: 57.0% vs. r-CWM: 18.1%). Pleurodesis after pleural biopsy is an independent risk factor of p-CWM.

Control of air leakage during pleurectomy/decortication by the ventilation and anchoring method.

OBJECTIVES: We previously established a novel method of lung repair called the ventilation and anchoring (V/A) method. We evaluated the usefulness of the V/A method for controlling air leakage during pleurectomy/decortication (P/D). METHODS: For this study, we enrolled patients with malignant pleural mesothelioma (MPM) who planned to receive P/D. Our lung repair method involves (1) suturing lung parenchyma for an apparent injured lesion and (2) coating the lung parenchyma with fibrin glue (FG) using the V/A method. The tidal volume (TV) was measured under pressure-controlled ventilation in the ipsilateral-affected lung 10 times at the following four points: after thoracotomy, at completion of visceral pleurectomy, after suturing lung parenchyma, and 5 min after coating with FG. The primary endpoint was the mean TV (mTV) change, and the secondary endpoints were the duration of air leakage and incidence of pleurodesis. RESULTS: Between April 2014 and April 2016, 25 patients of the 29 consecutive patients enrolled were eligible. The mTV significantly decreased after completion of visceral pleurectomy but significantly increased after repair of the lung parenchyma, especially after coating with FG. The median duration of postoperative air leakage was 4 days (range: 2-19 days). Postoperative air leakage > 7 days was observed in 11 (44%) patients. Of these 11 patients, 6 received pleurodesis; however, no further revision was needed. CONCLUSIONS: Significant increases in TV were observed after coating with FG via the V/A method during P/D. Coating with FG using the V/A method can contribute to a reduction in air leakage during P/D.

Relationship Between Physical Function and Health Utility in Patients Undergoing Surgical Treatment for Malignant Pleural Mesothelioma.

PURPOSE: Health utility, which is a measure of patient-reported outcome (PRO), has recently been used in health-related quality of life for patients with various cancers. However, the relationship between health utility and the physical function and of patients undergoing pleurectomy/decortication (P/D) as surgical treatment for malignant pleural mesothelioma (MPM) has not been reported in the perioperative and convalescent phases. This study aimed to evaluate the perioperative and postoperative health utility of patients undergoing P/D for MPM at one year postoperatively and to examine the relationship with physical function. METHODS: We included patients underwent P/D. Grip strength, knee extension strength, 6-minute walk distance (6MWD), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) were measured to assess physical function, and the Short-Form Six-Dimension (SF-6D) was completed to assess health utility. These assessments were performed preoperatively, postoperatively, and one year postoperatively. Statistical analysis was performed using one-way analysis of variance for comparison of pre and postoperative and one year mean values. RESULTS: There were 24 subjects (23 males, 65.5±8.3 year). SF-6D, 6MWD, FVC, and FEV1 values one year operatively improved significantly compared with postoperative. Additionally, SF-6D was correlated with 6MWD. CONCLUSION: Health utility were also correlated with exercise capacity.

Quality of life and lung function after pleurectomy/decortication for malignant pleural mesothelioma.

OBJECTIVES: Impact of pleurectomy/decortication (P/D) on quality of life (QOL) is not widely reported. We investigated QOL and lung function after P/D. METHODS: A single-centre, retrospective cohort study was performed among patients who underwent P/D for malignant mesothelioma between June 2014 and June 2018 at Hyogo College of Medicine. Data at 4 points before and 3, 6 and 12 months on QOL and lung function were evaluated with the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and pulmonary function tests. RESULTS: Forty-five out of 65 patients completed SF-36. Physical function and role physical decreased from 78 to 65 and 69 to 41 and did not recover. Body pain decreased from 74 to 52. It increased to 62 at 12 months but was lower than before. General health perceptions, vitality and social function decreased from 56 to 49, 50 to 47 and 63 to 50, respectively, but returned to baseline. Role emotional decreased from 75 to 54, then once increased to 63, but decreased again to 58. Mental health tended to improve from 58 to 70. Thirty-eight patients out of 45 completed pulmonary function tests. Forced vital capacity and forced expiratory volume in 1 s decreased from 98% to 61% and 93% to 67% and did not increase. Right-sided surgery or complications was the risk factors of poor lung function but no significant risk factors in QOL. CONCLUSIONS: This study suggests that P/D had an impact on QOL. Despite the lack of recovery in lung function QOL in mental aspects tended to improve, suggesting that pulmonary function tests alone are limited in assessing QOL.

Complications and Predictive Factors for Air Leak > 10 Days with Neoadjuvant Chemotherapy Followed by Pleurectomy/Decortication for Malignant Pleural Mesothelioma.

BACKGROUND: A few studies have reported the incidence and clinical implications of complications after pleurectomy/decortication (P/D). OBJECTIVE: The aim of this study was to assess the details of complications and predictive factors of particularly durable air leak with P/D. METHODS: Data on 163 consecutive patients who underwent neoadjuvant chemotherapy (NAC) followed by P/D for malignant pleural mesothelioma between September 2012 and May 2020 at our institution were retrospectively analyzed. Postoperative complications and the significance of various preoperative risk factors for air leak > 10 days (AL10) to identify the group having a higher risk for particularly durable air leak were investigated. Risk factors for AL10 were sought using univariate and multivariate analyses. RESULTS: Of 163 patients, 30- and 90-day mortality was 0.6% and 2.5%, respectively. Eighty-four (51.4%) patients experienced grade III or worse postoperative complications according to the Clavien-Dindo classification. The median duration of air leak was 7 postoperative days. AL10 occurred in 53 (32.5%) patients. Fifty-eight patients (35.6%) underwent pleurodesis and five patients (3.1%) underwent reoperation to control the air leak. On univariate analysis, performance status (PS; p = 0.003), prognostic nutritional index (p = 0.01), and pleural effusion (p = 0.04) were statistically significant risk factors for AL10, while on multivariate analysis, PS (odds ratio 4.0, 95% confidence interval 1.3-12.7; p = 0.02) remained the only variable predicted for AL10. CONCLUSIONS: Recent postoperative mortality rates in NAC followed by P/D are quite acceptable. Approximately one in every three patients experienced AL10, and PS may be a risk factor associated with AL10.

Three tumor markers for improved efficacy in the management of patients with malignant pleural mesothelioma.

BACKGROUND: Evaluation of tumor markers may facilitate follow-up of malignant pleural mesothelioma (MPM). We aimed was to evaluate the value of tumor markers for monitoring and predicting recurrence in patients with MPM. METHODS: In total, 152 patients who underwent curative-intent surgery after induction chemotherapy for MPM between July 2004 and December 2017 were retrospectively reviewed. Preoperative and postoperative (≤3 months after surgery) levels of soluble mesothelin-related peptide (SMRP), cytokeratin 19 fragment (Cyfra21-1), and tissue polypeptide antigen (TPA) and rates of recurrence and non-recurrence were evaluated. Factors associated with recurrence-free survival (RFS) were assessed using the Kaplan-Meier method and Cox proportional hazards model. RESULTS: Of the 152 patients, the positive rates of preoperative SMRP, Cyfra21-1, and TPA, levels were 26.7%, 8.6%, 9.6%, respectively; the respective postoperative levels were 4.0%, 6.3%, and 6.5%; the respective levels in patients with recurrence were 39.3%, 31.4%, 28.6%; the respective levels in patients with no recurrence were 3.7%, 0.0%, 3.8%. Nearly half (45.2%) of the patients with recurrence exhibited an increase in one or more tumor marker levels. Multivariate analysis revealed that the preoperative positive rates of one or more of the three tumor markers (hazard ratio: 1.8, 95% confidence interval: 1.1-2.8; P=0.02) were independent significant predictors of recurrence. CONCLUSIONS: The positive rates of SMRP, Cyfra21-1, and TPA in recurrence-free patients were extremely low, with high specificity. Preoperative levels of SMRP, Cyfra21-1, and TPA, which identified patients with a high risk for recurrence, could improve management of patients with MPM.

Initial evaluation of nivolumab in patients with post-operative recurrence of malignant pleural mesothelioma.

BACKGROUND: Limited options exist for treating post-recurrence patients with malignant pleural mesothelioma (MPM). This study aimed to evaluate the efficacy and feasibility of nivolumab in patients with post-operative recurrence of MPM in a real-world setting. METHODS: This study included 35 patients with post-operative recurrence of MPM. Treatment consisted of 240-mg intravenous nivolumab administration every 2 weeks until progressive disease (PD) or serious adverse events (AEs). Additional post-treatment data were evaluated, including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), post-treatment survival and AEs. Tumor response was assessed using the modified Response Evaluation Criteria in Solid Tumors. Survival analysis was performed using the Kaplan-Meier method. The feasibility analysis including AEs was performed with the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. RESULTS: Of the 35 patients who received nivolumab, median follow-up was 6 months. The median treatment duration was 3 months (range: 1-14 months), and median of 8 cycles (range: 2-32 cycles) was administered. Best overall responses were follows: 1 patient had complete response, 6 had partial response, 18 had stable disease and 8 had PD. The ORR was 20.0%, and the DCR was 77.1%. The median overall survival and PFS were 13.1 and 4.4 months, respectively. There were grade-3 AEs in four patients (11.4%). No grade-4 or -5 AEs were observed. CONCLUSION: Nivolumab treatment in patients with post-operative recurrence of MPM seems safe and clinical efficacy.

Clinical feature of diagnostic challenging cases for pleural biopsy in patient with malignant pleural mesothelioma.

OBJECTIVE: Pleural biopsy through video-assisted thoracic surgery (VATS pleural biopsy) is the most reliable diagnostic procedure for malignant pleural mesothelioma (MPM). However, definitive diagnosis of MPM is occasionally difficult to establish. This study aims to investigate clinicopathological features of MPM patients who failed diagnosis by the first VATS pleural biopsy. METHODS: Four hundred consecutive patients with suspected MPM who received VATS pleural biopsy between March 2004 and July 2017 were enrolled in this retrospective study. Patients, whose histological diagnoses were not definitive in the first VATS pleural biopsy, were followed up as atypical mesothelial proliferation (AMP) or non-specific pleuritis (NSP). Re-examination was performed in cases strongly suspected of having MPM. RESULTS: Of the 400 patients, 267 (66.8%) were pathologically diagnosed with MPM, 25 with metastatic carcinoma and 6 with benign pleural disease by the first VATS pleural biopsy. Of the remaining 102 patients diagnosed with AMP or NSP, 10 patients (9.8%) were subsequently diagnosed with MPM. Analysis of the clinical course revealed that only insufficient tissue for diagnosis was obtained via VATS pleural biopsy in all cases and that it was caused by very early stage without visible tumour in 4 patients, intrathoracic inflammation in 4 and desmoplastic MPM in 2. CONCLUSIONS: In our review, 9.8% of patients diagnosed with AMP or NSP in first VATS pleural biopsy were subsequently diagnosed with MPM due to insufficient tissue for diagnosis. Definitive diagnosis via VATS pleural biopsy is sometimes challenging in following situation; very early stage, intrathoracic inflammation and desmoplastic MPM.

Clinical Outcomes With Recurrence After Pleurectomy/Decortication for Malignant Pleural Mesothelioma.

BACKGROUND: Most patients with malignant pleural mesothelioma experience recurrence after treatment. However no clinical studies have evaluated postrecurrence survival after pleurectomy/decortication for malignant pleural mesothelioma. This study aimed to clarify postrecurrence survival, treatment, prognostic factors, and recurrence pattern after pleurectomy/decortication. METHODS: We conducted a retrospective cohort study of 90 patients who underwent neoadjuvant chemotherapy followed by pleurectomy/decortication at our hospital between September 2012 and December 2017. Survival and recurrence were calculated using the Kaplan-Meier method with the log-rank test. Clinical factors related to postrecurrence survival were assessed using multivariate analysis with the Cox proportional hazards model. RESULTS: Of 90 patients, 57 (63.3%) developed recurrence. The 1- and 3-year recurrence-free survival rates were 69.7% and 34.0%, respectively (median recurrence-free survival time, 19.0 months). With regard to initial recurrence, 39 patients (68.4%) developed local recurrence, 6 (10.5%) developed distant recurrence, and 12 (21.1%) developed both local and distant recurrences. The 1-year postrecurrence survival rate was 59.5% (median post-recurrence survival time, 14.4 months). Forty-three patients (75.4%) underwent a postrecurrence treatment. Multivariate analysis revealed that postrecurrence treatment (hazard ratio, 0.2; 95% confidence interval, 0.07-0.55; P = .002), performance status 0 to 1 (hazard ratio, 0.24; 95% confidence interval, 0.08-0.76; P = .01), and disease-free interval more than 12 months (hazard ratio, 0.4; 95% confidence interval, 0.16-0.99; P = .04) were the independent, favorable, and significant prognostic factors of postrecurrence survival. CONCLUSIONS: Postrecurrence survival after pleurectomy/decortication is acceptable, and postrecurrence treatment, performance status, and disease-free interval are important prognostic factors of postrecurrence survival.

The mTOR Signaling Pathway Is Associated With the Prognosis of Malignant Pleural Mesothelioma After Multimodality Therapy.

BACKGROUND/AIM: We performed multimodality therapy comprising preoperative chemotherapy, extrapleural pneumonectomy (EPP), and radiation therapy for patients with malignant pleural mesothelioma (MPM). Although multimodality therapy resulted in good prognosis, further improvement is required. Therefore, herein, we analysed the prognostic factors using surgical specimens and searched for suitable molecular targets to improve the prognosis after multidisciplinary treatment. PATIENTS AND METHODS: Forty-six patients with MPM underwent multimodality therapy. Paraffin-embedded surgical samples were used for immunohistochemistry to evaluate the expression of phosphorylated (p-) AKT, extracellular signal-regulated kinase (ERK), mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK), eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), and S6 ribosomal protein (S6RP). RESULTS: On univariate and multivariate analyses, significant differences were observed according to the histological type, pathological stage, and p-mTOR expression rate. CONCLUSION: The prognosis of MPM is affected by p-mTOR expression, suggesting that molecular-targeted treatment might be used during multimodal therapy for MPM.

Physical function and health-related quality of life in the convalescent phase in surgically treated patients with malignant pleural mesothelioma.

PURPOSE: According to reports, patients with lung cancer have decreased pulmonary function and exercise capacity after surgery. However, to date, physical function and health-related quality of life (HRQOL) after surgery for malignant pleural mesothelioma (MPM) have not been evaluated in detail in the convalescent phase. This study aimed to assess physical function and HRQOL of MPM patients following pleurectomy/decortication (P/D) in the convalescent phase. METHODS: The study included 16 male MPM patients who underwent P/D between September 2014 and August 2016. Physical function was assessed based on handgrip and knee extensor strengths, the six-minute walk distance (6MWD), and pulmonary function, including forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). HRQOL was assessed using the Medical Outcome Study 36-item Short Form Health Survey (SF-36). The assessment was performed preoperatively, postoperatively, and 1-year after surgery. RESULTS: The 6MWD, FVC, and FEV1 values 1-year postoperatively improved significantly compared with baseline (P < 0.05 all). Additionally, the scores of six of the eight SF-36 domains were significantly improved 1 year after P/D: physical functioning, body pain, general health, vitality, social functioning, and mental health (all P < 0.05). 6MWD, FVC, and FEV1 were correlated with vitality, mental health, and physical functioning (P < 0.05 all). CONCLUSIONS: Patients with MPM who underwent P/D showed improved physical function and HRQOL compared with postoperative values in the convalescent phase. Physicians, nurses, and rehabilitation staff should note these findings, which may provide insight into the development of customized rehabilitation strategies in the convalescent phase for such patients.

Surgical Risk and Survival Associated With Less Invasive Surgery for Malignant Pleural Mesothelioma.

We compared less invasive surgery with conventional surgery for malignant pleural mesothelioma (MPM). We retrospectively reviewed consecutive patients with MPM who received surgery at Hyogo College of Medicine between July 2004 and April 2016. Patients underwent multimodal treatment comprising chemotherapy (neoadjuvant and/or adjuvant) and surgery with or without 54 Gy hemithoracic radiotherapy. Patients were grouped into 3 groups according to the surgery intended: Conventional extrapleural pneumonectomy was intended in Group 1 (until August 2009); less invasive extrapleural pneumonectomy was intended in Group 2 (after September 2009); pleurectomy/decortication was intended in Group 3 (after September 2012). We included 152 patients (median age 64 [37-71] years; 131 men, 21 women), mostly with epithelioid subtypes (91.4%). Of them, 149 (98.0%) underwent neoadjuvant chemotherapy and 117 (77.0%) underwent surgery (60 had extrapleural pneumonectomy and 57 had pleurectomy/decortication). Macroscopic complete resection was achieved in 94.9% (111/117), and the mortality rates at 30 and 90 days were 1.7% (2/117) and 3.4% (4/117), respectively. The overall median survival time and progression-free survival for all 152 patients were 34.9 and 17.4 months. The overall median survival time for Groups 1, 2, and 3 were 18.5, 41.9, and 43.4 months, respectively. The progression-free survival for Groups 1, 2, and 3 were 12.0, 24.5, and 21.8 months, respectively. Compared with conventional surgical techniques, less invasive surgery for MPM yielded lower surgical risks and comparable or improved survival.

Pleural thickness after neoadjuvant chemotherapy is a prognostic factor in malignant pleural mesothelioma.

OBJECTIVES: Definitive diagnosis of the T-component is sometimes challenging in malignant pleural mesothelioma (MPM). Pleural thickness has been reported to be a prognostic factor for MPM and is a potential T-component. METHODS: We conducted a historical cohort study of patients who underwent neoadjuvant chemotherapy (NAC) and curative-intent surgery as a multimodal treatment for MPM from January 2007 to June 2016. The maximum measurement of pleural thickness among 3 levels and the sum at each level determined using axial computed tomography imaging before and after NAC were termed as "max" and "sum," respectively. We assessed the association between pleural thickness and the primary and secondary end points of overall survival and recurrence-free survival. Survival was analyzed using the Kaplan-Meier curve, log rank test, and multivariate Cox regression model. RESULTS: We enrolled 105 patients. We excluded 1 because of missing data; thus, the sample size was 104. The median follow-up period was 29.1 months with recurrence in 78 patients (70.3%) and death in 67 (60.4%). Max and sum ranged from pre (before NAC) values of 0 to 35 (median, 6.05) and 0 to 97 (median, 12.9) to post (after NAC) values of 0 to 30.8 (median, 4.25) and 0 to 67.0 (median, 9.25), respectively. Post values max and sum were associated with overall survival and recurrence-free survival. Post sum values were associated with recurrence (adjusted hazard ratio, 2.59; 95% confidence interval, 1.42-3.83) and death (adjusted hazard ratio, 2.13; 95% confidence interval, 1.16-4.52), respectively. CONCLUSIONS: Pleural thickness after NAC was an independent prognostic factor in patients who underwent multimodal treatment.

Poor Prognostic Factors in Patients with Malignant Pleural Mesothelioma Classified as Pathological Stage IB According to the Eighth Edition TNM Classification.

INTRODUCTION: The change in TNM classification of malignant pleural mesothelioma (MPM) between the seventh and eighth edition classifications has resulted in the downstaging of many advanced-stage patients into pathological stage IB. Many mesotheliomas without lymph node metastasis have been classified as stage IB in the eighth edition classification. Stage IB mesotheliomas comprised a heterogeneous group with different prognosis. It is necessary to clarify the prognostic factors in this group. METHODS: Between September 2009 and August 2016, a total of 89 patients with MPM underwent curative intent surgery [pleurectomy decortication n = 57 (64.1%), extrapleural pneumonectomy n = 32 (35.9%)] at our institution. Of these, 40 were reclassified as stage IB according to the eighth edition TNM classification. Independent unfavorable prognostic factors were identified by univariate analyses using the log-rank test and Cox proportional hazards regression models. RESULTS: Three independent significant factors were identified that indicated an unfavorable prognosis: a nonepithelioid subtype, lymphovascular invasion, and preoperative forced expiratory volume in 1 s (FEV1) < 2000 ml. Patients with no, one, and two of these risk factors showed 3-year overall survival probabilities of 94.7, 62.5, and 0%, respectively. The 3-year survival of patients with one factor did not differ significantly from that of patients with stage III MPM, whereas that of patients with two factors was significantly shorter (p = 0.015). CONCLUSIONS: Independent poor prognostic factors for patients with stage IB MPM patients, allowing subgroups with poorer and more favorable prognoses to be identified. This should help personalize decisions on adjuvant chemotherapy.

Fluorodeoxyglucose versus Choline Positron Emission Tomography/Computed Tomography Response Evaluation in Two Malignant Pleural Mesothelioma Patients Treated with Talc Pleurodesis and Neoadjuvant Chemotherapy.

Talc pleurodesis has been reported to increase fluorodeoxyglucose (FDG) uptake in the high attenuation areas of pleural thickening, making it difficult to distinguish between benign granulomatous inflammatory processes and malignancies, which may therefore interfere with the post-chemotherapy disease evaluation on FDG-positron emission tomography/computed tomography (PET/CT). We present two cases of malignant pleural mesothelioma treated with talc pleurodesis and neoadjuvant chemotherapy (NAC) before pleurectomy/decortication in which post-NAC FDG-PET/CT showed intense FDG uptakes in the high attenuation areas of pleural thickening with false positive result, whereas post-NAC 11C-choline PET/CT showed mild choline uptake of pleural talc deposit, which did not interfere with the post-chemotherapy disease evaluation. Thus we suggest choline-PET/CT may show little choline uptake to granulomatous inflammation and evaluate treatment response in malignant pleural mesothelioma patients treated with talc pleurodesis and NAC.

Lung metastases in an atypical type A thymoma variant.

A 35-year-old woman had undergone extensive thymothymectomy for type A thymoma several years ago. However, two small lung nodules were found 4 and 5 years after surgery. After a partial lung resection to remove these nodules, pathology revealed that they were metastases of the type A thymoma. A pathological re-evaluation confirmed that the primary tumor had in fact been an atypical type A thymoma variant, a subset added to the WHO classification in 2015. Pathology should be re-evaluated in all patients diagnosed with type A thymoma before 2015 since they may have the more aggressive atypical type A thymoma variant.