Accuracy of cell typing in nonsmall cell lung cancer by EBUS/EUS-FNA cytological samples

Endoscopic ultrasound-guided transbronchial or transoesophageal lymph node aspiration is increasingly used as a method of diagnosing nonsmall cell carcinoma. Data validating the accuracy of cell typing of nonsmall cell carcinoma using these cytological samples has not been assessed. 23 samples were identified in Edinburgh, UK and a further 25 in Cambridge, UK, with matching histological samples. The morphological cell type, as assessed on the cytological preparations and cell blocks, was recorded and immunohistochemical staining was performed, where possible, as an adjunct. The final cell type, as assessed by morphology with or without immunohistochemistry, was correlated with that reported in the paired histological samples. Cell blocks with tumour were available in 39 out of 48 cases. The accuracy of cell typing when no cell block was available was four out of nine cases. This increased to 25 out of 39 when a cell block was available, increasing to 33 out of 39 with the addition of immunohistochemistry. The overall accuracy of classification was 37 out of 48 cases. Accurate cell typing of nonsmall cell carcinomas can be performed using endoscopically derived fine-needle aspirates. The importance of obtaining sufficient material for the production of cell blocks is critical in allowing optimal assessment.