179 Chest Wall Lipoma

Clinical Presentation

Asymptomatic 91-year-old woman

Radiologic Findings

Coned-down PA (Fig. 179.1A) and lateral (Fig. 179.1B) chest radiographs demonstrate a peripheral opacity in the right superior hemithorax that forms obtuse angles with the adjacent chest wall (Fig. 179.1A). There is discrepancy in margin visualization consistent with an extrapulmonary location. Contrast-enhanced chest CT (lung window, Fig. 179.1C; mediastinal window, Fig. 179.1D) shows a peripheral mass that forms at least one obtuse angle with the adjacent chest wall (Figs. 179.1C, 179.1D) and exhibits fat attenuation with scant thin linear soft-tissue elements (Fig. 179.1D). The mass is contiguous with subcutaneous fat attenuation tissue.

Fig. 179.1

Diagnosis

Chest Wall Lipoma

Differential Diagnosis

None

Discussion

Background

Benign chest wall tumors may originate from blood vessels, nerves, bone, cartilage, or fat. The imaging manifestations of benign and malignant chest wall lesions overlap, but some entities have characteristic imaging features that allow a confident diagnosis. Lipomas represent the most common soft-tissue chest wall tumors. They are well-circumscribed, encapsulated masses of adipose tissue that may lie deep within the chest wall and/or protrude into the thorax, displacing the pleura, mimicking other benign or malignant pleural lesions.

Etiology

The etiology of chest wall lipomas is unknown.

Clinical Findings

Chest wall lipomas are typically incidental findings in asymptomatic patients. They occur most frequently in patients who are 50–70 years of age and are more common in obese individuals.