Examination of the utility of cryobiopsy for tuberculous pleurisy in thoracoscopy: A report of seven cases.

Thoracoscopy under local anaesthesia is effective for the diagnosis of tuberculous pleurisy (TP), mesothelioma and pleural metastases of lung cancer, etc. It has recently been reported that cryobiopsy is useful for obtaining sufficient tissue, achieving a greater depth, and avoiding crush artefact than biopsy forceps. However, the utility of the tissue obtained by cryobiopsy for culture for diagnosing TP is unknown. We compared positivity rates of tissue culture obtained by biopsy forceps and cryobiopsy in seven TP patients. The median tissue size was 2 mm by biopsy forceps and 6 mm by cryobiopsy. The pathological diagnostic rate of pleural tissue was 85.7% with biopsy forceps and 100% with cryobiopsy. However, the positivity rate of tissue culture was 57.1% with biopsy forceps and 28.5% with cryobiopsy. Since rapid freezing with a cryoprobe makes it difficult for bacteria to grow, it is possible that cryobiopsy might not be useful for obtaining a tissue culture in TP cases. However, since the sample size of this study was small, analysis of more cases is required to confirm our results.