Abstract
Background : Lung clear cell adenocarcinoma is rare and the pathogenesis of clear cell change in adenocarcinoma remains obscure.
Case : A 70-year-old woman was found in chest X-ray and computed tomography to have a tumor 5.3 cm in diameter in the upper left lobe. Bronchial brushing cytology showed many tumor cell clusters with papillary, honeycomb, and tubular patterns. Tumor cells were columnar, oval, and polygonal in shape with clear and/or finely vesicular cytoplasm. Nuclei were round to oval with fine chromatin and inconspicuous nucleoli. Glycogen and lipid droplets had not accumulated in cytoplasm. Histologically, tumor cells had clear cytoplasm and proliferated tubuloalveolar and papillary patterns. Tumor cells were immunoreactive to TTF-1, SP-A, CEA, and CK7, but not to CK20. Ultrastructurally, tumor cell cytoplasm contained multivesicular structures and numerous osmiophilic lamellar bodies suggestive of surfactant proteins.
Conclusion : Our findings strongly support the hypothesis that clear cell change in lung clear cell adenocarcinoma results from dysregulated overproduction of osmiophilic lamellar bodies.
