Diffuse malignant pleural mesothelioma:a retrospective clinicopathological analysis of six patients

LIU Qi-liang; HU Yan; LEI Mei

doi:10.3969/j.issn.1007-8096.2023.09.004

Abstract：Objective To investigate the clinicopathological characteristics of diffuse malignant pleural mesothelioma(MPM).Methods The clinical,imaging,pathological features and immunophenotypes were retrospectively analyzed in 6 cases of diffuse MPM with review of the relevant literature.Results Among the 6 cases of MPM,3 were male and 3 were female,with a mean age of 48.3 years,and the patients had chest pain or chest tightness as the main complaint.The imaging findings showed circumferential pleural thickening and pleural effusion.In pleural effusion,lactate dehydrogenase was elevated in 5 cases with a mean of(380.33±196.56)U/L(range 106-245 U/L),total protein was elevated in all cases with a mean of(48.48±11.46)g/L(range 0-25 g/L),and adenosine deaminase was normal in all cases with a mean of(17.4±4.05)U/L(range 0-40 U/L).Patients were treated for tuberculous pleurisy before diagnosis.Specimens were obtained by surgical partial excision(3/6)and thoracoscopic biopsy(3/6).Grossly,the pleural surface showed widely distributed white or slightly transparent mulberry-like nodules of vary ing sizes.The microscopic histological subtypes were all epithelioid,showing tumor cells arranged in unequal proportions as tubular,papillary,follicular,solid lamellar or micropapillary,with ovoid or polygonal tumor cells,eosinophilic and abundant cytoplasm,vesicular nuclei,and small nucleoli visible.Immunohistochemistry result showed positive for Calretinin,WT-l,CK5/6,D2-40,negative for NapsinA,TTF-1,P40,and BAP1 immunolabeling showed nuclear deletion expression in 4 cases.Conclusion Diffuse MPM is rare and highly malignant,easily misdiagnosed as tuberculosis and other diseases,and the diagnosis can be clarified by pathomorphology combined with relevant immunohistochemical markers.