title: The Role of KRAS Mutational Analysis to Determine the Site of Origin of Metastatic Carcinoma to the Lung: A Case Report.
abstract: Metastatic carcinomas involving the lung are a common specimen encountered in surgical pathology. These metastases may have different morphologic, and architectural patterns and may mimic primary pulmonary adenocarcinoma, especially the intra-alveolar (lepidic) pattern of spread which may simulate a primary pulmonary bronchioloalveolar carcinoma (adenocarcinoma in situ). We present the case of a metastatic pancreatic adenocarcinoma that morphologically mimicked bronchioloalveolar carcinoma of the lung in that the tumor had an exclusive intra-alveolar pattern of spread and had an immunophenotype that was noninformative as to the site of origin (cytokeratin 7+, cytokeratin 20-, TTF-1-). In this case, we used KRAS gene mutation analysis to support that the lung carcinoma represented a metastatic pancreatic carcinoma as they both possessed identical codon 12 KRAS mutations. We show that this method may be a useful way to prove site of origin of metastatic carcinoma-particularly if standard morphologic or immunohistochemical analysis is not definitive.
authors.affiliation: Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, P.O. Box 100275, 1600 SW Archer Road, Gainesville, FL 32610, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Alkhasawneh
authors.forename: Ahmed N
authors.initials: AN
authors.lastname: Alkhasawneh
authors.forename: Hui-Jia
authors.initials: HJ
authors.lastname: Dong
authors.forename: Chen
authors.initials: C
authors.lastname: Liu
authors.forename: Carmen
authors.initials: C
authors.lastname: Allegra
authors.forename: Robert W
authors.initials: RW
authors.lastname: Allan