Fetal adenocarcinoma of the lung

Last revised by Joshua Yap on 19 Feb 2023

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

Some reports suggest its occurrence at ~0.1-0.5% of all pulmonary neoplasms 1. Despite its "fetal" tissue morphology it typically presents in middle-aged to elderly patients (60 to 70 years old 2).

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

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

ADVERTISEMENT: Supporters see fewer/no ads