Severe Central Airway Obstruction Secondary to a Giant Endobronchial Hamartoma: A Case Report

Abstract

Central airway obstruction refers to the occlusion of more than 50% of the trachea, main stem bronchi, or lobar bronchus. It can potentially become a life-threatening condition. Pulmonary hamartomas (PH) are rare tumors with an incidence of 0.25%, constituting about 8% of all benign lung neoplasms. Only 10% of PH occur endobronchially, while the remaining appear peripherally. We present the case of a women with an endobronchial hamartoma that required emergent resection by bronchoscopy. This is 44-year-old woman, with a history of an endobronchial mass on the right main stem bronchus (RMSB) without histopathological diagnosis or surgical management. She presented with a history of chronic cough and expectoration. Upon admission, a chest X-ray was performed, showing opacities of the right lung and amputations of the RMSB. Bronchoscopy was performed and a tumor-like mass that occludes the RMSB was found, with valve effect causing intermittent occlusion. In anesthetic induction, she presents severe airway obstruction and cardiorespiratory arrest. During resuscitation maneuvers, the lesion that was obstructing the light is seen and resection was performed with electrocautery and cryotherapy probes. Histopathological report described an endobronchial chondromesenchymal hamartoma, with no signs of malignancy. The control X-ray showed adequate re-expansion of the right lung. In conclusion, although endobronchial hamartoma has a low incidence and has a slow growth rate, it can manifest as severe airway obstruction. To achieve a complete resection of an endobronchial lesion, both rigid and/or flexible bronchoscopy plus multimodal interventions are recommended.

Background

Central airway obstruction (CAO) originates at the level of the trachea or main stem bronchi. Moreover, it is associated with a high mortality and morbidity rate. If left untreated, it can lead to acute respiratory failure, a life-threatening condition.¹ Central airway obstruction is an occlusion of more than 50% of the trachea, main stem bronchi, or lobar bronchus.² It can be secondary to extrinsic compression, intrinsic lesions, or both. The etiology can vary from benign to malignant.³ Carcinoid tumors, adenocarcinoma, and small cell tumors are the most common malignant causes. Nonmalignant causes of CAO are less common than malignant, whereby most of them are due to benign strictures related to post-intubation tracheal stenosis and post-tracheostomy tracheal stenosis following by autoimmune and infectious diseases.² In these cases, the benign tuberculoid granuloma is the most common cause. Nonmalignant airway tumors are less frequent, and include tracheobronchial papillomatosis, mucous gland adenoma, hamartomas, leiomyomas, lipomas, and fibromas.^4,5

Clinical manifestations depend on the degree of luminal obstruction. Patients with a mild tracheal narrowing, defined as an obstruction of less than 50%, are often asymptomatic. Moderate occlusions that present an airway obstruction between 51% and 70% of the lumen may present with cough, hemoptysis, shortness of breath, chest pain, wheezing, and recurrent pneumonia or atelectasis. Whereas in patients who present with acute respiratory failure, severe stenosis (>70%) must be suspected.

Hamartoma is a rare type of benign neoplasm. In 80% of cases, it is located in the peripheral pulmonary parenchyma, while in the remaining patients it appears proximally inside the bronchi. Hamartoma has an incidence of 0.025% in autopsy series.⁶ Furthermore, in the general population, it has been reported to compromise the main stem bronchi in 1.4% of cases.⁷

In adults with chronic and intermittent respiratory tract symptoms, a diagnosis of hamartoma must be considered. However, it is an uncommon lesion. Fortunately, pulmonary hamartoma has a very little or no malignant potential and very low risk of recurrence.⁷ A complete endoscopy evaluation is the gold standard for diagnosis.⁸

We present the case of a female patient with a history of recurrent pneumonia and an acute CAO secondary to an endobronchial hamartoma, in whom bronchoscopy management was the best way to provide both acute diagnosis and treatment during cardiac arrest.

Case Presentation

A 44-year-old female from a rural area, mother of two children, non-smoker, with a history of exposure to wood smoke. She denied a medical history of hypertension, diabetes, or asthma and denied medications or previous surgeries. The medical family history had no relevant pathological findings. At the date of admission, she reported a history of 3 years of respiratory tract symptoms, consisting of a dry cough with minimal amounts of yellow sputum, increased mucus production, mild hemoptysis, and intermittent fever. She received some cycles of antibiotics due to her symptoms being interpreted as lower respiratory tract infections by medical care, but none of them had a beneficial effect. The patient denied any headaches, shortness of breath, stridor, and gastrointestinal or urinary symptoms.

Three months before admission, her dyspnea started worsening in the supine position. However, she denied exertional dyspnea, fever, or other symptoms. A computerized tomography (CT) scan of the chest from another health center revealed opacities in the right lower lung with a suspected endobronchial lesion. She was referred to our hospital to confirm the diagnosis with a bronchoscopy under general anesthesia, which is a routine and ambulatory procedure.

In the pre-anesthetic assessment, the patient was classified as ASA II, according to the American Society of Anesthesiologists, suggesting that she had a mild perioperative risk of morbidity and mortality. On admission, the patient reported only mild worsening of shortness of breath. The physical examination evidenced a temperature of 36.5 °C, blood pressure of 125/64 mm Hg, heart rate of 78 beats/min, respiratory rate of 17 breaths/min, and oxygen saturation in 92% with no oxygen supplementation.

There was a decrease in breath sounds at the base of the right lung, but no exertional dyspnea and no signs of respiratory failure, stridor, or cyanosis were seen. The rest of the physical exam was unremarkable: extremities without edema, no neck masses, and no cardiac arrhythmia. The abdominal and neurological examinations were normal.

Prior to the bronchoscopy, we started anesthetic medication. We used the target-controlled infusion (TCI) system to calculate doses of both propofol and remifentanil. Both drugs were started at 4 mg/mL and were titrated according to dose/site effect. A classic laryngeal mask was used for the passage of the therapeutic bronchoscope. After anesthetic induction and application of a muscle relaxant (60 mg of intravenous succinylcholine), she presented severe airway obstruction, presented difficulty in ventilation, and marked desaturation up to 26%, followed by cardiorespiratory arrest.

A bronchoscopy was performed and revealed a significant, circumferential, pedunculated soft mass of 4 cm that originated in the right bronchus. The lesion was occluding the lumen of the left lobe bronchus and the ipsilateral distal trachea, which probably was worsened by placing the patient in a supine position under muscular relaxation. With the displacement of the lesion, ventilation of the left lung was achieved while the endoscopic resection was carried out. Electrocautery and cryotherapy probes were used to achieve enucleation of the mass (Figure 1A-F). After resection, abundant purulent secretion was obtained from the right lung. We initiated intravenous norepinephrine due to persistent hypotension.

Figure 1.

(A-C) Endoscopic evaluation of the lesion in the right main stem bronchus. Masses are occluding the end portion of the trachea and intermittent occlusion of the left main stem bronchus during the respiratory cycle. (D, E) Image is showing basal segments of the lower right lobe after resection of the lesion. (F) Mucosa of the right intermediate bronchus with a superficial laceration performed after the resection of the lesion in the basal segments in the right lower lobe.

She was admitted directly to the intensive care unit with blood pressure of 114/66 mm Hg, temperature of 37 °C, heart rate of 140 beats/min, and oxygen saturation in 99% under invasive mechanical ventilation. She had decreased breath sounds in the right lung field, capillary filling less than 3 seconds and neurological Richmond Agitation Sedation Scale of −4.

Due to possible post-obstructive pneumonia, we started 1 g of intravenous vancomycin every 48 hours and 500 mg of intravenous meropenem every 12 hours. During hospitalization, she presented acute renal failure with transitory ultrafiltration, left ventricular dysfunction with prompt recovery, and without any cardiac repercussion. Relevant laboratory exams are presented in Table 1. Chest X-ray showed the right lung with generalized opacities, plus diffuse left alveolar infiltrates, as shown in Figure 2A-C. The control chest X-ray reported a decrease in alveolar infiltrates and a mild opacity of the right base lung (Figure 2D, E). Seventy-two hours later, the patient was extubated.

Table 1.

Laboratory Data.

Variable	Reference range	At admission, ICU	During medical care, ICU	Before discharge, ICU
Blood hemogram
Leucocytes (×103/µL)	3.9-10.4	39.0	10.4	9.5
Neutrophils (×103/µL)	1.5-6.1	35.0	6.2	7.0
Hemoglobin (g/dl)	11.2-15.7	13.6	9.70	8.10
Hematocrit (%)	34.1-44.9	44.7	29.9	25.4
MCV (fL)	79.4-94.8	95.10	89.9	88.8
Platelets (×103/µL)	182-369	510	159	150
Electrolytes
Sodium (mmol/L)	136-145	137.8	141.4	138.2
Potassium (mmol/L)	3.5-5.1	4.58	4.64	4.66
Chloride (mmol/L)	98-107	103.50	NA	NA
C-reactive protein		30.8
Lactic acid (mmol/L)		2.94
Renal function
Creatinine (mg/dl)	0.51-0.95	1.64	6.35	3.6
Urea nitrogen (mg/dl)	6-20	18.20	45.20	16.40
Arterial blood gases
pH	7.35-7.45	7.03	7.44
PaCO2 (mm Hg)	35-48	72.6	40.2
O2 saturation	94-98%	91	93.7
HCO3 (mm/L)	21-28	18.9	27
Echocardiogram
Right ventricular TAPSE (mm)	22.6 ± 4	19		24
Left ventricular LVEF		20%		55%

Abbreviation: ICU = intensive care unit; MCV = medium corpuscular volume; TAPSE = Tricuspid annular plane systolic excursion; LVEF = Left ventricular ejection fraction.

Figure 2.

A sequence of chest X-rays in posterior-anterior films. (A) Chest X-ray performed immediately after the resection by bronchoscopy. It showed cardio mediastinal structures with mild displacement to the right, orotracheal tube positioned at the T4 and amputation of the right main stem bronchus. Also, diffuse opacity in the right lung associated with atelectasis and alveolar opacities, suggestive of a consolidative pattern in the left lower lobe. Obliteration of the right costophrenic angle. Left costophrenic angle was normal. (B) Chest X-ray control in intensive care unit showed multiple pseudo-nodules scattered throughout in both lungs. A pulmonary consolidation was observed in the left lower lobe plus bilateral pleural effusion. Cardiac silhouette had a normal size. Proper endotracheal tube placement. Swan-Ganz catheter in the left lower pulmonary artery. (C) Chest X-ray at day 4, showing cardiac silhouette displacement toward the right hemithorax. Trachea with an orotracheal tube in a good position, enteral feeding tube with its distal end in the gastric chamber and Swan-Ganz catheter in the left lower pulmonary artery. There are atelectasis involving the right lower lobe. Reticular and nodular opacities were present in both lungs, and mild infiltrates in the left lower lobe. (D) Improvement of pulmonary infiltrates compared with previous chest X-ray. Volume loss of the right lung persisted. (E) Chest X-ray showing a normal cardiac silhouette. Trachea with displacement toward the right side with normal diameter. There are persistent signs of volume loss of the right lung with ipsilateral retraction of the trachea and mild reticular interstitials opacities without a consolidative pattern. Interstitial opacities are present in the left lower lobes. In addition, there is a discrete thickened peribronchovascular interstitium without a consolidative pattern. (F) Six months after discharge, a new X-ray was performed showing a mild volume loss of the right lung with a better aspect from the previous chest X-ray. Right retro-cardiac opacity probably due to atelectasis. There were no infiltrates, masses, or pleural effusion.

The histopathologic evaluation described a polypoid and irregular lesion; the size of the lesion was 4 × 2 × 1 cm³. It was lined by respiratory epithelium with some foci of squamous metaplasia interspersed with ulceration areas, without epithelial dysplasia. The chorion had a thick muscular layer of blood vessel wall in its interior, associated with lymphoplasmacytic and inflammatory cells. In addition to chondral tissue fragments, the lesion was surrounded by adipose tissue without mitosis, binucleations, or nuclear size increase. There were no observed signs of malignancy. These characteristics were compatible with endobronchial chondromesenchymal hamartoma (Figure 3A-F).

Figure 3.

(A, B) Mucosa lined by respiratory epithelium (arrow blue). Hyaline cartilage (arrow red) interposed with adipose tissue inside the chorion, without signs of malignancy. (C, D) Inside the chorion, there is a niche of chondral tissue (arrow red) without increased cellularity, binucleations, and mitosis. The epithelium lining without epithelial dysplasia. (E) Transition between chondral and adipose tissue (arrow red). Both of them are located in the chorion and have no malignancy signs. (F) The chorion has ulceration areas (arrow red), and it is occupied by 2 mesenchymal components (chondral and adipose).

With the removal of the mass, the patient recovered successfully and was discharged after 15 days without recurrence of symptoms. We performed a control bronchoscopy that revealed normal vocal cords, trachea, and carina. It showed a residual lesion in the basal segments of the lower right lobe that was resected and revealed the same histopathological findings. The architecture of the subsegmental bronchi of the right lower lobe was abnormal; they appear thinned, probably due to the presence of the slow-growing mass for a long time (Figure 4A-F).

Figure 4.

Control of bronchoscopy before discharge showing: (A) Normal appearance of the vocal cord. (B) Distal trachea and carina are normal. (C, D) Success resection of the lesion in the right intermediate bronchus wall, additional showing thin wall and the divisions of the right inferior lobe. (E, F) Residual lesion in the right lung’s basal segments corresponding to the sustentation site of the original resect mass. The residual lesion was resected and showed a similar pathology from the tissue that was resected previously.

Finally, the patient was discharged without oxygen supplement, with renal function recovery, and with a normal ejection fraction in the echocardiogram.

Six months after discharge, we examined the patient who denied respiratory symptoms, fever, or thoracic chest pain. The bronchoscopy did not reveal new alterations or masses and chest X-ray showed a mild volume loss in the right lung with a slight deviation of the trachea and mediastinum structures toward the right side. There are no pulmonary infiltrates, masses, or pleural effusion (Figure 2F).

Discussion and Conclusions

Hamartomas are usually a slow-growing mass with varied manifestations, including a severe CAO when more than 50% of the lumen are compromised.^2,9 Chronically, endobronchial lesions can manifest with cough and ineffective mucociliary clearance that lead to accumulation of mucus, causing atelectasis and recurrent pneumonia.³

In the case of this patient, the endobronchial hamartoma manifested with chronic cough, recurrent pneumonia, and mild hemoptysis. Furthermore, she presented severe airway obstruction as a major complication due to the obliteration of both bronchi. The neuromuscular blocking agent promoted the movement of the lesion toward the tracheal lumen and the left bronchus during anesthesia, causing airway obstruction and cardiac arrest. The endoscopic procedure allowed both diagnosis and successful resection.

Chronically, ineffective clearance of respiratory secretions can manifest as residual infiltrates or recurrence signs of infection in radiological findings. Therefore, in a patient with chronic respiratory tract symptoms, an endobronchial lesion should be suspected.¹⁰

Cosío et al.¹¹ performed a retrospective study of 47 patients with hamartoma diagnosed by bronchial biopsy between 1974 and 1997. The most frequent clinical manifestation was obstructive pneumonia (16 patients) in 44% of patients, followed by hemoptysis with 33.4%.⁷ In another cross-sectional descriptive study, Chaudhuri et al¹⁰ reported that the most common symptoms in patients with obstructive pneumonia were cough (100%), fever (96%), hemoptysis (53.3%), chest pain (38.5%), and dyspnea (33.3%). Furthermore, other studies reported asymmetric wheezing or localized stridor as the most characteristic physical findings.⁸

Histologically, the hamartoma is composed of 2 mesenchymal elements (either fatty, cartilaginous, bone, or soft muscle tissue) and respiratory epithelium, which gives it a biphasic appearance.¹² In contrast to the histological composition, in other series of cases, a diagnosis by non-invasive procedures did not exceed 30%.⁹ For example, an endobronchial location can be observed as “popcorn” in the X-ray due to the presence of calcification.¹³ On the other hand, the CT scans of the thorax become highly sensitive depending on the quantity of fat inside the lesion. Most clinical researchers have estimated that 50% of hamartomas have large deposits of fat tissue.⁹ Tomographic criteria include a diameter less than 2.5 cm, muscle margin, and detectable bone or fat tissue.⁹

The therapeutic approach must be adjusted according to the size, location, and complexity of the lesion.¹⁴ The primary method to resect endobronchial lesions is either the rigid or flexible bronchoscopy.¹⁵ In that case, ablative techniques are used,^16,17 including laser ablation, electrocoagulation, cryotherapy, or argon plasma coagulation. Nowadays, experts recommend a multimodal approach.

Pulmonologist should consider complementary techniques to guarantee the permeability of the airway during endoscopic resection. This decision depends on the diagnosis, extension of the lesion, the condition of the airway, and operator experience.

In the case of hamartomas with cryoresistent characteristics, this approach might be challenging due to its predominant fatty or cartilaginous tissue.¹⁸

The complications related to the therapeutic bronchoscopy are low, for example, events of bleeding are present in 1.1% to 2.8%.⁸ Perforation, ulcer formation, swelling of the airway, and mucosal tamponade are rare complications.¹⁹

Total intravenous anesthesia is the best anesthetic technique during bronchoscopy. An infusion of propofol and remifentanil through mathematical models with TCI is recommended to prevent dose-related side effects.⁸

After endoscopic therapy, we recommend a periodic clinical, radiological, and endoscopic follow-up.

In conclusion, although endobronchial hamartoma has a low incidence and its growth rate is slow, it can cause airway obstruction leading to chronic symptoms, recurrent infections, and occasionally severe CAO. Given the fact that obstructive manifestations are present when airway occlusion is greater than 50%, diagnosis tends to be delayed increasing the risk of respiratory failure. The radiological findings of endobronchial compromise do not have an obvious pattern, which is why these types of lesions must be suspected when recurrent infiltrates and lung parenchymal opacities are present. For the management, rigid or flexible bronchoscopy with multimodal intervention is recommended to resect the lesion and achieve permeabilization of the airway at the same time.