Endoscopic ultrasound and endobronchial ultrasound-guided fine-needle aspiration of deep-seated lymphadenopathy: Analysis of 1338 cases

Abstract

Background: We retrospectively studied 1338 samples of lymph nodes obtained by endoscopic and endobronchial ultrasound-guided fine needle aspiration biopsy (EUS and EBUS-FNAB) with an objective of characterizing the utility of this diagnostic modality in the assessment of deep-seated lymphadenopathy. The secondary aims were to establish the utility in the diagnosis of lymphoma and to determine the number of passes required to obtain adequate cellularity for flow cytometric analysis.

Materials and methods: On-site assessment was performed by a cytopathologist using Diff-Quik (American Scientific Products, McGraw Park, IL) stain. In addition, Papanicolaou and immunohistochemical stains were performed and additional samples were sent for flow cytometric analyses (n = 145). The final cytologic diagnosis was correlated with surgical pathology diagnosis and/or clinical follow-up. In select cases, fluorescence in situ hybridization analysis with specific probes was performed on Diff-Quik smears.

Results: Both morphology as well as ancillary studies (flow cytometry or immunohistochemical stain and/or fluorescence in situ hybridization) show that EUS and EBUS-FNA are effective techniques to detect and stage intrathoracic and intra-abdominal tumors. Operating characteristics show that these are highly sensitive (89%) and specific (100%) techniques for the diagnosis of lymphoma. At least two passes provided an average of 5.66 million cells (range, 0.12-62.32 million) for lymphoma cases.

Conclusions: EUS and EBUS-FNA are powerful modalities to stage malignancies and at least two passes can provide adequate cells for flow cytometric analysis. We also demonstrate that fluorescence in situ hybridization analysis can be performed on Diff-Quik-stained and mounted smears.

Keywords: Endoscopic ultrasound; endobronchial ulatrsound; fine-needle aspiration; flow cytometry; fluorescence in situ hybridization; lymph node; lymphoma; mediastinum.

Figure 1

A case of CLL/SLL. a) Aspirate smear from an enlarged subcarinal lymph node showing a moderately cellular smear with single small, relatively monomorphous cells (Diff-Quik, ȕ200), b) Aspirate smear showing small cells with clumped chromatin (Diff-Quik, ȕ400), c) Subcarinal lymph node specimen. Scattergram showing distribution of CD5 positivity and CD11c positivity in the gated population of cells, d) Scattergram showing distribution of CD22 positivity and CD23 positivity in the gated population of cells. FITC, fluorescein isothiocyanate; PE, phycoerythrin

Figure 2

A case of FCC. a) Aspirate smear from an enlarged peripancreatic lymph node showing a highly cellular smear with a polymorphous population of cells (Diff-Quik, ×400), b) Aspirate smear showing large and small cells, some with prominent nucleoli (Papanicolaou, ×400), c) Peripancreatic lymph node specimen. Scattergram showing distribution of CD10 positivity and CD19 positivity in the gated population of cells, d) Scattergram showing distribution of κ and λ light chain positivity with a predominance of λ light chain in the gated population of cells. APC, allophycocyanin

Figure 3

Fluorescence in situ hybridization performed on Diff-Quik smears, a) A case of FCC showing a positive IGH/BCL2 fusion for the t(14;18) (q32;q21), b) A case of mantle cell lymphoma demonstrating IGH gene rearrangement but with no evidence of IGH/CCND1 fusion