Molecular profiling of primary and metastatic neoplasms in the lung using cytologic material obtained by fine‐needle aspiration: Report of two cases

Abstract

Two cases are presented in which molecular analyses of cytologic material obtained by fine-needle aspiration were helpful in establishing relationships between morphologically similar neoplasms in the same patient. For appropriate clinical management, it is important to ascertain whether the tumors represent independent primaries or metastases. Alcohol-fixed cytologic material prepared as cell blocks and formalin-fixed paraffin-embedded tissue were microdissected and analyzed for allelic loss of heterozygosity at multiple preselected genetic loci. The first case illustrates a 69-yr-old man with multiple intrapulmonary nodules involving the upper and lower lobes of the left lung. Genomic analysis showed that the neoplasms in the left upper and lower lung lobes were independent primaries, because the loss of heterozygosity (LOH) patterns were substantially different. By contrast, the second case is that of a 58-yr-old man with a right thyroid nodule and multiple pulmonary tumors. LOH analysis confirmed that a sampled pulmonary tumor represented a metastasis from the thyroid primary, as similar LOH patterns involving locus D9S252 were observed on comparison of the thyroid and pulmonary neoplasms. These cases illustrate the practical diagnostic utility of genomic analysis using cytologic material in the assessment of primary and metastatic malignancies.

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“…Powerful molecular techniques including microarray analysis and molecular profiling may have a significant role in the future evaluation of TNs, while providing impetus for further insight into the molecular pathogenesis of both benign and malignant TNs [68-71]. Moreover, such techniques may allow deeper insight into both loss and gain of function of unidentified genes by examining panels of genes rather than one or a limited number of potential gene candidates.…”

“…Molecular profiling may also permit the distinction between primary and metastatic malignancies when dealing with multiple suspicious nodules at various sites. Using material retrieved by FNA, Schoedel et al [71], compared loss of heterozygosity (LOH) patterns and demonstrated genetic kinship of multifocal carcinomas in the thyroid and a separate nodule in the lung, supporting a diagnosis of metastatic thyroid carcinoma to the lung rather than an independent lung neoplasm.…”