FormalPara Key Summary Points

Endotracheal fibroepithelial polyp is a rare and benign disease of the airways.

Physicians should be aware that the symptoms of endotracheal fibroepithelial polyp may mimic asthma.

Chest computed tomography with 3-dimensional reconstruction is useful for guiding endotracheal bronchoscopic biopsy to confirm histological features of endotracheal fibroepithelial polyp.

Tumor ablation by high-frequency electricity through flexible bronchoscopy is the treatment of choice for endotracheal fibroepithelial polyp.

Introduction

Benign tracheal tumors are uncommon, and estimated at less than 2% of all airway lesions [1, 2]. Hamartomas and squamous cell papilloma are the most common type of benign tumors [3]. However, fibroepithelial polyps are pretty rare in the airways, especially large tumors [1]. Tumor resection through flexible bronchoscopy therapy may be the appropriate treatment for benign airway tumors such as fibroepithelial polyps [4]. In this case report, we present a rare case of tracheal giant fibroepithelial polyp that was successfully treated by flexible bronchoscopy using high-frequency electrocautery ablation. Written informed consent was obtained from the patient and her parents to publish this case report with all the data and figures.

Case Description

A 17-year-old girl was admitted to the hospital with severe acute respiratory failure. She had progressive wheezing, cough, and dyspnea on exertion over 12 months ago. Initially, her symptoms were determined to be due to asthma, and she was treated with the combination of inhaled bronchodilators and inhaled corticosteroids as well as systemic corticosteroids, without improvement. Written informed consent was obtained from the patient and her parents to publish this case report with all the data and figures.

Five days before admission, the patient showed symptoms of a respiratory problem, including cough, sputum, and shortness of breath. She was diagnosed with bronchial asthma and treated at a local hospital, but her symptoms did not decrease. She then developed respiratory failure and was transferred to Military Hospital 175. Immediately upon admission, the clinical examination showed decreased ventilation of the lungs without rales of bronchial constriction, and a wheezing sound in the upper third of the trachea spreading downward. The patient was initially diagnosed with life-threatening acute respiratory failure due to acute asthma exacerbation and it was differentiated with the diagnosis of tumor-induced tracheal obstruction. The patient was intubated for mechanical ventilation, and treated with bronchodilators and corticosteroids.

Chest computed tomography was performed for the patient. The 3D tracheal reconstruction detected a soft tissue structure with calcification, and within its leg attached to the posterior wall of the trachea from close to the epiglottis it extended down to 20 mm; its largest transverse diameter was 30 × 20 mm anteroposterior diameter, which caused the narrowing of the trachea (Fig. 1A–C). The patient received a tracheostomy under the narrow segment and above the sternum. A Shiley cannula was placed on the ventilator for support. Flexible bronchoscopy was performed and showed the lesion, which was a large tumor located just below the vocal cords, with legs attached to the posterior wall of the trachea. Its surface was smooth within increased surface blood vessels. This tumor caused the quasi-complete obstruction of the trachea (Fig. 2A). Tumor biopsies for histopathological examination was done. Histopathological results were consistent with a fibroepithelial tumor (Fig. 3), as described previously [5].

Fig. 1
figure 1

Chest CT scan revealed an intratracheal soft tissue tumor with small calcifications protruding from the posterior wall of the trachea (black arrow) on axial view (A) and coronal view (B). The 3D chest CT showed that the tumor occupied the airspace inside the trachea (white arrow, C). Neck CT scan, conducted before (D) and after (E) contrast injection, indicated the presence of a soft tissue tumor (blue arrow) protruding from the posterolateral wall of the trachea and showed enhancement

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Fig. 2
figure 2

A Bronchoscopy of the tumor (blue arrow). B, C Bronchoscopy 2 and 6 months after the tumor resection (blue arrows)

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Fig. 3
figure 3

Histology slides of the biopsy sample. A Fibroepithelial polyp, normal bronchial mucosa, and stromal tissue features many edema (red arrows). B Fibroepithelial polyp, stromal tissue features with abundant edema and often lymphoplasmacytic infiltrates were found

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The patient benefited from interventional treatment, using the technique of endotracheal tumor ablation by high-frequency electricity through flexible bronchoscopy under intravenous anesthesia. The forceps device was used for ablation, and a snare through the biopsy channel of the flexible endoscope. Coagulation mode with a capacity of 20 V was first performed to create the coagulation effect and avoided bleeding, followed by ablation of the tumor with 25 V ablation mode. The duration of each ablation cycle was 2 s. The ablation process went smoothly and the tumor was completely removed after 60 min of intervention. The patient was treated with antibiotics and corticosteroids for reducing inflammation after the intervention.

The mechanical ventilation was withdrawn 5 days after removing the Shiley cannula. The patient was discharged on day 10 after the tumor ablation. Follow-up 2 and 6 months after the intervention found the patient in a good health status without any shortness of breath, and totally recovered for all physical activities. At follow-up, the postoperative bronchoscopy revealed a slight bronchial mucosal scar at the resection site (Fig. 2B, C).

Discussion

Benign tumors rarely occur in the trachea compared with other malignant tumors [3]. Especially, benign tracheal tumors are also less common than those originating in the bronchial tree and lungs [6]. Fibroepithelial polyps are the most common type of benign tumors in the skin or mucus membranes of the genitourinary tract, but are very rare in the trachea. They can be solitary or multiple, and their size usually does not exceed 5 mm. However, rare cases of large tumors of the skin have also been reported [7, 8]. Gonzalo Labarca et al. found 30 cases of airway fibroepithelial polyps in their literature review. The average age at diagnosis of airway fibroepithelial polyps was around 60 years old, and they were mostly found in men [1]. Fibroepithelial polyps are considered to be the result of chronic airway inflammation, associated with chronic infection, cigarette smoke, chemical agents, or local airway injuries such as mechanical ventilation or tracheostomy [4]. Obesity or hormonal changes related to pregnancy or oral contraceptive use are potential factors for stimulating tumor growth [7]. However, in this case report, our patient was not obese and had no history of pregnancy or oral contraceptive use. Thus, this suggests that other conditions, such as chronic inflammation, might be a predisposing factor for tumor development.

Tracheal tumors often do not produce symptoms until they have grown to a sufficient size to cause significant airway obstruction. Therefore, there is often a delay in the clinical presentation and diagnosis for patients with this type of disease. In addition, diagnosis might be delayed due to the presentation of nonspecific symptoms such as cough, wheeze, and shortness of breath that can occur in other conditions, such as asthma and chronic obstructive pulmonary disease [2]. In this case report, the patient had been misdiagnosed and treated for asthma for 1 year until the onset of her severe respiratory distress and she required hospitalization. Imaging techniques are the most valuable method for accurately determining the location and size of endotracheal tumors, while chest X-rays are not sensitive to reveal tracheal tumors. Computed tomography is very helpful for determining an early diagnosis of tracheal tumor, and are necessary for analyzing detailed lesion characteristics, including the tumor size, location, and intratracheal and extratracheal extension. Furthermore, bronchoscopy should be performed to directly visualize a tracheal tumor [6].

Common causes of respiratory failure in patients with tracheal tumors might be due to inflammation and swelling at the tumor site and tumor bleeding, which cause acute narrowing of the airways, and which might be associated with acute respiratory infections. The early and accurate diagnosis of tracheal tumors is very important because it helps to reduce the risk of death for patients due to acute respiratory failure and to perform therapeutic techniques such as bronchoscopy, biopsy, and tumor ablation.

Obviously, the management of a tracheal tumor depends on its pathological type, the extension of the disease, and the patient’s comorbidities. Surgical resection is usually performed for most patients, with open segmental resection followed by primary end-to-end anastomosis [2]. Our patient is a 17-year-old female; thus, all kinds of interventions were carefully considered to minimize the damage and sequelae.

In the present case report, after conducting a multidisciplinary discussion, we decided to choose tumor ablation by high-frequency electrocoagulation through flexible bronchoscopy to free up the airway and minimize damage on the trachea, instead of surgical resection and end-to-end tracheal anastomosis in a young patient with a benign lesion. In fact, benign tumors are usually localized, and are generally treated with surgical resection with a very low recurrence rate. Endotracheal tumors treated with endoscopic excision have varying degrees of recurrence, but re-excision is usually feasible. Imagery and bronchoscopy are regularly used to survey for possible recurrence [9]. The combined use of snare and forceps during electrocautery helped us to completely remove the tumor from the airway. In this patient, we used a snare to cut the tumor periphery, then ablation of the tumor with hot forceps because the tumor’s low extremity was of 4 cm in length in the posterior wall of the trachea, and was unable to be cut by the snare.

Finally, there are many intervention methods to remove tracheal tumors through bronchoscopies, such as mechanical extraction, cryoprobe, and thermal energy in the form of laser, electrocautery, or argon plasma coagulation [4, 10]. The selection depends on the equipment of each medical facility and on the surgeon’s experience. Laser and high-frequency electrocautery are considered as superior. Laser wavelength and power density are the main characteristics that define the suitability of each laser for endoscopic treatment. Depending on the laser wavelength, effects can penetrate up to 10 mm and have a bigger or smaller ratio of absorption and scattering in soft tissue. The absorption and scattering of the laser beam also depends on the tissue composition and color. Electrocautery costs are low, applicators are reusable and can also be used through the flexible bronchoscope, while the technique is simple and easy. Although lasers may, in general, be more powerful and rapidly effective, when building a new interventional pulmonology unit, electrocautery as far as the thermal ablation technique goes offers more advantages over laser [10]. In this technique, pathological tissue can be removed by electrons that generate heat for tissue coagulation due to the higher resistance of the target tissue. The tissue effect depends on the wattage setting, the surface area of contact (a smaller probe will increase current density), and the time during which energy is applied [10]. Moreover, the interventional approach with high-frequency radio wave electrocautery also provides the advantages of optimizing local combustion efficiency without damaging the deep layer of the trachea.

Conclusions

Fibroepithelial polyps are rare benign tumors in the trachea, especially giant tumors causing acute respiratory failure. Initial symptoms of this disease are often atypical, with coughing, wheezing, or shortness of breath, leading to misdiagnosis for other respiratory diseases. Acute respiratory failure can occur if the tumors develop inflammatory, edematous, or bleeding lesions, leading to airway obstruction. The technique of endotracheal resection with high-frequency electrocoagulation via flexible bronchoscopy is a minimally invasive, effective, safe, and low-recurrence method.