Mediastinal lipoma as a cause of dyspnea.

Mediastinal lipoma is a rare intrathoracic tumor which can present as shortness of breath. We describe a morbidly obese patient with progressive dyspnea who got diagnosed endoscopically and is scheduled for surgical resection for a large benign mediastinal lipoma.

Case presentation

Our patient is a morbidly obese 51-year-old male (BMI 58) who was referred to the pulmonary clinic for progressive shortness of breath on exertion for one year prior to presentation.

He is a lifelong non-smoker and has a past medical history of diabetes, hypertension and obstructive sleep apnea. He has no history of occupational/environmental exposures or recent travel. He also reported occasional dysphagia to solid foods. Physical examination was significant for obesity and a normal heart and lung exam.

Routine blood tests were unremarkable. His CXR showed prominent mediastinum but clear lungs. An office pulmonary function test showed normal spirometry, lung volumes and diffusion capacity.

He had a transthoracic echocardiogram and was found to have a normal ejection fraction and right ventricular systolic pressure.

A non-contrast CT of the chest was obtained which showed a large oval shaped fat density, not sharply demarcated measuring approximately 5 cm transverse by 19 cm craniocaudal extending from the lower right neck into the right anterior mediastinum. (Fig. 1, Fig. 2). This displaced the innominate vein anteriorly, the brachiocephalic artery laterally to the left and the superior vena cava anteriorly. Lung parenchyma was essentially preserved. The mass had the consistency of fatty tissue suggesting lipoma.

Fig. 1

CT chest showing coronal views with anterior mediastinal tumor.

Fig. 2

CT chest axial view showing right mediastinal fatty tumor.

The patient underwent an endobronchial ultrasound guided transbronchial aspiration (EBUS-TBNA) of the mediastinal mass which confirmed a benign lipoma. He is currently undergoing pre-operative work up for resection of the lipoma.

Discussion

Primary pulmonary diseases can have atypical presentations [1,2]. Lung cancer is the leading cause of cancer related mortality worldwide [[3], [4], [5]]. Lipomas are usually benign tumors which are present subcutaneously and are extremely rare in the thoracic cavity. Few case reports have been described in the literature where primary mediastinal lipomas were discovered on imaging in patients either post mortem or incidentally [6,7]. Very rarely, they are discovered symptomatically. Dyspnea, chest pain and dysphagia are the commonest presenting complaints. Mediastinal lipomas comprise <2% of all mediastinal tumors [6,7].

Novel minimally invasive techniques have opened the thoracic cavity to the pulmonologists and patients commonly do not need surgery for diagnosis [8,9]. This is the first described case where EBUS-TBNA was used for diagnosis. Lipomas are found mostly in the anterior mediastinum and are slow growing and can be radiologically monitored in asymptomatic patients. When associated with symptoms, en bloc surgical resection is the treatment of choice. The rate of recurrence is low.

Conclusions

Symptomatic intrathoracic lipoma is extremely rare. Novel bronchoscopic techniques can be helpful for diagnosis. Surgical resection can be curative.