Mesenchymal tumors

Multiple pulmonary leiomyomatous hamartomas

Topic Completed: 1 August 2016

Minor changes: 30 September 2020

Copyright: 2002-2021,, Inc.

PubMed Search: Multiple pulmonary leiomyomatous hamartomas

Roseann Wu, M.D., M.P.H.
Page views in 2020: 718
Page views in 2021 to date: 1,043
Cite this page: Wu R. Multiple pulmonary leiomyomatous hamartomas. website. Accessed October 25th, 2021.
Definition / general
  • Proliferation of multiple smooth muscle nodules in the lung parenchyma
Essential features
  • Multiple, small, unencapsulated nodules of smooth muscle in fascicles
  • Extremely rare, with controversial relationship to benign metastasizing leiomyoma or leiomyosarcoma
  • Controversial whether are true hamartomas or represent metastasizing leiomyoma or leiomyosarcoma
  • Extremely rare, almost always asymptomatic middle aged women
  • Throughout lung parenchyma, occasionally bronchovascular distribution
  • Possible origin from contractile system of the lung acini (contractile interstitial cell)
Clinical features
  • Usually incidental
  • Biopsy of nodules
Radiology description
  • Xray: abnormal nodular shadows
  • CT: multiple small pulmonary nodules
Prognostic factors
Case reports
  • Surveillance, enucleation or surgical removal
Gross description
  • 2 - 15 mm white, firm, solid, well demarcated nodules
Microscopic (histologic) description
  • Excessive smooth muscle bundles in fascicles, not associated with tumor
  • Spindle cells with eosinophilic, fibrillary cytoplasm and blunt, elongated nuclei
  • Scattered glands and duct-like spaces may be seen
  • No mitoses, no nuclear atypia
Positive stains
Negative stains
Differential diagnosis
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