Endobronchial Lipoma in a Young Patient: A Rare and Atypical Case Report

Abstract

Endobronchial lipoma (EL) is a rare, benign pulmonary tumor that frequently causes diagnostic delays due to its nonspecific presentation. We report a case of a 32-year-old male chronic smoker who presented with a 15-day history of dry cough and tachypnea. Chest X-ray showed left lower lobe atelectasis. Contrast-enhanced computed tomography revealed a fat-density lesion in the carina on the left side extending into the left main bronchus, causing distal obstruction and left lower lobar collapse. Diagnostic bronchoscopy confirmed a large, pedunculated mass completely occluding the left main bronchus. The mass was successfully resected through electrocautery snare and cryoextraction. Histopathological examination confirmed a well-encapsulated lesion composed of mature adipocytes, consistent with EL. This case highlights the importance of considering EL in patients with obstructive symptoms and demonstrates the efficacy of bronchoscopic resection as the first-line therapeutic intervention.

INTRODUCTION

In 1854, endobronchial lipoma (EL), a rare, benign pulmonary neoplasm, was initially characterized by Rokitansky, while the first case was reported by Kernan in 1927, who resected EL bronchoscopically.[1] Pathogenetically, ELs arise from submucosal adipose tissue within the bronchial wall, resulting in gradual endoluminal growth.[2] The patients generally present with vague complaints, due to the mass effect, including chronic cough, dyspnea, and recurrent pneumonia, frequently misdiagnosed as asthma or chronic obstructive pulmonary disease.[3] Computed tomography (CT) is a critical diagnostic tool, often revealing characteristic fat-density lesions within the bronchial lumen. With advances in interventional pulmonology, bronchoscopic resection has now become the preferred therapeutic modality, offering a minimally invasive and curative approach.[4,5]

Although the epidemiology of EL is well-documented,[1,6,7] it is still underdiagnosed, as it frequently mimics common obstructive diseases, resulting in delayed diagnosis and avoidable complications. Herein, we describe a case of a young male who presented with acute symptoms, diagnosed early with imaging, and subsequently managed with bronchoscopic resection.

CASE REPORT

A 32-year-old male presented with complaints of a dry cough for the past 10–15 days. There were no complaints about chest pain, breathlessness, vomiting, fever, and weight loss. He was a chronic smoker (7–8 years). There was no history of tuberculosis, allergy, diabetes mellitus, or asthma and prior surgery. Physical examination was normal, except for the presence of tachypnea at rest and decreased breathing sounds at the base of the left lung on auscultation. Routine laboratory investigations were unremarkable, though white cell counts were slightly raised (14,200 cells/mm³).

Chest X-ray revealed atelectasis of the left lung. A contrast-enhanced CT of the chest revealed a well-defined, round, fat-density lesion measuring approximately 13 mm × 15 mm × 20 mm located within the lumen of the carina on the left side and extending into the origin of the left main bronchus, resulting in its obstruction [Figure 1]. Resultant collapse of anteromedial basal, lateral basal, and posterior basal segments of the left lower lobe noted. Imaging features were suggestive of tracheal or EL or lipomatous hamartoma. Few small nodular opacities were noted in the apicoposterior, superior lingular, and inferior lingular segments of the left upper lobe – likely an infective pathology, and minimal left pleural effusion was present.

Figure 1.

Non-contrast computed tomography (CT) soft-tissue window of the thorax. (a) Coronal image and (b) axial sections show a well-defined, round, fat-density lesion within the tracheal lumen at the level of the carina extending into the origin of left main bronchus resulting in luminal obstruction, likely representing an endobronchial lipoma. (c) High-resolution CT coronal image shows evidence of collapse of the basal segments of the left lower lobe secondary to left main bronchial luminal obstruction caused by an endobronchial lipoma. (d) Contrast-enhanced CT of the thorax axial section shows no significant postcontrast enhancement of the endobronchial lipoma

Under general anesthesia, bronchoscopy was performed, and examination revealed a large pedunculated mass arising from the left lateral wall of the lower trachea, completely obstructing the left main bronchus [Figure 2]. The mass was excised using an electrocautery snare and cryoextraction without bleeding. The patient remained stable and was discharged on the same day.

Figure 2.

Bronchoscopic view. (a) Large pedunculated mass arising from the left lateral wall of the lower trachea in the region of carina extending to origin of the left main bronchus, completely obstructing the left main bronchus (white arrow), (b) the mass was excised with electrocautery snare and cryoextraction (white arrow), and (c) clear lumen of left main bronchus after excision of the mass (white arrow)

On gross examination, the mass was capsulated and nodular (2 cm × 1.5 cm × 1.2 cm) with a yellowish cut surface [Figure 3]. Microscopy showed pseudostratified ciliated columnar epithelial lining with a subepithelial, well-circumscribed lesion composed of mature adipocytes separated by fibrovascular septa, with focal myxoid change; few entrapped benign seromucinous glands, and no evidence of malignancy [Figure 4]. Thus, the final diagnosis was EL.

Figure 3.

Gross examination of the endobronchial capsulated and nodular mass measuring 2 cm × 1.5 cm × 1.2 cm

Figure 4.

Microscopic examination (H and E stain) illustrating pseudostratified ciliated columnar epithelium (a – blue arrow, ×100) lining with a subepithelial, well-circumscribed lesion composed of mature adipocytes (a – green arrow, ×100; and b – green dots, ×100) separated by fibrovascular septa (a – red arrow, ×100), with focal myxoid change, few entrapped benign seromucinous glands (c – blue dots, ×40)

The patient was followed up telephonically for over 3 months, during which he remained asymptomatic.

DISCUSSION

Owing to rarity, EL accounts for only 0.1%–0.5% of all lung tumors and around 1.4%–13.0% of benign lung tumors.[1,6] EL has a predilection for male sex, is usually reported between the fifth and seventh decades, and is linked to smoking and obesity.[6,7] In our case, the age is considerably younger compared to the characteristic demography, thus broadening the known age range associated with EL. The strong male predominance and association with chronic smoking, as observed in our case, are consistent with established epidemiological data.[6,7] However, a specific genetic or hereditary predisposition is yet to be reported.

Clinically, EL is an insidious disease, with symptoms arising from bronchial obstruction. Common presentations include chronic cough, dyspnea, wheezing, and recurrent pneumonia.[3] Our case primarily complained of a dry cough without classic obstructive symptoms like dyspnea, which is a known but less emphasized presentation, highlighting the variable clinical presentation of EL. Asymptomatic cases are rare; most patients develop symptoms only after significant luminal occlusion occurs. The late symptom onset and nonspecific nature contribute to a significant diagnostic delay, often spanning years, as reported by Irani et al.[3]

Pathogenesis involves the proliferation of mature adipocytes within the submucosal layer of the bronchus. These lesions are typically slow-growing, encapsulated, and pedunculated, as observed in our case. They most commonly arise in the main or lobar bronchi, with a predilection for the right side.[3,6] Our case, involving the carina and left main bronchus, aligns with the minority of reported left-sided tumors.[4] The observed tachypnea and focal auscultatory findings, though nonspecific, are direct consequences of the obstructive physiology caused by the tumor.[2]

The differential diagnosis for an obstructing endobronchial lesion is broad and includes malignancies (carcinoid and carcinoma), other benign tumors (hamartoma and lipoma), and inflammatory lesions.[8,9,10] A fat-density lesion on CT scan, as seen in our case with characteristic Hounsfield units between −40 and −120 HU, is the most specific imaging feature for EL, effectively distinguishing it from hamartomas (which may contain cartilage and calcium) and vascular malignancies (which enhance with contrast).[4,6,8] While a chest X-ray, as in our case, often reveals indirect signs like atelectasis, a CT scan is the cornerstone of noninvasive diagnosis.[6] Ultimately, bronchoscopy with biopsy remains the diagnostic gold standard, allowing for direct visualization, tissue sampling, and often therapeutic intervention.[3,5]

Without intervention, EL can lead to severe complications from chronic obstruction, including atelectasis and empyema.[2] Although ELs are rarely associated with mortality, death is typically attributed to severe infectious complications. The primary goal of management is complete tumor removal to relieve obstruction and prevent permanent parenchymal damage. Fundamentally, the management of EL has moved from historical thoracotomy and lung resection (lobectomy/pneumonectomy) to bronchoscopic resection, including cryotherapy and electrocautery, as the initial treatment owing to its effectiveness and low recurrence rates.[4,6] In our case, successful treatment through a combination of electrocautery snare and cryoextraction exemplifies this modern, minimally invasive approach, which offers a shorter recovery time and preservation of lung function.

CONCLUSION

EL, though rare, should be considered in the differential diagnosis of patients presenting with unexplained cough or obstructive symptoms. A high-resolution CT scan showing a fat-density endobronchial lesion is pathognomonic. Bronchoscopic resection is the treatment of choice, providing a definitive cure with minimal morbidity. Early diagnosis and intervention are crucial to prevent irreversible pulmonary complications.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to his conceal identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.