Cytomorphological identification of advanced pulmonary adenocarcinoma harboring KRAS mutation in lymph node fine-needle aspiration specimens: Comparative investigation of adenocarcinoma with KRAS and EGFR mutations

초록

BackgroundKirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutation in pulmonary adenocarcinoma is clinically important due to its association with resistance to EGFR inhibitors and poor prognosis. To our knowledge, there has not been a comparative study focusing on cytological nuclear features of pulmonary adenocarcinoma harboring KRAS mutation (KRAS-AD). Hence, we compared the cytomorphology of metastatic KRAS-AD and EGFR-positive adenocarcinoma (EGFR-AD) in aspiration specimens from lymph nodes. MethodsForty lymph node aspiration specimens from forty KRAS-AD patients were collected at Samsung Medical Center (Seoul, Korea) from 2009 to 2013. As a control group, 40 EBUS-FNA lymph node specimens from 20 EGFR-AD patients were collected. EGFR-AD specimens were evaluated at Samsung Medical Center (Seoul, Korea) from 2012 to 2013. All 80 specimens were histologically confirmed to metastatic adenocarcinoma. Two pathologists performed a blinded review of all specimens. ResultsCompared with EGFR-AD, KRAS-AD exhibited more severe nuclear pleomorphism (P<0.001), coarse chromatin (P=0.001), cherry-red nucleoli (P<0.001) and naked tumor cells (P=0.002) with necrotic (P<0.001) and neutrophilic (P=0.008) background. ConclusionsOur study provides the first demonstration of cytomorphologic differentiation between metastatic KRAS-AD and metastatic EGFR-AD in lymph node aspiration specimens. Diagn. Cytopathol. 2015;43:539-544. (c) 2014 Wiley Periodicals, Inc.

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