Molecular cytopathology diagnosis of a lung neoplasm: Case report of an unusual non-small cell carcinoma with MET exon 14 skipping mutation.

Here we report the combined cytological and molecular diagnosis of a lung mass. The cytology and extensive immunohistochemistry on an endobronchial ultrasound-guided fine needle aspiration biopsy were inconclusive. By genomic profiling of the cell block material, we identified a MET exon 14 skipping mutation that indicated a lung origin and made the patient eligible for the tyrosine kinase inhibitor, crizotinib. This case is a prime example of complementing adequate aspiration and cell block processing techniques with molecular testing. Such an approach would augment the usability of fine needle aspiration biopsy, both as a diagnostic modality and as the first line to find therapeutic targets in the era of precision medicine.