Abstract
Object: To investigate cytomorphologic characteristics of pulmonary atypical adenomatous hyperplasia (AAH) compared to well differentiated adenocarcinoma (AD) of the lung.
Study Design: We analyzed imprint cytological specimens obtained from 4 cases of AAH and 8 cases of AD that showed ground glass opacity in chest CT.
Results: Compared to AD cases, cytomorphologic characteristics of AAH included:
1) Cell clusters in AAH cases consisted of about 20 cells and showed monolayer structures. No clusters consisted of more than 60 cells or overlapping papillary structures.
2) AAH cells were smaller and showed a lower nuclear cytoplasmic ratio. These were unified cuboidal cells with homogeneous staining cytoplasm. Columnar cells and foamy cytoplasm were absent.
3) AAH cell nuclei were oval and small. Nuclear irregularity was absent or rate.
4) AAH cases showed a lower incidence of intranuclear cytoplasmic inclusion and a higher incidence of binucleated cells.
Conclusion: Based on cytomorphologic characteristics, cytological diagnosis of AAH is possible in pulmonary lesions with ground-glass opacity.
