Mesenchymal tumors


Last author update: 1 November 2015
Last staff update: 7 June 2023

Copyright: 2003-2023,, Inc.

PubMed Search: Lipoma [title] lung

Roseann I. Wu, M.D., M.P.H.
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Cite this page: Wu R. Lipoma. website. Accessed September 21st, 2023.
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

Images hosted on other servers:
Endoscopy Endoscopy


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

Images hosted on other servers:
Complete encapsulation

Complete encapsulation

Microscopic (histologic) description
  • Mature adipose tissue underlying respiratory epithelium, with scattered lymphocytes and histiocytes
  • May show fibrosis and hyperchromatic stromal cells
  • Rarely has osteocartilaginous metaplasia
Microscopic (histologic) images

Images hosted on other servers:
Atypical lipoma Atypical lipoma

Atypical lipoma

Mature adipose tissue

Mature adipose tissue

Molecular / cytogenetics description
Differential diagnosis
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