PMC6628974_01
(A) Chest CT revealed an endotracheal mass of 11 mm in diameter. (B) Bronchoscopy showed a well circumscribed posterior soft mass occluding over 95% of the tracheal lumen. (C) The endotracheal mass was treated with electrocautery snare and APC via bronchoscope. (D) Histopathology of the tumor: spindle shaped histiocytes in a storiform pattern accompanied by stromal fibrous tissue hyperplasia with sclerosis, H&E 100. (E) H&E 400. (F) Immunohistochemical staining, Vimentin (+). (G) CD68 (+).. Abbreviations: CT, computed tomography; APC, argon plasma coagulation; H&E, hematoxylin and eosin.
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A chest computed tomography (CT) revealed an endotracheal mass of 11 mm in diameter and approximately 30 mm from the carina (Figure 1A). The patient underwent bronchoscopy that showed a well circumscribed posterior soft mass occluding over 90% of the tracheal lumen (Figure 1B). The patient refused surgical resection of the trachea and accepted bronchoscopic treatment with electrocautery snare and APC (Figure1C).  Histopathological findings: sections from routine formalin fixation and paraffin embedded tissue stained with hematoxylin and eosin revealed ovoid to spindle shaped histiocytes in a storiform pattern accompanied by stromal fibrous tissue hyperplasia with sclerosis (Figure1D, E), Immunohistochemically tumor cells were positive for vimentin and CD68 (Figure 1F, G), negative for CD34 and epidermal membrane antigen (EMA).
(A) Six months after first bronchoscopic treatment, tumor recurrence at the original site was observed. (B-I) Procedure of treatment with HK. (B) Bronchoscopic view before treatment. (C) EBUS assessment before treatment. (D) The high-pressure water jet (30 Bar) positioned near the tumor and injected a solution of 2% lidocaine into the submucosal layer. (E) The base of the tumor was elevated. (F) A pinhole of the mucosa with the HK. (G, H) HK was inserted into the hole, and a circumferential incision was made. (I) APC was performed to facilitate the ablation of the tumor base. (J) Bronchoscopic view at the third day after bronchoscopic treatment. (K) Nine months follow-up, bronchoscopy revealed no recurrence. (L,M) Chest CT on ninth month follow-up.. Abbreviations: HK, hybrid knife; EBUS, endobronchial ultrasound; APC, argon plasma coagulation; CT,computed tomography.
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Unfortunately, 6 months later, tumor recurrence was observed (Figure 2A, B). Tumor basal depth and blood flow was assessed by endobronchial ultrasound (EBUS) before treatment (Figure 2C). We used a water jet HK (Erbe Hybrid Knife  T-type I-jet, ERBE Elektromedizin) to perform electrosurgical circumferential cutting and dissection of the base of the tracheal lesion, and we used a water jet to inject a solution of 2% lidocaine into the submucosal layer with 30 Bar pressure (Figure 2D, E). After making a pinhole in the margin of the elevated mucosa with the HK (Figure 2F), the tip of the HK was inserted into the hole, and a circumferential incision was made (VIO mode ENDO CUT Q, effect3-width1-interval of incision4, Coagulation effect2 and 30W) (Figure 2G, H). The lesion in the submucosal layer was fully exposed and then treated with APC (Figure 2I, J). There was no recurrence at 9 months follow-up on bronchoscopy and chest CT (Figure 2K-M).