A rare cause of post-obstructive pneumonia: endobronchial fibrolipoma

Clinical History

A 51-year-old man with a history of heavy smoking and metabolic syndrome came to the emergency department of our hospital with high fever and right-sided chest pain for the last few days.

Imaging Findings

A chest X-ray revealed a consolidation in the anterior segment of the right upper lobe. After antibiotic therapy, the follow-up X-ray showed resolution of the consolidation. Four months later, the patient suffered from another consolidation in the same location. Subsequently, with the diagnosis of recurrent pneumonia, a chest CT was performed. The CT revealed a post-obstructive pneumonia caused by a well-defined fat-density mass into the anterior segmental bronchus of the right upper lobe. A bronchoscopy with biopsy was performed and revealed a total obstruction of this bronchus by a pearly tumour with smooth well-defined surface. The biopsy showed a benign neoplasm made up of proliferation of mature fibroadipose tissue under the normal bronchial epithelium. The diagnosis was endobronchial fibrolipoma. The patient underwent bronchoscopic treatment with rigid bronchoscopy and cryotherapy that allowed cryorecanalization of the endobronchial fibrolipoma and complete reopening of the endoluminal airway.

Discussion

Endobronchial lipomas are rare benign tumours of the bronchial tree, whose incidence ranges from only 0.1 to 0.5% of all lung tumours [1]. Most of them arise in the submucosal layer of the main or segmental bronchus, which shows fat tissue in the wall in histology. They are more common in men, in the sixth decade of life. Obesity and smoking are considered risk factors. Clinically, the patients present with symptoms of bronchial obstruction, such us cough, dyspnoea and recurrent pneumonia [2].
A CT study should be performed in order to localize the tumour and its complications, such us post-obstructive pneumonia or atelectasis. They are more often located in the main bronchi or lobar bronchi and despite their benign nature, recurrent obstructive pneumonia may induce nuclear atypia to suggest malignancy in the endobronchial biopsy [3]. Both CT and MRI are helpful in establishing the diagnosis because they can demonstrated the fatty component of the tumour. The T1 and T2 relaxation times and spin density of benign lipomatous tumours are in a range similar to those of normal fat. Since the sensibility and specificity of CT and MRI are similar, it depends on the preferences of the radiologist which technique to choose.
The bronchoscopy is the fundamental tool for a definitive histopathologic diagnosis and permits a curative treatment as in our case. Endobronchial fibrolipomas are round, polypoid, yellowish or pearly lesions with smooth borders and they are made up of mature fibroadipose tissue surrounding bronchial glandular structures, without malignant cells. It is important to know that the biopsies obtained by flexible bronchoscopy are often nondiagnostic due to the submucosal growth of the endobronchial fibrolipoma, which is covered by normal epithelium. However, rigid bronchoscopy is almost always diagnostic [3, 4].
The endoscopic treatment should be considered as the first therapeutic option, as it avoids both thoracotomy and lung resection. The surgical resection is preferred in peripheral destructive lung disease due to recurrent pneumonia or atelectasis, extrabronchial growth or difficulty of definite diagnosis and possible complicated malignant tumour [4]. Although endobronchial fibrolipomas are a rare cause of bronchial occlusion they must not be disregarded because of an early CT, and endoscopic diagnosis and resection help to prevent irreversible distal lung damage and radical surgery.

Differential Diagnosis List

Final Diagnosis

Endobronchial fibrolipoma of the anterior segmental right upper bronchus.

URL:	https://www.eurorad.org/case/13698
DOI:	10.1594/EURORAD/CASE.13698
ISSN:	1563-4086