Blind pleural biopsy in combination with cytology of pleural effusions.

The efficiency of a combination of blind pleural biopsy and pleural cytology was examined in a retrospective study of 181 cases observed between 1968 and 1978. The material contained 64 confirmed cases of malignant tumors and 20 of tuberculosis. Of the tumors, 81.3% were diagnosed by one or both methods; 18.7% remained negative. In 53% of the cases, the positive diagnoses corresponded between the two methods; in 26.6% the tumor was found only by cytology and in 10.9%, only by histology. Repeat investigations slightly improved the results with both methods. Reasons for false-negative cytology were bad preservation, fibrosis, nonexfoliative tumors and a mistake of preparation in one case. False-positive results occurred twice in histology, and two cases judged highly suspicious by cytology proved to be clinically negative. In cases of tuberculosis, histologic diagnosis was superior to microbiologic diagnosis.