CT-guided lung biopsy performed:
Macroscopy: Labelled with patient details only. Two core biopsies 6mm & 18mm.
Microscopy: Both cores show a malignant tumour, with a small amount of alveolated lung tissue. The tumour is in the form of fused glandular arrangements surrounded by a fibroblastic stromal response. Tumour cells have moderately to markedly pleomorphic nuclei with prominent nucleoli and a moderate amount of cytoplasm. The features are of pulmonary adenocarcinoma, acinar pattern.
Conclusion: Lung core biopsy: Adenocarcinoma.
The L858R mutation results in an amino acid substitution at position 858 in EGFR, from a leucine (L) to an arginine (R). This mutation occurs within exon 21, which encodes part of the kinase domain, and occurs with a frequency of approximately 43% in EGFR-mutated lung tumours (Mitsudomi and Yatabe 2010).
Multiple EGFR tyrosine kinase inhibitors (TKIs) have been developed or are in development conferring increased sensitivity.
There is currently no role for EGFR mutation in predicting response in NSCLC
Conclusion: Mutation detected - EGFR c.2573T>G p.Leu858Arg (L858R)