A practical guide for ancillary studies in pulmonary cytologic specimens

Abstract

Although most pulmonary cytologic specimens obtained by either exfoliation or fine needle aspirates can be reliably and accurately diagnosed based on pure morphologic criteria alone, a small proportion of cases require ancillary studies for either refining a diagnosis, for resolving a differential diagnosis or increasingly, for predictive purposes in primary lung carcinomas. This article aims to provide practical guidance on the use of common ancillary studies in pulmonary cytologic specimens. Cancer Cytopathol 2018;000:000-000. © 2018 American Cancer Society.

Updated guidelines for predictive biomarker testing in advanced non-small-cell lung cancer: a National Consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

“…The use of cytology specimens has not yet been validated to determine the expression of programmed death ligand-1 (PD-L1), despite the good correlation observed between cytology smears and cell blocks with biopsies [11]. Tissue-sparing protocols are recommended [12,13]. For liquid biopsies, the two key technical factors to maintain optimal preservation of circulating cell-free DNA (cfDNA) are the storage and shipping conditions of the sample, and the elapsed time between specimen extraction and processing [14].…”

Immunocytochemistry for diagnostic cytopathology—A practical guide

“…Most TC and AC are negative for TTF1; however, because occasional peripheral carcinoids can be positive for TTF1, this may lead to an erroneous diagnosis of adenocarcinoma if the neuroendocrine cytomorphological features are not recognised. In contrast to most pulmonary adenocarcinomas, carcinoids are negative for Napsin A 88–91 . While CK5/6 and p40 are typically negative in carcinoids, p63 may be expressed in a small proportion of cases 88–91 .…”

Molecular biomarker testing for non–small cell lung cancer: consensus statement of the Korean Cardiopulmonary Pathology Study Group

“…The main advantage of cell blocks is to allow serial sections for multiple tests. Because most biomarker assays have been validated on FFPE samples, cell blocks do not require additional validation [33][34][35][36][37][38]. Compared to alcohol-fixed cytology samples, the limitations of cell blocks are due to formalin artifacts in DNA and nuclear truncation [33][34][35][36].…”

“…Air dried or alcohol-fixed cytology samples such as smears and cytospins may offer higher quality nucleic acids than cell blocks [33][34][35][36][37][38]. Smears, cytospins, and liquid-based cytology allow an evaluation of the adequacy and cellularity of tumor cells on site and the opportunity to scrape tumor cells by macro/microdissection [33][34][35][36][37][38]. They enable the presentation of whole tumor nuclei for FISH [3].…”