Discussion
Lipomas are a benign tumours that originate from fatty tissue. [1, 3]. They can appear anywhere in the body; thoracic lipomas are rare. [1, 2, 3]
Generally, the majority of lipomas become apparent in patients at 40 to 60 years of age, and they tend to be more common in obese persons. [6]
The lipomas that involve the thorax can be divided into two groups:
- Subcutaneous: usually appears in the upper back, neck, and shoulder regions.
- Deeply seated: intrathoracic (or mediastinal) lipoma. This group can be classified into two classes:
• pure intrathoracic: located completely within the thoracic cavity
• mediastinal lipoma that have intra-and/or extra-thoracic lesions. In particular:
- cervico-mediastinal type which extends to the neck
- transmural type which penetrates the chest wall. [1, 2, 3, 6]
Deeply seated intrathoracic lipomas usually tend to have a big size and their detection is often late and incidental, e.g. while the patient is performing routine examinations or imaging investigations for mild symptoms [1]. Generally they are characterised by slow growth; for this reason, usually they are asymptomatic. [1, 5] The symptoms are often due to mass effect and depend on the site and size of the lesion. [5 and 6] The patient can have: dysphagia, dyspnoea, dry cough, jugular distention, and cardiac arrhythmias or even death. [4, 5, 6]
At a X-ray examination, a lipoma can appear like a well-defined rounded nodul/mass that presents soft tissue density. [3, 6]
On a Chest CT, lipomas show homogeneous fat attenuation of approximately (- 50 to -150 HU). [2, 4, 6]
MRI is useful to describe the extent of the mass, and the relationship between this and the adjoining organs. [3, 4] Also, it can be of help to identify the fatty nature of the lesion [4]; it presents a high signal intensity on both T1- and T2-weighted images. [6]
Usually radiologic investigations are useful for diagnosis, but can’t exclude the malignancy. [2]
In general, surgical resection is necessary to:
-prevent:
o increasing in size
o infiltrating development
o local recurrence
o malignant degeneration
- avoid a mass effect on adjacent structures and/or alleviate symptoms
- pathologic examinations and verification of the diagnosis [1, 2, 6]
MR is performed to exclude a possible suspicious mass not seen in CT; in this way the liposarcoma is excluded.
The clinicians decide to avoid a biopsy or a surgical resection because the patient is asymptomatic and prefers a clinical follow-up.
