High‐grade fetal adenocarcinoma of the lung is a tumour with a fetal phenotype that shows diverse differentiation, including high‐grade neuroendocrine carcinoma: a clinicopathological, immunohistochemical and mutational study of 20 cases

Abstract

Lung adenocarcinomas with H-FLAC features possess the potential for multidirectional differentiation, and are not strongly associated with known major driver gene mutations.

Differences between low and high grade fetal adenocarcinoma of the lung: a clinicopathological and molecular study

“…Our results demonstrated that H-FLAC tended to occur more frequently in elderly men with a history of heavy smoking but that L-FLAC was typically found in younger patients; these findings are consistent with the results of prior reports (2,4,7,10). Additionally, H-FLAC was often at an advanced stage at presentation, with a poor prognosis; in contrast, L-FLAC, was predominantly at stage I, with favorable outcomes (2,4).…”

“…Histologically, both prior reports and our findings indicated that H-FLAC histology is commonly combined with other histologies (4,10). Morita et al reported that H-FLACs were invariably admixed with components of other lung cancer types.…”

“…On the contrary, H-FLAC shows a membranous staining for β-catenin while lacking β-catenin gene mutations (11)(12)(13). FLAC is uncommon, and only a few studies with limited cases on L-FLAC and H-FLAC have been published) (2,4,(7)(8)(9)(10). In the present study, we retrospectively examined 3 L-FLAC cases and 5 H-FLAC cases to provide further information on the clinicopathological and molecular features of FLAC in Chinese patients.…”

“…L-FLAC is characterized by complex glandular structures with low nuclear atypia and prominent morule formation, which resembles the developing fetal lung during the pseudoglandular phase (6)(7)(8)(9). In contrast, H-FLAC shows predominant nuclear atypia while morule formation is rarely observed (2,4,10). Several studies have revealed that L-FLAC constantly exhibits aberrant β-catenin nuclear/cytoplasmic expression and frequent β-catenin gene mutations.…”

Prognostic contribution of non-predominant solid and micropapillary components in lung adenocarcinomas

“…The relationship between prognosis and rare variants has been less examined (4,5), and past studies (6)(7)(8)(9) have focused primarily on the relationship between prognosis and major histological patterns. These studies examined the relationship between prognosis and classification, and indicated that patients with lepidic predominant adenocarcinomas had the most favorable outcome of all subtypes of invasive lung adenocarcinoma.…”