Definition
• Benign circumscribed tumor of mature adipocytes
Clinical features
Epidemiology
• Very rare tumor of adults
Presentation
• Endobronchial lipoma: obstruction, shortness of breath, coughing
• Pleural-based lipoma: usually asymptomatic and found incidentally on imaging
Prognosis and treatment
• Excellent prognosis
• Endoscopic resection of endobronchial lesion
• Pleural-based lipoma may require surgical resection
Pathology
Histology
• Circumscribed lobulated proliferation of sheets of mature adipocytes
• Lacks cellular atypia, hemorrhage, or necrosis
Immunopathology/special stains
• Positive: S100
Main differential diagnoses
• Lipoblastoma: benign pediatric tumor composed of lobules of cellular fetal adipose tissue and lipoblasts with plexiform vessels and myxoid stroma
• Lipomatous hamartoma: has other mesenchymal elements and entrapped respiratory epithelium
• Metastatic liposarcoma: has atypical lipoblasts
Fig 1 Lipoma of lung. This endobronchial lipoma was excised because of dyspnea and shows mature adipose tissue with admixed fibrous tissue and a respiratory epithelial lining at low (A), medium (B),and high (C) power.
(Courtesy of Drs. Dani S. Zander and Haresh Mani, Hershey, Pa.)