Fetal adenocarcinoma of the lung

Fetal adenocarcinoma of the lung (FLAC) is a rare form of adenocarcinoma of lung (falls under invasive category).


Some reports suggest its occurence at ~0.1%-0.5% of all pulmonary neoplasms.  Despite its "fetal" tissue morphology it typically presents in middle aged to elderly patients (60 to 70 year olds)


It is an adenocarcinoma resembling developing fetal lung in its pseudoglandular stage (i.e. that seen at 8-16 weeks of gestation). It is considered different from a pulmonary blastoma due to a lack of a mesenchymal component

Fetal adenocarcinoma of the lung can be divided into two forms according to severity.

  • low-grade fetal adenocarcinoma (L-FLAC): low nuclear atypia and prominent morule formation and has a pure pattern
  • high-grade fetal adenocarcinoma (H-FLAC): often over 50% fetal morphology, and often associated with other conventional types of lung adenocarcinoma
Serum markers
Tissue/immune markers

History and etymology

It is thought to have been first described by WG Barnard in 1945 and 1952, as a biphasic tumor comprising an epithelial component surrounded by mesenchymal stroma resembling fetal lung, hence initially named as “embryoma of the lung".

See also