Cell Block Examination Is Critical for Sarcoidosis Diagnosis by Endobronchial Ultrasound-Guided Mediastinal Lymph Node Fine Needle Aspiration

Abstract

Intrathoracic sarcoidosis is often diagnosed by transbronchial lung parenchymal biopsy (TBBx), however, recent studies suggest endobronchial ultrasound-guided transbronchial fine needle aspiration of mediastinal lymph node (EBUS-FNA) is safer with superior diagnostic yield. We report our experience from 2008 to 2010 with combined EBUS-FNA and TBBx in 61 consecutive patients with clinical suspicion of sarcoidosis. One to three mediastinal lymph nodes (LN) in various locations were sampled using 21/22gauge needles with on-site interpretation. Additional one to two specimens per site were collected in Normosol® for cell block preparations. A definitive diagnosis of sarcoidosis was made in 51 patients (84%) by EBUS-FNA/TBBx studies (46) and clinical information (5); alternative diagnoses were established in 8 patients (13 %); the last 2 patients remained suspicious for sarcoidosis without confirmatory tissue diagnosis. Of the 46 biopsy (EBUS-FNA and/or TBBx) confirmed cases, 37 (80.0%) were diagnosed by EBUS-FNA. Cell blocks prepared from all 37 patients contained diagnostic material, 10 (27.0%) were interpreted as such by on-site evaluations. The diagnostic yield of LNs at different locations varied, being 100, 68, 50 and 20% in R12, subcarinal, R4, and R11, respectively. A total of 36 patients had both EBUS-FNA and TBBx performed during the same visit. Diagnoses were identical in 15 patients (42 %). TBBx independently identified 9 cases of sarcoidosis. This study indicates that cell block preparation is valuable for EBUS-FNA diagnosis of sarcoidosis. EBUS-FNA and TBBx are effective and complimentary tools for intrathoracic sarcoidosis diagnosis.

Contribution of cell block obtained by endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of malignant diseases and sarcoidosis

“…The improved diagnostic yield in granulomatous diseases when CBs are used is due to the fact that when the specimen is allowed to clot, recognition of granulomas is easier than with smear preparations. [ 8 9 ] Wang et al . found that in 37 patients who underwent EBUS-TBNA, 100% of CBs showed nonnecrotizing granulomas, compared to only 27% in smears.…”

“…found that in 37 patients who underwent EBUS-TBNA, 100% of CBs showed nonnecrotizing granulomas, compared to only 27% in smears. [ 9 ] This may be because the smearing of samples between two slides disrupts the epithelioid groups in the FNA samples; this does not tend to occur during CB preparation as sedimentation and paraffin embedding do not disrupt the histological structure. [ 5 ]…”

Endobronchial Ultrasound in the Diagnostic Evaluation of Sarcoidosis

“…It has recently been reported that cell block analysis in addition to the Diff-Quick smear examination can reduce the false negative rate by 33%. Furthermore, Wang et al [8], found that of 37 patients who had EBUS-TBNA carried out, 100% of cell blocks contained non-necrotizing granulomas compared to 27% of smears. This may be because smearing samples between two slides disrupts the epithelioid groups in FNA samples which does not tend to occur during cell block preparation.…”