Macroscopic assessment of pulmonary fine needle aspiration biopsies: correlation with cytological diagnostic yield

Fine needle aspiration biopsy (FNAB) is widely used in the diagnosis of pulmonary neoplasia. Previous studies have advocated the use of immediate cytological review at the time of biopsy to reduce the number of needle passes performed, whilst stating that in the absence of this, simple macroscopic assessment of sample quality was used. This latter practice is widespread, but there is no data regarding its accuracy or the level of intra-observer consistency. We assessed the degree of correlation between a macroscopic grading of the FNAB sample at the time of lung biopsy by the radiologist performing the procedure and subsequent diagnostic yield. 45 consecutive patients in whom pulmonary neoplastic disease was strongly suspected were included. Macroscopic sample appearances were graded on a five-point scale from 1 (blood with no particulate material) to 5 (solid tissue pieces). The positivity rate increased stepwise along with macroscopic grading from 50% for samples graded 1 to 100% for samples graded 5. Grouping the predominately haemorrhagic samples (graded 1-2) together and comparing them with the particulate samples (graded 3-5) demonstrates a statistically significant difference in diagnostic yield (p<0.001). This small study shows that a simple macroscopic grading of pulmonary FNAB samples can provide a good indication of likely cytological diagnostic yield and that radiologists can develop a degree of consistency in their assessment. In the absence of direct cytological input, this may provide a basis for decisions on the number of passes performed.