Aims: To evaluate the diagnostic accuracy of closed and open pleural biopsies in diagnosing malignant pleural mesothelioma.
Methods and results: The autopsy study group comprised 45 malignant mesotheliomas. All prior pleural biopsy investigations were reviewed. Forty-one of 45 (91%) had had an antemortem diagnosis of malignant mesothelioma. In these 41 cases, 57 prior diagnostic pleural biopsies had been performed [36 closed needle biopsies: 31 blind; five computed tomography (CT)-guided and 21 open pleural biopsies]. For definitive diagnosis open pleural biopsy yielded a sensitivity of 95% and specificity of 100%. For definitive diagnosis closed blind pleural biopsies yielded a sensitivity of 16% and specificity of 94%. Thirty-two per cent of ‘blind’ biopsies were inadequate. CT-guided pleural biopsies yielded a definitive diagnostic accuracy of 100% (5/5). Biopsy specimen size was important in obtaining a positive definitive diagnosis. Diagnosis was attained in 75% of specimens >10 mm in size compared with 8% <10 mm in size.
Conclusions: Overall, all procedures had utility but definitive diagnostic accuracy for ‘blind’ closed pleural biopsy was low (16%), dependent on biopsy specimen size and tumour subtype. Sarcomatoid subtype malignant mesothelioma yielded the lowest diagnostic accuracy. For all subtypes of malignant mesothelioma, open pleural biopsy produced the highest diagnostic accuracy (100% sensitivity, 95% specificity).