As a modern phenomenon, there is currently limited understanding of the possible toxic effects and broader implications of electronic nicotine delivery systems (ENDS). Large volumes of aerosolized particles are inhaled during “vaping” and there are now an increasing number of case reports demonstrating toxic effects of ENDS, as well as human studies demonstrating impaired lung function in users. This article presents a case of respiratory bronchiolitis interstitial lung disease (RB‐ILD) precipitated by vaping in a 33‐year‐old male with 10 pack years of traditional cigarette and prior treatment for mixed germ cell tumour. The patient had started vaping 10–15 times per day while continuing to smoke 10 traditional cigarettes per day. After 3 months of exposure to e‐cigarette vapour, chest computed tomography demonstrated multiple new poorly defined pulmonary nodules with fluffy parenchyma opacification centred along the terminal bronchovascular units. Video‐assisted thoracoscopy with lung biopsy of the right upper and right middle lobes was undertaken. The microscopic findings were overall consistent with RB‐ILD. This case demonstrates toxicity with use of ENDS on open lung biopsy with resolution of radiographic findings on cessation. We believe that this is the first case where open lung biopsy has demonstrated this and our findings are consistent with RB‐ILD.

Background: Next-generation sequencing (NGS) in lung cancer specimens from endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is usually performed on formalin-fixed paraffin-embedded cell block material. Objectives: Since DNA can be damaged by this process, we investigated the potential of using DNA extracted from Diff-Quik cytology smears made for rapid on-site evaluation during EBUS-TBNA. Methods: In a prospective study, 67 patients undergoing diagnostic EBUS-TBNA were ana­lysed. We compared cell blocks and smears for DNA yields and sequencing (TruSeq Amplicon Cancer Panel) outcomes. Smears were also evaluated for tumour cell fraction and overall cellularity (cell count). Results: Primary lung cancer was diagnosed in 64 patients and metastatic malignancy in 3 patients. The DNA yield from smears was significantly higher than that obtained from matched cell blocks (mean 1,740 vs. 434 ng; p = 0.001). For 33 cases with matched smears and cell blocks the mutation profiles were similar. Smears with abundant malignant cells (using a cut-off of > 25% tumour cell fraction and > 1,000 cells) accurately predicted high (> 50 ng) DNA yield and therefore success in triaging samples to sequencing. In terms of tissue workflow, using only smears as source DNA for sequencing was an improvement in the use of only cell blocks (54/67 [80.6%] vs. 41/67 [61.2%]); however, the use of cell blocks when smears were not available or did not yield sufficient DNA further improved the success rate to 62/67 (92.5%) cases. Conclusion: We recommend smears in laboratory workflows as the primary source of DNA for NGS following an EBUS procedure.

Background Cytology smears are commonly collected during endobronchial ultrasound–guided transbronchial needle aspiration (EBUS TBNA) procedures but are rarely used for molecular testing. Studies are needed to demonstrate their great potential, in particular for the prediction of malignant cell DNA content and for utility in molecular diagnostics using large gene panels. Methods A prospective study was performed on samples from 66 patients with malignant lymph nodes who underwent EBUS TBNA. All patients had air‐dried, Diff‐Quik cytology smears and formalin‐fixed, paraffin‐embedded cell blocks collected for cytopathology and molecular testing. One hundred eighty‐five smears were evaluated by microscopy to estimate malignant cell percentage and abundance and to calculate smear size and were subjected to DNA extraction. DNA from 56 smears from 27 patients was sequenced with the TruSight Oncology 500 assay (Illumina). Results Each microscopy parameter had a significant effect on the DNA yield. An algorithm was developed that predicted a >50‐ng DNA yield of a smear with an area under the curve of 0.86. Fifty DNA samples (89%) with varying malignant yields were successfully sequenced. Low‐malignant‐cell content (<25%) and smear area (<15%) were the main reasons for failure. All standard‐of‐care mutations were detected in replicate smears from individual patients, regardless of malignant cell content. Tier 1/2 mutations were discovered in two cases where standard‐of‐care specimens were inadequate for sequencing. Smears were scored for tumor mutation burden. Conclusions Microscopy of Diff‐Quik smears can triage samples for comprehensive panel sequencing, which highlights smears as an excellent alternative to traditional testing with cell blocks.

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