Atypical Adenomatous
Hyperplasia of the lung
Gross features:
- <0.5cm (most)
- frequently multiple
Histologic features:
- involving alveoli
and respiratory bronchioles
- Well-demarcated
focus of proliferation of cuboidal to low-columnar epithelium
- Slight thickening
of alveolar septa
- Gaps between the
cells often
- Similar appearance
to bronchioloalveolar carcinoma, non-mucinous type
- Some atypia but
less than adenocarcinoma
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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Molecular features:
- KRAS mutation
(significant proportion)
Other Features:
- Potential precursor
lesion for adenocarcinoma
(not all)
- Often incidental finding
in lung cancer resection specimen
References:
- Travis WD.
Pathology of Lung Cancer.
Clinics in Chest Medicine 2002; 23(1): 65-81.