Clinical significance of non-diagnostic pathology results from percutaneous transthoracic needle lung biopsy: experience of a tertiary hospital without an on-site cytopathologist

Background and objective: More non-diagnostic pathology results may be reported following transthoracic needle lung biopsy (TTNB) when no on-site cytopathologist is available. This study was conducted to analyse the final outcomes in patients with non-diagnostic pathology results, and the factors related to the adequacy of specimens. Methods: The medical records of consecutive patients who had undergone TTNB from January 2004 to January 2005 were retrospectively analysed. Non-diagnostic pathology results were classified into three groups: (i) atypical cells, (ii) non-specific inflammation and (iii) inadequate specimen. The final diagnosis and clinical outcome for each patient were analysed after additional diagnostic studies and clinical follow up. Results: TTNB was performed on 291 patients. Specimens were adequate in 256 cases. The results were non-diagnostic for 103 patients, and the percentages of atypical cells, non-specific inflammation and inadequate specimen were 15.5% (16/103), 50.5% (52/103) and 40% (35/103), respectively. In 14 patients (87.5%) the diagnosis of atypical cells was confirmed, and in 10 (62.5%) these were due to malignancies. In two patients (3.8%) the lesions reported as non-specific inflammation were eventually confirmed as malignancies. After repeated attempts to confirm their diagnoses, 22 patients (62.9%) with initial reports of inadequate specimen were diagnosed with specific diseases. Specimen adequacy correlated with technical skill, size of the lesion, guidance method and biopsy method. Conclusions: Non-diagnostic pathology results from TTNB, in the absence of an on-site cytopathologist, are of value in assessing the clinical probability of malignancy and can be useful in the management of lung lesions. However, many other factors should be considered in patients with inadequate specimens.