SESSION TITLE: Pleural Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Malignant pleural mesothelioma (MPM) is often detected by the presence of pleural effusion. At the advanced stage of the disease, irregular pleural thickening and/or tumor might be demonstrated by computed tomographic (CT) images, but it is usually difficult to detect MPM in its early stage. We present unusual case of MPM that was considered to be simultaneous occurrence of the bilateral pleura. One was suspected by cytological analysis of pleural effusion, and another was pointed out by fluorodexyglucose positron emission tomographic (FDG-PET) images.
CASE PRESENTATION: A 59-year-old man was referred to our hospital because of left pleural effusion detected at regular medical checkup. He has smoked a little and was exposed to asbestos for 28 years during engaged in the construction industry. A chest X-ray showed left pleural effusion. CT images demonstrated no irregular pleural thickening or pleural tumor on either side of the pleura. FDG-PET images showed mild accumulation of FDG along the right dorsal pleura. The hyaluronic acid level in left pleural effusion was 130,430ng/ml and cytological examination revealed MPM cells. Thoracoscopic pleural biopsy specimen of the left revealed the atypical mesothelial cells with invasion to the adjacent fat layers. Immunohistochemical analyses demonstrated that the tumor cells were positive for calretinin, Wilms’ tumor 1, and CAM5.2, and negative for CEA or thyroid transcription factor 1. Based on these findings, the diagnosis was confirmed as MPM, epithelioid type. Next, he underwent thoracoscopic exploration of the right. There was no visible tumor formation, but pleural biopsy specimen revealed that enlarged atypical mesothelial cells formed pseudoglandular structure and partially invaded to adjacent fat layers. The diagnosis was also confirmed as MPM, epithelioid type, as well as the left. Fluorescence in situ hybridization (FISH) analysis demonstrated no homozygous deletion of p16 in either specimen. The CT and PET images demonstrated no mediastinal lymphadenopathy or distant metastasis. He has been treated with systemic chemotherapy consisted of cisplatin and pemetrexed.
DISCUSSION: In the current case, thoracoscopic exploration revealed MPM in both sides of the pleura. MPM often progress from one side to the other of the pleura in the advanced stage of the disease. However, each lesion in our case was confined to the parietal pleura and was classified as stage IA based on TNM classification by International Mesothelioma Interest Group. So we consider that MPM developed simultaneously in both side of the pleura, though the tumor cells showed similar characteristics in immunohistochemical and FISH analyses. In this case, the CT images did not demonstrate irregular pleural thickening or tumor, but FDG accumulation suggested the disease involvement, and thoracoscopic exploration gave the diagnosis of MPM. The current case demonstrated the utility of PET-CT and thoracoscopic exploration for early diagnosis of MPM. MPM cases of clinical I or II could be candidates for extrapleural pneumonectomy, but it was not suitable in this case because of bilateral simultaneous onset. The clinical implication of less invasive surgical procedures such as pleural decortication in such situation might be worthy of consideration.
CONCLUSIONS: We reported the rare manifestation of simultaneous occurrence of bilateral MPM.
Reference #1: Gemba K, et al. Treatment and survival analyses of malignant mesothelioma in Japan. Acta Oncologica 2012 (in press)
DISCLOSURE: The following authors have nothing to disclose: Yasuko Fuchimoto, Nobukazu Fujimoto, Michiko Asano, Katsuichiro Ono, Shinji Ozaki, Shin Hirayama, Hideyuki Nishi, Takumi Kishimoto
No Product/Research Disclosure Information