Nonsmall cell lung carcinoma: diagnostic difficulties in small biopsies and cytological specimens: Number 2 in the Series "Pathology for the clinician" Edited by Peter Dorfmüller and Alberto Cavazza

Abstract

The pathological and molecular classification of lung cancer has become substantially more complex over the past decade. For diagnostic purposes on small samples, additional stains are frequently required to distinguish between squamous cell carcinoma and adenocarcinoma. Subsequently, for advanced nonsquamous cell nonsmall cell lung carcinoma (NSCLC) patients, predictive analyses on epidermal growth factor receptor, anaplastic lymphoma kinase and ROS1 are required. In NSCLCs negative for these biomarkers, programmed death ligand-1 immunohistochemistry is performed. Small samples (biopsy and cytology) require "tissue" management, which is best achieved by the interaction of all physicians involved.

FIGURE 1

Testing algorithm integrating diagnostic and predictive analysis in nonsmall cell lung cancer (NSCLC). Note the financial implication: the costs for predictive testing are added to those for diagnostic testing. FFPE: formalin-fixed paraffin-embedded; IHC: immunohistochemical; TTF: thyroid transcription factor; EGFR: epidermal growth factor receptor; HER: human epidermal growth factor receptor; ALK: anaplastic lymphoma kinase; NGS: next-generation sequencing; PD-L: programmed death ligand; FISH: fluorescence in situ hybridisation; NTRK: neurotrophic tropomyosin receptor kinase.

FIGURE 2

Histological and molecular subtypes in nonsmall cell lung carcinoma (NSCLC). SqCC: squamous cell carcinoma; AdC: adenocarcinoma.

FIGURE 3

Transthoracic needle biopsy of lung adenocarcinoma: all tumour cells are stained with 5A4 clone (anaplastic lymphoma kinase (ALK) immunohistochemistry (IHC)) original magnification a) ×40 and b) ×200 (Ventana, Tucson, AZ, USA); c) split signals are observed in >15% of the tumour cells by fluorescence in situ hybridisation (FISH) using break-apart probe. d) Biopsy of another patient with adenocarcinoma, where nearly all tumour cells are all stained by D4D6 clone (ROS1 IHC Ventana; original magnification ×200); e) split signals are observed in >15% of the tumour cells by FISH using break-apart probe (ZytoVision, Bremerhaven, Germany).

FIGURE 4

Predictive biomarker analyses in cytological specimens. a) Anaplastic lymphoma kinase (ALK) immunohistochemistry (IHC) on a formalin-fixed paraffin-embedded cell block and b) corresponding ethanol-fixed and previously Papanicolaou-stained cytological smear of a pulmonary adenocarcinoma (pleural effusion; Leica 5A4 antibody (Leica Biosystems, Newcastle upon Tyne, UK) on Ventana Benchmark XT (Tucson, AZ, USA) and Leica Bondmax automated immunostainers, respectively). c) ALK rearrangement shown by fluorescence in situ hybridisation (FISH) (two single red signals without corresponding green signals and two normal fusion signals per cell nucleus; break-apart FISH probe (Abbott Molecular, Abbott Park, IL, USA)). d) Papanicolaou-stained smear of ROS1-positive adenocarcinoma and e) corresponding ROS1 IHC (pleural effusion; Cell Signaling D4D6 antibody (Danvers, MA, USA) on Leica Bondmax automated immunostainer). f) Ethanol-fixed and previously Papanicolaou-stained smear with membranous and cytoplasmic positivity for programmed death ligand-1 positivity in a fraction of tumour cells (endoscopic ultrasound guided transbronchial fine-needle aspiration; Ventana SP142 antibody on Leica Bondmax automated immunostainer). a), b), d), e), f) Original magnification ×400; c) original magnification ×1000.

FIGURE 5

Tissue management interaction between the sample collector and the pathologist. Reproduced and modified from [127] with permission.