Lung tumor
Benign tumors

Author: Roseann Wu, M.D. (see Authors page)

Revised: 10 November 2015, last major update November 2015

Copyright: (c) 2003-2015,, Inc.

PubMed Search: Lipoma [title] lung
Definition / General
  • Very rare; usually endobronchial, usually men ages 50+ (Chest 2003;123:293)
  • Benign neoplasm composed of mature adipose tissue
  • Treatment of choice is bronchoscopic removal
Essential features
  • Endobronchial lipomas may show focal cytologic atypia and fibrosis but molecular evidence suggests similarity to lipomas of other sites
  • Endobronchial lipomas clinically mimic other tumors and may cause obstructive symptoms
  • Pulmonary lipomas lack the cartilage, myxoid matrix, entrapped bronchial epithelium, or other mesenchymal components seen in pulmonary hamartomas
  • Very rare, 0.1 to 0.5% of all lung tumors
  • Older men, mean age 65, majority with smoking history
  • May be associated with obesity
  • Usually endobronchial (large bronchi), very rarely parenchymal
  • More common in right lung
  • Typically sporadic
  • Endobronchial lesions may arise from peribronchial or submucosal adipocytes
  • Parenchymal lesions may arise from adipocytes of subsegmental bronchi or subpleural fatty tissue
Clinical Features
  • Slow growing, indolent
  • Discovered incidentally by imaging or during bronchoscopy for other reasons
  • Larger endobronchial lesions may present with cough, pneumonia, bronchiectasis, empyema, hemoptysis
  • May mimic endobronchial carcinoid, malignancy or asthma / COPD
  • CT or MRI can suggest diagnosis
  • Bronchoscopic biopsy or excision for endobronchial lesions
Radiology description
  • High signal intensity of fat in all MRI sequences
  • CT shows smooth, non-enhancing, homogenous mass with fat density
  • May see peripheral air trapping on CT with obstructive endobronchial lesions
Prognostic Factors
  • Benign, but large lesions may cause obstructive complications
Case Reports
  • Resection is curative
Clinical Images
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Lesion in situ

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Gross Description
  • Endobronchial tumors are generally <3 cm
  • Well circumscribed, polypoid or sessile, yellowish mass on bronchoscopy
  • Yellow-grey mass with firm capsule
  • Intraparenchymal lesions are well circumscribed, soft, lobulated, yellow
Gross Images
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Complete encapsulation

Micro Description
  • Mature adipose tissue underlying respiratory epithelium, with scattered lymphocytes and histiocytes
  • May show fibrosis and hyperchromatic stromal cells
  • Rarely has osteocartilaginous metaplasia
Micro Images
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Left lower lobe

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Atypical lipoma

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Mature adipose tissue

Molecular / Cytogenetics Description
Differential Diagnosis